*Pic courtesy of MotorTrend
Let's look at the rocker arm. As we go up in ratio, distance A is always greater than distance B. So the pivot arm is not in the center of the rocker arm, this can and will create a bending motion around the hold down bolt. As we go up in RPM, lift, and spring rate we are going to be putting more and more force on that hardware to try and RIP it out of the head.
*Pic courtesy of CorvetteForum
While that isn't the only reason something like this can happen, when you push lift higher and higher as well as the necessary spring rates to control a solid roller you can push it past the breaking point.
This is also why we do not suggest, nor will we modify a OE style head to run a shaft mount rocker arm system.
SO WHAT DO YOU DO???
Well, I'm glad you asked because a lot of cylinder head companies offer something just for this.
*Brodix BR7 - BS head
*Frankenstein F710 head
*CID LS7 Oval port
The three heads shown above are some of the most popular current offerings in the LS market for serious engine builds. Each will have their own benefits and key features but for now we are only looking at a few keep points. One of the first things you should see is that they lack any kind of rocker arm mounting point. Rather you have a very large, wide, flat base in which to mount a steel rocker arm stand to. Not only are you going to be bolting this to the head itself but rather than the small OE 8mm bolts these are massive 7/16" bolts in either a straight line, or a offset pattern to keep that stand bolted as firmly as possible to the head to keep it from wanting to rock as the valves are opened and closed.
*Crower stand system for All-Pro, Brodix, MAST style heads
*T&D system for CID heads.
As you can see these stands go the full length of the cylinder head and offer their own mounts for the rocker arms themselves. This also allows them to either use offset rockers, OR the ability to roll the rocker around to clear the intake port and keep the rocker with as minimal offset as possible to keep the forces more in a straight line. Something that you can't do with a OE head.
Why does this matter?
Probably the two biggest reasons are lift and spring rate. As you change the lift of the setup the geometry can and will have to change. If we are building a engine for 0.800, 0.850, 0.900 or more lift we need to not only have longer valves but we also need to be able to adjust the height of the stand to better dial in how the rocker arm is acting on that valve. Being able to do this on a OE casting and keep the rocker system stable is something that just doesn't happen outside of very low lift, low pressure setups.
The other issue is spring rates. Remember those little 8mm rocker arm bolts on your OE head? You might see 85-100lbs on the seat maybe 290-350lbs open on a OE type spring and as much as 150-200lbs on the seat and 400-500lbs open with a aftermarket setup. Solid roller spring rates are going to be far greater than that most of the time. While well sorted systems using light parts might still be in that 150-200lbs on the seat some can have as much as 200-300lbs seat pressure and 650-1200lbs OPEN! These loads get directly translated into the base and cylinder head so you want to make sure that you have a very stable and locked down assembly so as to not cause unwanted movement in the system.
If you recall from a prior post, just how much bending is going on in these systems even with a big stand and bolts.
https://horsepower-research.com/blogs/news/rocker-arm-ratio-spring-rates-lash-deflection-what-is-my-lift
Of course there is way more to picking the correct head for your particular application but the style of lifter you will be using plays a HUGE roll into what cylinder head casting we will start with to make sure you have the absolute best results and reliability.
When you get into aftermarket builds this can still happen if the rings are not filed to the proper gap. Most engine builders will err on the side of caution if they know it is a boosted engine and open the gap up on the wider side of the tolerance as there is no downside to doing so and will aid in not letting this failure happen.
There is another mode of failure than can still happen with heat and pressure. One of those ways is called collapsed rings. This can happen when to much heat is applied and yet there is still room for the ring to grow on the piston and not touch ends.
In this picture both rings are actually collapsed but one more so than the other. A good way to check on this during a rebuild is to have your "free gap" measured on the rings when they are still new and compare later during tear down. Some manufacturers can tell you a range to get you close if you do not have new measurements to go off of. On average most of your bigger bore sets are going to be around 0.500" on the top ring and the second ring in the 0.500-0.600" range. This is going to change depending on the static load that ring was designed to work at. If you pull the engine apart and find that you only have 0.200 or 0.300 then something is wrong in the tune or mechanically to cause your rings to have lost their spring tension in the the engine.
Will having a collapsed ring cause the engine to fail? More than likely no it will not because there will still be some ring seal from the combustion gasses in the cylinder it will just not be working as well as it should. Mostt will think that the spring tension is all that is causing your ring to seal and that isn't the case. Primarily it is cylinder pressure that causes the ring to seal which is why you have gas ports in the piston, or in the rings to aid in the sealing process. So sometimes you might not see this collapsed ring that often under WOT but will see far more blow by at idle and low speeds and typically more oil use. Either way it will not be doing it's job and there will be signs.
One other method of failure is micro welding.
This is the transfer of sporadic particles of aluminum from the piston ring groove to the top and bottom of the piston ring in an engine. This happens when the rings get so hot that the aluminum in the ring groove melts and adheres to the bottom of the piston ring causing it to hang up or not move freely in the groove of the piston. Unlike the collapsed ring this typically means the piston is also scrapped or at a min will have to have a wider ring groove cut into it to allow the grooves to go back to the proper smooth surface.
This process can occur early in the break in procedure when the engine is too heavily loaded before the rings have properly seated to the cylinder walls. While it can still happen later on, it isn't as likely once the rings have seated. Later in the engine’s life power adders with high cylinder pressures and extreme temperatures can bring on microwelding as can severe cases of detonation.
So what can you do to prevent these kinds of failures?
Proper ring gap is key #1 and that is included with every piston and ring set, if you have a question contact the manufacture for their input as they are going to know their product better than most.
Careful monitoring of the crankcase pressure during break in is another great way during break in. Apply only light loading to the engine during break in and reduce or eliminate any vacuum being applied to the crankcase during this period. This allows more oil to reach the ring grooves to help facilitate the mating process. If crankcase pressure increases, you can be sure the rings are probably dancing and you better back off and give them more time to seal to the ring groove.
Improving the ring groove and piston ring flatness and surface finish is also a critical factor that piston and ring manufacturers shoot for. Many piston manufacturers will offer a "pro ring groove" which means it is the last machine operation for the piston and thus there is less chance of them being damaged during the machine operations. One other way that has arrived is using a gas ported ring from Total Seal. By doing this, the groove can stay flat with no chance of machine damage from gas ports. When the ring is cut, it is then lapped flat to maintain a better surface finish free of burs.
The foundation, a new GM GenV LT1/LT4 block (they share the same PN).
Here you can see the block getting ready for the sleeving process. Only the front and rear main caps are in place and used to locate it during this process.
Freshly back from our friend Steve at Race Engine Development, the new LT block is now filled with a larger bore Darton sleeve to allow us to bring the bore out to a finished size of 4.185 and give us more cylinder length for the big stroke.
A few steps not shown before it made it into the hone, LS bearing machine work, rod clearance for the bigger stroke, and final deck surface. As it sits here in the hone, all caps are now back in place and a the torque plate is going on to size the cylinders before it comes out and is finally de-burred by hand before final wash.
Once the block is washed, dried and the cylinders cleaned and wiped down it can now make it's way into the assembly room. Here plug install takes place as well as the first steps to assembly, bearing fitment.
Once the final size of bearings is selected for clearance, caps are removed and the bearings are covered with Motul 10-40 break in oil for lube.
With the Callies Magnum crank balanced, cleaned and wiped down it is ready to drop in and begin assembly work.
The GenV LT's are no different than any other engine, thrust must be checked and set any time the thrust cap goes on. In this case, we are using a LS bearing set so we can have a full thrust face rather than the 1/2 thrust that GM has been using in these engines stock.
Once the thrust is set, the #3 cap can be torqued in place, side bolts installed and final thrust is checked one last time. The rest of the external plugs are installed and we begin the assembly of the piston and rods.
Forged H beam connecting rods with ARP 2000 7/16" bolts with a slender profile give us cam tunnel clearance while remaining robust enough to live on track. Pistons are custom 2618 forgings to our design made by Wiseco. Piston pins feature a tool steel dual taper design for added strength without the added weight of a thick wall pin you might find in a power adder application.
Once the rods are hung on the pistons, they get wrapped with a set of Total Seal Piston Rings with a steel top ring, and Naiper second with a 2.0mm oil ring. All pistons are lubed and dropped in and rod caps torqued.
Once we have the short block together we check rotational torque values, side clearances on the rods, rod to block clearance and apply final lube between parts.
At this point we have a "normal" 468 cid GenV LT short block. This will accept any drop in LT camshaft, hyd lifters, and all of the normal functions could be retained as you would in the production car. We have other plans however.
What has been lacking in the GenV world are cylinder heads. The LT1 and LT4 heads have huge ports and they will move a lot of air flow if asked to do so. This can also lead to some sluggish performance however in the low and mid RPM ranges where a lot of these cars live. Enter the CID LT casting. The great thing about these is that they come very small so you can design and tweak everything from valve size to port design and location. Our friend Greg Good has been no stranger to the CID cylinder head and has developed one of, if not the very best set of ports for these heads. Once they were returned to us the work is nothing short of amazing to see in person.
For this set we decided to use the OE LT4 valves given their light weight Ti intake and strong enough for power added exhaust valve which was also light enough to use in this application.
Now that we have our cylinder head selection finished, to fully use the size of the engine and show off the cylinder head while giving us a easy maintenance schedule we decided to go with one of our 0.742" lift hyd. roller profiles from Comp Cams. This also means we could not use a OE rocker arm either, more on that later.
The Pac1209x has been a proven dual spring setup that we have used with this camshaft and is small enough to fit into the pockets of the LT head as well as give us a low enough bind height for the lift of the camshaft.
Now that we have one head assembled, and know what our target spring install height needs to be we move to install of the cam and degree since we will not be using a OE phaser style gear this is very critical.
Using the LS2 single bolt gear will remove any chance of timing changes, and reduce the weight of the phaser. This will require the use of the Katech front cover since this also means the cam sensor needs to move closer to the gear.
Since we are going outside the range of the OE rocker arm we went with the steel bodied T&D machine LT drop in rocker arms. These have a smaller body to reduce weight as much as possible and give us a roller tip to allow for the larger lift.
With the cam locked down, it is time to install one head with checking springs and solid lifters to measure piston to valve clearance.
One thing we did learn during this process is that the T&D rocker has slightly more ratio (most rockers will) and actually measures out to a 1.86:1 ratio giving us 0.763 lift before deflection in the system when checking with the solid lifter.
Speaking of lifters, our choice lifter on any of the hydraulic lifter LS and LT engines has been the Johnson line of lifters. These have performed flawlessly for us in ever application we have used so far. With this we are using the standard travel link bar style, non-axle oiling.
Fully assembled head is now going on for good with ARP hardware. You can also see our DOD delete valley cover from Katech going on as well since none of that will be retained.
With both heads on, pushrod length measured the rocker arms can go on for good.
Something to note, the T&D rockers will NOT clear the OE valve covers, so a quick order to Katech gave us the clearance we needed in their cast GenV valve covers.
Back top side a new LT4 high pressure fuel pump, OE rails, lines, fitting and LT4 injectors will take care of the fuel supply.
All finished, plumbed and wired ready for the new intake manifold.
While it is true that the C7Z06 did come stock with a dry sump oil system we wanted to improve on this as well to give better oil control as well as provide a crankcase vacuum source. ARE offers a number of systems including this 4 stage package that, at least for the C7 Corvette, even allows the retaining of the A/C system which is nice to have in Texas.
Now you can see the Katech billet front cover as well as the new ARE pan and scavenge ports to pull the oil out of the engine which will be pumped back to a ARE oil tank as well.
Since the C7Z runs a blower pulley on the front side of the balancer there is room to put the dry sump drive on the front here as well. It is tight but everything tucks in around the steering rack without moving the engine or rack.
Final top, a MSD intake manifold and NW 103mm drive by wire throttle body to clear the low hood line of the Corvette. While this will limit max power, the ablity to keep the engine under the hood for aero was more important.
Wrapped and shipping out to the customer for install. Stay tuned for results when the car is finished!
]]>
Local customer wanted us to build a beefier engine for his procharged Corvette that could take more power and possibly more RPM than the OE short block that was in his car currently making around 1000whp. The idea was to run a bigger procharger later on and make more power further down the road when upgrading the head unit and intercooler system.
So lets get into the hardware.
Engine Block
Not to go to a tall deck or billet block that couldn't run water, and would be stronger than the OE block sleeved we went to a full skirt Dart aluminum LS block. This did a few things for us. A revised primary main oiling circuit, billet splayed bolted main caps, larger cam core options, more lifter options, longer cylinders, thicker deck, better material. Not only could we do all of this but it was lighter than the typical GM LSx cast iron block or Dart SHP iron blocks that would add even more weight to the car.
Over the typical surface / line hone / and cylinder finish we had to do some additional work to the block.
Given we knew we were going to go boosted and were shooting for 1500+ hp to the tires we wanted a more stable crankshaft so machine work was done for clearance on the center counter weights. Cam journal was up-sized from 55mm to 60mm using conventional cam bearings, lifter bores were taken from 0.842 up to 0.937 diameter units and lastly head studs sized for 1/2" hardware.
Crankshaft / Connecting rods / Pistons
Speaking of crankshafts, like other big HP engines you have seen us do in the past we really like to use Bryant Racing as they are one of, if not the best crankshaft manufacturer in the US. This billet piece offers us full width, 8 counter weights with their super finish to cut down on oil drag and windage. We retained in this application OE bearing sizes on the mains as well as the rods.
For our connecting rods we are using off the shelf Callies Ultra H beam connecting rods that will be holding onto custom designed HPR pistons made by Wiseco.
Not always required, but it is nice to do a hard anodizing to the pistons. While it does not make them burn proof it does greatly harden the ring lands so the rings do not want to stick as easily and it helps deter damage caused by knock. It does not make them foolproof so things can still go south if the tuning is not correct but just adds a margin of safety during the build. Rod bearings are coated and we are running a thicker wall, tool steel wrist pin. Pistons will be using a custom set of rings by Total Seal.
Short block
Once the block has been machined, de-burred, and checked we wash it and wipe it down with oil for assembly. First is main bearing clearance followed by setting the crank in place (crank is already balanced at this point). When installing any crankshaft, always make sure to check and set thrust. Which you have seen us do in other builds. Given the Corvette has a re-mounted torque converter it will not directly be bolted on the end of the crankshaft so in this application we did not feel the need for any special roller thrust bearing as you might have seen in the turbo Dart build.
Here you can see thrust is being checked in the block with the caps removed. It is constantly checked as the caps go on and get torqued in place. #3, the trust cap is the last one to be installed. Any issues in loss of thrust will have to be addressed and corrected as the caps go on.
Rings are file fit, cleaned and installed. Rod bearings checked for clearance as is the wrist pin clearance on the rod and on the pistons. Everything is washed again, and assembled for install into the block.
Once all rods and pistons are in, caps are torqued on the rods and we go about final checks on deck height, piston rock, break away torque, and rolling torque on the engine before it is stored prior to long block assembly (if we are waiting on parts at the time).
Heads
A set of Brodix BR7-BS LS7 heads were picked for this build so we could use the larger valve size, better port angle, and better selection of intake manifolds. These have been ported by West Coast Cylinder head before coming back to us for prep and assembly.
Valves are 2.250 Titanium intake and a 1.600 inconel exhaust. Weights shown and we wanted to use a light-ish valve to keep it stable above 7000 RPM.
With the aid of some custom parts and machine work we were able to use Comp Cams new dual conical valve spring and Ti retainers. Speaking to Comp about this project combined with the lobes we are using and lighter valve train parts we feel this will be a good test for the dual conical setup.
Cam and Lifters
As stated early on we are going to a larger camshaft core and increasing the journal size to 60mm to allow for a larger base circle and stiffer cam core.
While 5mm doesn't sound like a lot, it will greatly reduce the load on the cam bearings as well as reduce deflection in the valve train. Here you can see the 60mm vs a stock OE 55mm.
*TECH TIP*
When you switch cam cores, and change lifters, and change blocks from OE, you need to make sure your lifters can properly get oil not only at the base circle but also at full lift. The first time we checked this, we noticed that the lifter cut off the oil passage way at full lift. Luckily we were using a test Jesel lifter so when we placed the order for the real lifters to be used we noted this to make sure the oil band on the new lifters would allow oil flow through the cam oil journal at all times.
Here you can see the oil band on the lifter when the lifter is on the base circle.
Here it is at full lift and all but just a very tiny sliver has now been covered up blocking all oil to the other lifter. The actual lifters, have a much wider oil band allowing oil flow at all times.
Speaking of lifters....
Larger than your normal 0.842 lifter we again went bigger to a 0.937 tie bar lifter with offset pushrod cups. This allows us to straighten up the pushrods in the engine, run a bigger wheel on the lifter (0.850 vs 0.700) to help reduce the stress and friction on the camshaft lobes. Many times we have all seen pitting, and damage done to the cam lobe as well as failed axles and wheels. Sometimes this can be by improper valvetrain setup, sometimes it can be to aggressive of a cam for the smaller lifters or a combination there of. Since we are going solid we wanted a better lifter than stock so why not go with the best, Jesel. These are DLC coated tie bars made with a double 0.150 offset on the pushrods and larger axles.
Once we had the camshaft in, noted what we needed to do on the lifters the cam is then degree'd and locked in place.
Before the heads can be assembled for good there are a few more items to check off the list. 1. P to V measurements, 2. rocker stand height, 3. pushrod clearance, 4. deflection in the system.
Not always right the first time out of the box (i.e. you still need to run a pattern), the Crower kits come with a cool checking tool to allow you to setup your rocker arm stand height based off the valve length and lift of the cam. Here you can see two shims leveled out the tool.
Here the head is tightened in place with the stand now setup so we can mock up for P to V check using the checking springs and also check the rear lift, and pushrod clearances.
As you can kind of see in this picture, the pushrod is a little to close even with the smallish 3/8" pushrods so we will have to mark and machine the pushrod holes to aid in clearance of the larger diameter ones we want to use. This also means machine, clean, mockup and check again before final assembly.
Fast forward to machine work, clean, checking again...now we again set it up with the checking springs as well as a pair of the real springs so we can confirm lift and rocker arm ratio and note the changes from the checking spring to the real spring to see how much things move.
Why you ask do you do all of this?
This is why. On paper we have a 1.8 ratio rocker arm, 0.440 intake lobe and 0.441 exhaust lobe. This should give us 0.792 intake and 0.794 exhaust valve lift. When setup and measured on the engine with the checking spring we are seeing 0.837 intake, and 0.835 on the exhaust. So given the change in wheel size, and any additional ratio they build into the arm we have roughly a 1.9 ratio rocker arm. Now for the fun part. Using the same head, moving to the real springs we see a drop down to 0.807 on the intake and 0.800 on the exhaust. About a 0.030 reduction in lift with zero lash, meaning the system is deflecting that much. Take out the 0.014-0.016 ish of lash and we are actually about what the cam card said it would have been to start with. This is why real data matters, on the actual engine, using the actual parts. Not looking at this you can have valve springs running into bind issues, valves crashing into heads...any number of things. So for about the 4th time now we can pull the head back off, clean it for a final time and start spring setup and get to assembly.
First step is always check install height.
Clean, lube, and install your springs, retainers, and locks.
Final wipe down and install onto the block with proper hardware, lube, and torque specs.
Stands can go on for good now, and rockers pre-oiled before installing pushrods and bolting down rockers.
Rockers set with a rough lash by feel. All arms installed and torqued in place before going to final lash adjustments.
Getting ready to set lash, torque the adjusters before capping off with Comp's new billet LS valve covers.
]]>
Engine (which I'll do a build on later), is the aluminum full skirt Dart LS block paired with a set of 6 bolt Brodix BR7BS heads that is held down using a 6 bolt setup and 1/2" main head bolts. So not a lot of flex there. Rocker arms are a steel body Crower setup that uses the larger 7/16" offset hold down locations rather than the stock 8mm inline bolt pattern.
So lets get down to the test today. Today we are looking at system deflection and how this is going to relate to spring setup and ultimately actual lift that the engine will see at the valve when everything is assembled for good and running.
Camshaft: Slightly larger than your normal LS cam, this one we are testing with today has a 60mm journal so we could run a bit more lift on the lobe while maintaining a stronger core. This is also the stronger tool steel core as well. Here you can see the rough size difference when placed beside a stock LS cam (don't worry that one won't be used again)
60mm LS Comp cam on the left, OE 55mm core on the right.
Since we are up sizing the camshaft we also chose to upside the lifters as well, all about durability for this one. Jesel DLC coated 0.937 diameter link bar lifters with 0.850 wheels are up from the OE LS 0.842 w/0.700 wheel. This will help keep the lifters more stable in the block, reduce stress on the cam lobes as well as give us some room to offset them to straighten out the pushrods.
Jesel double offset link bar 0.937 lifters
The heads themselves are Brodix BR7-BS heads which offer a nice wide base for the rocker stands, offset mounting bolts for greater stability and much larger 7/16" hold down bolts.
Brodix heads without the stand mounted
Now you may ask, why am I showing this, and why does it matter. The main reason for the background on the above parts is so you can see just how much more robust these are than your normal OE 8mm hold down bolts and stock lifters with a shelf double spring setup. Keep this in mind as the new few measurements are taken. You can also see that each pair of rockers has a rather large shaft going through them and held down to the stand with 3 bolts to lock them in place.
Step one: Stand height setup. Each head / stand pairing is going to have some variation based on the rocker setup, valve length used, and lift of the cam. In this case Crower offers a nice quick rough setup to get you close to what you need to be after bolting the stand in place and torquing it to spec.
Height gauge
Once your have your stand approx where it needs to be, you can install a pair of checking springs and a pair of your real springs installed to approx where you want to be for install height. Once the head is bolted in place, get your stand setup and align the gauge with the retainer / spring and zero to make sure you can repeat your measurements as you turn the engine over.
One pair of checking springs, one pair of real springs
You will check the valve lift at 0 lash on one intake and one exhaust with the checking spring and then again using this same rocker arm on the intake / exhaust with the real springs installed.
Running through the lift with the real spring
With the engine in question we have 0.440 intake lobe lift, 0.441 exhaust lobe lift. Crower states a 1.8 ratio rocker and the camshaft was ground for a 0.850 wheel lifter.
Final numbers?
Checking springs Intake 0.837" lift at the valve, exhaust 0.835 which gives us a real approx rocker ratio of 1.9 on the intake and 1.89 on the exhaust. I say this because there maybe a slight angle to the pushrods or it might have had a thou or so either way on the lash adjustment and any variance in the gauge itself. Of course this is more than the 0.792 / 0.794 listed on the card due to the slight increase in rocker ratio.
Real spring numbers: We are seeing 220lbs on the seat and approx 740 lbs open pressure with the Comp dual spring setup we have chosen to use. Measurements taken on the pair with the springs installed using the same rocker and same pushrod (7/16 diameter) are 0.807 intake and 0.800 on the exhaust side. So we are loosing approx 0.030 valve lift just due to the assembly bending / moving during opening. This can be in the pushrod, in the rocker arm, in the stand, at the valve...every point is going to have a bit of bending when you are trying to push back on it with over 700lbs of force. Add in about 0.014 lash and your final lift numbers at the valve are now only 0.786 approx.
Is this surprising? No not at all, for that kind of spring pressure getting your deflection under or close to 0.030 is a good number to shoot for. What about the checking spring lift? Again no real surprise here, most rocker companies do fib a little on the rockers and give you a slight bit more than what is stated to make up for things like this. It should be checked because if you are tight on coil bind, or tight P to V then you need to watch this as you might end up with more than you bargained for.
So when customer ask us about solid roller builds, a few things that you see here in this post should be looked at. Do you have to go 60mm cam and big lifter combo? Most certainly not for most solid roller builds that are out there but the stand and how it bolts to the heads is a very important part of this. I'm sure we have all seen someone running a solid roller on a OE head with a big spring and it rip a rocker right out of the head because all it has is one little 8mm bolt holding it down.
Once you have your now "real" data on your setup, you can go back and make sure all of your springs will be setup correctly and free from coil bind.
This is a bit harder to do with a hyd. lifter setup as there is movement to the plunger in the lifter and that will vary with pump up / pump down on the lifters....but hopefully this will show you that things are never 100% what they say on paper when it comes to lift.
We've identified a problem and to help both ourselves and our customers using the new DART LS-NEXT SHP blocks. We have had some trouble with fitting the OEM windage trays and oil pump pickups on the DART LS-NEXT SHP blocks due to DART LS-NEXT SHP's beefier and unique splayed bolt main caps which do not line up with the GM factory OEM LS hardware.
DART offers a windage tray kit that works on some aftermarket pans that we sell as well but it doesn't work for most of the GM OEM factory pickup tubes. These often mount on multiple locations on the factory blocks so we needed to design these brackets to keep from having to figure out new ways of mounting all these different OEM windage trays, pickup tubes and oil pans every time.
To remedy this situation we designed our own patent pending brackets that mount directly to the DART LS-NEXT SHP main caps and basically duplicate the GM factory OEM windage tray and oil pump mounting studs. This allows the factory GM windage trays and oil pump pickups mount right up just like on a factory LS1/LS2/LS3/LS7 or LSX block.
We also made these to sit at approximately .180 higher to clear 90+% or more of the 4.000, 4.100 and 4.125 crank rotating assemblies that we use on a daily basis. Of course they clear the stock or smaller stroke cranks with almost any rods although some aluminum rods may still need more room at times.
Of course it's always the end user's and/or assembler's duty to check clearances to all rotating parts but the usual 4.000 and 4.125 rotating assemblies don't need extra washers with our adapter brackets like they do on the OEM blocks. However if you do need more windage tray clearance you can still add additional washers to space your particular windage tray up even further.
The DART LS-NEXT SHP block's front and rear main caps do not have splayed bolts and are also about .060 lower than the three middle main caps so I include 4 additional washers so one each can be added to the front and rear under the windage tray and between our spacers to make the windage tray sit flat before bolting it down and checking your clearances.
Lastly you MUST always, on all engines, check your oil pump pickup's clearance to the bottom of the pan when the pickup is mounted to the main cap spacers you just installed and solidly mounted to the oil pump and everything is torqued down. At this point you must verify you have 0.275” to 0.350” clearance to the bottom of the oil pan when it is also firmly torqued on and down with the oil pan gasket in place as well.
In general you will need to push the pickup back down as with the extra clearance built in to these spacers the oil pump pickup with be too close to the bottom of the pan now. We usually use wide masking tape over the pickup tube and then use play-doh or modeling clay and see how much clearance we have left after bolting the pan down. We then tap the pickup tube down with a dead blow mallet or hammer till we have our clearance in the right range. Keep in mind that this may take from 3 to 10 adjustments so just take your time until it's the correct clearance! This clearance must always be set and adjusted multiple times just like we do on OEM and LSX blocks so it just takes time.
With our kit the DART LS-NEXT SHP block becomes very easy to work with even easier than an OEM or LSX block with ARP studs as you do not have to drill out the windage tray to make it fit over the larger ARP main studs like you do on the factory setup. Its just as easy as when you are re-using the factory main bolts on a factory block and you don't have to add the usual 3 X 3/8ths washers to each stud either as the spacers we make already are about three washers taller already. You only need to add the one washer on each corner at the front and rear to take up the slack from these caps being slightly lower than the 3 center caps.
The HPR DART LS-NEXT SHP windage tray mounting brackets use 5/16ths by 18 threaded fasteners to bolt them to the caps and are torqued to 15 ft pounds on the center mounting bolt and on the two windage tray mounting studs that use 5/16ths locking nuts. You can always use a little Blue Loc-Tite as well if it makes you happy but it's not usually necessary,
--
Erik Koenig
HP Research
]]>
*Photo from Trend Performance
We all know what they are and if you have built an engine in the past you have more than likely cussed a number of piston pin locks in your day as well. But what are your options? What can happen to these seemly small parts inside your engine?
Most of the time we open our new box of forged pistons and we will find pistons, rings, piston pins, and locks all wrapped up for us ready to go, and many will leave it as that and go on. Today's kits are generally designed with a good pin and "close enough" machine work that the home user can put it together on their street ride and not have any real issues. What if your build isn't just a normal street car? What if you see issues when tearing down and engine, what can something like the piston pin tell you?
Everyone loves to see the shiny "cool" parts in the engine. The crank, the pistons, the camshaft, the rocker arms, but when you stop to think what the little piston pin sees for loads on it, you will get a better respect for what it has to hold up to under load. Take a normal LS forged piston that would weigh in around 470 grams add in the pin (108 grams), rings (40 grams), and small end of the rod (180 grams)...at upwards of 6500 RPM you might have a load on the pin well over 8,000 lbs if not more happening over 100 times a second. So each yank and throw of the crankshaft is putting quite the load on these guys.
You will find most kits today from companies such as Wiseco, JE, and CP pistons will include a 0.150 to 0.180 wall, quality steel pin with every kit. For most of us that is perfectly fine and will never run into issues. What if you are wanting to do something more than a rebuild or slight upgrade? What is going to happen? What are my options?
As we have talked about before, there is a lot of load being placed on the pin itself. Like anything, if you put a great enough force on it, it will either break or bend. In this case we typically only see a slight deflection under extreme loads.
The Pro Series pistons we typically use and offer from Wiseco will include a 0.150 wall, 5115 Chromium alloy steel pin which will be enough for most performance builds and much stronger than a 1018 alloy OE style pin. For direct injected engines and higher hp boosted applications Wiseco offers a step up into the 9310 low carbon, hardened steel alloy pin with a thicker 0.200 wall for added strength. After this point we can go into a number of offerings from manufacturers like Trend Performance with their H-13 Tool Steel pin, which has a high enough melting point that they can be DLC coated if the customer chooses to do so. Going further up the ladder we can get into more exotic tool steels like M2 and their TP-1 pins that are generally found in NASCAR and NHRA pro racing.
What are the draw backs? With anything there is always going to be some trade offs when going to a bigger / better / different pin design and material. Most of your normal street performance builds would not need the thicker pins, so you can save your money and bob weight by not using a thicker pin. With most LS builds the difference from the std pin to the 9310 pins can be the difference from 104 grams to 132 grams in pin weight, which adds up. The more exotic pins, like the M2 and TP-1 can run as much as the cost each of a good set of forged connecting rods, which not only eats up weight but your budget too. So we always try to balance out what is needed weight and cost wise in each of our customer builds.
There are some compromises out there as well, and that can be a double taper walled pin that we sometimes like to use for our road racers. These use a heavy wall, tool steel material in the center and then it is taper drilled on each end where the mass is not as greatly needed. here you can have something with a better material but stay close to a stock pin weight. You can see an example of that below
Lets take a look and see a few examples of pins and what kind of wear they show and what to look for if something bad is going on.
Here you can see a brand new, un-used piston pin. The surface is free of defects and there are no markings across the wear surface.
Below you can see a pin that has been ran without issue. There are some markings from the pin and also the piston but nothing more than general wear. Nothing shown here can catch your finger nail, nor can you feel it across the surface of the pin. The light scratching you see is typically from small particles in the oil. The two rings are un-used areas that make up the clearance from the rod to the pin boss in the piston.
In this picture now you can see what can happen when greater than normal forces have been applied. In this particular piston pin you can see material transfer from not only the rod bushing (gold color), but also from the piston itself (dull silver on the edge). In this case the engine was running a little to much boost/timing and had started to slightly lift the cylinder head combined with more than likely a little detonation going on. These factors combine to make a high load on the top of the piston causing it to bend around the pin transferring material to the pin as well as forcing the pin into the rod doing the same. Would an even stronger pin cause this from not happening? Maybe so, but more than likely no. When extreme errors happen within the chambers of an engine even the strongest of materials can start to fail.
It should be noted that when damage to the pin shown above happens that damage is also done to the piston and the connecting rods as well. This can cause you to have to replace not only the pins but in some cases the pistons and re-bush the connecting rods as well to fix the damages.
We should also take a moment to mention clearances. Some times damage can come from improper assembly too. Today parts manufacturers do their best to make sure you can assemble their kits at home with little more than hand tools and assembly lube but that is not always the case. Each time we assemble an engine here at HPR we take the time to measure each and every rod and piston to their respective pins to make sure we have adequate clearance needed for the oil and to make sure they are going to work without issues.
Many times it is nothing more than a burr left over from manufacturing, but in some cases they can be to close, not allowing the proper oil flow around them.
If you have a question about what might be right for your build, give us a call or email and we would be happy to help you on your selection.
]]>OEM Thrust bearing main location
OEM Thrust bearing main location
HPR machine work to clear CCW crankshafts
HPR machine work to clear CCW crankshafts
Stef's custom one off LSNext dry sump oil pan. First one ever made.
Peterson dry sump oil pump
front side of the fuel pump....notice the fitting size
Fuel pump assembly
Yes you are reading that correctly, 700 lb/hr injectors
Intake manifold, rails, and TB's
Nice sized pair of TB's
Side shot
Aluminum 1.8 ratio intake rocker arm
Steel 1.8 ratio exhaust rocker arm
Rocker arms installed, ready for lash
exhaust at full lift
intake at full lift.
Wear pattern right in the middle, even with over 0.9xx of lift
Top to Bottom: Titanium, forged, aluminum
big end cap design
Bearing dowel in cap.
small end
piston, pin, rod, and buttons
piston pin installed
piston pin button
pin button installed
button retained by oil rings
final assembly ready for install
Jesel cartridge style key way lifter.
#1 Crankshafts
There are a number of different ways to make and design crankshafts, the three main ways are; casting, forging, and billet. Depending on the budget, power level, use, and number of units being built what might be the best way to go about it.
-CAST-
Casting is probably the most popular off all ways, especially for production use due to the quick and economical way to manufacture the cranks. If you are going to produced crank shafts by the 10's of thousands in one rough size and shape, it is very easy to turn them out quickly without a lot of cost. Production, low HP, low RPM engines are fine with cast crankshafts and can run for hundreds of thousands of miles for a normal driver. Prices can range from $300-600 ea
-FORGED-
Forging is the most popular aftermarket upgrade when people talk about a "built" engine. The forging process produces a more compacted material which leads to a much stronger piece at the end. You have a few more options when it comes to the material itself which, again is going to produce a stronger final piece. You will be limited slightly in design with these as there is a high cost in making the forging dies when making the blanks. Counter weight design and stroke are generally limited on how much you can add or move. In the last few years the OE has switched to forged crankshafts for the high performance cars like the LS7, LS9, LSA and similar engines. Because the forging dies are more limited on what the final product is, and the machine wear/time to produce the final product is more....these generally will cost slightly more than a casting. Custom machining can add to this even more. Material is typically 4340. Pricing on average can be $800-1800
-BILLET-
When you select a billet crankshaft you have even more control over the final design. Because the crankshaft starts as a solid block of steel, counter weight design, counter weight placement, stroke, main, and rod journals can all be controlled to what ever you would like to do. Because the piece starts as a forged billet, and you have more control still over material choices you can produce an even stronger crankshaft than forged. Most top level drag racing, including Top Fuel, and top level road race cars will use billet crankshafts. Material can be 4340, 300M or other specialty materials. Pricing generally starts around $3000 and can be over $7000 depending on design and material used. The other downside, other than the cost, is the build time. Billet cranks are only made by a handful of companies and lead times can top 10-14 weeks.
-Counter Weights-
Counter weight design can, and is, a vital component of any engine build. Each OE is slightly different in how they produce crankshafts, some OE engines will design and use crankshafts that have counter weights on each (or each pair), of rods to give a more naturally balanced crankshaft. Chevy for what ever reason (probably cost), chose to eliminate the counter weights from the center of their crankshafts. By doing so this typically makes the front and rear counter weights the largest, and reduce as they make their way to the center were no counter weight is included, cast or forged. As you can see in the picture below a forged LS crankshaft is on the right with the standard counterweight design as compared to a fully counter weighted crank on the left...in this case billet.
full counter weighted crank on the left, standard Chevy on the right
Adding the additional counter weights to the middle of the crankshaft will help strengthen the crankshaft even more, and reducing its tendency to S shape under load. Without the weights there, the 2 and 4 journals are acting like bike cycle pedals, trying to twist the crankshaft. CCW (Center Counted Weighted) crankshafts will help to reduce this by naturally balancing out the engine. By greatly reducing the chance to S bend the crank will greatly increase main bearing life of most performance engines. CCW crankshafts are highly suggested to be used in high RPM applications and high HP applications. You will find CCW crankshafts used in NASCAR, ALMS, NHRA, and other pro level racing. Be it a build to make 1500 and more, or a 500hp LS turning 9000 RPM, a CCW crankshaft is the way to go. For the last 10 years, typically only billet crankshafts could be used for a CCW LS crank, but there are a handful of CCW forged crankshafts to help bring some of the costs down.
Our build.
This LS turbo build is using both a billet, and CCW crankshaft by Sonny Bryant. Because of the high HP requirements of the build by the customer (topping 2000hp) the crankshaft needs to be a strong as it possibly can as it will see a lot of load by the power demands and also continued high RPM use while making passes. This, the center piece of the engine, needs to be one of the most reliable parts of the build.
This particular crankshaft topped the $4000 mark by being a billet piece as well as a CCW design. Another interesting feature using two thrust bearings which I will cover in the next installment as we go over the block as well.
In closing, there are a number of ways you can build your engine and many price points to choose from as well as design. Just the crankshaft costs can range $400-$8000 before ever assembling the engine. While it would be IDEAL for every engine to use a billet CCW crankshaft, in reality, most builds it is not needed. Speak to your engine builder as what be right for your particular build.
Some things to note on these: This all new design from Wiseco has been developed specifically for boosted engines and higher stresses, up to 2000HP!. Wiseco's new three pocket design allows for extra material were needed but does not drastically increase weight.
Each rod is wrapped and protected and kept separate from the others so no damage can happen during shipping.
Like most rod sets, they are all matched closely on weight, but in the case of the BoostLine rods, each one is given it's own serial number which matches the sheet inside the box showing the exact weight and critical dimensions of that particular rod.
As with any forced induction style of build, and extreme HP use these are going to be a bit heavier than other similar I and H beam rods so care must be taken when balancing the rotating assembly.
HorsePower Research currently has sets on the shelf and we hope to be featuring these in some up coming builds soon! Ask your sales person for details!!
]]>
HPR is DFW's premier engine machine shop and assembly location for LS, LT, Ford and other late model engines.
Erik Koenig
HPR's main designer and engine builder, Erik Koenig is no stranger to the high HP world of engines. Some may know Erik from his prior company in Houston, HKE or may have had Erik as their teacher at the prestigious S.A.M. school in engine assembly and machine work. Erik has been in the world of building, and machining engines for some of the biggest shops in Texas and some record setting cars around the world.
Machine shops vs Engine assembly vs Engine builders. There is typically no shortage of engine machine shops across the country, and many can machine parts. The knowledge of the person operating the machine, as well as the care and upkeep of the machine itself is how accurate they can machine the parts in front of them. This does not mean they know what tolerances should be set or how the parts physically interact with each other. Then you have Engine assembly shops, again depending on the people there and history what you are going to get back. Most of these are production shops that set everything to either factory OEM specifications or just "throw" engines together to move them in and out of the shop quickly. While this is better for their bottom line, it isn't so much so when it comes to what you get back from them as a product. If they do not understand what it takes to correctly measure, machine, and fit the pieces together so it works correctly, this typically ends in issues with the engine or higher failure rates once running. An actual Engine builder knows more than just what kind of parts to use, but also how to make them work and last. Some materials are going to grow when heated, you are going to have deflection in parts as they bend and move and a real builder will know these things. Just because the part is new, doesn't mean it is right or correctly machined for use in YOUR engine. Erik takes the time on each and every part in the engines so that they are built, and built right the first time. This typically means a little longer on assembly time but in the end, the product you are left with is much higher quality piece that you know has the care and time put into it if you would have done it yourself. That is what makes HPR so much more than your local machine shop, but a true high performance engine builder.
To add to our knowledge of machining parts, and assembly work we also design assemblies from the ground up. Many of our short and long block assemblies are of Erik's own design. Many of the components you will find in our 442, 468, and 527 LS assemblies are exclusive to HPR and Erik himself and are not able to be bought as off the shelf parts nor would many machine shops know how to make them fit in the engine blocks they were designed for.
Combining Erik, HKE, and HPR together as one entire unit is also going to allow more expansion into the future with more house designed engine parts like intake manifolds, camshafts and other related parts to push the HP and TQ numbers even further!
Stay tuned for more exciting news!
]]>
Another Koenig design, the 442 LS3 by HPR. Erik's custom forged rotating assembly give this stock LS3 engine block a full liter more of displacement without costly re-sleeving processes. The increased displacement will mean much more torque not found with the typical 402/414 builds that are commonly found. Finish it off with a custom top end package by HPR or fit your own components to suit your build requirements.
]]>
One of our signature engines is the 468 cid LS. The Erik Koenig designed piston, rod, and crank combo make this unique in that everything fits inside of a standard deck height LS block (iron or aluminum) so fitment in almost any chassis does not require any special engine mounts or exhaust.
Serial number 001 will be making its way into a local road race car, stay tuned for updates!
]]>