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LOL. Sorry man dont see the damage on your trunions. I do see wear marks which would occur anytime surfaces rub against each other. Whats with all the dire posts?
The metal particles from the Comp trunnions destroyed my oil pump leaving me with zero oil pressure with 25,000 miles on the pump. New Melling 10296 is in now and I don't know if the metal particles damaged anything else in my motor. If a sponsor is selling a product, it should be at least as good as the OE part, but this is not the case and the owner is left paying for the damage the product caused. Take another look:
Let me clarify first and foremost, many variable's can and will contribute to the damage on trunions that have been shown in pictures.
1. Spring pressures
2. Valve-train weight
3. Camshaft lobe design 4. Lubrication (Effectiveness and Efficiency)
5. Lifter preload
Just a few to get people thinking.
I think this is a great looking product but I would tend to agree with some of your thoughts and some bearing lubrication calcs might be in order to figure out if the oil many are using is adequate in this application. I know the Mobil-1 tends to be a bit thin and many are using it.
I would also add a "6" to your list, which would be valve train stiffness. For example, many throw in 5/16" pushrods with these stiff springs and high acceleration rate cams not realizing that the pushrods are responding as pole vaults and likely wreaking havoc with the valve train. Very easy to blame parts when the combination may actually be the source of the issues. This can even happen with the kit being discussed in this thread as well.
Your listed items might also be the source of some of the issues with the Comp kit as well as opposed to simply blaming the kit. Hard to tell without an adequate autopsy of parts including the setup they were used in.
Also, with regards to your bronze you are seeing, these motors typically show a lot of bronze in UOA's so what you are seeing may not be the kit, unless you only started seeing it after the kit installation.
The metal particles from the Comp trunnions destroyed my oil pump leaving me with zero oil pressure with 25,000 miles on the pump. New Melling 10296 is in now and I don't know if the metal particles damaged anything else in my motor. If a sponsor is selling a product, it should be at least as good as the OE part, but this is not the case and the owner is left paying for the damage the product caused. Take another look:
Sorry, I do not buy that. There is no way that small amount of particles are going to ruin your pump. If you have a ruined pump, the pump was bad when it was installed, or you have some other problem.
Let me clarify first and foremost, many variable's can and will contribute to the damage on trunions that have been shown in pictures.
1. Spring pressures
2. Valve-train weight
3. Camshaft lobe design
4. Lubrication (Effectiveness and Efficiency)
5. Lifter preload
Just a few to get people thinking.
I specifically asked for accelerated wear data to support this new trunion kit when it hit the market. Nothing was ever and has ever been supplied.
Decided to try a set for my own experimentation as I had my doubts knowing the limitations of bronze. LS engines typically run (idle 30lbs - upper rpm range 60lbs) of oil pressure when hot. Oiling is less than desirable in the upper half of the engines unless chamfering modifications have been made to help alleviate sharp edging and radius areas on the block and head's.
The last two oil changes in my 06 LS2 20K mile Corvette have shown with bronze particulates inside the oil filter, although none was apparent in the drained oil from careful inspection the ~500 mile changes.
Too many are jumping this bushing bandwagon due to the fact it's something new. (myself included)
I had a couple of detailed conversations with Chris about this product and I'm not bashing, rather sharing my experience that I spoke of earlier. the only positive proponents of this product appear to be the one's marketing it's sale.
I am going to disagree to a degree. Yes, all those items do play into the situation, but the manufacturing of the trunnions have a much larger part of the equation than just about anything you list except #4. Hardness is probably the largest factor. When you run a 60-65 Hrc roller over 40 HRc material at the speed the rocker moves, it isn't going to take long until you see wear. Now add to that surface finishes. The Summit trunnions I have will probably be scrap in 10k miles. The surface finish is so poor that the rollers will pick up the metal off the bad finish and throw it into the oil.
The trunnions need to be manufactured out of 52100 bearing steel with a hardness of around 60 HRc to get them to last. Using 4140 material with a hardness of 40 HRc and a finish of 18 Ra isn't going to cut it on a bearing surface especially when you add all the items you mentioned.
I am going to disagree to a degree. Yes, all those items do play into the situation, but the manufacturing of the trunnions have a much larger part of the equation than just about anything you list except #4. Hardness is probably the largest factor. When you run a 60-65 Hrc roller over 40 HRc material at the speed the rocker moves, it isn't going to take long until you see wear. Now add to that surface finishes. The Summit trunnions I have will probably be scrap in 10k miles. The surface finish is so poor that the rollers will pick up the metal off the bad finish and throw it into the oil.
The trunnions need to be manufactured out of 52100 bearing steel with a hardness of around 60 HRc to get them to last. Using 4140 material with a hardness of 40 HRc and a finish of 18 Ra isn't going to cut it on a bearing surface especially when you add all the items you mentioned.
I'm not taking that as a disagreement, rather additional relevant topics of intrest.
However 99% of the consumers have little knowledge of material specifications let alone material types.
My independent lab had much different results with the material analysis than posted. But keep in mind they were brand X and the data your referring too was brand y.
52100 vs. 4140 portray much different elemental makeups. 52100 is MUCH more costly to purchase. Once you add the additional cost to material, what was thought of as an economical improvement to existing OEM rockers has not became a competitors market. You have now catapulted into a full roller rocker costing tier.
I'm going to state once again this bushing kit is not the best option for most consumers unless you have the proper equipment to resize each and every rocker bore.
Everyone bashes on a particular valve train supplier. When in reality they have many moons of valve train engineering, testing, prototyping, and resources to far exceed our logical thinking.
I'm going to state once again this bushing kit is not the best option for most consumers unless you have the proper equipment to resize each and every rocker bore.
are you saying that even the LS3 rockers need to be sized? I thought it was just the LS7 rockers.
I installed the bushing kit in my garage, with a vise bolted to my workbench, following the directions somewhat...aka-sockets, big thick washers, Alabama on the radio and a beer or 2 at the first of the year(I may have read more into the directions, sorry). When I took the needle bearings out more than a few needles dropped out during the process. So far this little 416 has been 7800 on shift and almost 8000 in the lights with a looser converter and some jetting changes.(these LS7 lifters are the bomb if you get the preload correct). Last pass should have been a 8.89@152mph(per CrewChief Pro) but my BG400 said enough and died, leaving me coasting past 1000' mark. I guess I need to take them back apart and get the tolerances right.
I installed the bushing kit in my garage, with a vise bolted to my workbench, following the directions somewhat...aka-sockets, big thick washers, Alabama on the radio and a beer or 2 at the first of the year(I may have read more into the directions, sorry). When I took the needle bearings out more than a few needles dropped out during the process. So far this little 416 has been 7800 on shift and almost 8000 in the lights with a looser converter and some jetting changes.(these LS7 lifters are the bomb if you get the preload correct). Last pass should have been a 8.89@152mph(per CrewChief Pro) but my BG400 said enough and died, leaving me coasting past 1000' mark. I guess I need to take them back apart and get the tolerances right.
I'd be more concerned about the notches in your pistons and those bent valves first!
OEM hollow stems and Wiesco pistons.....least of my worries....original shortblock/heads I built in garage 4 years/250 passes ago. Hardest part now is slowing the car down to 9.60 index consistently.
OEM hollow stems and Wiesco pistons.....least of my worries....original shortblock/heads I built in garage 4 years/250 passes ago. Hardest part now is slowing the car down to 9.60 index consistently.
So your stock shortblock came with Weisco slugs?
Add weight to slow it down.......what we here in the South refer to as a rolling swingset @ 2500lbs
The metal particles from the Comp trunnions destroyed my oil pump leaving me with zero oil pressure with 25,000 miles on the pump. New Melling 10296 is in now and I don't know if the metal particles damaged anything else in my motor. If a sponsor is selling a product, it should be at least as good as the OE part, but this is not the case and the owner is left paying for the damage the product caused. Take another look:
These aren't the pics you posted, unless I missed them somewhere else. Any way these have failed clearly.
I'm not taking that as a disagreement, rather additional relevant topics of intrest.
However 99% of the consumers have little knowledge of material specifications let alone material types.
My independent lab had much different results with the material analysis than posted. But keep in mind they were brand X and the data your referring too was brand y.
52100 vs. 4140 portray much different elemental makeups. 52100 is MUCH more costly to purchase. Once you add the additional cost to material, what was thought of as an economical improvement to existing OEM rockers has not became a competitors market. You have now catapulted into a full roller rocker costing tier.
I'm going to state once again this bushing kit is not the best option for most consumers unless you have the proper equipment to resize each and every rocker bore.
Everyone bashes on a particular valve train supplier. When in reality they have many moons of valve train engineering, testing, prototyping, and resources to far exceed our logical thinking.
Checking prices on 4140 vs. 52100 shows 52100 is double the price of 4140. So for a 12" length, 4140 is $7.20/ft. and 52100 is $13.40/ft. It takes about 1.5" per piece after you cut it off to make a single trunnion. Machining time and grinding time will be the same for both materials
All said and done, the material cost and maybe a bit of heat treating is all that is added to the final cost. That would be about $25 a SET to make them out of the correct material so they last. I think almost everybody on here would shuck out an extra $25/set to get a set of trunnions that hold up, and that is assuming you couldn't find a bearing with an inner race.
Checking prices on 4140 vs. 52100 shows 52100 is double the price of 4140. So for a 12" length, 4140 is $7.20/ft. and 52100 is $13.40/ft. It takes about 1.5" per piece after you cut it off to make a single trunnion. Machining time and grinding time will be the same for both materials
All said and done, the material cost and maybe a bit of heat treating is all that is added to the final cost. That would be about $25 a SET to make them out of the correct material so they last. I think almost everybody on here would shuck out an extra $25/set to get a set of trunnions that hold up, and that is assuming you couldn't find a bearing with an inner race.
You removed your first response before I could react.
4140 vs 51200 are very different in chemical makeup.
The higher carbon content causes more distortion at HT, therefore your assumption is incorrect. 52100 can and will distort to .030" during HT.
The lower carbon in 4140 allows it to settle in very close to nominal machining size.
The cost to manufacture 52100 with the extra grinding operation that will be required would be greatly increased. PRECISION GRINDING IS VERY COSTLY.
Property Results 52100
Chemistry Data : [top] Carbon 0.98 - 1.1 Chromium 1.3 - 1.6 Iron Balance Manganese 0.25 - 0.45 Phosphorus 0.025 max Silicon 0.15 - 0.35 Sulphur 0.025 max
well i bit the bullet and ordered a set of these for my 4.8, it has lunati .660 dual valve springs and a stock ls6 cam. Im considering either the tu1 or a texas speed grind for my next upgrade. after i install them ill post in this thread a small review.
The grinding op will add nothing or maybe a few dollars to the cost. On top of that, I would not even grind it anymore. None of your automotive manufacturers grind. They all hard turn which will cut the cost even further. I have customers that manufacture bearings. They do not even get .03" runout on a 15" diameter bearing.
Besides, getting a 19Ra like the finish on the trunnions I had is hardly precision grinding especially for a bearing surface.
I had a pretty lengthy discussion about this topic with my brother over the weekend (a production engineer in the auto industry, and a very competent hot rodder in his own right) and he said that they are all doomed to fail at some point - some just sooner than others.
There is a pretty simple way to determine the root cause of any issues.
1. Baseline a stock performance engine with each of the commercially available trunnion kits installed. Stock (the control), Comp/Summit/BTR, and the Straub kit. Run for a single 5000 mile OCI to determine if there is a change in the particulate matter in the oil analysis.
2. A shitbird budget built modified "performance" engine (jank pushrods, over-cammed with aggressive ramp rates, parts-bin beehives, and hillbilly stratospheric shift points) run with each of the commercially available trunnion kits installed. Stock (the control), Comp/Summit/BTR, and the Straub kit. Run for a single 5000 mile OCI to determine if there is a change in the particulate matter in the oil analysis.
3. A properly modified performance engine (proper pushrods, sanely-cammed with smooth ramp rates, good valve springs, and sensible shift points) run with each of the commercially available trunnion kits installed. Stock (the control), Comp/Summit/BTR, and the Straub kit. Run for a single 5000 mile OCI to determine if there is a change in the particulate matter in the oil analysis.
Until this (or something similar) is done you are all pissing in the wind. At the end of the day, more often than not, the issue is user error.
PS. Anyone got a picture of a high-mileage stock trunnion run with a decent sized performance cam? I wonder how it looks...
The grinding op will add nothing or maybe a few dollars to the cost. On top of that, I would not even grind it anymore. None of your automotive manufacturers grind. They all hard turn which will cut the cost even further. I have customers that manufacture bearings. They do not even get .03" runout on a 15" diameter bearing.
Besides, getting a 19Ra like the finish on the trunnions I had is hardly precision grinding especially for a bearing surface.
We redesigned our trunnions to increase the amount of oiling to the bearings in January, which is why we've been out of these kits for most of this year. Unfortunately our supplier isn't able to run the new design in their grinding machine without extensive modifications.
We're in the market for a new manufacturer, even using new materials and new processes if needed. So if anyone knows someone, please send them our direction, or PM me their contact information.
We're in the market for a new manufacturer, even using new materials and new processes if needed. So if anyone knows someone, please send them our direction, or PM me their contact information.
07-03-2016, 12:38 AM
