Trunion upgrade questions
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Staging Lane
Joined: Feb 2005
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Trunion upgrade questions So i have been reading around about how some people have been having issues with the comp trunion upgrade. I have 123xxx miles on my car with the stock rockers. i have had a .610/.610 lift cam for two years so far and have had no issues. next week im upgrading my lifters, pushrods, new spring kit and 243 heads. i was thinking about doing the trunion upgrade as well but if so many people are having issues with comp i might just leave them alone. So how many people here are actually having problems with the trunion upgrade? How long did it take? is it even worth upgrading?
Comp, Lunati and someone else I think, sells a trunion kit. If they source them from different suppliers I don't know. There have been several threads recently with Comp trunion failures. Now if it was a result of inadequate hardening of the metal or an improper setup I don't know that either. The only thing we know for sure is I don't know a lot of things, LOL.
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Thread Starter
Staging Lane
Joined: Feb 2005
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Comp, Lunati and someone else I think, sells a trunion kit. If they source them from different suppliers I don't know. There have been several threads recently with Comp trunion failures. Now if it was a result of inadequate hardening of the metal or an improper setup I don't know that either. The only thing we know for sure is I don't know a lot of things, LOL.
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If you use too much lift on the cam, the D shaped retainer will wear and eventually pop right out of the side.
We sell quite a few of the Comp trunion upgrades, and even before they had them, sold quite a few of the Harland Sharp upgraded rockers.
Quite a few places will recommend the upgrade for lifts over .610. The needle bearings inside the rockers will wear over time. There is no "change interval" for them, but being able to do the install yourself with everything included in the kit and having peace of mind are pretty well worth it.
We sell quite a few of the Comp trunion upgrades, and even before they had them, sold quite a few of the Harland Sharp upgraded rockers.
Quite a few places will recommend the upgrade for lifts over .610. The needle bearings inside the rockers will wear over time. There is no "change interval" for them, but being able to do the install yourself with everything included in the kit and having peace of mind are pretty well worth it.
Thread Starter
Staging Lane
Joined: Feb 2005
Posts: 52
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There are several threads on this subject worth reading, I started one a while ago.
There are only 2 upgrades that are good for a street car Harland Sharp & CHE
CHE's are bushings & expensive, HS are more than the other bearing style kits but use better steel for the shafts, plenty of failures of the cheaper bearing kits.
Summit, PAC, & Comp also sell less expensive kits that I would avoid & if you read Summit's product details they tell you "Designed for race applications only" & as far as I know the only ones that tell you that.
http://www.summitracing.com/parts/sme-143002/overview/
The difference between the Sharp kit & most of if not all the less expensive kits is that they use full heat treated 52100 steel for the shafts & the others use a case hardened steel like 8620.
The case hardened shafts are only a surface heat treat meaning the outside of the shaft is hard, prob .02-.030 deep but the inside is still soft.
The case hardened shaft is a poor choice for something that has a hard bearing with & the load from the valve train on it.
There are plenty of unhappy people on here that have had the Comp kits fail, the early Harland Sharp kits also failed but I believe they had surface heat treated shafts also.
There are only 2 upgrades that are good for a street car Harland Sharp & CHE
CHE's are bushings & expensive, HS are more than the other bearing style kits but use better steel for the shafts, plenty of failures of the cheaper bearing kits.
Summit, PAC, & Comp also sell less expensive kits that I would avoid & if you read Summit's product details they tell you "Designed for race applications only" & as far as I know the only ones that tell you that.
http://www.summitracing.com/parts/sme-143002/overview/
The difference between the Sharp kit & most of if not all the less expensive kits is that they use full heat treated 52100 steel for the shafts & the others use a case hardened steel like 8620.
The case hardened shafts are only a surface heat treat meaning the outside of the shaft is hard, prob .02-.030 deep but the inside is still soft.
The case hardened shaft is a poor choice for something that has a hard bearing with & the load from the valve train on it.
There are plenty of unhappy people on here that have had the Comp kits fail, the early Harland Sharp kits also failed but I believe they had surface heat treated shafts also.
Im a firm believer in 'you get what you pay for'. To me there just wasnt a whole lot of feed back on what people were using and how they were holding up. The HS kits look really nice and i would love some feedback on the Brian Tooley kits as well. This car is my DD so i will want something to last me as long as possible. 90% of the Trunion threads on here are "How to's". Just trying to get as many opinions as possible before i jump the gun. Thank You everyone
FWIW, we have used the comp trunions in our road race Corvette and Camaro for the last couple years with no issues
Prior to that a stock rocker on the Vette spit out the needle bearings.
Prior to that a stock rocker on the Vette spit out the needle bearings.
http://540ratblog.wordpress.com/2013...-test-ranking/
Now I'm not sure how much this test proves, so that's up to you how you feel about it. Just throwing info out there.
On the topic of trunnions, what I do know is that you have to install them true, if they're misaligned in the bore, it will cause premature failure.
Probably about 15k miles. I never really went over 3500RPM as the clutch slipped really badly. Luckily I caught it early and I was able to clean up the mess before anything REALLY bad happened.