COMP Trunnion Upgrade
Thread Starter
Staging Lane
Joined: Apr 2024
Posts: 53
Likes: 8
COMP Trunnion Upgrade I have a new LS3 engine, and installed the Comp trunnion upgrade today. However, I noticed when done I didn't install all of the bearings with numbers facing outward. For the bearings put in backwards, can I just push them out like I did the OEM bearings, or are they compromised once they're installed?
You're probably not going to get too many responses. Because a fairly significant number of us have used the Comp "upgrade" and found premature wear on the axles. So they aren't highly regarded. Mine were bad at only 20,000 miles, and the axles all (except 1) showed significant galling. I bought mine in 2014, so maybe they're better now. I can't answer your question, because I don't remember which way the numbers go, or even if it matters. I DO remember the unusual wear, however. Best of luck to you....
Last edited by grinder11; Sep 26, 2024 at 08:52 AM.
Thread Starter
Staging Lane
Joined: Apr 2024
Posts: 53
Likes: 8
Thanks - I figured it out. I just popped out the bearings which were reversed (numbers facing inward), reversed them so numbers face out, and then pressed them back in. I did see the negative hits on the Comp trunnion upgrade in a lot of places, so fingers crossed. If I want to buy a completely new set of arms with roller bearings, then what make/model has a great reputation? (i'm pushing 580-590 HP after headwork and stage 2 TSP cam).
Thanks - I figured it out. I just popped out the bearings which were reversed (numbers facing inward), reversed them so numbers face out, and then pressed them back in. I did see the negative hits on the Comp trunnion upgrade in a lot of places, so fingers crossed. If I want to buy a completely new set of arms with roller bearings, then what make/model has a great reputation? (i'm pushing 580-590 HP after headwork and stage 2 TSP cam).
I have the latest BTR V2 trunnion setup on my LS7. In spot checking 2 rocker trunnions, they look good as new. I figure that they are more highly stressed in a 1.8:1 rocker setup (LS7) than with the 1.7:1 ratio rockers. If they're good on 1.8s, they should be fine with 1.7s. As someone posted, you may want to rethink running the Comp setup. BTR had an earlier trunnion upgrade (V1?) that BTR wasn't satisfied with, so they changed the axle material to a higher grade bearing steel. If Comp changed their design, I am not aware of any part# change. The fine metallic wear particles floating around inside an engine from galled axles can't be helping anything, for sure.
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TECH Resident
Joined: Mar 2012
Posts: 861
Likes: 404
From: Texas
You're probably not going to get too many responses. Because a fairly significant number of us have used the Comp "upgrade" and found premature wear on the axles. So they aren't highly regarded. Mine were bad at only 20,000 miles, and the axles all showed significant galling. I bought mine in 2014, so maybe they're better now. I can't answer your question, because I don't remember which way the numbers go, or even if it matters. I DO remember the unusual wear, however. Best of luck to you....
Bad heat treatment ?
Inferior metalurgy?
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Verdad Gallardo I don't know. But there were a lot of unhappy members here that had failures. They weren't catastrophic, but there were problems. Only one of my 16 axles looked as good as new. 15 of 16 were worn several thousandths on each bearing diameter. 93.75% failure rate is unacceptable.....
It turned out to be poor hardening processes in the trunnions.. I was under the impression that Comp has since redesigned the units and the newer ones are good?? Not sure where I heard that actually. As stated, lots of powdered steel in the engine over time is hard on bearings.
TECH Resident
Joined: Mar 2012
Posts: 861
Likes: 404
From: Texas
The date on the box is 3/07/24.
I'll keep an eye on them.
