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Researching trunnion upgrade from stock needle bearings to whatever the next upgrade is available. There are captured needle bearing upgrades like Comp Cams, and then a slew of brass bushing types.
Planning on a mild cam upgrade soon with lift in the 550-570 range. A daily driver, no racing, maybe 5000+ rpm on an on-ramp, occasionally. In other words no sustained high rpm.
Since I will swapping out springs anyway, figured I’d do the trunnions “while I’m in there”, maybe trays too, but I haven’t studied that aspect too much.
Important,.. again this is not a race car, and I’m trying to keep costs minimal without using junk parts, but I don’t need Diamond Jim double dog throw down top fuel level parts either, so let’s keep this real. I’m retired and do not own a 10 car garage with full time NASCAR technicians at my beckoned call…. It’s little old me and whatever is in the tool chest.
Researching trunnion upgrade from stock needle bearings to whatever the next upgrade is available. There are captured needle bearing upgrades like Comp Cams, and then a slew of brass bushing types.
Planning on a mild cam upgrade soon with lift in the 550-570 range. A daily driver, no racing, maybe 5000+ rpm on an on-ramp, occasionally. In other words no sustained high rpm.
Since I will swapping out springs anyway, figured I’d do the trunnions “while I’m in there”, maybe trays too, but I haven’t studied that aspect too much.
Important,.. again this is not a race car, and I’m trying to keep costs minimal without using junk parts, but I don’t need Diamond Jim double dog throw down top fuel level parts either, so let’s keep this real. I’m retired and do not own a 10 car garage with full time NASCAR technicians at my beckoned call…. It’s little old me and whatever is in the tool chest.
I'd leave the stockers in there. Many "upgrades" touted by the aftermarket are actually downgrades. With the lift you're talking about, with the driving habits you're talking about, stock trunnions are fine. I have an LS7 in my C5. I heard all the stories about stock trunnion bearings not being that great, so I went with the Comp Cams "upgrade". The needles wore into my trunnion surfaces, and my magnetic drain plug pulled a LOT of metal powder from the oil. .550"-.570" lift is pretty much OEM C5 LS6 lift. You'll be fine. If you do go with a different setup, I've heard good things about CHE bronze bushings trunnions. Best of luck to you....
I went with the Comp Cams "upgrade". The needles wore into my trunnion surfaces, and my magnetic drain plug pulled a LOT of metal powder from the oil.
This seems to be a common failure with the Comp kit. I have reason to believe that this is what trashed the LS2 in my GTO. Went with bronze bushings after the rebuild. The valve train is slightly quieter than before and there's no potential for failure. Only downside is that they do wear down over time and will eventually require replacement.
Not too shabby for a 204/222 551/570 baby cam…Just enough upper end, and with no bottom end loss. Supposed to love the LS6 beehive springs. Don’t want to spend money just for the sake of it, but if the bronze bushing trunnions would be a prudent upgrade…
Last edited by vette4fl; Jan 10, 2022 at 09:57 PM.
Interesting video. My C-5 is pretty much a basic, easy driven, "cruiser", but the "hot rodder" that lives deep within me, doesn't like marginal parts in his car. Back when the mention of rocker arm trunnion issues first became an issue, I installed the Comp Cams trunnions in my car. Drove it for 2-3 summers with them in it. When the bushings became available as a DIY kit, I bought a set of them from Brian Tooley Racing (BTR). They've been in the car for about 4-5 years, now. I will say that the valvetrain is quieter with the bushings in place.
Thanks to those who contributed. With the carnage waiting to happen with the OEM trunnion bearings, I’m surprised more people didn’t chime in. Glaring problem in my eyes.
Anyway, this gave me time to find out what the problem is, who the players are, and what choices are out there.
Im going with the Smith Bros bushing kit. They make their own **** in the USA, and many of the other bushing kits sold are made by them. Then there’s problems with the needle bearing models no matter who makes them, the free floating bushings are great but priced for committed racing programs.
So here we are. $160 for the real deal straight from a US manufacturer who’s been building stuff like this for generations.
Thanks to those who contributed. With the carnage waiting to happen with the OEM trunnion bearings, I’m surprised more people didn’t chime in. Glaring problem in my eyes.
It may not be as "glaring" a problem as people think. For some reason, GM decided to avoid the "tried and true", completely round, rocker arm trunnion. Instead, they went with that funky 3 sided deal. Truth be told, as long as you retain the stock cam, with it's lift that the engineers designed them for, we're all probably OK. I first heard of the "spitting bearings" issues when guys started putting in cams with higher lift that stock.
While the aftermarket trunnions have an unlimited, so to speak, range of rotation, limited only by the bolt that secures them to the cylinder head, the OE trunnions have a specific, limited range of travel. They work for the OE cams, but not for a number of the aftermarket cams.
While the range of motion on the stock trunnion is indeed limited, I have found no evidence of that having any contribution to failure, since the failures also occur with stock cams. That leads me to believe that rocker speed and resulting harmonics from directional change stress is the culprit..
In other words running a stock cam engine at high rpm’s creates similar stress conditions as the higher speeds from a higher lift cam, especially in older designs with even steeper ramps.
To your point, it stands to reason that the trunnion operating with a higher lift cam would be exposed to these forces more frequently, since that is the objective!
Last edited by vette4fl; Jan 12, 2022 at 03:31 PM.
While the range of motion on the stock trunnion is indeed limited, I have found no evidence of that having any contribution to failure, since the failures also occur with stock cams. That leads me to believe that rocker speed and resulting harmonics from directional change stress is the culprit..
In other words running a stock cam engine at high rpm’s creates similar stress conditions as the higher speeds from a higher lift cam, especially in older designs with even steeper ramps.
To your point, it stands to reason that the trunnion operating with a higher lift cam would be exposed to these forces more frequently, since that is the objective!
Good work! While nobody needs any of these "Comp" issues, and it sucks that an "upgrade" is actually a downgrade, that's fixing something that doesnt seem broken to begin with, LS1 owners at least can purchase new rocker stands. I've got their junk on my LS7 heads, and you probably know where I'm going with this. The LS7 has cast in, machined bosses. I wonder what kind of shape the cast in aluminum rocker bosses/stands are in, if the rocker trunnion axles show wear? You could scrap the entire head because of junk engineering!! The LS7 heads have enough issues without Comp giving them an additional push towards the scrap pile! My guess is aluminum loses big time against hardened steel! Can't believe Comp sells such junk. We want Crane, we want Crane!!!!
This seems to be a common failure with the Comp kit. I have reason to believe that this is what trashed the LS2 in my GTO. Went with bronze bushings after the rebuild. The valve train is slightly quieter than before and there's no potential for failure. Only downside is that they do wear down over time and will eventually require replacement.
So it sounds like a pay me now, or pay me later type of thing with the CHE over the bushing styles.
Let us know how they work out for you. They seem to be the best!
Just curious, as to how you consider the CHE bushing kit the "best". The way I see it, you have several suppliers (CHE, Straub Technologies, Brian Tooley Racing, and Smith Brothers) all selling a similar product, for a somewhat limited market. I would be hard pressed to believe that every one of those suppliers is tooling up, on their own, to manufacture those parts. Just my $0,02 worth.....
Just curious, as to how you consider the CHE bushing kit the "best". The way I see it, you have several suppliers (CHE, Straub Technologies, Brian Tooley Racing, and Smith Brothers) all selling a similar product, for a somewhat limited market. I would be hard pressed to believe that every one of those suppliers is tooling up, on their own, to manufacture those parts. Just my $0,02 worth.....
The CHE kit is different from the rest because the bushings aren't press fit into the rockers. They are very slightly undersized and are supposed to "float" within the rockers, allowing them to spin and wear more evenly (at least in theory). The rest are press fit and only the trunnion moves, wearing down the bushing in the same general area. Installation is easier too.
Just curious, as to how you consider the CHE bushing kit the "best". The way I see it, you have several suppliers (CHE, Straub Technologies, Brian Tooley Racing, and Smith Brothers) all selling a similar product, for a somewhat limited market. I would be hard pressed to believe that every one of those suppliers is
tooling up, on their own, to manufacture those parts. Just my $0,02 worth.....
CHE has the “best” design,and they manufacture their own product. Their free floating style bushing addresses the limitations and/or shortcomings of their competitors.
Smith Brothers uses the standard bushing style, and they not only designed it and make it here in the USA, their product is sold under other brands such as Straub. It’s less expensive than CHE, but not less quality.
Brian Tooley sells a needle bearing style they claim is their own design, which is made with imported parts, and is just coincidentally is a carbon copy of the Comp Cams product (which is poorly machined). BTR claims theirs are not made by Comp.
These are my observations.
Last edited by vette4fl; Jan 19, 2022 at 02:47 PM.
CHE has the “best” design,and they manufacture their own product. Their free floating style bushing addresses the limitations and/or shortcomings of their competitors.
Smith Brothers uses the standard bushing style, and they not only designed it and make it here in the USA, their product is sold under other brands such as Straub. It’s less expensive than CHE, but not less quality.
Brian Tooley sells a needle bearing style they claim is their own design, which is made with imported parts, and is just coincidentally is a carbon copy of the Comp Cams product (which is poorly machined). BTR claims theirs are not made by Comp.
These are my observations.
I think what you're saying is fact, and since another posted the same facts, I would have to say you are correct. I do think Smith Brothers is a very good, high quality company, with excellent customer service. In the real world, I don't know if the floating design would make a big difference. BUT-Since I prefer my wrist pins to be of the "floating" design, I don't see how this could possibly hurt the rocker arm wear factor, either. So thanks for the education on CHE. When I change mine out this Spring, as much as I like Smith Brothers, CHE will have my business!
….Since I prefer my wrist pins to be of the "floating" design, I don't see how this could possibly hurt the rocker arm wear factor, either. So thanks for the education on CHE. When I change mine out this Spring, as much as I like Smith Brothers, CHE will have my business!
You touched on an interesting point. Perhaps there is a good reason wrist pins are either pressed or free floating, but not needle bearing.
Rocker Trunnion Upgrades
