Slack in new rockers?

[iamdub]

I just received 16 new "GM Genuine" valve rockers, part number 12681275. They appear to be genuine as well as the bags they're in. As with more and more "domestic" brand parts, these are made in China.

The trunnions have a lot of slack. I know they're supposed to move side-to-side. But these move up and down, too. I don't recall stock rockers having play in this direction.

Vid:

What y'all think? Is someone peddling a load of defects that should've been scrapped?

 

[Foggy]

Crap.. I literally just did my trunnion upgrade on friday night... SO all my rockers
were out on the bench.. I didn't even check or feel them for that motion.. So I'm no
help, maybe someone else can check one they have lying around

 

[Rocket Man]

I just received 16 new "GM Genuine" valve rockers, part number 12681275. They appear to be genuine as well as the bags they're in. As with more and more "domestic" brand parts, these are made in China.

The trunnions have a lot of slack. I know they're supposed to move side-to-side. But these move up and down, too. I don't recall stock rockers having play in this direction.

Vid:

What y'all think? Is someone peddling a load of defects that should've been scrapped?

I did a trunion upgrade on stock rockers on 2 trucks and I can say that’s not normal. Mine didn’t move side-to-side but a tiny bit depending on how far I pressed the bearing in ( too much and it will feel like it’s binding and won’t freely move) and not at all up and down. Why not do a trunion upgrade?

 

[randeez]

Oil gap

 

[gooffeyguy]

I agree with randeez, plus once bolted down the spring pressure will keep movement minimal.

 

[Geotrash]

Mine had a little bit of both vertical and side play in them after 110K when I did the trunnion upgrade on my 2012 last year. I used the BTR kit and they're snug.

 

[Rocket Man]

I guess I never checked mine until after I did a trunion upgrade so maybe that’s normal for stock ones idk.

 

[iamdub]

I did a trunion upgrade on stock rockers on 2 trucks and I can say that’s not normal. Mine didn’t move side-to-side but a tiny bit depending on how far I pressed the bearing in ( too much and it will feel like it’s binding and won’t freely move) and not at all up and down. Why not do a trunion upgrade?

The only upgrade I consider a true upgrade is the Max Effort kit from RPMSpeed. The bearing kits that use the trunnion as the inner race might be (and probably are) better than when they first came out. But, they rely on proper hardening of the trunnion and that's an extra possibility for failure. The Comps failed at this step when they first came out. I'm not totally sold on the brass bushing style for longevity yet, either. My setup isn't any more wild than a stock LS6 and those go for hundreds of thousands of miles on the stock rockers. I'm still using my stock 215K-mile rockers. The aftermarket stuff could be an upgrade, but which brand? How do I know the big name brand (BTR, TSP, etc. isn't a re-packaged ebay brand, all from the same source? I'll never know until thousands of miles later (years for me) if their hardening process was properly performed or if the brass (soft metal) actually doesn't wear like one would think, etc. I just don't wanna find out the hard way.


I moved my originals radially to check for slack and there was no movement. Otherwise, I wouldn't have reused them. That's why these surprised me.

 

[iamdub]

Oil gap

You serious or guessing?

I agree with randeez, plus once bolted down the spring pressure will keep movement minimal.

Yes, between the spring pressure and pressurized lifters, they'd be firm with the gap at the top.


I stopped at a dealership yesterday and compared mine to the previous part number that this replaced (10214664). Other than having different slightly different casting shapes and stamps and not saying "MADE IN CHINA (MAINLAND)" on the bag, they were identical:

After seeing this, I'm assuming it's in the design. But, why? And why does it seem to not be mentioned anywhere else? Maybe it allows the bearings to rotate, distributing the wear more evenly? I don't see why this was even a concern as mine have gone over 200K and still have no slack. Surely the oil between the bearings and trunnions isn't making them that firm.

 

[randeez]

You serious or guessing?

i was mostly not being serious
but theyll prob be fine, tightened down the trunnion is fixed theres plenty of needle bearings in there to support it

 

[Geotrash]

The only upgrade I consider a true upgrade is the Max Effort kit from RPMSpeed. The bearing kits that use the trunnion as the inner race might be (and probably are) better than when they first came out. But, they rely on proper hardening of the trunnion and that's an extra possibility for failure. The Comps failed at this step when they first came out. I'm not totally sold on the brass bushing style for longevity yet, either. My setup isn't any more wild than a stock LS6 and those go for hundreds of thousands of miles on the stock rockers. I'm still using my stock 215K-mile rockers. The aftermarket stuff could be an upgrade, but which brand? How do I know the big name brand (BTR, TSP, etc. isn't a re-packaged ebay brand, all from the same source? I'll never know until thousands of miles later (years for me) if their hardening process was properly performed or if the brass (soft metal) actually doesn't wear like one would think, etc. I just don't wanna find out the hard way.


I moved my originals radially to check for slack and there was no movement. Otherwise, I wouldn't have reused them. That's why these surprised me.

I had the same concerns. But, FWIW I pulled all of the rockers when I did my cam swap the 3rd time and checked for play and smooth motion on all of them (about 12K on the BTR trunnions at the time, I believe). All were still snug and all were smooth turning. I don't plan to revisit them again unless I have to pull the heads for something again. Fingers crossed!

I've said that if I had it to do over again, I wouldn't bother with a trunnion upgrade, but your experience with new stock rockers makes me wonder.

 

[iamdub]

I had the same concerns. But, FWIW I pulled all of the rockers when I did my cam swap the 3rd time and checked for play and smooth motion on all of them (about 12K on the BTR trunnions at the time, I believe). All were still snug and all were smooth turning. I don't plan to revisit them again unless I have to pull the heads for something again. Fingers crossed!

I've said that if I had it to do over again, I wouldn't bother with a trunnion upgrade, but your experience with new stock rockers makes me wonder.

I just don't see why they'd make such a change if the older design apparently was very sound.

I'm sure the good name brand trunnion upgrade kits are reliable now and, had I known this about the stock ones, I probably would've gotten the BTR kit to have a better feeling about them. The Max Effort kit is $300 and is just overkill for me, IMO. These stock ones were $160 shipped. But, I don't want saving $140 to cost me thousands.

Also, I just ran across a video comparing the BTR V1 and V2 kits. The V2 resolves my concerns about trunnion hardening. I still don't like the circlips, but that's a really minor concern.

 

[iamdub]

i was mostly not being serious
but theyll prob be fine, tightened down the trunnion is fixed theres plenty of needle bearings in there to support it

I just want the bearings to stay in there to support it.

If this is an intentional design by GM, I'll roll with it. I just wanted to make sure that it was and I didn't get a load of defects.

 

[Geotrash]

I just don't see why they'd make such a change if the older design apparently was very sound.

I'm sure the good name brand trunnion upgrade kits are reliable now and, had I known this about the stock ones, I probably would've gotten the BTR kit to have a better feeling about them. The Max Effort kit is $300 and is just overkill for me, IMO. These stock ones were $160 shipped. But, I don't want saving $140 to cost me thousands.

Also, I just ran across a video comparing the BTR V1 and V2 kits. The V2 resolves my concerns about trunnion hardening. I still don't like the circlips, but that's a really minor concern.

Yeah, I apparently bought my v1 kit just before they came out with the v2. And I agree, the v2 is a better design. But, I haven't seen any examples of the BTR v1 kit failing in the field either (I've searched), so who knows.

 

[iamdub]

Yeah, I apparently bought my v1 kit just before they came out with the v2. And I agree, the v2 is a better design. But, I haven't seen any examples of the BTR v1 kit failing in the field either (I've searched), so who knows.

I'm sure they're fine. I'm apprehensive only because I bought a Comp trunnion upgrade kit years ago, back when they were a new idea, and found out much later after finally putting those rockers into service that those kits were faulty. The problem was insufficient/improper hardening of the trunnions and the bearings were quickly eating into them. No way would a well-respected company such as BTR simply copy that design without resolving the fault. The V2 kit just makes it 100% impossible for that failure to occur and is probably more for peace of mind since consumers might relate the V1 design to those others that failed.

 

[Just Fishing]

Up and down movement does seem odd...
If in doubt, replace them.

Any objections to going with a full roller set?

Of course the pita part would be having to verify rocker geometry afterwards...

 

[Just Fishing]

I'm sure they're fine. I'm apprehensive only because I bought a Comp trunnion upgrade kit years ago, back when they were a new idea, and found out much later after finally putting those rockers into service that those kits were faulty. The problem was insufficient/improper hardening of the trunnions and the bearings were quickly eating into them. No way would a well-respected company such as BTR simply copy that design without resolving the fault. The V2 kit just makes it 100% impossible for that failure to occur and is probably more for peace of mind since consumers might relate the V1 design to those others that failed.

Do you still have that comp set?
If you do, thought about sending them an email?
If you can proove you bought them new, it might be more likely they would replace them.

 

[gooffeyguy]

Up and down movement does seem odd...
If in doubt, replace them.

Any objections to going with a full roller set?

Of course the pita part would be having to verify rocker geometry afterwards...

I've had to use an adjustable pushrod to figure out correct pushrod length when building an engine.

They also make roller rockers with adjustable seats that the pushrod sits in, so no need to have the perfect length pushrod, but that would be tedious setting them all up correctly, lol

 

[swathdiver]

I've had to use an adjustable pushrod to figure out correct pushrod length when building an engine.

They also make roller rockers with adjustable seats that the pushrod sits in, so no need to have the perfect length pushrod, but that would be tedious setting them all up correctly, lol

Old school way with solid lifters!

 

[gooffeyguy]

Old school way with solid lifters!

There was an episode of Engine Masters where they tested solid roller lifters in place of hydraulic roller lifters