New Trunnion Upgrade

[GEARBOXGARAGE]

I still believe the bearing selection in all of these needle bearing upgrades is where the problem lies. I just disassembled an engine that came back to be freshened up and 14 of the 16 shafts were damaged, the 2 that weren't the outer bearing race was damaged so they were on their way to damaging the shafts.

Tim, This portion of your post above has me thinking that perhaps the material selection or somewhere in the manufacturing process of the bearing shell could be a large part of the issue. But if continued testing of the bronze bushings prove to be a superior upgrade, the needle bearings become irrelevant. I'm glad I came across this thread and seen that you were doing an in-depth test on alternatives. I'm just getting into LS engines and was considering the needle bearing upgrade or going to something like a Harland Sharp. Do you have any more longevity testing results for the bushings? Very interested to see if there is a failure mode with the bronze bushings.



Thanks,

[71RS/SS396]

Tim, This portion of your post above has me thinking that perhaps the material selection or somewhere in the manufacturing process of the bearing shell could be a large part of the issue. But if continued testing of the bronze bushings prove to be a superior upgrade, the needle bearings become irrelevant. I'm glad I came across this thread and seen that you were doing an in-depth test on alternatives. I'm just getting into LS engines and was considering the needle bearing upgrade or going to something like a Harland Sharp. Do you have any more longevity testing results for the bushings? Very interested to see if there is a failure mode with the bronze bushings.

Thanks,

Sorry I just saw this post. So far the bushings have been holding up just fine. I've disassembled both mine and Deb's rockers and neither showed any substantial wear. CHE is now producing a DIY kit that allows the rocker to rotate around the bushing as well as the shaft so you don't need a press to install them. I think the needle bearing used in the needle bearing style upgrade is just plain overloaded for the application. I wouldn't recommend the Harland rockers unless you need the adjustability for lashing a solid cam.

This trunion shaft come out of an engine someone brought to us that had spun 2 rod bearings, locked-up oil pump, and a bent crank, it was dumping fairy dust in the engine from the trunion shafts disintegrating. This engine had 12,500 miles on it with a pretty mild cam.

[Dave95Z28]

So based on your testing so far would you recommend one product over the other? Straub or CHE? Is the CHE DIY kit much closer in price to the Straub kit?

Thanks,

David

[71RS/SS396]

So based on your testing so far would you recommend one product over the other? Straub or CHE? Is the CHE DIY kit much closer in price to the Straub kit?

Thanks,

David

I like the CHE design better simply because I believe it's lighter and will have less friction, but that's not to say the Straub kit won't get the job done. Both have held up well so far. I honestly don't know what CHE is charging for the kit (they've been sending them to me at no charge to test), they told me it was going to be around $250 but I've seen a few posts from folks saying they were $200 right now so I would contact them if you're interested. http://cheprecision.com/html/contact.php

[another69]

Very interesting thread, I guess it shows that some "upgrades" can be a step backward sometimes. At what point is it really necessary to upgrade the factory rockers? Is it a cam lift or more of an RPM issue? I'm surprised that there are not more aftermarket arms out there for LS motors.

[71RS/SS396]

Very interesting thread, I guess it shows that some "upgrades" can be a step backward sometimes. At what point is it really necessary to upgrade the factory rockers? Is it a cam lift or more of an RPM issue? I'm surprised that there are not more aftermarket arms out there for LS motors.

Once you get much over .600 lift the stock trunion cannot be used. There are aftermarket rockers but they're not necessarily better depending on the application. The stock rocker is both strong a lightweight but it has lift limitations so that's why the trunion upgrades become necessary. In my case I'm running LS7 heads which pretty much rules out any aftermarket shaft rockers because once you machine the stock pedestal area to mount the shaft pedestals you take away half of the threads and make the head really thin near the intake port so you either crack the head or pull the threads out. All of the other aftermarket rockers I've seen add unnecessary weight for my application which then forces you into higher spring rates to control the valvetrain and shortens the lifter life.

[another69]

Would it be fair to say that the stock rockers (LS3 in my case) are fine below .600 lift? This may be a little off topic, but are the factory pushrods ok too, or do those need upgrading as well?

[71RS/SS396]

Would it be fair to say that the stock rockers (LS3 in my case) are fine below .600 lift? This may be a little off topic, but are the factory pushrods ok too, or do those need upgrading as well?

The stock rockers should be fine below .600 lift as long as you don't have some crazy aggressive ramps that require really high spring rates, have the valve springs set-up properly, and change the springs regularly. The stock trunions have gotten a bad rap for coming apart but I believe a lot of that comes from the springs being the wrong rate, not set-up properly, and or not changing them enough and losing control of the valvetrain, once that happens the harmonics sent through valvetrain tears stuff up. I ran the stock rockers in my wife's car for 3 years with a lot of abuse (she's not afraid of the rev limiter) but I changed the valve springs every year. Performance cams wear the springs out quicker. As far as pushrods go it's hard to say what you need, depends on the lifters, cam, and springs you're using.

[another69]

It's just the "hot cam" LS3 crate motor in my case, so I don't think that cam is really aggressive compared to many out there. Was the dropped valve issue only with LS7 motors? Would yearly valve spring replacement be considered maintenance on a close to stock motor like mine, or just with serious cams?

[71RS/SS396]

It's just the "hot cam" LS3 crate motor in my case, so I don't think that cam is really aggressive compared to many out there. Was the dropped valve issue only with LS7 motors? Would yearly valve spring replacement be considered maintenance on a close to stock motor like mine, or just with serious cams?

That cam was designed to be easy on the valvetrain, you should be fine with it if you're mainly street driving it, if you're tracking the car a lot I would still change the springs or at least check them at the start of the season, it's cheap insurance.
I think most of the LS7 valve dropping problems are caused by the valve guide not being concentric to the seat which causes the stem to be bent back forth every time the valve opens and closes, eventually it breaks the stem off, we check them and repair if necessary when we assemble the heads and have not had one drop a valve yet.

[rallystyle]

tim
have you seen anything about the new Texas speed roller rockers ? they where released at pri this year and you can get them with the bushings instead of bearings setup. wanted to see what your thoughts on them are.

[71RS/SS396]

tim
have you seen anything about the new Texas speed roller rockers ? they where released at pri this year and you can get them with the bushings instead of bearings setup. wanted to see what your thoughts on them are.

No I have not, but I suspect they are the new ones that Comp released which I have not seen in the flesh so I don't have an opinion one way or the other.

[badazz81z28]

It seems more of these are popping up! Is CHE Worth the extra money?

https://www.stevemorrisengines.com/s...d-service.html

[badazz81z28]

I like the CHE design better simply because I believe it's lighter and will have less friction, but that's not to say the Straub kit won't get the job done. Both have held up well so far. I honestly don't know what CHE is charging for the kit (they've been sending them to me at no charge to test), they told me it was going to be around $250 but I've seen a few posts from folks saying they were $200 right now so I would contact them if you're interested. http://cheprecision.com/html/contact.php

I went ahead and bought the CHE. If you call in they are $199 plus shipping. Jealous Tim got them for free! Lol

[another69]

How are they to install?

Are they durable enough to survive high street miles?

[71RS/SS396]

How are they to install?

Are they durable enough to survive high street miles?

They actually live better than the needle bearing style upgrades on the street from what I've seen.
Installation is pretty simple if you have a way to press out the stock shafts and bearings. The CHE bushing just slips in for installation, the Straub kit requires you to press the bushing in.

[badazz81z28]

Oh yeah!!

[another69]

Let us know how these survive, I'm very interested in this upgrade

[Spzany]

This rocker trunion shaft had 4,500 miles on it

Thank you for sharing this I have the same set up now ! Hearing quite a bit of valve chatter at idle upgrade has around 7000 miles on it
I was wondering how the bushings worked out for you and was kinda curious what you did to address the valve guide issue in your ls7 !? Thanks in advance for your time ,just trying not to grenade a 13k Dillon engine here lol

[badazz81z28]

Thank you for sharing this I have the same set up now ! Hearing quite a bit of valve chatter at idle upgrade has around 7000 miles on it
I was wondering how the bushings worked out for you and was kinda curious what you did to address the valve guide issue in your ls7 !? Thanks in advance for your time ,just trying not to grenade a 13k Dillon engine here lol

For LS7 heads, have them checked. The guides can be checked for wear and the seats aligned with the guides. I had mine sent in to Texas Speed and checked out good with 30k miles on them. I also run the CHE trunnion kit, no issues thus far, but very few miles.