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Rocker Trunnion Upgrade

Redline457

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Hi all, has anyone carried out this upgrade ? I’m told this is excellent upgrade for rocker bearing reliability. Any particular brand better than another ?
 

Skylarking

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There are upgrade kits that allow you to ditch the compromised factory D tyre trunion which uses pressed side plates to hold the roller needles in place. These side plates can fail (fall off?) and thus the roller needles are no longer confined and make there way throughout the engine...

These upgrade kits replace the D type trunion with a fully circular trunion that uses circlips to hold the needle roller bearing within the rocker body itself. There are also other upgrade kits that replace the roller bearing with bronze bushes. Either kit reuses your existing rockers and resolves the factory defect.

Then there are complete rocker replacements kits that use either roller bearings or bronze bushes with round trunions or you can go to shaft based roller rockers...

As for which brand is better, no idea but probably the bigger question is do you want to stay with roller bearings or go to bronze bushings? Do you want to reuse your rockers or by new? Do you want to go to shaft based roller rockers or stay with trunion. It all comes down to what your aims are, what other mods you plan and how much money you want to dedicate to this.

At some stage, I’ll have to answer these questions myself :p

As to trunions, the following article are a starting point and may be helpful:

https://www.enginelabs.com/news/needle-bearings-versus-trunnion-bushings-with-the-chevy-ls/

and a good DIY upgrade process is listed below:

https://www.ssforums.com/threads/how-to-upgrade-weak-oem-rocker-trunions.50722/
 
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lmoengnr

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Factory engine?
Factory cam?
Factory valve springs?
Factory rockers don't normally fail under normal conditions(If they were investment cast properly in the first place).
If you spend more time close to redline, increased valve seat pressure, increased valve lift, increased cam duration, then spend the money and get decent roller rockers, with roller bearing pivots on trunnion and nose.
 

Pollushon

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It's necessary on a performance build and worthwhile on any LS that's getting on in km. Takes the stupid needle bearing cages out of the picture, leaving nothing to tear your motor up.

I've done a few kits over the years, it's fiddly and tedious, if you look around you can get pre-made sets for not much more than the kit
 

Redline457

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Thanks guys for the reply’s , good articles Skylarking. My engine has 74.5k kms on it now, has WP supercharger on it with W407 cam this includes upgraded valve springs and lifters. I don’t rev it to the redline at all, to be honest I’m considering a rebuild due to the dreaded piston slap, but once the engine has warmed up after about 4 to 5 kms it runs like a dream, doesn’t us any oil, with regards to the trunnion upgrade I’m just looking at reliability and removing the weak link. I presume the bronze bush would be the way to go as it completely removes the needle bearings ? If I don’t rebuild the engine I’d still like to do the trunnion upgrade.
 

Redline457

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Any recommendations to a reliable shop to get this done in SE Melb ?
 

Pollushon

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I'd definitely get it done on a build like that, are you sure they didn't already? Don't worry about the slap, it's an LS thing, warm up carefully and you'll go 300k like I did no problem. I solved slap in my current LS with a Callies, Scat and Carrillo stroker build
 

Redline457

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Hi Pollushon, no it hasn’t been done, I do baby it until it has warmed up . Might see if HPF can do it.. stroker kit now your teasing me !!! Haha
 

Pollushon

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Allow me to tease you some more... Stroker with 12 pounds of M122 boost ;)

20210116_161928_1.jpg
 

Skylarking

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@Redline457, with a build like yours, i'm surprised the known weakness of OEM trunion failure letting needle bearing loose wouldn't have been addressed. Have you talked to the shop that did the work about your concerns?
 
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