Trunion "Upgrade" Failure
Thread Starter
10 Second Club
Joined: May 2018
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The comp shaft stock style rockers may "handle" up to .700 lift but they will still side load the valve and can cause improper wear.
The stock rockers dont lock up though. Thats somewhat an improper way to put it. Its an arc'd pad. If it were flat that could be an idea, but the only real issue for other wear is from an untrue pad or untrue alignment from the rocker bolt boss in the head, the rocker rail itself, or the rocker assy then the tip. OR the valve itself. Guide tilt etc. You can blame it on so much it becomes a "rabbit hole" issue.
The stock rockers dont lock up though. Thats somewhat an improper way to put it. Its an arc'd pad. If it were flat that could be an idea, but the only real issue for other wear is from an untrue pad or untrue alignment from the rocker bolt boss in the head, the rocker rail itself, or the rocker assy then the tip. OR the valve itself. Guide tilt etc. You can blame it on so much it becomes a "rabbit hole" issue.
Hmm, I installed rockers in this link, with the LS3 CHE options, back in April. I've put maybe put 4000 daily driver miles on the engine since then; .how soon/often do I need to check for wear? If I was nervous about them and switched to another rocker arm style (or back to my original rocker arms that I have in storage), then I think I may have a separate issue. I have the Johnson axle-oiling lifters, so would I potentially need different length pushrods if I changed lifters? It seems I've read that you don't even want to move existing rocker arms to different valves as it'll throw off the preload.
https://www.texas-speed.com/p-1088-t...m-package.aspx
https://www.texas-speed.com/p-1088-t...m-package.aspx
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Thread Starter
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Joined: May 2018
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If you are under .600 lift I would go with the ws6 store / rpm speed max effort rockers. Over .600 I would go with steel roller tip rockers. That's my prior experience. Opinions may differ.
Any alum rocker is going to not only be heavier but also have a much shorter fatigue life vs steel and can still have deflection. Picture an adult sized playdough fun factory and thats how they make alum rocker arms. So any flaw in the material or process etc will show up in an entire batch BUT wont just show up only in one set as they are made in huge batches.
I cannot attest to how the comp cams rockers are made but the tsp are investment cast just like stock with some obvious strengthening of the areas for the tip etc.
They do require a shorter pushrod, which is good. They arent nearly as bulky as most other alum rocker and normally dont require any spacers or super thick gasket etc.
I haven't installed a set of the new comp cams sets so i cannot say anything there.
As far as the other guy changing from a johnson to a reg lifter you would need different pushrods. Likely .025 longer but i dont like to measure pushrods on paper. Its always best to measure on the engine.
Also, make sure you have the right spring for a roller rocker. Some have good pressure but might not be as stable with more weight on them due to design or material and dont recommend roller rockers with them. Always ask your spring provider there.
I cannot attest to how the comp cams rockers are made but the tsp are investment cast just like stock with some obvious strengthening of the areas for the tip etc.
They do require a shorter pushrod, which is good. They arent nearly as bulky as most other alum rocker and normally dont require any spacers or super thick gasket etc.
I haven't installed a set of the new comp cams sets so i cannot say anything there.
As far as the other guy changing from a johnson to a reg lifter you would need different pushrods. Likely .025 longer but i dont like to measure pushrods on paper. Its always best to measure on the engine.
Also, make sure you have the right spring for a roller rocker. Some have good pressure but might not be as stable with more weight on them due to design or material and dont recommend roller rockers with them. Always ask your spring provider there.
Thread Starter
10 Second Club
Joined: May 2018
Posts: 168
Likes: 21
The comp shaft stock style rockers may "handle" up to .700 lift but they will still side load the valve and can cause improper wear.
The stock rockers dont lock up though. Thats somewhat an improper way to put it. Its an arc'd pad. If it were flat that could be an idea, but the only real issue for other wear is from an untrue pad or untrue alignment from the rocker bolt boss in the head, the rocker rail itself, or the rocker assy then the tip. OR the valve itself. Guide tilt etc. You can blame it on so much it becomes a "rabbit hole" issue.
The stock rockers dont lock up though. Thats somewhat an improper way to put it. Its an arc'd pad. If it were flat that could be an idea, but the only real issue for other wear is from an untrue pad or untrue alignment from the rocker bolt boss in the head, the rocker rail itself, or the rocker assy then the tip. OR the valve itself. Guide tilt etc. You can blame it on so much it becomes a "rabbit hole" issue.
What part of the rocker is he talking about?
The only lift limitation to the stock rocker arms i knew of previous to this was the shape of the tip, and as it went over a certian valve lift that it would no longer be centered on the tip of the valve stem. Thus, side loading the valve slightly. People still run them this way, though, so...
You never said what this guy meant when he said "locking up" over .600 or .630 lift. WTF does that even mean?
i would think any application that uses higher than the stock spring pressure and an aggressive cam lobe is going to put more stress on the rocker trunnion, regardless of the design of the trunnion.
Last edited by dreadpirateroberts; Dec 26, 2019 at 04:18 PM.
