Trunion "Upgrade" Failure
was checking a few things on my engine tonight, as well as changing the oil, so i decided to check my rockers. i have straub trunnion kit installed. i have no pictures since i didn't dissemble my rockers.
none of the rockers installed could be wiggled side to side easily while the associated lifter was resting on the cam base circle (spring closed). They could with significant effort.
also, spinning them once removed, in a certain position they would feel notchy. if i slid the trunnion fulcrum over, no notchy feeling.
this is telling me that grooves are already starting to wear in the bushings. there are only a few hundred miles on this set.
i haven't noticed any noise or loss of performance, though. no man glitter in the oil.
will be switching to the che kit and checking after a few hundred miles.
none of the rockers installed could be wiggled side to side easily while the associated lifter was resting on the cam base circle (spring closed). They could with significant effort.
also, spinning them once removed, in a certain position they would feel notchy. if i slid the trunnion fulcrum over, no notchy feeling.
this is telling me that grooves are already starting to wear in the bushings. there are only a few hundred miles on this set.
i haven't noticed any noise or loss of performance, though. no man glitter in the oil.
will be switching to the che kit and checking after a few hundred miles.
If that were true youd definitely see that on any dyno graph and more valves would get bent, completely wiped out, or ported pistons because nearly every more aggressive aftermarket cam and basically any ls3 cam would do that.
The theory there doesnt pan out. Especially with how many cylinder heads ive personally and professionally seen and disassembled with nearly every cam you can imagine.
The theory there doesnt pan out. Especially with how many cylinder heads ive personally and professionally seen and disassembled with nearly every cam you can imagine.
I looked at mine with a microscope. Pretty easy to see how deep the heat treat went. Not very deep.....
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I can guarantee you that the I'd have gotten more run time on the stock rocker over installing the Comp's.
My evidence!
After less than 5,000 miles.
You can expect to see some bronze due to initial break-in. I feel the bronze I saw was from premature guide wear from the jacked up TSP heads. I still have the LS7 rockers with the Straub's and not afraid to run them either. When you start hearing excessive valve-train noise you better do some investigating.
You can expect to see some bronze due to initial break-in. I feel the bronze I saw was from premature guide wear from the jacked up TSP heads. I still have the LS7 rockers with the Straub's and not afraid to run them either. When you start hearing excessive valve-train noise you better do some investigating.
Just finished taking all of mine apart. Like I said, only a couple thousand miles as I mostly just drive to and from the track.
Same as 01CamaroSSTx just posted. Some perfect, some badly failing, some on one side only.
One ****/nerdy thing I did when I assembled mine was to sort through a good pile of used rockers to get 16 with no wear on the face that rides on the valve stem. Then lightly sanded that face with 1000 grit wet/dry on a flat alum plate. Followed that by polishing with jewelers rouge and a buffing wheel. Practically a mirror finish.
Now that they have been run it's easy to see where they contact the valve stem. Not wearing, just have witness marks.
It's easy to see that they don't ride anywhere near the heel of the pad. Nor do they try to run off the toe.
I believe that if you could lower the rocker stands, this pattern could be centered better. I doubt any such part exists to do that.
My cam lift is .617/.598 btw.
It was painful tossing $120 worth of parts in the recycle bin...….
Same as 01CamaroSSTx just posted. Some perfect, some badly failing, some on one side only.
One ****/nerdy thing I did when I assembled mine was to sort through a good pile of used rockers to get 16 with no wear on the face that rides on the valve stem. Then lightly sanded that face with 1000 grit wet/dry on a flat alum plate. Followed that by polishing with jewelers rouge and a buffing wheel. Practically a mirror finish.
Now that they have been run it's easy to see where they contact the valve stem. Not wearing, just have witness marks.
It's easy to see that they don't ride anywhere near the heel of the pad. Nor do they try to run off the toe.
I believe that if you could lower the rocker stands, this pattern could be centered better. I doubt any such part exists to do that.
My cam lift is .617/.598 btw.
It was painful tossing $120 worth of parts in the recycle bin...….
The ends of the pad hardly ever get touched by even some high lift stuff. The valves are the same way. The way in which the valves would get sharp edges isnt by riding the rocker pad on the edge, but by moving material. At a certain point it gets to the edge. Youll notice they will have a cup or divet in the middle. Thats not normally due to rocker issues from my line of thinking. Thats likely lubrication or valve material issue. Or both. Once that divet wears enough then the valve cannot rotate properly either. And down the rabbit hole that goes.
I don't know who Comp uses for heat treating. I know several years ago a business owner who owned a steel heat treating business was trying to corner the US market. Based on first hand accounts, I know that the quality coming out of that heat treating business was sub par.
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I don't know who Comp uses for heat treating. I know several years ago a business owner who owned a steel heat treating business was trying to corner the US market. Based on first hand accounts, I know that the quality coming out of that heat treating business was sub par.
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.