Comp Cams Trunion upgrade potential problem
I did mine this morning and I got a few that came out like crap too. Most of them came out nicely and a few that were a little stiff. Then there were 2 that are just wtf. One of them rotates halfway around then jams up enough so I can't even rotate it by hand. The other one feels "lumpy" when I rotate it. Almost like theres a couple bumps inside.
I just pressed the first 8 trunion kits into the new rockers. They are as smooth as silk. I won't have time to do the rest right now, but I will let you all know how it goes.
Last edited by speedtigger; Jun 22, 2011 at 04:54 PM.
I pressed the 2nd 8 trunion upgrades into my new rockers on my lunch break. All 16 are glass smooth and perfect.
So, for me, this issue is over. Kudos to Comp Cams Technical Service Manager David Ising. His immediate and thorough attention to my product issue assures me that the company does care very much about customer service.
Full Disclosure:
There are certain things that were different while achieving my successful results vs. my first efforts. Here is what they were:
Because there are these variables, I cannot say conclusively if the problem was the out of round bearing shell condition that David at Comp Cams suspected.
I will say these things about my experience:
I would recommend that anyone doing this installation use a small arbor press (1 to 1 1/2 ton). The feedback from the smaller press (my old one was a 2 1/2 ton unit) allowed me to feel the bearing installation very well. I think this guarantees full flush installation of the bearing without the chance of deforming the rocker body with excess pressure. I would not personally use a vise for this same reason.
These kits produce a finished product with very small bearing clearances compared to the factory trunion and bearing set up. If anything is even slightly out of alignment or the rocker is even slightly deformed or there is any damage or debris in the rocker bore or the rocker bore, trunion and bearing is even slightly out of tolerance, the finished product will almost certainly be a sticky binding rocker that is sure to experience premature wear or failure.
So, for me, this issue is over. Kudos to Comp Cams Technical Service Manager David Ising. His immediate and thorough attention to my product issue assures me that the company does care very much about customer service.
Full Disclosure:
There are certain things that were different while achieving my successful results vs. my first efforts. Here is what they were:
- This trunion kit was shipped to me with the bearings on the trunions and retainer clips installed.
- They were carefully individually wrapped inside the box.
- The rocker arms used for this install were brand new - The last installation used rockers that had 55,000 miles.
- I purchased a brand new and smaller 1 ton arbor press for this installation.
- I tapped out the factory bearings with a hammer and punch as opposed to pressing them out like the previous set as I wanted to follow Comp Cams directions to the letter.
Because there are these variables, I cannot say conclusively if the problem was the out of round bearing shell condition that David at Comp Cams suspected.
I will say these things about my experience:
I would recommend that anyone doing this installation use a small arbor press (1 to 1 1/2 ton). The feedback from the smaller press (my old one was a 2 1/2 ton unit) allowed me to feel the bearing installation very well. I think this guarantees full flush installation of the bearing without the chance of deforming the rocker body with excess pressure. I would not personally use a vise for this same reason.
These kits produce a finished product with very small bearing clearances compared to the factory trunion and bearing set up. If anything is even slightly out of alignment or the rocker is even slightly deformed or there is any damage or debris in the rocker bore or the rocker bore, trunion and bearing is even slightly out of tolerance, the finished product will almost certainly be a sticky binding rocker that is sure to experience premature wear or failure.
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great service after trunion problem quite a while back i purchased a set of already upgraded rockers from Tim at Carshop inc. http://www.carshopinc.com/
these were already fitted with the better bearings. I was just about to fit them when i saw this thread, and then checked all 16 rockers closely. I found one was indeed very slightly notchy, the rest were perfect. rather than fit them and then worry endlessly, i emailed tim for advice. at no cost he's sending me a new rocker (i live in the UK),no questions asked. Thats great service in my book, as it must be 5 or 6 months since i purchased them.
(never got round to fitting them due to other life issues!)
big thumbs up to them for sorting this out with no hassles.
these were already fitted with the better bearings. I was just about to fit them when i saw this thread, and then checked all 16 rockers closely. I found one was indeed very slightly notchy, the rest were perfect. rather than fit them and then worry endlessly, i emailed tim for advice. at no cost he's sending me a new rocker (i live in the UK),no questions asked. Thats great service in my book, as it must be 5 or 6 months since i purchased them.
(never got round to fitting them due to other life issues!)
big thumbs up to them for sorting this out with no hassles.
quite a while back i purchased a set of already upgraded rockers from Tim at Carshop inc. http://www.carshopinc.com/
these were already fitted with the better bearings. I was just about to fit them when i saw this thread, and then checked all 16 rockers closely. I found one was indeed very slightly notchy, the rest were perfect. rather than fit them and then worry endlessly, i emailed tim for advice. at no cost he's sending me a new rocker (i live in the UK),no questions asked. Thats great service in my book, as it must be 5 or 6 months since i purchased them.
(never got round to fitting them due to other life issues!)
big thumbs up to them for sorting this out with no hassles.
these were already fitted with the better bearings. I was just about to fit them when i saw this thread, and then checked all 16 rockers closely. I found one was indeed very slightly notchy, the rest were perfect. rather than fit them and then worry endlessly, i emailed tim for advice. at no cost he's sending me a new rocker (i live in the UK),no questions asked. Thats great service in my book, as it must be 5 or 6 months since i purchased them.
(never got round to fitting them due to other life issues!)
big thumbs up to them for sorting this out with no hassles.
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I think the units from Carshop that you are talking about are something completely different than the Comp Trunion upgrades. I had a set of those rockers from Car Shop and sent them back as they were filled with debris. They may be fine, but the fact that they were filled with debris inside of a sealed package shook my confidence. The Carshop rockers also do not have a c-clip for positive bearing retention. I hope they are fine for you, but they were not for me.
is there a picture of the comp cam units and the circlip? i will have a look at mine tonight, not been fitted yet.
Last edited by chris-m; Jul 7, 2011 at 06:32 AM.
The bearings in those rockers are nothing like the Comp Cams or Harland Sharp trunions. The first thing that I noticed was that the trunion was very small in diameter compared to the comp cams trunion. The next thing that I noticed was that needle bearings were much largerer in diameter and fewer in number than the Comp bearings. There is no retaining clip like the Comp set up and the bearings do not have double sided full compliment drawn cup outer races. They only have a cup edge bearing retainer on one side. So, if the inner races slides off the trunion the needle bearings will spill out.
Between the design differences, the debris in the bearings, and the fact that the ones I received looked as if they had been installed before, I lost confidence in them. They may work fine and have a long life, but I was just not comfortable trusting my engine to them. It may just be my own personal neurosis, but I returned them.
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The story that I was told by Car Shops is that those rockers were built by a GM subcontractor to replace the existing rockers. GM did not end up buying them, so those were sold to the aftermarket and Car Shops bought some.
The bearings in those rockers are nothing like the Comp Cams or Harland Sharp trunions. The first thing that I noticed was that the trunion was very small in diameter compared to the comp cams trunion. The next thing that I noticed was that needle bearings were much largerer in diameter and fewer in number than the Comp bearings. There is no retaining clip like the Comp set up and the bearings do not have double sided full compliment drawn cup outer races. They only have a cup edge bearing retainer on one side. So, if the inner races slides off the trunion the needle bearings will spill out.
Between the design differences, the debris in the bearings, and the fact that the ones I received looked as if they had been installed before, I lost confidence in them. They may work fine and have a long life, but I was just not comfortable trusting my engine to them. It may just be my own personal neurosis, but I returned them.
The bearings in those rockers are nothing like the Comp Cams or Harland Sharp trunions. The first thing that I noticed was that the trunion was very small in diameter compared to the comp cams trunion. The next thing that I noticed was that needle bearings were much largerer in diameter and fewer in number than the Comp bearings. There is no retaining clip like the Comp set up and the bearings do not have double sided full compliment drawn cup outer races. They only have a cup edge bearing retainer on one side. So, if the inner races slides off the trunion the needle bearings will spill out.
Between the design differences, the debris in the bearings, and the fact that the ones I received looked as if they had been installed before, I lost confidence in them. They may work fine and have a long life, but I was just not comfortable trusting my engine to them. It may just be my own personal neurosis, but I returned them.
I spoke to two other board members who used the CarShop rockers and are satisfied with them. Hopefully you will have the same positive experience. Their cost effective pricing makes them very appealing.
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I'm in the middle of installing the Comp Cams Trunion Kit ... did 8 of the 16 yesterday.
https://ls1tech.com/forums/15137102-post34.html
All bearings seemed to press in fine and the rocker arms all rotated smoothly. A couple seemed a hair notchy until I lubed the bearing up well after assembly with motor oil and rotated then a few times.
One thing I've noticed is that Comp Cams puts all the trunions in 2 bags ... 8 in each bag. They are free to bang around on each other, and if you look at the bearing surfaces on the trunions you can see small nicks and a few pretty good sized nicks. This could also be the reason some feel notchy after assembly. If you find a big nick, ensure the material hasn't risen above the bearing surface, and if it has sand it out with 2000 grit paper. Comp Cams needs to re-think how they package these trunions so they don't chew each other up in rough shipping situations. A needle bearing surface should be the last thing you want nicks in.
I'd suggest inspecting all the bearing surfaces on the trunions before assembly to ensure there are not large nicks that will change the bearing surface and cause the needle bearings to to roll over a nick.
BTW - I tried to measure the OEM rocker arm bearing hole and the Comp Cams bearing OD to see how much interference fit there was. I think I saw ~0.003" ... but I was using dial calipers so not sure how accurate that was.
During bearing installation, I cleaned up all the mating surfaces and used some motor oil to help the pressing. Also used a small arbor press to ensure all pressing was straight and so far all bearings have seemed to press in with the same amount of force.
That's how I did mine too ... puts no real stress on the rocker arm.
https://ls1tech.com/forums/15137102-post34.html
All bearings seemed to press in fine and the rocker arms all rotated smoothly. A couple seemed a hair notchy until I lubed the bearing up well after assembly with motor oil and rotated then a few times.
One thing I've noticed is that Comp Cams puts all the trunions in 2 bags ... 8 in each bag. They are free to bang around on each other, and if you look at the bearing surfaces on the trunions you can see small nicks and a few pretty good sized nicks. This could also be the reason some feel notchy after assembly. If you find a big nick, ensure the material hasn't risen above the bearing surface, and if it has sand it out with 2000 grit paper. Comp Cams needs to re-think how they package these trunions so they don't chew each other up in rough shipping situations. A needle bearing surface should be the last thing you want nicks in.
I'd suggest inspecting all the bearing surfaces on the trunions before assembly to ensure there are not large nicks that will change the bearing surface and cause the needle bearings to to roll over a nick.
BTW - I tried to measure the OEM rocker arm bearing hole and the Comp Cams bearing OD to see how much interference fit there was. I think I saw ~0.003" ... but I was using dial calipers so not sure how accurate that was.
During bearing installation, I cleaned up all the mating surfaces and used some motor oil to help the pressing. Also used a small arbor press to ensure all pressing was straight and so far all bearings have seemed to press in with the same amount of force.
I tapped out the factory bearings with a hammer and punch as opposed to pressing them out like the previous set as I wanted to follow Comp Cams directions to the letter.
Last edited by ZeeOSix; Jul 11, 2011 at 12:15 PM.
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The bearings in those rockers are nothing like the Comp Cams or Harland Sharp trunions. The first thing that I noticed was that the trunion was very small in diameter compared to the comp cams trunion. The next thing that I noticed was that needle bearings were much largerer in diameter and fewer in number than the Comp bearings.
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mine look just like what i recall the original trunions looked like, will compare properly when i get round to swapping them.
Contact Comp Cams ... I'm sure they'll send you new trunnions. 
