LS3 tear down finding at 50k, 20k with GPI SS3 Cam, bushed trunnions, etc

[acammer]

Hey everyone. I thought I'd share with the group as this is the sort of information I feel like I was always trying (and struggling) to find as I was making decision on my last cam package - how well does everything hold up? I've compiled my results into a video, but I'll talk through them here as well.



The car is a 2011 Camaro SS with the manual 6spd transmission. I bought the car with 16k miles on it in 2016, and it already had American Racing long tubes, ported throttle body, Cold Air Inductions intake, and dyno tuning from a local tuning. In 2017 I added 4.10 gears, and in 2018 with 30k on the odometer Josh at New Age Hotrods (side note - if your in the upstate NY area - this is your guy for install and tuning!) installed a GPI SS3 camshaft, along with BTR660 springs, Smith Bros bushed trunnions, Chevy Performance HD timing chain with LS2 damper, 25% powerbond underdrive pulley, and a ported rod mod intake. The heads never came off the car.

The car baselined 414whp with the bolt ons, and made 485whp , a solid result that the car would eventually back up at the track, running a best of 11.67@119 on a 1.70 60' time at 4,100lbs race weight. The car saw lots of WOT and RPM over the next 20,000 miles, I was targeting shifts at 7200rpm for optimal shift recovery, and know that the motor saw 7600+rpm on a few occasions. That's more than a BTR660 can comfortably control, and was definitely playing with fire.

This spring I took the 1,200 mile drive down (in the car - no trailer) to GPI to install our new version of our Max Package. The Max Package will be a whole other thread, and I can't wait to share the results with you, as it's a potent combination. We did baseline the car to validate our testing, and we made 487whp just the way it rolled in off the street. We removed the Cold Air Inductions intake and put the car into speed density mode, and retuned the VE as we suspected we had some degree of intake restriction based on teh data. We were able to make an even 500whp with the induction system ahead of the throttle body removed. This paved the way for an intake manifold test we conducted - what sort of power is a 103mm throttle body worth on the factory manifold? I'll have those results coming soon to share, in a separate thread.

Then we pulled the motor from the car and took it down to the short block, so we could have a good look at everything, and conduct some nice precise measuring for our new package to validate fitment, clearances, etc. Knowing the life the valvetrain was made to suffer, I was particularly interested in the condition of the cam, the lifters, and the bushed trunnions, despite everything being nice and quiet in the valve-train. What we found was very unexciting.

Every OEM lifter looked quite good, no divots or gouges in any of the wheels, just standard finish wear. The cam also looked good, pictured are the two "worst" lobes - you can see one lobe does have a small divot forming at the peak of the lobe, and another has a few very small divots forming at the edge of where the wheel rides. I'm confident that this would have continued on just fine for a good long time, but I'm trying to be transparent. For the dumb stuff I was doing to this with the valve-train out of control at times, this is not unexpected, nor is it concerning. This is why I "preach" hardened cam core when available, and quality lifters - the cam lobe/lifter wheel interface is an area where you're always going to get wear, and potentially damage. Anything you can do to run top quality materials and components there, especially if you're going to mix in a healthy amount of abuse, is warranted.

The cam chain was nice and snug, and had less slack than what has been observed even with some new chains. The LS2 chain damper had an odd chunk missing from it, found that in the pan. I went back through my original build pictures, and it looked good at install, so definitely weird, but not seemingly harmful in any way.

The bushed trunnions showed the most wear of any item. While they felt nice and snug in assembled form, on disassembly you can see there is some wear into the bronze of the bushing. The 4 pictures (2 intake, 2 exhaust) are the worst of the set. I would not call this abnormal or unexpected. After all, this is a bronze bushing, and ultimately a wear item. I had a recent conversation with forum member demonspeed who had some more significant bushing wear, and I think he summed it up best - bronze bushings should be treated like aftermarket valve springs - they need to be inspected and replaced as indicated by wear. A good valve-spring checking interval is 20k, and then every 5k there there-after - and I think that rule of thumb would apply well here. Spring pressure, oil quality, and the life they live will ultimately dictate the service life they will give.

Everything else looked great on the motor. The bores were clean, no evidence of piston to valve contact. I was half expecting some light eyebrows on the tops of the pistons as I definitely had seen RPM beyond the springs capability to fully control. The factory oil cooler was shockingly still completely dry. All in all, I was impressed with how good everything looked, and that gives me good confidence for the next few seasons with the new Max Package.

The takeaway here I think is the bushed trunnions. You guys definitely want to put eyes on those once they've got some miles on them. This is not a dig in any way at Smith Bros, there product did exactly what it was supposed to - it provided a stable and safe platform for the OEM rockers, taking place of the OEM needle bearings which can wreck havoc inside the motor if they come apart. Just like I'd expect to spend a couple hundred bucks on valve-springs every 20-30k miles, I would also anticipate freshening up worn bushings on a similar interval. You guys that have that sort of mileage on a set, I think you should be putting eyes on those, just like you should be popping a few springs off and checking that they are still giving you the pressures you need.

Hope this helps somebody at some point. If nothing else, it's fun to look at motor parts.

[demonspeed]

To add my bronze bushed trunnion story… I purchased my 13 1LE used with around 80k miles. It had Kooks, rotofab, BTR stage 4 cam and .660 springs, and unknown brand of bronze trunnions. I want to reiterate that I do not know what brand the trunnions are. This setup had approximately 40-50k miles on it along with a lot of street abuse from the previous owner, as well as several track days by me (20 minute sessions at WOT aren’t easy on anything), but shifts were low 6500 or so. This setup made 450 on a Mustang dyno.

After my last track day I started to get random misfire codes. I changed plugs and wires, but that was no help. Moved coil packs around, but the misfires would just hop all over the place. Finally in the fall I took the car for a quick ride with my daughter up the street when I heard some not good sounds Upon tear down, #7 piston was cracked, rod bent, as were the valves and guides. Assumption was detonation (it was #7, of course!). Oil was sent to Blackstone who detected excessive amounts of bronze…

When rebuilding, I planned on reusing the bronze bushings as the rockers seemed tight. It wasn’t until I was trying to set preload and measure for pushrods that things became peculiar. When trying to tighten the rockers, they’d get tight, but torquing would result in a sort of “pop” and getting loose. This was consistent across most of them, so I pulled it apart and popped the bushings out. I was very shocked at how worn they were, especially since they felt nice and tight. Oil had been pushing through them for some time, but some were very ovaled - including #7. This explains all of the misfires (the trunnion shaft hopping around), and ultimately the shaft getting enough space to push up on the valve more than pushing in on the pushrods and compressing the lifters. Had I paid attention to that oil analysis, I would have immediately pulled those trunions - it was a very expensive oversight on my part.

My new build now includes the BTR shaft mount rocker kit with needle bearings. While I’ll personally never use the bronze bushings again, the miles mine had, along with the abuse they took, it’s no wonder they ended up like they did. Like springs, though, we all need to inspect our trunions. As cheap as they are, just replace them every 20k miles or so like springs - solid bushings or needle bearings.

[tartagliazl1]

You’re right Josh is the man, i have my next appointment with him on June 3rd.

[1JEWLDSSRS]

This is AWESOME stuff, both of you guys, cammer,,demonspeed!! Thanks so much for sharing your thoughts and experiences, knowledge, and unfortunently, problems with us on the forum. This kind of material IS exactly why I really love this forum.. You can learn soooo much on here to make owning, working on and ENJOYING every time you get to drive your Camaro!! Thanks again guys...

[Tajefe Couple]

Great stuff as usual Andrew. Really helps my comfort level knowing I've got the right parts in my car.
Demonspeed want to thank you for sharing your real world experience. Don't think without you sharing would have ever worried about the trunnions when the time comes to check the springs again. It's a shame what it cost you but shows how people like you on this forum are so valuable. Wonder how many engines you just might help to save by simply taking your time to inform all of us thank you and much

[1JEWLDSSRS]

Originally Posted by Tajefe Couple

Great stuff as usual Andrew. Really helps my comfort level knowing I've got the right parts in my car.
Demonspeed want to thank you for sharing your real world experience. Don't think without you sharing would have ever worried about the trunnions when the time comes to check the springs again. It's a shame what it cost you but shows how people like you on this forum are so valuable. Wonder how many engines you just might help to save by simply taking your time to inform all of us thank you and much

^^^ Amen to that!!! Couldn't have been said any better!! . Now my decision is what do I want to do, go back with the Smith Brothers again, or CHE, or just do the shaft mounted rockers. She is only a street car that gets driven like it should and enjoyed, no racing at all. Thanks again guys!!

[Chris49066SS]

Originally Posted by Tajefe Couple

Great stuff as usual Andrew. Really helps my comfort level knowing I've got the right parts in my car.
Demonspeed want to thank you for sharing your real world experience. Don't think without you sharing would have ever worried about the trunnions when the time comes to check the springs again. It's a shame what it cost you but shows how people like you on this forum are so valuable. Wonder how many engines you just might help to save by simply taking your time to inform all of us thank you and much

I second that, thanks demonspeed and andrew! Great info and writeups here!

Wayne, same here, question is, which shaft rockers are you thinking? I am still after the T&Ds, and those beautiful GPI valve covers. Sidenote- red valve covers to match the LOD, or black with a custom painted red flag/blue GPI logo instead of the all white logo?

[1JEWLDSSRS]

Originally Posted by Chris49066SS

I second that, thanks demonspeed and andrew! Great info and writeups here!

Wayne, same here, question is, which shaft rockers are you thinking? I am still after the T&Ds, and those beautiful GPI valve covers. Sidenote- red valve covers to match the LOD, or black with a custom painted red flag/blue GPI logo instead of the all white logo?

Hey Chris, not sure on the shaft mounts as I don'r know that much about them at all, never had to consider them as I didn't think there would be an issue with the bronze bushings. But ya learn about aftermarket performance stuff, especially when something happens to one of us, as we enjoy our Camaros. On the valve covers, I powder coated mine to match my LOD intake. And they look killer with the yellow Accel coils on them. I might have to send cammer a PM and see what he suggests on the rockers. Like I said, I don't race her at all, and try to keep the revs under 7400..

[morepowerjoe]

Originally Posted by 1JEWLDSSRS

^^^ Amen to that!!! Couldn't have been said any better!! . Now my decision is what do I want to do, go back with the Smith Brothers again, or CHE, or just do the shaft mounted rockers. She is only a street car that gets driven like it should and enjoyed, no racing at all. Thanks again guys!!

Hey buddy just wanted to let you know that I recently purchased a set of new oem rockers with the che trunnions already installed in them from gpi and couldn't be happier. I picked up the new set because my original set had a good amount of wear in the ball / cup part of the rocker wear the pushrod goes to. Just an option for you cause I know your getting up there in mileage too. lol
But nothing like my 167k I don't think!

[acammer]

I would welcome someone with similar mileage tearing down a set of CHE trunnions to see how those look. I would imagine you'll see similar wear, but maybe they are a little bit different material makeup and could be better, or even could be worse. The bottom line holds up, it's something that you will expect to see wear on at some point, and should put your eyeballs on every so often.

[1JEWLDSSRS]

Originally Posted by morepowerjoe

Hey buddy just wanted to let you know that I recently purchased a set of new oem rockers with the che trunnions already installed in them from gpi and couldn't be happier. I picked up the new set because my original set had a good amount of wear in the ball / cup part of the rocker wear the pushrod goes to. Just an option for you cause I know your getting up there in mileage too. lol
But nothing like my 167k I don't think!

Hey bro, thanks for the update on what you went with. Like I said I am not too sure what I am going to do yet as she isn't my main driver anymore, but she does have 125k miles on the rockers, 25k on the trunnions since the cam swap. Got to do some shopping I guess and research.. I appreciate it..

[Badbubba]

Nice inspection and results. That chain looks tight!

[Bob570]

Originally Posted by acammer

I would welcome someone with similar mileage tearing down a set of CHE trunnions to see how those look. I would imagine you'll see similar wear, but maybe they are a little bit different material makeup and could be better, or even could be worse. The bottom line holds up, it's something that you will expect to see wear on at some point, and should put your eyeballs on every so often.

I have a set of CHE trunnions on my car with about 20k on them that I can tear down soon. I tore them down at 8k and they still looked brand new, so I expect they will still look really good. I posted the results of that on LS1tech a couple years ago.



IMO the design is much better vs the pressed in type of bronze trunnions.


I spin it to 7000 rpm with a 0.600" lift cam, TSP 660 polished springs, and that was a pretty brutal 20k miles.

[acammer]

Originally Posted by Bob570

I have a set of CHE trunnions on my car with about 20k on them that I can tear down soon. I tore them down at 8k and they still looked brand new, so I expect they will still look really good. I posted the results of that on LS1tech a couple years ago.



IMO the design is much better vs the pressed in type of bronze trunnions.


I spin it to 7000 rpm with a 0.600" lift cam, TSP 660 polished springs, and that was a pretty brutal 20k miles.

Definitely interested to see your results. I can agree that the CHE full floating design has advantages from both an install and possibly a longevity perspective. I would not be surprised if the CHEs show less overall wear, after all there is a lot to be said of the old adage - "you get what you pay for". By that logic, I should get great service life from the shaft rockers in the car now - I guess we'll see!