irrational

I just installed a set of these straub bronze bushing rocker bearing replacements in my stock 4.8 rockers. Install was very easy, used a vise to remove old bearings, cleaned out inside of old rockers with compressed air and hot water/soap. Lubed the inside of the bushings and pressed them in the rockers with the new trunion included. I used a drill press and two sockets to press the bushings in without an issue.

I found no metal debris when pressing bushings in like shown in the pictures a couple pages back, however i did find that if the bushings were pressed in too tightly they caused the trunion to get stuck and you could feel the trunion cutting into the bushing. A couple taps with a hammer on either side made them free again.

Ive been running this setup for about three and a half weeks now in 113 degree weather in california with rotella 15w40 and lunati gold dual valve springs and stock ls2 cam without a single issue. On first startup i had no issues with loud noises or squealing, after alot of WOT pulls tuning the engine ive had zero issues with these and would suggest them as an upgrade at this point in time.

themealonwheels

iTrader: (20)

To circle back, I changed the oil for the first time since the bushing upgrade. 3500 miles, included the 2016 Hot Rod Power Tour and about 2k miles in daily driving activities over just under 3 months in an LS1 in my 6sp Isuzu Hombre. Absolutely no metal flakes, and this was the set I was worried about since I installed it without assembly lube (kit didn't include it when I bought it). Thanks, Chris!

427

iTrader: (3)

Anybody else running them with restricted pushrods? I do have a center guide above the rocker that probably helps with oiling slightly, but I'm curious if anybody else is running restricted stuff.

Kurt

Cstraub

iTrader: (1)

Thank you sir.

Cstraub

iTrader: (1)

Thank you sir.

jblankenship

iTrader: (5)

I was running 11/32 Manton's. Probably 3000 miles. They were slightly too long and started getting some PTV from lifter pump up. When I replaced the lifters I went back with texas speech 5/16.

DietCoke

iTrader: (18)

Mine are restricted, .040 hole.

427

iTrader: (3)

That's good news others are running restricted. I have one engine that is 500 open running high rpm with restricted pushrods (.040), but it's in Tennessee so it's tough taking a look at them I suspect it's fine as the filter has been clean and I have more oil dripping on the trunnion than most, but the reduced pushrod flow had me over thinking it a bit. Can't wait to see them this winter!

Kurt

Cstraub

iTrader: (1)

From a customer with a C5 after a trunnion retro fit in his words:

Update: Having now run my new springs through two low RPM heat cycles, today I road tested and really spun up the LS6. Valve train has quieted quite a bit from the sewing machine noises it was making with the GM needle bearings (although those were entirely normal sounds). I'm just resting easier now. Glad I installed the trunnion kit. Glad I replaced the orig. yellow '03 springs.
Last edited by Zeeb; Today at 12:37 AM.

redram2007

iTrader: (6)

When I installed mine using the sockets recommended it allowed me to push it in too far. So when the first one was complete it was tight. I think a washer along with the socket would help prevent that from happening as it would stop it flush. I'm going to push them back out a tad, find a washer and and get the bushings flush. Is there a no go on the amount of movement laterally? Sorry for my lack of proper terms as I'm no machinist lol.

CR500

Chris, did you ever get a look at the bushings you talked about in posts 213 and 384? Did you mic the wear?

Mercier

iTrader: (15)

With the bushings flush with the outside edges of the rocker, there will be a small amount of lateral play..my guess is .030" or so but my indicator is holding the trunnion between my thumb and index finger and shaking it back and forth. If I can hear a "tink, tink, tink" sound it's right. This actually goes for all the styles of upgrades(bearings and bushings). You could put a proper dial indicator on it and test that way but it's just not necessary. IMO, you would have to be FAR off to cause problems. And if you are that far off(out) you wouldn't be able to put the snap rings on.

redram2007

iTrader: (6)

Thank you Mercier

427

iTrader: (3)

You can tap the end of the shaft and add clearance lateral. I set mine around .010

Kurt

Cstraub

iTrader: (1)

We sampled 100 GM rocker castings and found the casting varied about .011" from narrowest to widest in the housing where the bushing would be pressed in. We made bushing .015" narrower than the narrowest casting we found. Any lateral clearance greater than .006" and less than .040" is fine.

redram2007

iTrader: (6)

Thank you both!!

Cstraub

iTrader: (1)

They have inspected them visually but not taken them apart. Engines are still quiet just like they were during initial install.

I do have an experimental airplane company that will be testing an engine combination based on an LSX platform. Endurance testing for rpm between 1000 and 4200 rpm will be taking place in the next 60 days. Engine will be run at max rpm of 4200 rpm for 100 hours and taken apart. On this test customer will have OEM trunnions, Aftermarket Needle Trunnions, and Bushing Trunnions. Once the data has been collected from this test then it will be run for 250 hours non stop. Will put all 3 trunnion types on this build also.

Cstraub

iTrader: (1)

Your welcome sir.

CR500

Visually inspected the assembly, .... Don't think that would reveal much.

I'll be waiting on your endurance results.

Thanks!

Tuskyz28

After 10k miles or so..... Will the valvetrain needing to be freshened up from not running a roller rocker ?