So I developed a valve train noise while on an easy late night jaunt a couple of months ago and with it finally above freezing I decided to take a gander. A mechanics stethoscope narrowed the noise down to around cylinder #2. The plugs looked great, plug wire resistance was fine, so i anticipated finding a bent pushrod or collapsed lifter etc, but the exhaust valve rocker arm was loose as soon as I pulled the valve cover. I KNOW it was exactly as it should have been when I assembled it - so I assumed the rocker bolt had backed out, which would have been super sloppy on my part. I habitually double check bolts during a rebuild. But with the cam on base circle for that valve it was easy to pull and disassemble. Sure as ****, the bronze bushing had worn significantly and was into the oiling reliefs on both bushings. This was a Smith bro's kit, and I installed them myself. I'm wondering if I somehow installed it wrong somehow but I don't think so. The bushings haven't walked etc. So who knows. I'm not shy about 6900 rpm shifts here and there.....and I'm running a 233/239 cam with .600 dual springs. Either way, Smith Bro's gets no love from me.



So maybe order a Brian Tooley rocker set with a trunnion kit installed? Initially I contemplated replacing this one rocker and sending it, but why wait for more problems. Any feedback on Brian Tooley or Michigan Motorsports trunnions?

 

Smith Bros manufactures most of the brands that market this style trunnion. I. Had a thread on this recently and the consensus seemed to be that the CHE floating trunnions are the bomb.

here’s a link:

https://www.corvetteforum.com/forums...-upgrades.html

 

I would call them. They have a good reputation.
Maybe they will replace the bushings.
Did you check others for wear? If they are fine, I suppose it’s a possibility that one rocker isn’t oiling like the rest.

When my early Comps failed, I went with the Tooley V2 trunions. The bronze idea just didn’t sit well with me.

 

How many miles did you have since the rocker upgrade?

 

I ordered a set of BT rockers / trunnions last night. A captured bearing seems much more appealing now in lieu of bronze bushings after seeing this. I'll check a few more when I get them off.

These trunnions have just about 4k miles on them and I ran zddp additive for all of those miles as well. It has to be an oiling issue with that rocker.

Thanks for the thought gentlemen and confirming my suspicion I should ditch the bronze bushings.

 

While you’re changing them, I’d be curious to know how securely they fit in the saddles, and if they all measure the same in diameter.

 

I'm somewhat curious why there are now a couple of discussions going on, regarding the rocker trunions, especially the bronze bushing pieces, because it was initially thought that they were the way to go. I installed the Straub Technology trunions in my car, I think it was 3 years ago, and so far, they seem to be functioning OK. However, given the other discussion, that originated a couple of weeks ago, it has me thinking, and I did some research. It appears that there are several vendors who sell similar set ups......which caused me to think, how many manufacturers of these bushings actually are there, as I doubt that these bushings are a "huge demand" item. What I'm getting at, is there just one or possibly two (CHE, for one, as their design is slightly different, and then "all the rest") who are making the parts, while there are several retailers.......

 

Smith Bros manufactures the bronze bushing style and markets them not only with their own label, but also provides their product for private labeling by Straub and others.

Comp has their own needle bearing version that is the most noted for failure.

CHE manufacturers a free floating variant of the bronze bushing style. I’ve not read of any failures with these.

BTR markets a needle bearing trunnion they claim is not the same as Comp. BTR told me they used to manufacture their own bearings, but have since outsourced that process.

 

I went with the Smith bros kit because the "can withstand more load" blah blah blah. My curiosity got the best of me and I pulled the number 8 intake rocker simply because I didn't need to turn the motor over to do it - and guess what, it was starting the same thing. It wasn't as severe as the #2 exhaust rocker and therefore wasn't loose, but here it is. I'm relieved to be pulling these off and replacing them with a traditional trunnion rocker. I'll check them all when I get them off. A read the threads on ls1tech where dudes were saying "show me or it didn't happen"....well here it is. And it isn't a one-off rocker arm problem either. I wonder if the oil grooves on the trunnion are too shallow or if it's just an inferior bronze material from the bushing supplier.

 

Are you planning on contacting Smith?

 

Damn brother,, That sucks! I was thinking about purchasing that style a while ago.. Thanks for posting and the heads up

BC

 

This is a link to an article discussing bushings vs needle bearings on lifters. Perhaps not an exact one to one comparison to rocker bearings, but the descriptions seemed relevant to this post.

A key point made was that the needle bearing was less dependent on oil flow, and that the bushings were subject to more drag speeding up on the cam lobes, which may be comparable to the force on rockers when they change direction.

Anyway, it’s thought provoking…

https://www.performanceracing.com/ma...earing-lifters

Another link specifically on LS rockers:

https://www.autoserviceprofessional....n-ls-weak-link

 

I am impressed! This second version of the BTR roller trunnion has some great features, including higher grade of steel, oiling holes drilled in the trunnion body, and end washers covered by HD snap rings.

 

Pardon my ignorance for I have not seen one of these up close new. You're saying that middle oil groove should be deeper and these wore down the bushing ID? Or they spun in the rocker body, or both?

I am still on stock rockers and cam due to class restrictions for racing, but I spin the engine to 7200-7400 on occasion with regular 6800rpm shifts. I like the idea of a replacement that wont send needles down into the pan, or wear a bunch and have sloppy rockers.

Did you just get the BTR trunions, or did you get their shaft kit as well?

Also, the cam you're running is not THAT big. With those lift numbers, I wonder if a PAC1219 or similar beehive spring would be a little easier on the bushing vs a heavy dual spring setup with lots of pressure.

 

Out of curiosity, I'd be interested in knowing, from those who installed the BTR roller bearings, if the engine still has the "sewing machine sound" that people have referred to. Mine did, both stock, as well as the Comp Cams rocker bearing kit. After I installed the Straub bushings, the sound went away, and the engine was much quieter.

 

Have you had any issue with the Straub kit? How many miles do you have on yours? I have some I will put in when I get the heads back on my car, curious about this wear issue as I haven't heard many complaints about the Straubs. I wonder if it's related to cam size?

 

I haven't had any issues that I'm aware of, but my car is strictly street driven, and I probably haven't put more that 3-4000 miles on it, since I installed the bushings. Prior to that, I probably didn't have any more than 3-4000 miles on the Comp Cams trunions/bearings, that were my first supposed upgrade. I'm getting to damned old, to be putzing around in an unheated garage, at this time of year, but in a few weeks, when the weather warms up, I plan on pulling the valve covers and looking things over.

 

I went with the Manton trunnion set. At 80,000 miles and prolly 40-50 HPDE track days I thought it would be time to freshen up the valve train. Well, the 2004 LS1 (stock with headers and tune) OEM trunnion needle bearing were in perfect condition on disassembly. I felt I wasted my time and money. I have only used Mobil 1 5W-30 since I have owned this car at 40,000 miles. The Dewitt radiator with oil cooler probably helps as well.

Added LS6 springs and valve hardware along with valve stem seals while I was in there. The valve stem seals were visually the only component that appeared ready for replacement.


https://www.texas-speed.com/p-13933-...nnion-kit.aspx

 

It’s only a waste if the engine blew up due to rocker failure, while your new trunnions were still on the shelf. Looks like a nice setup.

 

That looks like a variation on the CHE kit, at least the "free floating bushing" aspect of things, but those trunnions look like that only support 40-50% of the bushing. Is that picture messed up?