New Trunnion Upgrade

[71RS/SS396]

We've seen the early stages of bearing failure with the popular trunnion bearing upgrades with any mildly aggressive cams. I seen the bearings start to deteriorate in as little as 4,000 miles so I've been looking for alternatives.
Straub Technologies has announced a bushing solution that I think has promise as a better solution for durability. I just sent a set of rockers to CHE Precision prior to finding the ones from Straub. I will use the CHE bushings in my wife's car and ordered a set from Straub for mine so we can compare the 2 to see if there's any difference. CHE charges $420 for the bushings and the installation and will not sell you the bushings to install yourself. Straub will sell you the shafts and bushings at the cost of $159. http://www.straubtechnologies.com/ls...trunnion-kits/

[jwcarguy]

Originally Posted by 71RS/SS396

We've seen the early stages of bearing failure with the popular trunnion bearing upgrades with any mildly aggressive cams. I seen the bearings start to deteriorate in as little as 4,000 miles so I've been looking for alternatives.
Straub Technologies has announced a bushing solution that I think has promise as a better solution for durability. I just sent a set of rockers to CHE Precision prior to finding the ones from Straub. I will use the CHE bushings in my wife's car and ordered a set from Straub for mine so we can compare the 2 to see if there's any difference. CHE charges $420 for the bushings and the installation and will not sell you the bushings to install yourself. Straub will sell you the shafts and bushings at the cost of $159. http://www.straubtechnologies.com/ls...trunnion-kits/

Good info!

Thanks for the heads up on another option out there

Jeff

[GregWeld]

Tim --- I follow a machinist / engine builder on Instagram @Steeldustmachine
and they found that factory rockers are way off on the face/rocker tip. He's been offering a set that he trues up. That rocker tip being off side to side probably puts a lot of pressures were they don't belong!

[71RS/SS396]

Originally Posted by GregWeld

Tim --- I follow a machinist / engine builder on Instagram @Steeldustmachine
and they found that factory rockers are way off on the face/rocker tip. He's been offering a set that he trues up. That rocker tip being off side to side probably puts a lot of pressures were they don't belong!

I don't doubt he's finding some things but here's a pic of a trunion shaft out of an engine with 4,500 miles on it. If the rocker were severely tilted you would see damage close to center on one bearing surface and the other bearing surface would be damaged out near the retaining clip. In the pic the one side is damaged worse than the other but both sides are damaged near the center of the shaft.

[71RS/SS396]

For anyone that cares and is still following this thread. I received the Straub trunion upgrade kit, the shafts are REM finished and have oil groves machined in them, the shafts also appear to be harder based on a simple test we did using a spring loaded center punch.

[waynieZ]

Tim, do you know anyone who is using these already and what they think of them?

[glassman]

I just upgraded my trunnion's along with the purchase of PRC' heads n Comp cam.....Cant remember the brand trunion, but went with the "C" clips.

Will keep an eye out for this week spot, thanx,

Mike

[Che70velle]

CHE has been doing this with bushings for 5 years, so it's not a new thing for LS engines. I ran bushings in my shaft rocker SBC dry sump race engines 15 years ago. The technology is sound, so don't shy away from it...however...this is really only necessary for "all out race applications" or a build where the owner is always up around 6k to 7k rpm, with a valve train that is brutal. The typical aftermarket bearing trunnion upgrades are fine for the average street car that sees an occasional blast. I did my trunnion upgrade, with bearings, at 80k miles, and my shafts were perfect, with no wear.

[71RS/SS396]

Originally Posted by waynieZ

Tim, do you know anyone who is using these already and what they think of them?

I don't personally know anyone that are using them but have read some posts on forums from folks using them with positive feedback on the CHE ones, the Straub kit is new and much more affordable.

Originally Posted by Che70velle

CHE has been doing this with bushings for 5 years, so it's not a new thing for LS engines. I ran bushings in my shaft rocker SBC dry sump race engines 15 years ago. The technology is sound, so don't shy away from it...however...this is really only necessary for "all out race applications" or a build where the owner is always up around 6k to 7k rpm, with a valve train that is brutal. The typical aftermarket bearing trunnion upgrades are fine for the average street car that sees an occasional blast. I did my trunnion upgrade, with bearings, at 80k miles, and my shafts were perfect, with no wear.

I don't think this is an "all out race" problem, if you track your car with any regularity you're going to eventually have this problem. That shaft I posted in the pic of has 4,500 miles on it with mixed street and a few track days. The cam is in the .620 range which is pretty common nowadays, so it's not some monster crazy cam with crazy spring pressure. The aftermarket needle bearings are narrower than the factory bearing so it has less area to spread the load out. I think the bearing is where the problem lies since it looks just as bad, if not worse than the shaft. I've tried pretty much every companies needle bearing upgrade kit out there, they all eventually fail. The bearing used is the same regardless of whose kit you buy which is where I believe the problem lies. I've sent the shafts out to be Rockwell tested and some are harder than others, there's also some that have different designs on the shaft to feed more oil to the bearing.
Now that Straub has a bushing kit that's the same price ($150) as the needle bearing kit I see no reason to not go that direction if you're going to do a trunion upgrade. The CHE upgrade is expensive ($420) and you have to send them the rockers or exchange yours, they will not sell you the shafts and bushings. I'm going to try both companies and see if there's any difference in durability.
I'm not selling any of this stuff, I'm simply sharing the info from my own experience, everyone should make the choice they feel most comfortable with.

[Che70velle]

Agreed. I'm simply referring to the title of the thread, by stating this isn't a new technology. Also, there are a LOT of guys out there with a LOT more than 4500 miles on their bearing trunnion upgrades. Just don't want anyone to think the sky is falling with their trunnion upgrade they made. I have no dog in this fight, whatsoever, believe me. I will go bushings on my next build. I would have this time around, but I didn't have the coin for the CHE stuff.