New Trunnion Upgrade
 

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

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.

http://i1009.photobucket.com/albums/...4.jpg~original

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.

http://i1009.photobucket.com/albums/...3.jpg~original

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

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

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 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.

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.

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.

Good information Tim.

I probably should've titled it differently. I believe the kit from Straub could be a game changer based on price point if it holds up as well as the CHE mod.

Yes, if the Straub stuff is legit, it will be a game changer for sure. I'm glad this discussion is here, as most people aren't aware the of the technology.

Here's my first take on the comparision between the 2 bushing upgrade kits:

The CHE kit uses a spiral lock clip instead of a snap ring like the Straub kit.

The CHE trunion shaft is .709 vs .625 for Straub but this does make the bushing thinner than the Straub.

I still like the fact the Straub kit has oil grooves in the shaft

Both kits rotate very smoothly with vitually no drag, I honestly cannot tell the difference in resistance between the bushings and the needle bearing, but this is with no load so that could change.

When we pressed the bushings in flush with the outside of the rocker on the Straub kit there was .025" of axial movement of the shaft, so we machined up a fixture with a .01" step in it to press the bushing past the outside and closer to center which gave us .005" axial play and also makes it so the snap ring isn't trying to control the axial movement. I would like to see this bushing about .10" wider than it is but it's not the end of the world the way it is.

http://i1009.photobucket.com/albums/...2.jpg~original

Is the new trunion upgrade going into the whipple motor? Please keep the updates coming.

We'll see how this works out on my engine first.

As Greg mentioned, there's a machinist near me that trues the tips on them. In talking with him on the last motor I dropped off, he did point out the main point of failure.. the lack of oil puddling at the top of the rocker. The factory rocker doesn't have a "cup" for oil to pool into and thus somewhat starves the bearing underneath. Nate, the machinist, is using the Smith Bros. trunnions, as he is thoroughly impressed with their quality. He's right at 420$, also.. but he trues the tip.. and that includes shipping. https://instagram.com/p/BBJHMcBwGQY/

That kit looks to be the same as the Straub kit. We're building a holding fixture to do the same thing to the tips of the rockers but I don't think that's why the needle bearing kits are failing.

Bump. Any updates?

Thanks for the link. I have the comp cam upgrade on my ls1 and will look into the bushing for the ls7. How long would you anticipate a bushing lasting?

I just pulled the CHE rockers off of my wife's car after 3,000 miles and everything looked great. One thing I did notice about her car was the valvetrain is noticeably quieter, I'm not really sure why that is.

I don't have a guesstimate on how long the bushings will last, that's why I will be checking them every few thousand miles until I get a handle on their life. The bushing should be what wears, the problem with the needle bearing style upgrade is when the bearing fails it kills the shaft too. Fyi, the LS7 rockers tend to have a undersized bore and can make the bushing tight. I had to hone several of my rockers to get them to rotate freely. If you don't have the ability to do that you should send them to one of the companies offering the installation service.

If I go that way, I'll have to. Interested to see your findings down the road.

I posted this on another site, but will post here too for opinions.....

I am not a certified engineer, but have done engineering work in the past & was a product designer for years before I became a software product consultant For Siemens PLM Software. But I did stay at a Holiday Inn Express last night (LOL).

But Here is my thoughts/concerns.

I worked as a designer for about 5 years for a company that makes turbo chargers. One of the parts in the turbos I worked on was a thrust plate. It looks like this:
http://i.ebayimg.com/images/g/z20AAO...Ocg/s-l300.jpg

The three pads near the center are the areas where the mating part rides on. The recessed area around them is the area where oil travels. The 3 pads actually have a slight ramp on the leading edge that allows the oil to be “pulled” into the area where the pressure is applied to lubricate it. Obviously the turbo spins in one direction so the oil is constantly pulled onto the pads where it is needed.

These bushings for the rockers also have an oil groove to get the oil between the shaft & the bronze bushing. BUT, this bushing doesn’t make a full rotation around the shaft, so the oil never gets to the bottom side of the shaft where all the pressure is being applied. With only rotating (guessing) 15 degrees, the oil is not drawn down to where it is required, and with the force being applied at the bottom will push together tight & not allow the oil to penetrate.

If you look at standard small block chevy rocker arm pivot balls, they have oil grooves on them that allow the oil to get to the area where there is the most pressure.
http://static.summitracing.com/globa...1401b-16_w.jpg

So even though I like this design compared to the ones with all the little needle bearings, I’m not convinced these are going to work much better.

That’s just my opinion.

Where the load is is going to change as the rocker rotates, there's clearance between the bushing and the shaft so I believe it will get oil to the bottom as the load changes. I have no idea what the bushing material is since both companies were not willing to share that info but I do know there are impregnated bronze materials available that require little to no oil. We make our own cam thrust bushing out of impregnated bronze because the needle thrust bearing flex's, contacts the block thrust plate, and puts a burr on the thrust plate, that bushing gets very little oil and has been fine.

We'll see how it works out maybe it will, maybe it won't, all that I know is the current needle bearing kits available are not the answer. I'm going to pull several rockers off of my engine in the next week or so, press the bushings out, and check them for size against brand new ones. My engine should be the first one to have problems since the lift and ramp angles of the cam are really aggressive it tends to beat the valvetrain parts up.

I will say I like this design best so far, just wondering what the longevity is.

For those still interested, following, doubting, hating, what have you. I pulled several rockers off of my car and pressed the bushings out, they look just fine, a light polishing on the load side but still look new where there's no load. This is after a few thousand miles which is where the needle style would start to show some signs of bearing failure. My car I would consider to be on the extreme since the cam is over .675 lift with aggressive ramp angles, spring pressures are 175-450, the engine is rpm limited at 8,000.

http://i1009.photobucket.com/albums/...g.jpg~original

Nice Tim!

Thanks for posting Tim. Have you used an ID mic to get wear numbers? Is this at 3k miles?
Been wondering how they are holding up.

Thanks GDub.
This was after about 2,000 miles of mixed street and racing. I did not check the size but you cannot feel anything, in fact I can still see some of the tool marks in the polished area so I doubt you would be able to measure any difference. I fully expect these bushing to eventually wear out but I would much rather have the bronze dust than the hardened steel dust from the needle bearings.

Thanks! I'm still here watching for results.

I was contacted by CHE as a result of this thread. They are going to offer their bushings in a DIY kit now for $250.

Tim, do you have updates for these units? I figured you'd have your engine apart this time of year...
I have a new engine project in mind, and I'm going bushings this time around.

Scott, I've taken the rockers apart on both my wife's car (CHE) and mine (Straub) to inspect them for wear/damage. So far both of them have held up well, on my wife's car I saw maybe .0001" of wear over 5,000 miles but I believe that will settle down because the ground surface of the trunion shaft is pretty rough when I look at it under a magnifier when they're new, hers were polished nicely on the load side after some miles. The CHE bushings being released for diy install are going to be slip fit versus pressed which I believe will actually work better and lower the moi and friction loss of the rocker since it will be able to rotate around the bushing. We haven't had the opportunity to test the new CHE design yet but I believe it will be the best bushing upgrade available.

For anyone interested in the CHE trunion upgrade they're on sale this month for $200 shipped if you contact them.

Other than the larger diameter shaft, is there any proof that one is better than the other? Che vs Straub. And with the larger diameter shaft, the bushing becomes thinner, so is it a pro or a con? Price difference now, we are looking about about $50?

The bushing being thinner is a benefit in this case since it makes it lighter (it's about half of the weight of the Straub bushing), any weight you can remove from the rocker will aid in control of the valvetrain. The CHE bushing also has a spiral oil groove machined in it as well.With that being said. Is it necessary to go that far? I don't know yet, I'm trying both kits on 2 different engines and so far they've both held up better than the needle bearing style upgrades.

I'm not doing an all out race engine, so these arent really a requirement for me, but I took advise of a certain tuner on the cam choice & used one that has about a .611/.610 lifts, so I'm thinking I should change to something other than stock "bearing". Was concerned about the little needle bearings from the beginning.

I have an blown up engine in the shop (we didn't build it) that I think died a slow death from all of the fairy dust being sent through it from the needle bearing upgrade. This engine had a mild performance cam with .600 lift, it had 12,500 miles on it.

Here's one of the trunion shafts out of the engine

http://i1009.photobucket.com/albums/...2.jpg~original

Guys, I can't thank you enough for starting this thread. I recently picked up a set of 243 heads for my ls1 chevy II. When the time comes to swap heads I am also planning on changing out the cam, doing a rocker trunnion upgrade, high volume oil pump ect at the same time. After reading this thread and many on ls1tech I decided to order a set of CHE trunnions at $200 shipped. Talked to Matt he was very helpful.