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-bushing-trunnion-kits/

[DJW32]

Tim,

This is the third company that I have seen with the same trunion upgrade. Do you know who is actually manufacturing these?

- - - Updated - - -

Tim,

This is the third company that I have seen with the same trunion upgrade. Do you know who is actually manufacturing these?

[Bonehead]

Tim,

This is the third company that I have seen with the same trunion upgrade. Do you know who is actually manufacturing these?

- - - Updated - - -

Tim,

This is the third company that I have seen with the same trunion upgrade. Do you know who is actually manufacturing these?

Yup. Seems to be the new popular off shore product. There will always be a failure of a product, but I'm not seeing evidence of mass failures of the name brand trunion upgrade kits. If its happening, no one seems to be talking about it.

- - - Updated - - -


Tim,

This is the third company that I have seen with the same trunion upgrade. Do you know who is actually manufacturing these?

- - - Updated - - -

Tim,

This is the third company that I have seen with the same trunion upgrade. Do you know who is actually manufacturing these?

Yup. Seems to be the new popular off shore product. There will always be a failure of a product, but I'm not seeing evidence of mass failures of the name brand trunion upgrade kits. If its happening, no one seems to be talking about it.

[71RS/SS396]

Tim,

This is the third company that I have seen with the same trunion upgrade. Do you know who is actually manufacturing these?

- - - Updated - - -

Tim,

This is the third company that I have seen with the same trunion upgrade. Do you know who is actually manufacturing these?

I think they may be coming from multiple sources. CHE Precision makes bronze valve guides, lifter bushings, rod bushings.....etc so I think they may be making their own. I doubt Straub is making his own but don't know the source. I'll be one of the first ones to get the ones from Straub so I'll try to update this thread with some pics and thoughts on them.


Yup. Seems to be the new popular off shore product. There will always be a failure of a product, but I'm not seeing evidence of mass failures of the name brand trunion upgrade kits. If its happening, no one seems to be talking about it.

- - - Updated - - -



Yup. Seems to be the new popular off shore product. There will always be a failure of a product, but I'm not seeing evidence of mass failures of the name brand trunion upgrade kits. If its happening, no one seems to be talking about it.

Do you have any facts that support these are made off shore? Unless you press the beariings out you won't be able to see it until the bearing actually totally fails. It doesn't matter what brand of the needle bearing style you buy, they all use the same bearing which is where the problem lies imho. I've had the different companies shafts rockwell tested, some are harder than others but that doesn't seem to matter, the needles start to fail and chew up the shaft.
If you're mostly street driving your car it will likely take some time for this to happen, but if your car gets the snot beat out of it most of it's life like mine you will see the problem quicker.

- - - Updated - - -


Tim,

This is the third company that I have seen with the same trunion upgrade. Do you know who is actually manufacturing these?

- - - Updated - - -

Tim,

This is the third company that I have seen with the same trunion upgrade. Do you know who is actually manufacturing these?

I think they may be coming from multiple sources. CHE Precision makes bronze valve guides, lifter bushings, rod bushings.....etc so I think they may be making their own. I doubt Straub is making his own but don't know the source. I'll be one of the first ones to get the ones from Straub so I'll try to update this thread with some pics and thoughts on them.


Yup. Seems to be the new popular off shore product. There will always be a failure of a product, but I'm not seeing evidence of mass failures of the name brand trunion upgrade kits. If its happening, no one seems to be talking about it.

- - - Updated - - -



Yup. Seems to be the new popular off shore product. There will always be a failure of a product, but I'm not seeing evidence of mass failures of the name brand trunion upgrade kits. If its happening, no one seems to be talking about it.

Do you have any facts that support these are made off shore? Unless you press the beariings out you won't be able to see it until the bearing actually totally fails. It doesn't matter what brand of the needle bearing style you buy, they all use the same bearing which is where the problem lies imho. I've had the different companies shafts rockwell tested, some are harder than others but that doesn't seem to matter, the needles start to fail and chew up the shaft.
If you're mostly street driving your car it will likely take some time for this to happen, but if your car gets the snot beat out of it most of it's life like mine you will see the problem quicker.

[rallystyle]

let us know how it turns out. what is your thoughts on them vs a full roller rocker setup? do you think the cam lift or springs are causing this to happen?
thanks

[71RS/SS396]

let us know how it turns out. what is your thoughts on them vs a full roller rocker setup? do you think the cam lift or springs are causing this to happen?
thanks

Any performance cam is going to add stress to the valvetrain parts due to the faster valve action and higher springs rates, that's just life with them. We typically use something in the .620 ish lift range in a 427.
I know the spring set-up is not the issue they're set-up properly. The shaft/full roller stuff adds weight to the valvetrain and shouldn't be necessary with the spring rates we use. The shaft rocker systems also don't play well with LS7 heads, the machining required to mount them makes the casting so thin near the ports that they typically will crack, that's the only reason I haven't gone to a solid lifter in mine, I don't want to go to an aftermarket head. I run a stud girdle on mine and haven't had any other issues other than the fulcrum bearing starting to fail.

[gray86hach]

Straub is the manufacture of these. 100% usa parts. I have a set here they are nice.

Tim

[71RS/SS396]

Straub is the manufacture of these. 100% usa parts. I have a set here they are nice.

Tim

Cool, I should see mine any day now. I should also see the CHE ones within the next week so I'm going to compare the 2.

[71RS/SS396]

This rocker trunion shaft had 4,500 miles on it

https://static1.pt-content.com/images/pt/2016/02/20160208_083924-1.jpg~original (http://s1009.photobucket.com/user/tmackg71/media/20160208_083924.jpg.html)

[Corey R.]

I am trying to understand what is good or bad in the above photo. Is it a Straub or some other shaft? Are the silver portions areas of concern? What is it that we are looking at?

[DJW32]

Tim,
Have you talked with Kurt urban about these? I'm curious what he thinks.

[71RS/SS396]

I am trying to understand what is good or bad in the above photo. Is it a Straub or some other shaft? Are the silver portions areas of concern? What is it that we are looking at?

Corey, the shaft is failing and the needle bearing outer race basically looks the same. This is from the popular needle bearing trunion upgrade NOT the Straub bushing style upgrade.

Here's a different pic

https://static1.pt-content.com/images/pt/2016/02/20160208_083354-1.jpg~original (http://s1009.photobucket.com/user/tmackg71/media/20160208_083354.jpg.html)

[71RS/SS396]

Tim,
Have you talked with Kurt urban about these? I'm curious what he thinks.

Yes I have, he thinks it will be more durable but will likely sacrifice a small amount of power since you have more surface area with the bushing it will have more friction. Without testing them on a dyno or a spintron we're not really sure how much loss there will be... I would rather have the durability myself, I'll just push the skinny pedal down a little more if need be.

[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.

https://static1.pt-content.com/images/pt/2016/02/20160216_161953-1.jpg~original (http://s1009.photobucket.com/user/tmackg71/media/20160216_161953.jpg.html)

[LonnieJ]

Thanks for updating:) Very strongly considering these!

[1BADBET]

What bolts were you using?

[71RS/SS396]

What bolts were you using?
12.9 shcs, we typically use our own stud girdle as well.

[1BADBET]

Stud girdle?? Can you post a pic of your valvetrain set up, im curious to see what it looks like.

Thanks

[71RS/SS396]

Stud girdle?? Can you post a pic of your valvetrain set up, im curious to see what it looks like.

Thanks

This is my wife's engine but the same exact set-up I have.

https://static1.pt-content.com/images/pt/2016/02/20160102_095437-1.jpg~original (http://s1009.photobucket.com/user/tmackg71/media/20160102_095437.jpg.html)

[1BADBET]

the trunions look galled or worn under where the the bolt goes through, is that correct or is it just the picture maybe?

[71RS/SS396]

the trunions look galled or worn under where the the bolt goes through, is that correct or is it just the picture maybe?

They're galled on the bearing surface, on the bottom side where all of the load is. It appears that the bearing itself gives up first and all of the debris from that is causing the trunion shaft to get galled.

[71RS/SS396]

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.

https://static1.pt-content.com/images/noimg.gif (http://s1009.photobucket.com/user/tmackg71/media/20160223_180512.jpg.html)

[1BADBET]

I can't tell how the rockers are fastened with the system your using but are they bolted down solid? Even if the bearings fail the bottom of the trunion where the bolt is wouldnt gall unless it's moving. I've never seen or heard of anyone using a girdle on a pedestal style rocker system and as far as I can tell this guy is the only one making them, so this is a first for me

[71RS/SS396]

I can't tell how the rockers are fastened with the system your using but are they bolted down solid? Even if the bearings fail the bottom of the trunion where the bolt is wouldnt gall unless it's moving. I've never seen or heard of anyone using a girdle on a pedestal style rocker system and as far as I can tell this guy is the only one making them, so this is a first for me

The bolt is not galling, that picture is of the trunion shaft, the bearing surfaces of the shaft are galling. We machine a collar that the rocker mounting bolt passes through and the bar clamps to those collars, Here's a pic of the stud girdle where you can see the underside. The stud girdle works just like one for a small or big block Chevy.

https://static1.pt-content.com/images/pt/2016/02/Stud20girdle-1.jpg~original (http://s1009.photobucket.com/user/tmackg71/media/Stud%20girdle.jpg.html)

[1BADBET]

I port cylinder heads for a living, you can read the about me in my profile if you like I'm not some guy who learned the trade a jiffy lube. I do understand what is going on but maybe I'm not explaining myself very well.

A traditional small and big block Chevy has a screw in stud rocker that, for the lack of a better description, "floats" on the stud. The rocker is positioned near the top of the stud that is what causes the studs to flex, all the load is near the top, so the top of the studs are tied together to help keep them from flexing.

A stock lsx rocker IS a pedestal style, they're not individual like the jesel stuff most people associate with pedestal rockers but non the less they are. They do not float on the stud like the traditional Chevys do they are bolted to the head solid and the trunions sit on the rocker bar.

What I am trying to say is that the part of the trunion that sits on the tie bar is supposed to be bolted down and not move. From the picture it looks like that part of the trunion is also galling or showing wear just like the area where the bearings ride. This should never happen as they are "supposed" to be bolted down solid, even if the bearings fail or rocker breaks the trunion has a bolt going thru it and the trunion itself shouldn't move and it looks as if it is.

That's why i mentioned not being able to tell how the rockers are fastened to the head with your valvetrain. It would seem that they are not bolted down, or maybe that system with the girdle is converting the lsx rocker to a stud like the old stuff, which is a step back. That would explain the abnormal bearing wear and failure.

There is 15 different companies making stud girdles for a Chevy, none make one for an lsx engine. They make them for fords, that have been converted to Chevy style rockers. This is done because the Chevy style rockers are cheaper and easily adjusted. With a pedestal, lsx or ford or jesel, they need either an adjuster not on the pushrod side or shim the stand to set valvetrain geometry. The pedestal is either time consuming or expensive. My guess is the rockers are converted to stud for ease of adjustment. Adjusting the rocker bar is possible but time consuming and all the tip heights have to be right on, there are ways of making things a little easier but it takes a little time.

If you want to keep it cheap they make conversion studs for lsx heads and Chevy rockers but you need to use the Chevy rocker, the trunions are bigger in the center around the stud where it's going to want to bend up. (Imagine putting your finger on a piece of weld rod while it's on the bench and someone lifts both ends, it bends in the middle where your finger or in this case the bolt or stud, is.)

Again not trying to ruffle any feathers I'm just trying to help. I type like a talk and some people think I'm a lite rough till you get to know me. 4 years in the marines, 2 tours in Iraq, 0 sensitivity training lol :-)

[1BADBET]

And I believe jesel sells a rocker system for the ls7 head that requires no machine work. I'd give them a call if that's what your looking for.

[71RS/SS396]

I port cylinder heads for a living, you can read the about me in my profile if you like I'm not some guy who learned the trade a jiffy lube. I do understand what is going on but maybe I'm not explaining myself very well.

A traditional small and big block Chevy has a screw in stud rocker that, for the lack of a better description, "floats" on the stud. The rocker is positioned near the top of the stud that is what causes the studs to flex, all the load is near the top, so the top of the studs are tied together to help keep them from flexing.

A stock lsx rocker IS a pedestal style, they're not individual like the jesel stuff most people associate with pedestal rockers but non the less they are. They do not float on the stud like the traditional Chevys do they are bolted to the head solid and the trunions sit on the rocker bar.

What I am trying to say is that the part of the trunion that sits on the tie bar is supposed to be bolted down and not move. From the picture it looks like that part of the trunion is also galling or showing wear just like the area where the bearings ride. This should never happen as they are "supposed" to be bolted down solid, even if the bearings fail or rocker breaks the trunion has a bolt going thru it and the trunion itself shouldn't move and it looks as if it is.

That's why i mentioned not being able to tell how the rockers are fastened to the head with your valvetrain. It would seem that they are not bolted down, or maybe that system with the girdle is converting the lsx rocker to a stud like the old stuff, which is a step back. That would explain the abnormal bearing wear and failure.

There is 15 different companies making stud girdles for a Chevy, none make one for an lsx engine. They make them for fords, that have been converted to Chevy style rockers. This is done because the Chevy style rockers are cheaper and easily adjusted. With a pedestal, lsx or ford or jesel, they need either an adjuster not on the pushrod side or shim the stand to set valvetrain geometry. The pedestal is either time consuming or expensive. My guess is the rockers are converted to stud for ease of adjustment. Adjusting the rocker bar is possible but time consuming and all the tip heights have to be right on, there are ways of making things a little easier but it takes a little time.

If you want to keep it cheap they make conversion studs for lsx heads and Chevy rockers but you need to use the Chevy rocker, the trunions are bigger in the center around the stud where it's going to want to bend up. (Imagine putting your finger on a piece of weld rod while it's on the bench and someone lifts both ends, it bends in the middle where your finger or in this case the bolt or stud, is.)

Again not trying to ruffle any feathers I'm just trying to help. I type like a talk and some people think I'm a lite rough till you get to know me. 4 years in the marines, 2 tours in Iraq, 0 sensitivity training lol :-)

No offense taken, I just edited my earlier post since I realized what I typed was not accurate as far as the pedestal style rocker vs sbc/bbc. Everything is bolted down tight, nothing is moving. I'm not sure what you're seeing in the pic, most likely something looks odd due to the angle of the pics. I'm not really looking for cheap, I cannot use a Jesel set-up on the LS7 heads and I don't think they're necessary for the spring rates we're using nor do I want the added weight. I still believe the bearing selection in all of these needle bearing upgrades is where the problem lies. I just disassembled an engine that came back to be freshened up and 14 of the 16 shafts were damaged, the 2 that weren't the outer bearing race was damaged so they were on their way to damaging the shafts. I think the modified stock rockers will get the job done if we can solve the trunion bearing failure. I'm going to assume that you don't know who Kurt is based on your reply, he's a pretty smart guy that has been at the LS game as long or longer than anyone out there, he built a lot of the race engines for GM in the early LS days.

[1BADBET]

I'm not looking at what failed so much as I'm trying to figure out the why. This isn't an on the ragged edge race motor and i have used the trunion kits on several engines and know there is a ton out there having no issues either which makes me think there is another issue.

If you look at where the trunion would touch the rocker bar, that part looks like it's worn and this is supposed to be a non moving part. The second thing is the needles are wearing into the trunion in evenly. In the second picture it's digging in on the inner edge of only the one side and shows no wear on the outer edge of the trunion. It looks like there's something else going on. Either valve train harmonics or bolts stretching or a 100 other things, not just the bearing coming apart from abuse. If Thays the case the bronze bushings are gonna get ate up just the same as the needle bearings. I'd get new comp bolts for the trunion rockers and run it without the girdle see it that fixes it, it could also be the spring pressure, or valvetrain geometry and the rocker bar needs to be shimmed due to longer valves ect.

Just seems like there is more going on, I'd investigate further than just replacing the bushing.

[71RS/SS396]

I'm not looking at what failed so much as I'm trying to figure out the why. This isn't an on the ragged edge race motor and i have used the trunion kits on several engines and know there is a ton out there having no issues either which makes me think there is another issue.

If you look at where the trunion would touch the rocker bar, that part looks like it's worn and this is supposed to be a non moving part. The second thing is the needles are wearing into the trunion in evenly. In the second picture it's digging in on the inner edge of only the one side and shows no wear on the outer edge of the trunion. It looks like there's something else going on. Either valve train harmonics or bolts stretching or a 100 other things, not just the bearing coming apart from abuse. If Thays the case the bronze bushings are gonna get ate up just the same as the needle bearings. I'd get new comp bolts for the trunion rockers and run it without the girdle see it that fixes it, it could also be the spring pressure, or valvetrain geometry and the rocker bar needs to be shimmed due to longer valves ect.

Just seems like there is more going on, I'd investigate further than just replacing the bushing.

I've tried it with and without the girdle and had the same results, the geometry is fine, its been checked multiple times, we've done deflection tests to see if there's any thing crazy going on there too. We buy brand new heads from GM and send them to Advanced Induction and have them ported and completely checked out to make sure there's nothing goofy with the guides or seats. The shaft I posted just happened to be worn that way, some are worn evenly, as I said earlier the outer race of the bearing fails first. I think the damage to the shaft is a result of the trash from the outer race getting sent through bearing. This is a real problem with any engine that gets run hard with any regularity, you cannot see or feel this in the rocker until it completely disintegrates so if you haven't pressed them apart you don't know something is going on. Have you actually pressed apart the ones you say are fine? I've spoken to several people that specialize in cylinder head and valvetrain components and a lot of them are seeing the same thing infact some are about to stop selling the needle bearing upgrades. This is not a problem with one particular mfr. we've tried them all, the common denominator is they all utilize the same bearing. The bronze bushings have a lot more surface area so they will handle more load. I'm going to use the bushings in the 2 cars I personally own since I know they're not being over revved and I know what the maintenance level is on them. My car will be a good test since it has a far more aggressive cam in it and is harder on the valvetrain parts.

[1BADBET]

What kind of rpm are you turning? Who's cam is it?

[71RS/SS396]

What kind of rpm are you turning? Who's cam is it?

Comp, the engines typically peak at 6,800 but we recommend the rev limit be set at 7,000.

[Samckitt]

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:
https://static1.pt-content.com/images/noimg.gif

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.
https://static1.pt-content.com/images/noimg.gif

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.

[1BADBET]

Factory redline on ls7 engines is 7000-7200rpm depending on who you talk to and lots of guys are moving that up. That's on the stock trunions. I've had guys turn 7500 all day no issues and know of several others doing the same. i think there has to be another issue causing your problem. I was expecting you to say your turning a lot more rpm than that. Old school Chevy stud rockers go 7k without a stud girdle and no problems.

[71RS/SS396]

Factory redline on ls7 engines is 7000-7200rpm depending on who you talk to and lots of guys are moving that up. That's on the stock trunions. I've had guys turn 7500 all day no issues and know of several others doing the same. i think there has to be another issue causing your problem. I was expecting you to say your turning a lot more rpm than that. Old school Chevy stud rockers go 7k without a stud girdle and no problems.
Yep, I know all of that. I'm not real sure why you think there's not a problem with these trunion upgrade bearings, if you google trunion upgrade bearing failure there's plenty of forum threads talking about it, this is not isolated to us. Kurt has been at the engine building game for more than 30 years, he understands the dynamics of an engine better than anyone I've ever met. He has a list of accomplishments a mile long and worked closely with GM developing the performance of the LS when he worked at Wheel to Wheel. He was the first one into the 6's in a LS and did it with a modified factory block with only 352 ci in a car borrowed from Mike Moran. I think he knows what he's doing.

[71RS/SS396]

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:
https://static1.pt-content.com/images/noimg.gif

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.
https://static1.pt-content.com/images/noimg.gif

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.
I don't think this is a oiling problem, there's no evidence of heat/bluing which you would typically see with lack of lubrication. I have no idea what bronze material is being used since the standard answer you get is "it's a proprietary material" but there are several bronze materials that don't require direct lubrication. If you look at the pic of the Straub shaft it does have slots machined in it to direct oil into the bushing at the top.

[Samckitt]

I don't think this is a oiling problem, there's no evidence of heat/bluing which you would typically see with lack of lubrication. I have no idea what bronze material is being used since the standard answer you get is "it's a proprietary material" but there are several bronze materials that don't require direct lubrication. If you look at the pic of the Straub shaft it does have slots machined in it to direct oil into the bushing at the top.

"At the top" is the key words. It is rotating back & forth, not a complete revolution. With the tubro, there is a complete rotation so the oil is constantly drawn into the contact surface between the bushing & the thrust surface. With the pressure between the rocker & the bushing being on the bottom side, & no complete rotation, oil isn't going to get in between them in that area. That's my thought.

[71RS/SS396]

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.

https://static1.pt-content.com/images/pt/2016/07/straub20bushing-1.jpg~original (http://s1009.photobucket.com/user/tmackg71/media/straub%20bushing.jpg.html)

[LonnieJ]

Thanks for the update Tim:)

[Motown 454]

Thanks.

[71RS/SS396]

FYI, CHE is going to offer their bushings in a DIY kit now for $250.

[GEARBOXGARAGE]

I still believe the bearing selection in all of these needle bearing upgrades is where the problem lies. I just disassembled an engine that came back to be freshened up and 14 of the 16 shafts were damaged, the 2 that weren't the outer bearing race was damaged so they were on their way to damaging the shafts.

Tim, This portion of your post above has me thinking that perhaps the material selection or somewhere in the manufacturing process of the bearing shell could be a large part of the issue. But if continued testing of the bronze bushings prove to be a superior upgrade, the needle bearings become irrelevant. I'm glad I came across this thread and seen that you were doing an in-depth test on alternatives. I'm just getting into LS engines and was considering the needle bearing upgrade or going to something like a Harland Sharp. Do you have any more longevity testing results for the bushings? Very interested to see if there is a failure mode with the bronze bushings.

Thanks,

[71RS/SS396]

Tim, This portion of your post above has me thinking that perhaps the material selection or somewhere in the manufacturing process of the bearing shell could be a large part of the issue. But if continued testing of the bronze bushings prove to be a superior upgrade, the needle bearings become irrelevant. I'm glad I came across this thread and seen that you were doing an in-depth test on alternatives. I'm just getting into LS engines and was considering the needle bearing upgrade or going to something like a Harland Sharp. Do you have any more longevity testing results for the bushings? Very interested to see if there is a failure mode with the bronze bushings.

Thanks,
Sorry I just saw this post. So far the bushings have been holding up just fine. I've disassembled both mine and Deb's rockers and neither showed any substantial wear. CHE is now producing a DIY kit that allows the rocker to rotate around the bushing as well as the shaft so you don't need a press to install them. I think the needle bearing used in the needle bearing style upgrade is just plain overloaded for the application. I wouldn't recommend the Harland rockers unless you need the adjustability for lashing a solid cam.

This trunion shaft come out of an engine someone brought to us that had spun 2 rod bearings, locked-up oil pump, and a bent crank, it was dumping fairy dust in the engine from the trunion shafts disintegrating. This engine had 12,500 miles on it with a pretty mild cam.

https://static1.pt-content.com/images/pt/2016/12/20161205_150832-1.jpg~original (http://s1009.photobucket.com/user/tmackg71/media/20161205_150832.jpg.html)

[Dave95Z28]

So based on your testing so far would you recommend one product over the other? Straub or CHE? Is the CHE DIY kit much closer in price to the Straub kit?

Thanks,

David

[71RS/SS396]

So based on your testing so far would you recommend one product over the other? Straub or CHE? Is the CHE DIY kit much closer in price to the Straub kit?

Thanks,

David

I like the CHE design better simply because I believe it's lighter and will have less friction, but that's not to say the Straub kit won't get the job done. Both have held up well so far. I honestly don't know what CHE is charging for the kit (they've been sending them to me at no charge to test), they told me it was going to be around $250 but I've seen a few posts from folks saying they were $200 right now so I would contact them if you're interested. http://cheprecision.com/html/contact.php

[another69]

Very interesting thread, I guess it shows that some "upgrades" can be a step backward sometimes. At what point is it really necessary to upgrade the factory rockers? Is it a cam lift or more of an RPM issue? I'm surprised that there are not more aftermarket arms out there for LS motors.

[71RS/SS396]

Very interesting thread, I guess it shows that some "upgrades" can be a step backward sometimes. At what point is it really necessary to upgrade the factory rockers? Is it a cam lift or more of an RPM issue? I'm surprised that there are not more aftermarket arms out there for LS motors.

Once you get much over .600 lift the stock trunion cannot be used. There are aftermarket rockers but they're not necessarily better depending on the application. The stock rocker is both strong a lightweight but it has lift limitations so that's why the trunion upgrades become necessary. In my case I'm running LS7 heads which pretty much rules out any aftermarket shaft rockers because once you machine the stock pedestal area to mount the shaft pedestals you take away half of the threads and make the head really thin near the intake port so you either crack the head or pull the threads out. All of the other aftermarket rockers I've seen add unnecessary weight for my application which then forces you into higher spring rates to control the valvetrain and shortens the lifter life.

[another69]

Would it be fair to say that the stock rockers (LS3 in my case) are fine below .600 lift? This may be a little off topic, but are the factory pushrods ok too, or do those need upgrading as well?

[71RS/SS396]

Would it be fair to say that the stock rockers (LS3 in my case) are fine below .600 lift? This may be a little off topic, but are the factory pushrods ok too, or do those need upgrading as well?

The stock rockers should be fine below .600 lift as long as you don't have some crazy aggressive ramps that require really high spring rates, have the valve springs set-up properly, and change the springs regularly. The stock trunions have gotten a bad rap for coming apart but I believe a lot of that comes from the springs being the wrong rate, not set-up properly, and or not changing them enough and losing control of the valvetrain, once that happens the harmonics sent through valvetrain tears stuff up. I ran the stock rockers in my wife's car for 3 years with a lot of abuse (she's not afraid of the rev limiter) but I changed the valve springs every year. Performance cams wear the springs out quicker. As far as pushrods go it's hard to say what you need, depends on the lifters, cam, and springs you're using.

[another69]

It's just the "hot cam" LS3 crate motor in my case, so I don't think that cam is really aggressive compared to many out there. Was the dropped valve issue only with LS7 motors? Would yearly valve spring replacement be considered maintenance on a close to stock motor like mine, or just with serious cams?

[71RS/SS396]

It's just the "hot cam" LS3 crate motor in my case, so I don't think that cam is really aggressive compared to many out there. Was the dropped valve issue only with LS7 motors? Would yearly valve spring replacement be considered maintenance on a close to stock motor like mine, or just with serious cams?
That cam was designed to be easy on the valvetrain, you should be fine with it if you're mainly street driving it, if you're tracking the car a lot I would still change the springs or at least check them at the start of the season, it's cheap insurance.
I think most of the LS7 valve dropping problems are caused by the valve guide not being concentric to the seat which causes the stem to be bent back forth every time the valve opens and closes, eventually it breaks the stem off, we check them and repair if necessary when we assemble the heads and have not had one drop a valve yet.

[rallystyle]

tim
have you seen anything about the new Texas speed roller rockers ? they where released at pri this year and you can get them with the bushings instead of bearings setup. wanted to see what your thoughts on them are.

[71RS/SS396]

tim
have you seen anything about the new Texas speed roller rockers ? they where released at pri this year and you can get them with the bushings instead of bearings setup. wanted to see what your thoughts on them are.

No I have not, but I suspect they are the new ones that Comp released which I have not seen in the flesh so I don't have an opinion one way or the other.

[badazz81z28]

It seems more of these are popping up! Is CHE Worth the extra money?

https://www.stevemorrisengines.com/steve-morris-engines-store/engine-parts-and-short-blocks/rocker-arm-kits-and-parts/ls-rocker-arm-trunion-bushing-upgrade-kit-and-rebuild-service.html

[badazz81z28]

I like the CHE design better simply because I believe it's lighter and will have less friction, but that's not to say the Straub kit won't get the job done. Both have held up well so far. I honestly don't know what CHE is charging for the kit (they've been sending them to me at no charge to test), they told me it was going to be around $250 but I've seen a few posts from folks saying they were $200 right now so I would contact them if you're interested. http://cheprecision.com/html/contact.php


I went ahead and bought the CHE. If you call in they are $199 plus shipping. Jealous Tim got them for free! Lol

[another69]

How are they to install?

Are they durable enough to survive high street miles?

[71RS/SS396]

How are they to install?

Are they durable enough to survive high street miles?

They actually live better than the needle bearing style upgrades on the street from what I've seen.
Installation is pretty simple if you have a way to press out the stock shafts and bearings. The CHE bushing just slips in for installation, the Straub kit requires you to press the bushing in.

[badazz81z28]

Oh yeah!!137886137887

[another69]

Let us know how these survive, I'm very interested in this upgrade

[Spzany]

This rocker trunion shaft had 4,500 miles on it

https://static1.pt-content.com/images/pt/2016/02/20160208_083924-1.jpg~original (http://s1009.photobucket.com/user/tmackg71/media/20160208_083924.jpg.html)
Thank you for sharing this I have the same set up now ! Hearing quite a bit of valve chatter at idle upgrade has around 7000 miles on it
I was wondering how the bushings worked out for you and was kinda curious what you did to address the valve guide issue in your ls7 !? Thanks in advance for your time ,just trying not to grenade a 13k Dillon engine here lol

[badazz81z28]

Thank you for sharing this I have the same set up now ! Hearing quite a bit of valve chatter at idle upgrade has around 7000 miles on it
I was wondering how the bushings worked out for you and was kinda curious what you did to address the valve guide issue in your ls7 !? Thanks in advance for your time ,just trying not to grenade a 13k Dillon engine here lol


For LS7 heads, have them checked. The guides can be checked for wear and the seats aligned with the guides. I had mine sent in to Texas Speed and checked out good with 30k miles on them. I also run the CHE trunnion kit, no issues thus far, but very few miles.

[Spzany]

Yeah I have che trunnion upgrade on order ! I had the guides replaced around 7000miles ago and the exhaust valves as well to a solid stainless valve ! I will check the valves guides again when I replace the trunnions ! I was just wondering if your guides and valves are stock or what set up you have ?

[RSX302]

I have been running the CHE trunnion upgrade on my LS engines for years. Every time I've removed (for other engine reasons) and give back to CHE for inspection, they tell me they hardly have wear and look perfect. I oil back up and put back on the engine. The CHE LS rocker trunnion system has been tested for years on top team high revving race engines. My heavy foot, 297/305 .624 lift, weekend warrior LS is no match for these. They seem bullet proof!! Knowing how good they are, I would not use anything else. BE CAREFUL OF IMITATORS!!