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For anyone that hasn't already heard the news and might be interested, we at CHE Precision offer a trunnion conversion kit for LS rockers.
These trunnion and bushing conversion kits require only the use of snap ring pliers and assembly lube or oil to assemble, and are made from the same materials that we have been using on our trunnion conversions since February of 2006. They are made from our proprietary bushing and valve guide material that we have been using for over 30 years. The bushings are designed to slip fit onto the trunnion and into the rocker and therefore do not need the use of special tools or a press. This design will increase the amount of usable wear surface, as the bushings will continue to rotate in the rockers and around the trunnion. Our oiling design is the same as it always has been, grooves that are machined in a spiral pattern around the bushing on the OD and ID. The trunnions are heat treated steel and precision ground to hold a +/-.0002” tolerance. The trunnions will accept both OEM and ARP bolts, as they always have, and we recommend a maximum lift of .670”. They were originally designed for Wegner Motorsports for use in the Spec Motor programs, and they have tested them to 9500 RPM without any failures.
We have kits in stock at this time, and pricing will be $199.95 plus shipping. Please feel free to contact me with any questions or concerns you may have and I will be happy to help.
Matt @ CHE, are these kits different than the kits we used to have to send our rockers in and have you guys install? Any difference in any of the install process?
Matt @ CHE, are these kits different than the kits we used to have to send our rockers in and have you guys install? Any difference in any of the install process?
Hi slogo, these are the same as the ones we do in house, except we made some changes to allow end users to easily do the conversion at home with out the downtime and costs associated with sending them in. We give you snap rings instead spirolocks, and we made the bushing to be installed without a press. Otherwise the materials and design are the same as they have always been.
hmmm those look nice. Not sure I'm ok with the bushing slip fitting into the trunion. So there has to be some clearance for the bushing to rocker body and then from the busing to the trunion. The larger trunion also means thinner bearing material. Any pics of the new style installed? How much play is in it?
Also what is the cost normally after december passes?
Last edited by customblackbird; 12-13-2016 at 12:35 PM.
hmmm those look nice. Not sure I'm ok with the busing slip fitting into the trunion. So there has to be some clearance for the bushing to rocker body and then from the busing to the trunion. The larger trunion also means thinner bearing material. Any pics of the new style installed? How much play is in it?
Also what is the cost normally after december passes?
Agreed. Having had just disassembled a set of factory rockers this weekend I can say that the machined finish that held the outer race of the stock bearing is not something I want moving against a bronze bushing. Meaning these are press fit with good reason, IMO.
Should have my Straub bushings installed this weekend.
hmmm those look nice. Not sure I'm ok with the bushing slip fitting into the trunion. So there has to be some clearance for the bushing to rocker body and then from the busing to the trunion. The larger trunion also means thinner bearing material. Any pics of the new style installed? How much play is in it?
Also what is the cost normally after december passes?
Hi customblackbird, thank you for your questions. There is clearance on both the OD and Id of the bushing to allow it to rotate freely. Since the OEM rocker bodies are honed the ID size is fairly consistent. We hold our manufacturing tolerances to +/-.0002" on the bushings and trunnions so there is only some side to side play, but not up and down. Yes, our bushings are thinner than other kits that are available, but they are much thicker than the rod bushings we manufacture from the same material. I will include some pictures of some assembled rockers and of them installed in one of our test vehicles. The design has been tested on a dyno to 9500 RPM by Wegner Motorsports and were torture tested in various racing programs from Drag to Auto-Cross. We have found that the bushings in fact do rotate, therefor distributing what little wear there might be all around the bushing instead of one single spot. If you would like to purchase a set, but you feel uncomfortable after seeing them, I would be happy to take them back.
The after December price is ultimately up to the owners of the company, but I would assume it would go back to $260 shipped.
For my approach to the assembly I took advantage of our current cold snap of about -30*C (-20*F) and left the bushings and trunnion shafts outside for a day. This dropped the OD of the bushings from .813" down to about .810" (+/- .0005), which reduced the interference fit in the rocker bodies from about .003-5" down to about .001-.003". Some almost went together with hand pressure. Although I did used a Summit bench vice installation to ensure accurate installation.
Pretty much the easiest thing I have assembled in recent memory.
Is that a new design on the trunion? I see an extra groove right down the center I haven't seen on previous versions.
Looks new to me. A thin spiral oil channel in the trunnion is all that's needed so I don't know why they put that thick channel in the middle. I have the second design and have no problems at all.
New Straubs? They look like he revised the design again lol. Idk if its a good thing that he keeps changing it (experimenting to improve the design) or if I should be worried that hes changing them so often that its due to some negative reason.
The way i see this newest design is that the chanel allows oil to make its way all the way around the bushing. The older designs has the cutout at the top and thus that small area is also a "void" Since all pressure is pushing the rocker off the stand its forced to the top of the bushing where the "void" is. This is effectively less surface area do to the void. and requires oil to make its way around the busing with no channels. The new design looks like the channel is in series with the oil flat feed on the top of the bushing. Oil feeds out the flat from the rocker and through the channel.
I personally like the swirl design I see in the CHE, but not that the bushing slips into the rocker body. I also dont see a large area for the oil to feed into those swirl channels like the straub has the large empty flat.
New Straubs? They look like he revised the design again lol. Idk if its a good thing that he keeps changing it (experimenting to improve the design) or if I should be worried that hes changing them so often that its due to some negative reason.
The way i see this newest design is that the chanel allows oil to make its way all the way around the bushing. The older designs has the cutout at the top and thus that small area is also a "void" Since all pressure is pushing the rocker off the stand its forced to the top of the bushing where the "void" is. This is effectively less surface area do to the void. and requires oil to make its way around the busing with no channels. The new design looks like the channel is in series with the oil flat feed on the top of the bushing. Oil feeds out the flat from the rocker and through the channel.
I personally like the swirl design I see in the CHE, but not that the bushing slips into the rocker body. I also dont see a large area for the oil to feed into those swirl channels like the straub has the large empty flat.
My thoughts exactly. I have the design with no grooves and I'm not sure I'm okay with that after seeing two revisions. I haven't installed the rockers yet but have installed the trunions and bushings. Do I need to be concerned???
Right, because we should have the vendors just make something once and leave it alone, and never think to improve upon it. Like Comp did with their trunnion kits (lovely bit of a wear issue there) or their cam core/lobe whine issues.
If you want known reliability just stick with the OEM trunnions (as delivered by GM) and a cam that suits their designed travel/load limitations. Otherwise, drop another $150 and get the newest design from Straub, and sell off the older version.
My concern is was there an issue with the previous design to warrant a couple revisions? I'm not here to toss money down the drain. Maybe send out a message warning the end user of the flaw??? I'll guarantee that if I upgrade it won't be for another Straub kit but just go the route I should have went to begin with and get a roller rocker.
Right, because we should have the vendors just make something once and leave it alone, and never think to improve upon it. Like Comp did with their trunnion kits (lovely bit of a wear issue there) or their cam core/lobe whine issues.
If you want known reliability just stick with the OEM trunnions (as delivered by GM) and a cam that suits their designed travel/load limitations. Otherwise, drop another $150 and get the newest design from Straub, and sell off the older version.
I think the issue is people may have just purchased it like 2-3 months ago and there's already a significant variation in the design. Will the original version work? Why the change? Those are valid questions.
Nobody wants progress to stop... but unfortunately, without a large R&D budget, most aftermarket parts are "alpha or beta" examples and you are the R&D...
I think the issue is people may have just purchased it like 2-3 months ago and there's already a significant variation in the design. Will the original version work? Why the change? Those are valid questions.
Nobody wants progress to stop... but unfortunately, without a large R&D budget, most aftermarket parts are "alpha or beta" examples and you are the R&D...
Well said.
I have the 2nd design and I just retrofitted mine not even 3 months ago and they aren't installed on the heads yet. BUt Since this thread has been active there are 3 different versions. Improvements are good, but we would like to hear why from Chris Straub himself. If he found something out from those test vehicles he installed them on it should be passed down. Otherwise I see a product that has issues that he keeps working on to fix an issue. Otherwise I can't explain why he has had so many revisions so quickly. Id rather not install them if there is a known issue with them.
Clearly by the newest design he was having oiling issues otherwise he wouldnt have added the oil channel around the entire trunion.
New Straubs? They look like he revised the design again lol. Idk if its a good thing that he keeps changing it (experimenting to improve the design) or if I should be worried that hes changing them so often that its due to some negative reason.
The way i see this newest design is that the chanel allows oil to make its way all the way around the bushing. The older designs has the cutout at the top and thus that small area is also a "void" Since all pressure is pushing the rocker off the stand its forced to the top of the bushing where the "void" is. This is effectively less surface area do to the void. and requires oil to make its way around the busing with no channels. The new design looks like the channel is in series with the oil flat feed on the top of the bushing. Oil feeds out the flat from the rocker and through the channel.
I personally like the swirl design I see in the CHE, but not that the bushing slips into the rocker body. I also dont see a large area for the oil to feed into those swirl channels like the straub has the large empty flat.
We have shipped over 7000 kits this year. We had 5 reports of "squeak" at first start up. Since we have shipped the kits with Driven Assembly lube no more reports. One thing we get from customers is that the valve train in their car is the quietest it has ever been with the bushing kit.
We have shipped over 7000 kits this year. We had 5 reports of "squeak" at first start up. Since we have shipped the kits with Driven Assembly lube no more reports. One thing we get from customers is that the valve train in their car is the quietest it has ever been with the bushing kit.
Yes we all know this. you already sold me as I purchased your kit already and installed on my rockers. Have yet to install them on the motor which is being upgraded. I used your driven lube and engine assembly lube so make sure I get no wear on startup.
We are merely inquiring about your most recent new design. Clearly it has a positive affect otherwise you wouldnt have changed it, again. We want to know its purpose and if the 1st and 2nd designs are still fine even tho you have improved oil channeling on the 3rd design.
yes we all know this. You already sold me as i purchased your kit already and installed on my rockers. Have yet to install them on the motor which is being upgraded. I used your driven lube and engine assembly lube so make sure i get no wear on startup.
We are merely inquiring about your most recent new design. Clearly it has a positive affect otherwise you wouldnt have changed it, again. We want to know its purpose and if the 1st and 2nd designs are still fine even tho you have improved oil channeling on the 3rd design.
12-12-2016, 09:30 AM
