Well, the forecast is for snow either today or tomorrow, so it looks like the 'Vette and Camaro will be going into hibernation within a day or two. Time for another winter project!

There has been some talk about rocker arm bearing failures on the forum, however I'm not positive that I fully understand the situation. Is it limited to the LS7 engines only, or are all the LS engines potentially in for this failure?

If they all are a "problem waiting to happen", I'd rather address the situation before it causes me any issues. There was some discussion a couple of months back about the kit from Comp Cams, that has new bearings and trunnions for the OE rocker arms. Supposedly, you "simply press out the OE parts, and press in the improved pieces"......

Has anyone here actually done this mod yet? If so, it it fairly easy and straight forward?


TIA !!

 

Sorry to hear you are getting snow. I fear we are not far behind

I have not done the trunnion kit, but there have been a lot of reports of guys that have. The needle bearing problem can happen in any year rocker, especially if you have aftermarket parts that put more load on the bearings. From what I have read it is a fairly straight forward installation but as I remember one guy had issues and Comp had to send him a new set. They did straighten it out for him. If you are running stock rockers, sounds like a nice upgrade.

 

Leadfoot,

Yep, I'm thinking of putting my vette away for the winter as well.

Great question by the way! The needle bearings on early rockers in the LS series engines were the issue. If you have a concern about this replacing with the stock replacement would be my personal choice. The replacement addressed this issue with many improvements. The attached photos show the newer design and how the needle bearings have an improved capture system in place compared to the earlier design.

For what it’s worth, I would not do any of the trunnion replacements that I have seen. My primary concern with this design is the lack of the number of needles in the bearings compared to the stock design. With the high loads that the rocker has to endure the more needles the better load carrying capacity. With needle bearings it is all about point loading, the more points of contact I have the less load each point has to carry. All of the trunnion replacements I’ve seen reduce the total number of needles. This equals higher loads on each needle.

 

My sons 2000 Z28 had a rocker come apart. The bad part about it was he did not know it came apart on him till he was changing his oil and found the rollers stuck to the drain plug. He came in the house and was crushed about finding them. We thought it over and decided we had to find the culprit. Either rockers or lifter was our thinking. We got lucky and the first valve cover we took off we found the bad rocker. The next day he bought a new rocker from the Chevy dealer. We have discussed getting a set of the replacement trunions or retrofit kits as we have been calling them.

 

[QUOTE=Eric D;1572250261]Leadfoot,

Yep, I'm thinking of putting my vette away for the winter as well.

Great question by the way! The needle bearings on early rockers in the LS series engines were the issue. If you have a concern about this replacing with the stock replacement would be my personal choice. The replacement addressed this issue with many improvements. The attached photos show the newer design and how the needle bearings have an improved capture system in place compared to the earlier design.

For what it’s worth, I would not do any of the trunnion replacements that I have seen. My primary concern with this design is the lack of the number of needles in the bearings compared to the stock design. With the high loads that the rocker has to endure the more needles the better load carrying capacity. With needle bearings it is all about point loading, the more points of contact I have the less load each point has to carry. All of the trunnion replacements I’ve seen reduce the total number of needles. This equals higher loads on each needle.

Do you have a part no. for these? I have been looking on vendor sites as well as GMPP for these with no luck.
Thanks

 

Rex, the part number should be 10214664, but I'm not where I can double check it right now. This part number is also used on the LS3 and LS9 exhaust rocker. The intake rocker for the LS3 and LS9 is different than the LS1. The intake on the LS3 and LS9 have an offset rocker.

 

Eric, very nice pictures! Would you happen to know what defines "early" vs. "late" design rocker arms? My car is a late production '01 Corvette.

BTW, how's the weather in Howell? I have a distant cousin who lives there. (Cedar Lake Road, IIRC........) We got some rain today, which was threatening to turn to snow, so I cleaned up the 'Vette, changed it's oil, took the good wheels and tires off of it, and put the cover on. Tomorrow, the Camaro gets the treatment......

 

I've done it and you can read all about it here:

http://forums.corvetteforum.com/c5-t...n-upgrade.html

http://forums.corvetteforum.com/c5-t...n-upgrade.html

Recently I've discovered a bushing to replace the bearings that may be a good alternative. You can view it in the catalog:

http://www.cheprecision.com/html/products.html

 

"t'boss"...good info, especially the conversion kit from CHE Precision. It reminds me of a design that Crane Cams was working on a couple of years ago...

 

I remember the cranes. Kinda funny how old technology becomes new and improved.

 

It was in the 30's all day today, windy and overcast. About what one would expect for Nov 27. Your cousin is pretty close..

The last change to the rockers I believe was late in 2006. I plan on replacing them all on my 2000 vette this winter.

 

I will be installing the COPM Trunions this winter. They appear to be of good quality. Materials are just as important as design, and in this dept., the aftermarket COMP pieces may have an edge. In my experience, GM does the bare minimum to get by. I'm not faulting GM here...why put bearings that can last twice as long as the projected life of a vehicle? The quality of commercial roller bearings are quite good, and heat treated shafts are a definite plus.

The instrictions aren't so good though. You will need a press and a simple fixture to hold it as you're pressing. Maybe trackboss will chime in with more installation details.





Here are the instructions included with the trunions:

 

We have been doing the trunion upgrade at the shop for a while now. It is a very nice upgrade in my opinion.

 

"Go time", good post! I find it interesting that Comp shows a couple of "pucks" to set the bearing depth properly, but won't include them. How much more could it cost, to add it to the kit, $5-6?

Just for grins, I sent an inquiry to CHE precision, to find out how much their kit is. I think it would make an interesting comparison. I remember reading about a similar type of rocker arm insert that Crane Cams was working on, and they said the real advantage to their design was not having to reverse the direction of the needle bearings as the rocker pivoted back and forth. I guess when you get to that level of concern you're really "splitting hairs", but that's probably what seperates the winners from the losers....

 

Looking at the Comp instruction sheet, it says "tap out the old trunions"... Do they come out fairly easily, or do you need some sort of special tool to do that, without damaging the rocker?

 

Looking at the instruction sheet and the photos it looks like they are using non-caged needle bearings. That's good. It seems to me I recall seeing photos of a trunion system that used caged needle bearings. Was that a different supplier? Anyone know how many needles are in each of these bearings?

Its_Go_Time, Nice grpup of photos!

 

How badly do you want to know?

By caged, do you mean on the inside where the shaft passes thru? Something to hold the rollers in place while the bearing is out? I think right now, the only thing holding those rollers in is the grease.

 

I find it strange too. Especially when you consider that this is something that the average, or even above average, home mechanic is gonna have a hard time making. If we can't make it ourselves, we have to pay a machine shop. That or measure very carefully while pressing the arms on, which would be very time consuming. Getting the .175 depth is important.

 

These are a simple, yet time consuming, install. They now include directions because I suggested it to them. I used sockets and an arbor press to install them. No special tools. The factory trunnions probably could be tapped out, but they are in there pretty good. The comp bearings are caged when installed properly. Read my posts on the other threads I linked above and you can see how I installed them.

 

Trackboss,

In this photo that Its_Go_Time posted, this looks like a non-caged needle bearing. Is this the same bearing you are using?