leadfoot4

StraubTech

Thank you for the post.

neutron82

I made a thread not too long ago about replacing my comps with your kit, here's the link if you or anyone else hasn't seen it https://www.corvetteforum.com/forums...s-of-pics.html

StraubTech

Nice detail in your thread.

leadfoot4

The UPS driver brought my Straub kit this morning. My plan is to do the swap either tomorrow or Saturday......however, the weather has been SO hot and humid the last several weeks, it's borderline unbearable. I was out in the garage for about 30-40 minutes, a little while ago, clearing the workbench and cleaning off the arbor press, getting the tools ready ready to do this job, and I was already breaking into a sweat.

leadfoot4

UPDATE...........

Heat be damned, I "got busy" today, removing the Comp trunnions and bearings, and installed the Straub trunnions and bushings. It turned out to be the classic "good news, bad news" situation.

The good news was that my Comp trunnions were in perfect condition, the "running surface" of them was smooth as glass. So, there was no "trash" in my engine. The bad news, so to speak, is that I just removed parts that were OK.

More good news, however, my initial observation is that the bushings are infinitely quieter than the needle bearings. Somewhere in other discussions on this topic, it was indicated that the blue Loctite used on the bolts, should set up overnight, before driving the car. I'm impatient, somewhat, and after installing the new parts, I stopped for lunch, then went back to install the valve covers, coil packs, hook up the plug wires, etc, so the Loctite had about 90 minutes, or so, to set.

Therefore, I just HAD to start the car first of all, to make sure I did everything correctly, and secondly, to see if the level of noise that the engine generated, had changed, and indeed it had. The valvetrain is now quite enough so I can hear the fuel injectors cycling. I let it run for just a minute or so, before shutting it down, but a road test is scheduled for tomorrow......

RonSSNova

What? Your Comp parts were ok?
Amazing.
internet wisdom would have us all believe they are junk......
I'm stunned.

leadfoot4

In the interest of honesty and fair play, however, I must add the following "facts" to the discussion. The Comp set-up in my car had maybe 4-4500 miles on it, has a stock LS1 cam/valve spring package, and doesn't get the living crap driven out of it. BUT, if the noise reduction I initially noticed remains for an extended period of time, I think it was worth the effort. There were times when I was embarrassed to start my car anywhere near a crowd, as the "sewing machine noise" was pretty loud, although not consistent.

LoneStarFRC

Both mine and Neutrons Comps WERE junk. Believe what you want.....

leadfoot4

What cam and valve springs were you running?

LoneStarFRC

I think the fact you still had OE springs, plus being low mileage played a big role in the current condition of your Comps you removed.
Comps design of having needle bearings riding directly on the trunnion shaft is a bad idea from the get-go. Even the OE GM design didn't do that.
Stronger aftermarket performance springs used by many many people seems to be an aggravating factor in turning their trunnions to trash more rapidly.
I also am not aware of ANY caution, limitation, or proviso from Comp regarding the use of stronger valve springs with their so-called "upgraded" rocker arm kits, so apparently they think they are fine with any spring.

LoneStarFRC

Cam is 224/246 .661 lift (.367 lobes w/1.8:1 RAs).
The springs are PAC 1208X duals. Pressures are 160 closed/482 open

leadfoot4

So, you ARE running a more radical cam, and stronger springs, that OE equipment. Not trying to start an argument, just getting the facts straight. You WOULD tend to think that Comp, a manufacturer of high performance parts, would take that into consideration, when designing and specing-out a replacement part, but it appears they didn't, or did get a bad batch of raw material.

One other thing to toss in the mix, would be the motor oil being used. I've been using the Mobil1 "high mileage" formula, 5W30 oil, the oil with the higher levels of ZDDP, for quite a while. Maybe that helped reduce the wear.

LoneStarFRC

The fact than I, and many many many others are running stronger springs and higher lift cams is no secret and the multi-page thread on this subject over at LS1tech (which I also participated in) is VERY revealing of the problem with Comp's so-called RA "upgrade".
If the Comp RAs are so great (except for higher spring pressures and/or higher lift cams) they need to SAY SO.
As I said, to date, I'm not aware of ANY restrictions vis-a-vis spring pressures being announced by Comp either now, or in the past.

You made a wise choice in getting rid of them.

leadfoot4

I certainly don't disagree with your comments, and if indeed, Comp didn't think of higher spring pressures being a problem, then yes, they're at fault. But let's look at it another way. Let's suppose it's not a design issue, but a bad batch of material. Back when I graduated high school, I had a summer job at a local GM Delco plant. I worked in the automatic machining area, where we had 5 spindle lathes, churning out thousands of electric motor shafts every day. These shafts started out as 10 foot long bars of round steel stock.

The Comp trunnions are approximately 1.5" in length. So, out of a 10 foot bar of steel, you could get, allowing for a little loss in the machining process, 78 trunnions. That's 7.5 sets of trunnions per bar. How many of the trunnions, or sets of trunnions, have turned up bad? All it would take, is 5-6 bars of substandard steel, to get out in the field, and the internet would be on fire....as it appears to be.

In the case of the machinery that I saw at the GM plant, 5-6 bars of steel, if they all went through the same automatic lathe, would be made into shafts in 2 hours or less. The other question would be, when were the bad sets made? Is it all from one time frame, or are they sprinkled out in a "one-sey, two-sey" fashion, over several years?

I'm NOT saying that Comp didn't drop the ball, just saying that there might be more to it, than a blanket condemnation of the product.



On a happier note, I took my car out for a "test ride" earlier today, and all seems to be well. I drove about 10 miles, and after backing into the garage, where any extraneous sounds will reverberate off the walls, I have to say that the car is much quieter than before.

billla

Every picture I've seen of galled trunions had an unusual wear pattern on them that - to me - indicated they were potentially not installed concentric with the rocker bore. To date, I haven't heard of any *failures* - just galling seen on disassembly.

Don't get me wrong - I agree there's some concern there, but I'm not sure it's as bad as represented in terms of the number of issues being seen and the scenarios associated with those issues.

Regardless, I guess we'll see as time rolls by.

Mike94ZLT1

Just ordered a set, along with the install kit from Summit and an Arbor press from Amazon. Thanks for the writeup!

LoneStarFRC

I installed mine back in the May-June timeframe. Initially, I also included the optional socket head cap screws that Chris offers with his kits, only to discover they were too long. The problem, I quickly realized, is that LS7s do not use a rocker stand because the RAs bolt directly to a boss on the heads. I just reused my OE LS7 bolts and all was well.

When Chris first offered the optional bolts, he didn't take that into consideration I guess, and assumed all LS engines use the same length bolt. One quick call to Tim (who was terrific) at Straub, and within a day or so, they had changed their website adding a "Notice" involving owners of LS7s and the need for a short bolt, that they also quickly began offering.

I sent my incorrect length bolts back for a full credit, including the nominal shipping costs.

That quick level of response and good customer service, speaks volumes about Chris and his team at Straub, to say nothing of the good product he's offering.
The installation was easy peazy Mike.

leadfoot4

I have to disagree.....I don't think that you can install the bearings "incorrectly", as they simply press into a recess that's part of the rocker arm. The trunnion then rides on these bearings, and there is enough "play", as observed by me, to accommodate any "off axis" rotation of the trunnion. What I think I see, is galling at one point of the trunnion, the point where the loading from the open valve spring would be at it's max rate. If I had to make an educated guess, I'd say that the trunnions weren't hardened correctly.

Secondly, if there was an issue with the rocker arms not being right, it would most certainly show up when installing the Straub bushings, as they have far less "slop" than the needle bearings do, so any inconsistencies would not allow the bushings to be installed. In doing the installation in my rocker arms, I did not see any occurrence of that.


To me, this also brings up another question. Roller rocker arms have been around for DECADES, without these issues, CompCams rockers included. Why, suddenly, are there this time of wear related failures, from a long time part supplier?

LoneStarFRC

Either that or the needle bearings themselves are of an inconsistent size, or both. Consistent size of needles is critical as only approx 8-10 (~) of them on the bottom side take the main load as the rocker moves back and forth in it's arc. If even ONE or TWO needle(s) is slightly larger than the rest, then IT/THEY takes the concentrated load, directly onto a VERY small area of the trunnion.


The roller rockers you speak of from Comp, Crane, Harland Sharp, etc are designed from the ground up with dedicated trunnions and bearings. These Comp "upgrade" units are designed as a retrofit and to be user installed. It's entirely possible Comp has been the victim of some VERY poor QC issues, or even counterfeit/fake Chinese suppliers parts.
I don't know for sure, but either way it's THEIR problem, NOT the customers (except of course for being the victims of shoddy quality/design).

The OE GM RAs are actually a very strong design, with very little weight over the nose (where it's critical). Had they not experienced build/quality issues in the past with needles being puked out into engines, I think it probable that neither Comp, nor anyone else, would have come out with an "upgrade" kit.
As it stands now, I think that Straub and CHE (although more expensive since they are not designed to be user-installed) are the two best retrofit designs out there for the many people that don't want, or can't afford, the much more expensive full roller rockers.