Rocker Arms and Shafts- Wear Condition

[KTL]

All,

Please take a look at these and rate them for wear condition. I'm planning to rebush and rotate rocker shafts. The bigger question is how'd they get this bad?











Plan is to return to using the larger, original cam oil line fittings. But by the looks of the bushings and shafts, the splash-oiling holes in the rocker shafts aren't doing a very good job. Or my cam spray bars are plugged with some debris?

Thanks,

[afterburn 549]

spray tubes in upside dwn ??

[SP2]

Wow, that looks really bad. I took mine out of my SC at 95k miles and they looked pristine compared to that. Looks like no oil. I agree with the question are the spray tubes located properly. Or are they clogged? Was each cylinder bank like that, or just one side, or just one rocker pair. The spray tubes are not symmetrical, so you can put them in backwards and they will not line up properly. There a there 2 little holes that spray the cam lobes and one that sprays the rocker. How did your cams look? Or are the little oil lines that go to the cam tensioners, that then feed into the spray bars, clogged? Good luck.

[Jeff Alton]

I am just thinking out loud so bear with me..... The smaller orfice in the fitting to the cam tower is THE replacement part. As in, the original large orfice part has been superseeded. So, that leads me to believe that particular part is not the problem. Mind you, I have only torn one motor down that had this part in it for any significant mileage and it showed no wear in this area. Small sampling pool, hardly conclusive....

My guess is there is a problem somewhere else. Plugges spray bars? Could be.

Is this the first time this motor has been apart?
If it was rebuilt earlier, what sort of assemble lube was used?
It looks from the pics like the scoring was not a continuous event, but happened for a short period. Either that or some debris was caught in there and never worked itself out... But it is hard to tell from the pics.

Do they all look like that?

As for reconditioning... I would get the shafts polished and then send them along with your rockers to get rebushed back to the stock clearance. I use camgrinder for this.

If they all look like that, and the motor has been apart before, I would also suspect the assembly techinique.

If it has not been apart it looks like debris got in there and that may or may not be from the oil line orfice. If it was a lack of oil I would expect to see less scoring and more heat and consitent wear marks.

Cheers

[KTL]

The above are pictures from only cylinders #2 and #3. I still have eight more rockers to remove and look at.

I don't believe my motor has been apart before. The spray bars and the rocker shafts appear to be in their original installed position. I haven't looked very closely at the spray bars yet. But I don't recall getting the impression the plugs for the bars looked like they have been replaced.

I would think if the rockers had been R&R'd before, that you'd see two ridges on each end of the shaft since it's probably hard to get the shaft back in, at exactly the same lateral position as it was before removal. But, who's to say the shafts couldn't have been previously replaced altogether?

More pictures to follow.

[dion914-6]

I had two rockers and shafts look like that after missing a shift at Mid-Ohio a few years back. But mine also loosened the shaft to the point that it started backing themnelves out and caused an oil leak. I fixed that problem, decided to run it the next weekend at Nelson's Ledges where the issues returned. Once I tore into the engine, your pictures are exactly what I found.

Not saying it's the same thing, just relaying my experience.

Dion

[Jay Auskin]

My 3.2L had similar wear (~125K miles). Just not as ugly as KTL. I do have noticeable "ridges" in the shafts, even when no scoring is evident. There is no way they can be polished and used again. The spec for a shaft is 17.996mm-18.00mm. Yes, that's .004mm, or .000157 inches. Yes, there might be acceptable "wear" limits, but it's hard to justify putting it back in.

Oh yeah, the pics...I dunno Kev, we must drive too fast. These are the worst, and others aren't as scratched, but have wear "ridges"

[afterburn 549]

It has to be lack of lubrication

[KTL]

It's apparently a combination of things. Lack of lubrication, yes. The only thing I can think of is poor oil change history and/or poor oil selection because the cams tubes are in the right position

Also lack of proper installation. I've found some other things in the timing system installation that are not good. Right bank had the cam sprocket installed backwards (dish facing out instead of in)with one less shim than typical. I'm guessing if I were to check the sprockets, they wouldn't be within allowable measurements for parallelism.

Cams have some issues that are not good. #3 exhaust lobe has a hole at the apex of the lobe, #5 lobe has some edge chipping.

The saga continues..............

[cstreit]

Yikes dude, that's a little freeky.

I'm wondering how much of an aligment offset that causes. It's one thing to replace your sprokets, chains, etc.. But I'd hate for you to have to replace the layshaft sprocket as well.

[KTL]

Originally posted by cstreit
Yikes dude, that's a little freeky.

I'm wondering how much of an aligment offset that causes. It's one thing to replace your sprokets, chains, etc.. But I'd hate for you to have to replace the layshaft sprocket as well.

How funny that my gruppeb topic is titled "Yikes" eh?

My engine has always been a little grumbly and I just assumed (totally baseless wild assumption) that the layshaft bearings could be suspect. After finding this stuff, i'm tending to think my grumblings have been due to this? If nothing else, it proves these engines are pretty tough and well designed to be running strong with well worn rockers, shafts and possibly misaligned right bank.

[SP2]

Dude, who put that engine together before? One sprocket faces in and the other side out. Good thing you took this apart. Whoever did it did not check sprocket depth.

[KTL]

I have no idea. I bought it from a dope in 2000 and it's been running strong ever since. Covered 20K miles with it and nothing major has gone wrong with it. Last 2 years of driving it hard at DE events and no problems other than an increase in oil usage at mid-year this past season. Probably valve guides (wild guess) and not a major concern yet since usage is still within reasonable consumption

Only reason I discovered this is because I am taking apart the left bank for a cam housing/chain box leak. I first discovered the rockers and shafts being badly worn, so I then decided to take the cam out. After seeing the bad wear on the left side, I decided to move to the right side. It was yesterday afternoon that I finally got to the right side and found the backwards cam sprocket and -1 shim condition.

I'm hoping to take the rocker assemblies and cams out of the right side tonight and see what else i'm up against. Funny thing is I could probably put this back together and not really suffer much at all. I think it's a testament to these engines that they can run strong and not self-destruct when worn and not assembled 100% correct. But who's to say I didn't catch the imminent self destruction just in time? Whatever the case, i'll get it back together better than it came apart.

[KTL]

Additional pictures of camshaft defects below. Not sure how bad these are. I'll point camgrinder in the direction of this topic and see what he thinks.

Craig Garrett brought up a good point that these defects are quite likely to be from before I owned the car. Because i've never seen any sizeable chips on either of my drain plugs during oil changes.

[camgrinder]

Originally posted by KTL
It's apparently a combination of things. Lack of lubrication, yes. The only thing I can think of is poor oil change history and/or poor oil selection because the cams tubes are in the right position

I agree with this idea.

The cams look serviceable. And should take the 964 profile.