OK, I've been posting about the process of the top end rebuild on my L98 over the past weeks, including new 1.6 RR. Today I got it fired up, and timed and it was a touch rough but not too bad. I was running mostly today in the 800-1500 rpm range while I check for issues. I didn't have any noticeable tapping from the valve train just a problematic air pump.

This afternoon I took the time to drain the temporary coolant and top off the system with distilled and antifreeze. I toke it for a short ride around the neighborhood, sounded fine, even out on the main road accelerating to about 2400 rpm, seemed fine. Turned it off and after about 15 minutes went to get some gas in the car and about 3 minutes into the 10 minute drive I had a fairly loud tapping

Car is hot now so I didn't do anything, it sure sounds as if the noise comes from the driver side valve cover. What are the typical things that could have happened?

Would a rocker nut have backed off the stud?????
These are self aligning, could they get out of alignment????
Could it be related to a lifter issue?? Seems less likely.
The stock valve covers are tight with the new rockers, could that be an issue??? I think that would have been immediate.

Just tossing out ideas, I've got to pull the air pump anyway, so I guess we'll get a look at the valve train to see.

Any idea of what to check and look for are appreciated.

 

Pull the cover an take a look.
If a rocker poly lock is loose it will spin by hand.
If the rocker stud is loose both the poly lock and the stud both will spin as one by hand......usually the pushrod will have jumped out of the rocker's seat and will be flopping around if this has happened.
Inspect the inside of the valve cover for marks/scuffs from the rockers. look at the rockers also. Let us know what you find.

 

OK, I said I wouldn't work on it this evening but I couldn't help myself. So I got the valve cover up just enough to notice that the rocker for the intake on #3 was loose, I could rattle it back and forth!!!!!

So I guess I will recheck all those on this side since I'll have it off. God why couldn't it be a bit easier to get the valve covers off! With the injector harness, and other rap it a rocket science to get them off!

I wonder if an after market set would be any easier? Oh well I'll get back after it tomorrow night I guess.

 

I'm kicking myself for not spending the xtra cash and getting 2 piece VCs. Don't know what I was thinking - that I don't make mistakes, or RRs don't come loose. How stupid is that? After one just backed off recently, I now think it ruined the lifter (or a vice-versa thing), cause there is some slight ticking back which was gone after readjustment, but the vehicle is running fine aside from that. The rocker will either loosen, the sound get worse (and the lifter collapse - worst case scenario), or I'll get by this summer and swap in lifters when I change intakes. In any event, 2 piece covers would lessen the burden, and I urge any of you with RRs to get the 2 piece VCs if you can....

 

Just to be safe, you might want to recheck all 16. If one was loose, there might be more, even on the opposite bank. Easier to check now in the garage than stranded at night on the side of the road 200 miles from home.

 

I hear you, and may do that over the next week or so. I guess I do have one critical question though, Why are rollers more difficult to keep on properly? The nuts that came with mine have the set screw in the middle that you run down onto the stud to lock everything in place, heck the stock nuts have nothing! Seems a bit backwards to me that these are the ones that have more issues.

Had I know this, I think I could have been talked into saving a couple buck and used a stamped roller tip rocker, even giving up a bit on the performance side.

 

Are you sure it's the rocker causing the sound? Could you undo the nut with your fingers? If the lifter is on the base circle of the lobe, that rocker will feel pretty loose from side-to-side even when properly adjusted. You should not be able to move it up or down at all, but side-to-side, yes.

I put a couple drops of blue loctite on my set screws to keep them from backing out as added insurance.

 

Does anyone make a 2 piece cover for a centerbolt type cover???? Not sure how that would work?

 

I'm not sure of anything yet, could only get the cover loose last night, got to remove it tonight.

As for the loctite, that sounds like a great idea.

 

Loose feeling rocker is not the same thing as a jam nut or rocker stud being loose. Rockers can seem loose depending on there position on the cam lobes. Remember the lifters work with a cushion of oil in them so they may seem loose but they may still be adjusted properly....assuming they were done correctly the first time you adjusted them...you don't want to go tightening them up again.

Sorry for the confusion but the advice I gave was to check to see if the lock nuts or studs were loose or if anything was hitting the valve covers. Hope this helps.

 

It's all good things to check, my post is still a bit early as I didn't have time to get the cover up and off completely. I hope tonight I can see what I've really got going on.

 

Another common cause is to have installed the rocker arm wrong. the flat side of the trunnion has to face UP.

You should also check the underside of the rocker arms to make sure that has been NO contact with the valve spring RETAINER. If there's been any contact anywhere there should be witness marks, usually on the valve cover or the rocker arm itself.

Jake

West Point ROCKS!

 

I made sure of the flat side of the trunnion, so I would be surprised if it were that, but I'll double check that when I get it open. I figure I'm getting that tapping noise from something and so I should see a mark on something from where it has hit.

 

OK, got the valve cover off and found my thought was right #3 intake was very loose, the nut had backed off from the trunnion. Push rod checked out OK, rocker looked fine.

It looks like potentially what is a problem help, I think the vavle covers with these rockers is very close on clearance and potentially maybe even hitting just a bit. I've included a couple pics for you review.

Now I did some grinding before install to remove drip tabs and even ground a bit of material from the center posts you'll see. but there are a couple marks above where the drip tabs were that I can't remeber if I did during the grinding or not.



In the photo above I think you can see where the nut backed off of #3 intake and left a slight mark just above the drip tab.



So I've installed the rocker and readjusted, then went and snugged a bit more on all the others on that back for safe keeping.

But I don't think I'm going to install these covers, I think I'm going to pick up some aftermarket covers that maybe are 1/8 taller or so just for insurance. If I throw these back on and I've got issue with them just rubbing I'm asking for trouble, and that will **** me off.

Not to mention but with one on and off the paint job that I worked too hard on looks like crap already!

Anyone that can offer a recommendation on a cover that is very close in size, chrome or polished preferred that doesn't break the bank?

More to come!

UPDATE

I had a chance to measure the covers and the center post are 3" to the inside top of the cover, then I put the tape measure between the rockers on the seat for the post and the highest point is the poly nut at about 2 5/8" so I think there is enough room after all, I guess I was just frustrated! I think I'll put loctite on these and then button up this side for now and see how things are.

 

A few years ago when I switched to rollers, I did not tighten the set screws sufficiently. (My first time.) I had lifters come out, one rod bend, and rockers come completely off so that they were laying on their side under the cover. The engine didn't actually stop until an exhaust valve rocker came loose (my guess). Anyway, I put it all back together and it has been just fine and has done something like 10 track days. I only replaced the bent rod. All to say that these parts are very rugged.

The second time I set the set screws, I SET THE SET SCREWS. They make a little EECK sound when you take them that last bit. Some people turn the set screw and nut together the final 1/8th (I think, but maybe 1/4) to make them tight. I also used locktite. Anyway, I'm sure that you will be OK and I am confident that there is no way that you damaged a lifter. Other than the bent rod, there was some dimpling on the bottom of a few aluminum roller rockers. Again, I've done about 10 track days and 1,000s of miles of regular driving since then.

It was really odd. I drove for a week in advance and the 150 miles to Laguna Seca (Mazda) and everything was fine, but on the first track lap, the first rocker came loose. I decided to see if I could get into AAA+ range (100 miles) because it wasn't getting any worse, but about 25 miles later the engine just stopped.

 

One additional safety check I'm going to do is I'm going to make a quick plastic template of the inside contour of the cover and check the position of the rockers to be sure there is enough room before closing it up. If not then I can decide on a little grinding or replacement as needed.

 

OK, I did make the template and the covers looked like they would be OK, but could be close, while I have the one off I took the drip tabs down totally flush to make sure.

I reinstalled #3 intake and adjusted, checked the entire driver side bank and all others looked good. I did drop a dab of thread lock onto each one for a little insurance, then closed it up.

Cranked it up and all quiet, in fact it is running pretty smooth over all, thanks for the help all!

 

Be sure to pay attention to valve train noise. A member on the CamaroZ28 forum has been complaining about valve train noise and has tried all sorts of things trying to track down the cause. He's changed valve springs, pushrods, rocker arms, etc. with no success.

Yesterday he posted photos of a broken rocker stud! Seems the noise was trying to tell him something.

Jake

West Point ROCKS!

 

Yeah, I'm taking it easy on running it thus far, and I'm prepared that potentially I could have to open the passenger side to recheck those rockers, but I'm hoping it is all good for now, sure sounds like its all good.