Clicking Exhaust Valve - Alfa Romeo Bulletin Board & Forums
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post #1 of 26 (permalink) Old 11-08-2004, 09:19 PM Thread Starter
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Clicking Exhaust Valve

I've tried every suggestion here on the forum regarding other's complaints of a clicking valve. I have a '91 Spider, which is supposedly notorius for having noisy valves. I've changed to Castrol 20w/50, Marvel Mystery Oil, tightened everything up, including the exhaust manifold. Repaired a hole in the muffler. No leaks as far as I can tell.

The other valves sound nice and smooth - a smooth purring sound comes from the engine, regular slight noises associated with an engine. I tried a long handled screw driver to my ear, ran it along the cam cover, but heard nothing. But standing near the exhaust side, or even ten feet away, I can hear a clicking sound - cold or warmed up. It almost sounds as if it is just one valve.

Car is at 57K. I have no reason to believe this car was not meticulously maintained by the PO - I just bought it, BTW. I've heard from others that adjusting valves may or may not cure it and probably won't - I have yet to adjust them and am sort of afraid to do so as there seems so much discrepancy about how to actually perform the job (and I'd rather not pay a mechanic as I've done valve adjustments before on other vehicles). I understand that the Cardisc is not shadetree mechanic friendly on the matter.

Anyone care to offer their two cents?
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post #2 of 26 (permalink) Old 11-09-2004, 03:23 AM
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Of course you should do the valve adjustment, that is the only way to make the noise go away (if it in fact is an out of spec. valve).
No black magic and certainly not difficult, takes a little time the first time around though.

Just out of interest, what kind of arguments have you heard against adjusting the valve shims?

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post #3 of 26 (permalink) Old 11-09-2004, 09:31 AM Thread Starter
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Big Swede -

It's not that I'm opposed to doing a valve adjustment - just that if you search through the forms there is a lot of disagreement about how the valve adjustment should be done - for example, one post will say "do it this way" and another post will say, "no, do not do it that way or you'll trash your engine".

I say that with no offense to anyone - I understand there are different engines and ways of doing things.

And some who adjusted their valves said the clicking did not go away. Regardless, I want to adjust them, if I only understand the job completely and how to do it correctly. I really need some newbie friendly instructions because I'm not all that familiar with my engine yet.
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post #4 of 26 (permalink) Old 11-09-2004, 12:23 PM
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The first thing you should do is to pull the valve cover and check the valve clearances. This will also give you the opportunity to check the cam lobes and followers for wear, which could also cause a similar noise.

If the valves are within spec (.19/.21) but the noise is still excessive you can go ahead and adjust them to .17/.19, which was factory spec for earlier 2 liter motors. This won't hurt anything and may quiet them down a bit.

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post #5 of 26 (permalink) Old 11-09-2004, 12:34 PM Thread Starter
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Joe -

So once I get the cam cover off, how do I turn the engine over by hand, and how do I find the timing marks? I assume I need to do both to be able to check the valves - that is, I don't know the correct procedure to get the valves where I want them.

So does .19/.21 refer to intake/exhaust, respectively?

And how do I check cam lobes for wear?

And incidentally, do I have to readjust timing and the timing chain after adjusting valves?

Thanks again for all your help - I just called my local Alfa place and they said it was 4 hours labor to adjust the valves. It sounds like it should only take about an hour once I know how to do it.
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post #6 of 26 (permalink) Old 11-09-2004, 04:36 PM
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I don't get it, how many ways can there be? measure, remove the cams and replace the shim...

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post #7 of 26 (permalink) Old 11-09-2004, 04:42 PM
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To measure the clearance you will need the heel of the cam (opposite the pointed lobe) to face the follower. At any given time, only a few will be in this position. So, the procedure is to pull the cam cover, measure the clearances you can, write them down, and turn the motor over to a position where you can measure the other clearances. The easiest way to turn the motor over by hand is to push the car forward in 5th gear.

If you need to adjust a clearance, you will need to remove the cam(s) and check the size shim you currently have, then calculate to get the correct clearance. This link makes it all very easy:

http://www.alfacentro.com/features/valve/index.html
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post #8 of 26 (permalink) Old 11-09-2004, 04:49 PM Thread Starter
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Did BigSwede have a bad day?

Maybe you should write a book - your instructions are so thorough. Man, I'm going to go out to my car right now and "measure, remove the cams and replace the shim"

Not only are you of no help whatsoever, you went out of your way to try and insult me. That's pretty lame.
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post #9 of 26 (permalink) Old 11-09-2004, 06:51 PM Thread Starter
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Joe - Thanks for the response -

So just so I'm crystal clear - do the lobes have to be pointing exactly straight up, or just at any point so they are not touching the followers (are those what limit the valves movement?). Also, I'll assume that when the lobe is not touching the valve or follower that I'm to take my measurement at that point, which should be .019/.021. Correct?

Then advance the car in fifth gear until the other lobes arent touching, then take my measurements. Right?

And to get to the shims, I remove the cam (only if the measurements aren't right) - I guess I'll need a special tool to measure the shims. I guess what threw me off in my head is the idea of those shims being the things that establish the clearance, rather than a rocker arm or something.

Ok, that sounds pretty easy the way you explained it, thanks - I'll check those and then figure out if anything is off.
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post #10 of 26 (permalink) Old 11-09-2004, 07:19 PM
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There's a couple of pics in this thread that show a cam removed. Note that the cam chain does NOT leave the cam sprocket at any time. This is mandatory in order to maintain proper cam timing. I can talk a whole LOT faster than type so I PMd you my numbers. Give a call if you need to.

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post #11 of 26 (permalink) Old 11-09-2004, 07:23 PM
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Just curious--has anyone ever tried turning the engine over (on a non-posi rear end car anyway) by jacking up the drive wheel and turning that while the car is in gear? Seems easier than pushing the car around, especially if you have a driveway like mine that's gravel and uneven. I've been meaning to try it but haven't had the opportunity yet.

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post #12 of 26 (permalink) Old 11-09-2004, 07:47 PM
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Quote:
Originally Posted by Farace
Just curious--has anyone ever tried turning the engine over (on a non-posi rear end car anyway) by jacking up the drive wheel and turning that while the car is in gear?
Works fine, just keep one rear wheel touching the ground and you can turn the engine over that way.

ocduff -

Sounds like you've got the right idea. You'll need some feeler gauges to check the clearances. If Papa's helping you out you're in good hands for sure. The job is not bad at all, just take your time and work carefully and you might just enjoy it.

Joe
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post #13 of 26 (permalink) Old 11-09-2004, 07:57 PM
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I'm not taking any side here but I see Big Swede's point. You seem to be a novice in the OHC department, working without a shop manual for reference, yet your going to attempt to adjust one of the engines most critical assemblies.

You can slip a feeler gauge under the cam lobes but what then?
Do you know the procedure for splitting the timing chain? What position the crankshaft must be in to do so? That the camshafts must be removed to remove the cam followers,to get to the shims? That a micrometer is needed to measure shim thickness?

I'm not questioning your ability to do the work; I'm questioning your knowledge of what it entails.

It would behoove you to buy a shop manual before tackling any valve adjustment. I'm sure you'll consider it money well spent.

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Last edited by GTD; 11-09-2004 at 08:10 PM.
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post #14 of 26 (permalink) Old 11-09-2004, 08:23 PM Thread Starter
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GTD - I think I must have misread Big Swede's post if you think he was suggesting what you are suggesting, which is basically the point I was trying to make - I don't know what this job entails.

I guess everyone here has been a big help - basically, I just wanted to know the job before I tackled it. And I did buy the car to educate myself - I like working on it. And hey, even if I had the $$$ I wouldn't be in a rush to take it to a shop. I'd like to learn how these beautiful cars work.

I have all the tools and I've never screwed up a job yet - but it looks like I will need the shop manual. I think it's time to break down and buy the cardisc manual

And Papajam - thanks for the offer to help me out. You know, it is the quality of information and willingness of help that I decided to buy my car. I will be giving you a call when I have all the knowledge I need to do this job.
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post #15 of 26 (permalink) Old 11-09-2004, 08:28 PM
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Wise decision!

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