KAmey1970

After advice (see "Looking for mechanic" post) I've decided to try DIY my new 1983.

After a week of owning the car a strange "clacking" noise has appeared near the fan. I don't own a stethoscope and feel a bit nervous using one with the car running.

The sound appears it comes from near the belts, possibly towards the left side of the engine?

To help describe the noise, it sounds almost as if it is a deisel engine.

As I have admitted before I am a mechanical moron, so any advice as to what this may be will be greatly appreciated.

I am learing as I go along!

Kevin

Flint

Clacking? Mettallic sounding? Maybe more of a rattling? When you say "left" do you mean as you face the engine, i.e. "driver's side"? Do all the belts look okay (not twitching or vibrating strangely)? Is it dependent on engine speed?

If you agree with any of the above statements: don't drive it anywhere, it's probably the waterpump. I can describe in obscene detail the sounds your engine will make if the WP goes out while in interstate traffic and you can't safely pull off fast enough.

Don't mean to scare you...that's worst case scenario.

KAmey1970

I would describe it as a "diesel engine" clack. It would be more on the passenger side, best that I can tell. I will take a better look at the belts when I get a chance and get back to you.

Searching the boards, I saw something about timing belt tensioner busing my be gone. Does this sound reasonable?

Garth S

Do you have an air pumo on the right (passenger) side?
With the engine running, avoiding the belts, use a hose/wood dowel/long screwdriver to 'listen' to such things - and you may pin it down.

KAmey1970

Ok, just got back from running the car. Definitely (best I can tell) is coming from the front of the engine, just behind the fan, where all the belts and flywheel meet.
The best I can describe the sound is as if it was a diesel engine. The sound does change with rpms, but I cannot hear the sound above 2500 rpms because of the sound of the engine. I do not know if it is gone, or just muffled.
Any thoughts?

pewter82

Might be the smog pump going bad, my 82 had the same type of sound.

Garth S

With the latest info, our comments on the air/smog pump are likely incorrect. The area you describe is the water pump - hidden behind the cover. If you have 'stethoscoped' each accessory (AC, air pump, PS, & Alt), then try the center cover.
Remove the air tubes, and view the timing belt through the top vents:if there are any indications of chaffing of the belt edges, it is time to disconnect the battery ....
Under the covers, the tension roller carrier arm bushings could be worn - and the lateral flopping around could be contacting the cover. The water pump could be going, etc - very hard to call, but from the location specified, it would be wise to check the timing belt condition.
BTW, are all the V-belts tracking OK? - or is there any wobble at the multi groove pulley?

pewter82

I stand corrected. I'll be quiet now.

KAmey1970

Ok, it is definitely on the left hand side. I put a long screw driver on it, the middle and right side of the cover.

I took off the left hand side of the cover. The belt did not sit uniformly around the flywheel. Instead, it was what I would call cockeyed. The top of the belt felt tight, but the bottom seemed very loose.

Maybe just readjust the tension?

This is my first real "repair" on the car. Gulp....I don't want it to be a complete WP and TB.

Kevin

KAmey1970

I found this searching the forums:

Reason: My '83 had almost exactly the symptoms you describe, but I could tell the knack-knack was coming from the front of the engine. I discovered the cause was the timing belt assembly. Specifically, the tensioner rides on a small plastic/nylon bushing. The bushing had disintegrated, causing the tensioner to skew off-center slightly, the belt to run off-center in the area around the tensioner, and apparently (I'm guessing) allowing the tensioner to move under cyclic variations in tension and cause the knack-knack sound.

The early bushings are quite thin and disintegrate easily. I did the regular WP/TB replacement when I discovered the problem and at the same time upgraded to the next version of the tensioner arm ('87?) that has a much thicker bushing to solve this problem. This tensioner arm is otherwise backward compatible and no other changes (save perhaps the tensioner mounting bolt) are required. FYI, there is even one later version of the arm where the tensioner roller is positioned to be in the centerline of the bushing (to prevent skew forces) but that upgrade also requires other changes (you can do a search on the list to find out more).





Does this make sense? Does this mean a complete TB and WP replace?

docmirror

Okay, take things easy, and lets diagnose before getting too involved. Clacking noise, ocming from front, partially left side of engine. The first indication is either belts or fans. You've given other info about taking off a cover and "it not fit uniformly around the flywheel".

Let's stop here. You don't have a flywheel on your car. The flywheel on cars is located at the back of the engine where it attaches to the output to the trans on a 5 speed. I don't know what cover you took off, but I'm going to assume it's the timing belt cover on the upper left side. We will need more accurate info to help you diagnose FIRST, then fix. You have the shop manuals on your computer, while we diagnose, you start reading. Read up on the alternator, power steering, AC, and smog pump belt exchange.

Your car can run without any of these belts on for a short time. If you take them ALL off you will be able to eliminate the possiblity of an aux belt causing the noise. The good news is, that if your timing belt fails, best infromation is that you have a NON-INTERFERENCE engine. That means, if your timing belt breaks, the valves will not crash into the pistons. This isn't a guarantee, but it's the best information I have at the time.

So, take off all the aux belts on the engine. Pay attention to the order they go on, and mark the belts if you are uncertain about the origin. The Porsche uses a somewhat complex tensioning system for some of the belts using a tension shaft screw and nut. The engine will start and run, but the AC, fan, PS, and alternator won't work. This means you will loose the charge in your battery after a while. Don't run it too long. Is the noise still there?

If yes, it's going to be a bit of work to pin it down. Leave all the belts off, and take off both upper timing covers. You will want to remove the snorkels from the front air dam, to the air filter. Now, get the timing covers off. Investigate the drive to the distributor, on the left side. Investigate the timing belt, and the gears. Take some photos of things while visible, and post here. We'll have another look then.

If the noise is gone with the aux belts off, put the innermost belt on and test. Then proceed outward one belt at a time and retest. The noise will come back when you have attached the belt that causes it.

It's very early to speculate, but common causes are; Timing belt and gears, distributor drive setup, and water pump. The TB WP job isn't too bad. If you put your location in your signature, we'll know where you are, and someone might be able to come by and assist or have a look with you.

Info we need; Timing belt light on when key is on, engine off? Timing belt light on when engine is running? Any guages read funny? Some photos of the timing belt, gears, dist drive.

Hang in there.

KAmey1970

Sorry about using the turn "flywheel," what I meant was sprocket.

I took off the left cover and peered at the tensioner arm which is definitely moving back and forth with the sound of the clack. It appears as if the bushings are completely gone. I will try to get some pictures together for you guys.

I appreciate all the help. I owned a 914 before this and found a very knowledgable person to help with repairs. ( He rebuilt some calipers for me) He said my 918 was a "money pit." That may or may not be true, but I think with help like I have been getting on this forum, that I may be able to save some money on repairs.

I ordered the bushings from 928intl as well as the owners manual.

Thanks again everyone.

I'll keep you informed.

KAmey1970

I typed 918 instead of 928, blame the screwdrivers! And not the philips head type!

docmirror

AAARrrrrrgggghhhh..... SIT in your car. Raise your LEFT hand. This is the LEFT side of the car! Always! I don't care if you're from UK, Japan, etc. The left side of the car, is the side where the distributor drive is.

So, you now have a sound from the RIGHT side of the car, after having removed the RIGHT side timing cover. Yes, I know it's on your left, when bent over the engine. But in reference to sitting in the driver's seat, this is the right side of the car. So, the tensioner you see near the bottom of the cover is moving in time with the clack? Then it looks like your tensioner is toast. Not a super hard job to do. Here's the thing. WYAIT(while you are in there, or while you are at it), you should inspect the entire belt system, as it is very important, and a known weak area of the car. You should plan on replacing the belt, as well as upgrading the tensioner(WP too?) to the later style.

Do you know the history of the car's maint? When was the last TB service done? Did the tensioner get rebuilt? Later tomorrow, several of the cognscenti will speak up with the advice on the work needed, that have been in your situation. I have done a TB job, on a 1990 car, and it's about a 10-14 hour job for a novice, including tensioner work, but not water pump. As you get more comfortable with the job it can be done in less than 4 hours.

Do a rennlist search in the 928 group for tenisoner rebuild, probably lots of hits on that. Edit your signature to tell us your approx location please.

docmirror

BBBBuuuummp. Anyone confirm this on the 83 possible tensioner issue? Refurb/upgrade options for him?

Thanks,