928ntslow

I have had the cam covers off a few time and have not seen anything to indicate there is a cam problem. Not that I was looking for anything, but I have looked and nothing jumped out at me. Easy enough to check it again. However, based on the previously info, a broken cam would not change in sound the way this has. The sounds would/should be constant.

It is very possible that the oil might be the issue and is easily enough changed.

BTW, when I get the cover off, how do I check chain tension and tighten if needed? I looked in the WSM and couldn't find anything more than torquing to spec which is the tensioner itself to the head.

Tom. M

make sure you check the bolts holding the cam chain tensioner down to the head and also check the oil feed line to the tensioner. Maybe pull it (it's a banjo style) and clean it..maybe even pull the tensioner and clean it too...perhaps a clogged passage doesn't let oil get to it until it exceeds a certain pressure...

BTW>.when you crank over the engine..the cam chain tensioner should pump up as the cams rotate...it will be obvious.

AO

The cam chain tension is self adjusting. You might, however, want to put a mirror under the lower pad to check it's condition as this is the one that wears the most on the Driver's side head. Just ask BigDave what a failed tensioner does to the head...

928ntslow

Yes, just checked the WSM again and realized the tensioners are self adjusting. There is a check valve noted in the same text that I have heard can become clogged.

Me thinks the most logical thing to do is try some different oil. This is the first time I have used the Rotella T. It could be that simple. may as well try before I get too deep.

Thanks...will report back.

Sailmed

Once upon a time in the land of newbies.....
I owned a Harley dealership and had a customer call...

"My new bike is making noise"

"Well, what does it sound like"

Now this was back in the dinosaur era - you know - pre cell phone....

He rode to a pay phone, called me up, placed the receiver next to the bike...

and said....

"here - listen to this"

Like Duh....... I think thats the special re-entry modifier... bring it to us and let us take a listen to be sure!

928ntslow

Great analogy Mike and worth a laugh, but this is a bit more descriptive. Others have experienced the same issues and when you are on an internet forum, the best one can do is describe what they hear. Many issues have been resolved in this forum in this very same manner. Additionally, many of us work on these cars ourselves and are knowledgeable enough to know where to begin with any particular issue. Hard to compare calling the dealer with no knowledge of what you have.

Thanks for sharing!

Sailmed

Thats all it was for my friend
I know how frustrating it can be to chase down noises. I have received many a look - like I had a third eye or something - when I take the longest screwdriver I own, and while placing the handle against my ear - and the working end upon various portions of the car - search out the source of the noise. It works wonders.
I might suggest you head out to the drugstore - buy a cheap stethescope - remove the bellows end and replace it with a rod - makes for the nicest piece of equipment you will find - and looks a bit more professional when shoving a screwdriver in your ear.
Just sayin.....

Leon Speed

This might be of some help..it's fun to read anyhow...http://www.remanufactured.com/Engine...gnosis_101.htm

928ntslow

Andrew...KISSES!!!

I drained the Rotella T, which looked like water coming out, with my old standby Mobil 1 15W50. "Noise" be gone! 5 bars at idle now.

I used the Rotella T as I have seen it suggested on R'list before and others seem to like it...and it's cheap. Didn't work for my application as it appears. Sometimes, the last thing you can think of is the most obvious...which has to be pointed out by others.

Thanks to all else for their input. ISSUE RESOLVED.

Now onto the next thread as I have a couple of other issues with this car to deal with.

Mrmerlin

nothing like thicker oil, glad it was an easy FIX, keep em flying

AO

Kewl!

PorKen

Weird! Cool though. That was a nasty noise.

I recently switched from Rotella to M1 10W40, because of cost, but I didn't notice much of a difference.

928ntslow

UPDATE: As nice of a thought that it was, the noise came back. I didn't bother to add to this thread because I wanted to find out EXACTLY what the hell it was. Using heavier weight oil delayed the noise so that after the motor reached operating temps, the tick/clack had returned.

SO....I contacted Greg Brown at Precision Motorwerks in Anaheim as he has probably seen just about every possible issue that a 928 has experienced. Greg was nice enough to take the time to respond to my concern. He suspected that since this was an 85 car, the engine may be a very early 85 engine. I gave him the engine number and he said he would look it up. Turns out it was an early engine and there was an inherent issue with the chain tensioner that a TECH BULLETIN was sent out and replacement parts available.

What the dealio was is that the chain tensioners are spring loaded with oil pumped through them. Apparently, the original "displacement vent plate" sitting atop the spring would shift in time, not allowing oil pressure within the tensioner to be maintained. The part would not seat properly and allow oil to bypass this part and just leak out the top of the tensioner. No big deal except that it would make lot's of noise. Porsche produced a replacement part noted as a "Spring Guide" which sits on top of the spring and will not shift.

This was a fantastically easy fix when speaking of 928's. Fortunately, Greg had a pair at his shop so he shipped them off to me. The biggest issue (which I didn't have) is removing the cam covers as they use the old style bolts which thread into fittings. I have had my covers off a few times, so I knew I wouldn't have this issue of the fittings screwing off with the bolts.

Anyway, Greg suggested stuffing shop towels underneath the cam to block the oil galley just in case a crush washer decided to make a run for it when disconnecting the chain tensioner oil line fittings. They're aluminum, so a magnet won't help. Fortunately, I was careful and didn't drop one. After the banjo and check valve bolts are removed, there are two allen head bolts holding on the chain tensioner. You can zip tie or just hold the tensioner together as you compress and slip it out from the chain loop.

Pull the top off and remove the old vent plate and place the retainer on top of the spring and stuff it back in between the chain loop. The actual time it took to do this after the cam covers were off was about 10 minutes for both sides.

Needless to say, that bothering, embarrassing, continual pissing me off ticking/clacking sound is just a memory. I do hope that if anyone else with an early 85 engine stumbles across this thread and is able to make the fix.

Below is the Technical Bulletin and the pic of the chain tensioner with the old and new parts. The little disc on the left is the old "displacement vent plate" and the part on the right is the new "Spring Guide".

PorKen

Yay!

(Greg Brown...whatever...I told you there was a bulletin about this a long time ago, but did you listen to me...no... )

928ntslow

Dude...you specifically said CHECK VALVE...CLOG...and weren't even sure about that. I'll give you the fact that you said...uhmm...sumthin from somewhere that your heard sumthin.