Carlsbergas

i just started to knock from nothere. and it sounds like a deasel, but only at idle whats going on ? please help, i need to fix this asap

here is a vid

jmj951

How much does the oil pressure drop at idle?

To me, it doesn't sound like the knocking completely goes away at higher RPM's. If it's not related to the oil pressure or to some other problem causing oil starvation in the top end, you might just have a bad lifter.

86 951 Driver

What is the oil pressure?

Carlsbergas

Oil pressure is constant on 4 like always, but the knock is really loud

jmj951

I recommend you pull the cam tower. First thing you must do as soon as you pull it off is inspect the lifters (because oil will drain out over time). See if all the lifters are full of oil, and if any one of them are obviously different than the others. If the problem is not in the cam tower and you have any other problems in the top end, such as a broken valve spring, you'll probably be able to see it with the cam tower off.

If you haven't pulled the cam tower off before, let us know. There's a lot involved.

Carlsbergas

no i havent done that yet..

Carlsbergas

i see you are from aurora, im located in Lemont

jmj951

Yes and no - my car stays at my house in Aurora for now, and I'm back there once or twice a year, but we're overseas with the military right now, otherwise I'd run over to help you out.

Carlsbergas

o ok got it. ill look for guides here on forums about removind cam tower

jmj951

Are you comfortable doing a project like that? The car will probably be apart for a while. If you haven't done it before, you inevitably run into a situation that requires a tool you don't have. For example, it would be best to use a flywheel lock, have a timing belt tensioner, you'll need an extra long allen socket to reach the hex-head bolts that are deep through the plug holes of the cam cover, etc.

There are a few other guys on the board in the western suburbs.

Carlsbergas

well we have 4 more german cars so we are good on tools, exept i dont have flywheel lock and timing belt tensioner, i might buy new timing belt kit, it doesnt have alot of miles but car wasnt running alot in past few years. did like 5k miles in 3 years and when i bought few months ago i already did 4k miles

jmj951

Okay, good luck. Post updates!

Carlsbergas

Hmm.. leaking oil from under the distributor cap.. so can this be the cause ?

txhokie4life

Hard to tell from the video -- but it sounds like lifters -- (and based on your good oil pressure)

however, pull off your oil filter -- cut it open and see if there is any debris.

That will help give you get an idea if you have a bearing problem or not.

And no -- leaky oil is not the source of your noise -- but I suspect your cam seal is bad and leaking.

I've pulled the cam tower so many times I don't even think about it.

You don't really have to have a flywheel lock -- but I'm sure if you can find one it will give you peace of mind.

Also on the timing belt -- you don't need a special tool -- but it probably helps.

Not sure of your year.....
the 86 has a slightly different setup than the 87+
For the 86
Haven't done it in a year -- but either a wrench and a socket or two wrenches do the trick.

87's with the spring tensioner are cake.

Try to find some local 951 Gurus -- there has to be someone nearby. We have about half a dozen racers in Austin!

Mike

Carlsbergas

mine is 89. looks like i will be changing timing belt and water pump too since i got that far