Fluidplay

Ski- could this be a detonation problem? Kinda going back to the idea of a timing issue. When I looked at the plugs yesterday there was definetly a dry carbon build up, not much, but there.
Throwin it out there....

Jfrahm

I think it's a spun bearing or loose main cap or something like that. I suggest doing the jackstand test again with hot oil and a brake stand if need be. Loading the engine with the brake on is not hard on the brakes if you do not overheat them, also a great way to get a turbo spooled at legal speeds in my quiet neighborhood.

Can you post a sound clip?
-Joel.

Ski

How far are you from Laguna Hills?

Vision Motorsports
22681 Granite Way
Laguna Hills, CA 92653

Tel: (949) 770 2888

used to do a lot of 951 work, mostly 911 stuff now but give Dwain a call, if RSM is what I think it is, less than 20 miles away? They have a dyno in house I believe, maybe they can help isolate the sound at least, with the car loaded.

Also, I had a cheap compression gauge once that read horrible, I mean bad - engine rebuild bad. No smoke, no oil burning - got a better gauge/hose assembly and the numbers were much better.

Edit - just talked to Dwain, he said give them a call

TurboTommy

I know you said your motor mounts were new, but that doesn't mean something might still not be hitting when the engine is twisting with some load. This happened to me once and it took me quite a while to find the noise.
Also, if the e-brake is worn or broken inside, it can make that noise when you take off (I can't remember if you mentioned in any of your posts if you knew where the sound was roughly coming from)

Fluidplay

Bret- I'm very close to Laguna Hills, in fact my office is literally a block away from Vision. I had originally approached Dwain do the rebuild back in 2006, but at that time he said he was no longer taking any 951's in. My loss...

I'll give Dwain a call tomorrow. Thanks for doing that!!

Ski

He still works on the track cars he built for people, I suspect he'll still work on them he's just not building anymore of them to race. He has no parts in stock anymore, sold most of the stuff to shops in the area. I was one of his first customers of the Kokeln turbos when LR sold the Kokeln brand.

Ski

Dennis, did you get the car by Vision?

Fluidplay

Gave them a call in the am...Dwain was busy left a voice mail. Tried again this afternoon...was informed that Vision no longer works on 944's. I explained to the receptionists that Dwain was aware of the situation and referenced your name (hope that was ok) she came back on line and confirmed...the shop no longer is taking in any new 944's for service.

On a positive note, there is a P-shop about 30 miles north that apparently still works on 951's.
Factory werks in Huntington Beach.

Thanks for your help Bret, very much appreciated!

951Tom

I had a knock that sounded like a rod bearing. I was pretty convinced and had began to price a rebuild. I then discovered 2 of the 4 bolts that hold the ac/alternator belt pulley onto the front of balance shaft drive gear broke off. I never got any belt squeal. They are hard to see because the power steering pump drive pulley covers them. 4 new bolts later and all was quiet. Hope this helps.

Fluidplay

Tom - It all helps...checking anything and everything. I'll put it on the list of possibilities. Thanks

theedge

It knocks 6-8 times as you pull away in first.... Does it keep knocking if you maintain a very low speed? Like a few miles an hour?

Fluidplay

good question...no, it doesn't. Once the clutch is out and I'm accelerating the knocking stops or at least subsides to a point where it's not audible. mmmm feels like an ha ha moment. Feel the need to confirm this...be right back!

Fluidplay

ok, here's what I did...got my neighbor to drive the car while I rode along side on a bike. Had him take off very slow (heard the knocks) and maintain approx. 5 mph. I heard no knocks beyond the initial take off until he shift into 2nd at about 20mph heard a few of knocks and that's it.

KuHL 951

It might be a shot in the dark but if it only knocks when the clutch is slipping maybe one fly wheel bolt has backed off and is contacting the metal part of the clutch disc? Once the clutch is locked up it stops making noise right? The clearance is very small that's why the cheese head bolts are so shallow. Have you had any clutch work done in the last year or so?

Fluidplay

The clutch was replaced with engine rebuild...and this possibility is high on the list. Thanks