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Join Date: Jun 2010
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Hi There, Im in maitland NSW. Sorry if i seem a little vague, its just im getting used to navigating all this and i only joined up today.
Old 06-12-2010, 06:14 AM
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I had this happen once in all the years I built motors. Built the motor again after a unnamed well tuner built it and 4k miles holed a piston. I broke the motor and dynoed it confirmed AFRs rechecked headstuds and gave it my blessing. The car was delivered half a nation away and the owner calls mad as hell. Oil is spewing from the base gasket so I paid to have the transported back and tore it down. Also discovered that the car was delievered with 10 miles on it more than what it left with it. It was assumed that the driver took the car on a joy ride and hammered it cold which causes things to swell very fast and on a cold motor it will lift the cylinder or at min cause it to shift in spot crushing or shifting the base gasket. Needless to say I never used that transport company again.
Old 06-12-2010, 11:24 AM
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Thank you guys for your suggestions. I have now droppet the engine and inspected. I found as I expected that the base gasket has slided and causing the leak.
How this has happened I do not know. Maybe when I re-assebled the engine that they shifted position? Or maybe when the there was a misfire due to false air and wrong plug cable position.?
I have verified that there was enough torque on the studs. They does not seem to have slipped out of the the base

Here i s pic of what it looks like.

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Trond R.
1979 930: Garret GT35r turbo, EFI, carerra intake, Link EMS, custom GT2 cams, 98mm JE P/C, 964 crank (stroker), custom valves & ported (XtremeCylinderHeads) etc..etc..
1972 914-6 GT replica project
1986 944 Turbo
Old 07-04-2010, 02:25 PM
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I'm out of my element here, but why is the copper gasket missing/crushed/discolored/etc. everywhere but where it blew out? It's almost like the pressure on it was not even, didn't seat right, etc. Could the cylinder or base be uneven?
Old 07-04-2010, 04:41 PM
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I think this is an example of the head studs loosening or not being uniformly torqued. They allowed the cylinder to move slightly (or just enough) to walk the soft copper shim out (deform it). These do not "blow out". Totle - great picture.
Old 07-04-2010, 07:03 PM
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For the life of me, I don't know why a manufacturer would put Teflon, a non-grip, non-stick surface, on a barrel gasket. Use the standard copper gaskets...probably cheaper and work better, no doubt.
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'85 930 Factory Special Wishes Flachbau
Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P
Old 07-05-2010, 05:41 AM
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Except for the work involved I would be tempted to have the case decked and trued.
Old 07-05-2010, 08:15 AM
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Quote:
Originally Posted by 911st View Post
Except for the work involved I would be tempted to have the case decked and trued.
How much can you safely shave off w/o causing valve-to-piston clearance issues?
Old 07-05-2010, 09:12 AM
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IIRC, we used a copper spray on my copper gaskets and used o-rings on the cylinder bases.

Did the OP use these?
Old 07-05-2010, 09:21 AM
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To me it looks like it was assemblied that way, the area on the copper shim sitting outside the sealing surfaces doesn't look like it was ever in contact with the cylinder base.
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Old 07-05-2010, 10:35 AM
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Quote:
Originally Posted by CaptainCalf View Post
How much can you safely shave off w/o causing valve-to-piston clearance issues?
I do not think much needs to be removed to squair things up and factory shims can be used to maintain stock clearance.

However, I hear one can take off 1mm for about a .5 point of compression increase and have no issue with SC cams clearing the pistons.
Old 07-05-2010, 12:07 PM
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base gskt

Hi Totle! I was wondering how you went with your motor? Did you find the exact cause of the problem?
Old 08-15-2010, 06:49 AM
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Quote:
Originally Posted by Andy930 View Post
Hi Totle! I was wondering how you went with your motor? Did you find the exact cause of the problem?
Hi Andy,
The problem is now fixed :-) It was the faculty base gasket.
My guess is that the gasket had slipped when I assembled after the rebuild.

I noticed now that there was some play on the base gasket, so I was really careful now that it was centered before torquing the top.

Unfortunately at the same time my external oil thermostat failed, so I was running hot. Maybe low on oil as well, even I had good oil pressure.
But the result was that I now found out that my new UMW K27-7200 had been suffering from this causing it to leak oil into exhaust.
Replaced now with my old K29 and car is running smog- and oil leak free :-)

Need to send my turbo to UMW for rebuild :-(
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Trond R.
1979 930: Garret GT35r turbo, EFI, carerra intake, Link EMS, custom GT2 cams, 98mm JE P/C, 964 crank (stroker), custom valves & ported (XtremeCylinderHeads) etc..etc..
1972 914-6 GT replica project
1986 944 Turbo
Old 08-15-2010, 02:09 PM
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