I had the same results after overfilling my 1990 C2 Coupe. I am now very strict with my checking/filling routines.

However I also had a leaking power steering pump drive seal (also known as the camshaft seal). There is an ally casting with a tell-tale hole through which oil drips straight on to the RH heat exchanger. The seal was around £2 + VAT, the PS drive belt was soaked in oil so this was renewed and there was around 4-5 hours of labour. The result was topping up went from 8 times a year to 2, (3000 miles a year approx) and that horrible burnt oil smell greatly reduced. I will have to live with the other couple of minor leaks which are engine-out jobs.

 

velvetred, I'm slightly confused - you say you went from 8 top ups to 2 in a year is that because the leak from the power steering was ALSO an engine oil leak?

 

Did they note where the leak on your cylinders was ?

 

what are good leakdown numbers 30 seems like a big number, but not bad enough to rebuild ?

 

[QUOTE=Indycam; Did they note where the leak on your cylinders was ?

They couldn't say, in fact they were hesitant to confirm it was a leak noise at all. Lets see what the numbers say.

 

[I]velvetred, I'm slightly confused - you say you went from 8 top ups to 2 in a year is that because the leak from the power steering was ALSO an engine oil leak?[/I]

Just to clear things up.The leak was from the power steering pump drive seal, which is the end of the right hand cam. It is most definately engine oil and not PS fluid. Although i had had the car serviced at a reputable indie, they had not picked this up and i was told that the minor oil leaks were an engine out job and to defer them until, say, a clutch change was recquired. However, the main source of leakage was from this PS drive seal and is easily fixed with the engine in situ. I say "easily fixed" being relatively speaking as i still had a bill for £360.

 

I will defer to the broad, wise community that is Rennlist to answer that one...Im curious as well what the general opinion of what constitutes a good set of comp/leak figures? The seat-of-the-pants-o Meter tells me its pulling like a loco=good compression (and no burnt oil either). From many discussions I've had the many variables of the temperature, age of the equipment, calibration etc make the figures a fairly rough gauge. A engine that was totally shot would return shocking numbers, its def. not a good way to measure power outputs!

 

I'm giving up smoking, no patches involved.

 

Well then , maybe remove the over flow pipe/hose so that oil from the tank can not go to the intake , as a test ?
Make sure no junk gets into the intake or oil tank when doing this test , if you choose to do the test .

 

UPDATE: 09/24/08
With the excess oil sucked out and a few hundred k's of open throttle the old donk is blowing like she should. The odd puff when I close the throttle from high RPM but nothing to worry about.

 

Speaking of oil. Im thinking of switching to Brad Penn for the next change...any naysyers?

 

Having read this thread I'm not sure if this belch of smoke is coming out of the exhaust or from oil dripping on the exhaust? The latter is evident by puffs of smoke coming out of the wheel arch and even through the spoiler grill. I had this and it turned out to be a leaking seal on the oil sender on the top of the engine. Replacing it with the new design of seal cured the problem for me.

 

If you find that you are still having the smoking problem you should do some research on "honing" late aircooled cylinders. I'm under the impression that all 964's had Nickasil cylinders. this means that there is a very thin coating in each bore that the rings are designed to ride on. If you hone the cylinders and disturb the coating there is a chance the rings will never work properly, and I would imagine a glazed bore would be a very common outcome. Accepted practice for reusing a Nickasil cylinder seems to be simply washing them out with soap and water, or using a red scotch brite pad at the most. If for some reason the cylinders are alusil (doubtful, I think these were phased out with the 3.2) then they can be honed, but there is a very specialized process to expose the silica in the cylinder walls. Did this shop know what they were doing?? I get very nervous when anyone tells me that they had porsche cylinders "honed".

 

I'll pull the airbox off and have a squizz with the torch.

 

There was a moral to this story. Anyone else perplexed by the troubling wafts of smoke drop me a line and I will tell you my tale offline.