To distill this to it's essence. This is a private sale. I'm looking at an '86 930 with a little over 63K miles. the tranny was rebuilt less than 1K miles ago along with other work including a 60,000 mile service. The car looks very good and runs that way too.

At the time all this work was performed the (well respected I might add) Porsche service facility (they only work on air-cooled cars) noted the following leakdown numbers and I'm copying this exactly:

#1 > 12%
#2 > 8%
#3 > 8%
#4 > 4%
#5 > 16%
#6 > 4%

When I saw the receipt I immediately consulted my wrench who is confused as to how these numbers can be interpreted as anything but bad.

However, when I spoke to the shop about the car yesterday (prior to seeing the car) I was told nothing but good things about it.

The seller said he recalled some conversation that they had at the time about the car being cold when the leakdown was performed and that as a result these numbers reflected a sort of worse case scenario.

I spoke with the shop owner this evening and inquired about having another leakdown performed. He told me he stands by the leakdown results and that performing another would be a waste of my money. I think he tried to me that were these not done cold I could expect a 25% improvement bringing the worst case cylinder to 12%.

Basically, they said that in their opionion I should either get comfortable with the numbers or pass on the car. However, in their opinion the engine was solid and they did not see the numbers as a source of concern. I was also told that in looking at each plug when they were removed they were all in equally good shape and the engine did not burn oil and drove very well.

Is there anyway this could be possible and would these numbers alone steer you away from this car?

 

Can't help you on the numbers, but take it some where else and have it done. Don't rely on the previous owners wrench.

I also don't like the way they say "get comfortable with the numbers or pass on the car". Makes me want to run. They are selling it had.

 

You typically do not want to go over 5% deviation from each cylinder. Basically you need to "plan" for a topend rebuild. If you have a chance get another leakdown done. Or swing the price of the car to your favor.

 

I responded to this on Pelican--pass; the spread is too wide between cylinders.

But I didn't notice something else until now--this facility did the service work for the seller before he put it up for sale? If so RUN AWAY and don't stop. If you have a complete boner for this car, then take it to another shop for a good PPI, including the leakdown.

I accepted the word of the seller's shop once (a reputable independant), and ended up doing a complete, bottom up, split case engine rebuild after purchase.

 

What's the price of the car. If you are getting it for $15k it's one thing vs. if you are paying $35k.

 

Seems like the gang on here have given great advice. To summarize:

1) If you are getting the car cheap (like used Toyota Camry cheap) then its worth picking it up otherwise RUN!

2) eBay \ Autotrader has some beautiful 930 cars all day long that will be a better buy (engine health)

3) Re-do a leakdown and compression - with the engine warm and throttle open!!!

Buying a sick 930 based on emotion = a great close first-name basis relationship with your banker

Yasin

 

Thanks guys for the great advice. I chose to run although I'll admit it was hard to get my feet going.

This was an Autotrader car. It looked great and was real close to home but the story kept getting worse the closer you got to it. I'' probably always wonder if I was being too critical but when it comes to these cars I understand that it's better to be safe (with money) than sorry (without).

Until next time....

 

It has been said that you should do compression tests when HOT.

 

Although anything over 10% would concern me, I wouldnt necessarily run from it yet until I knew what the compression test numbers were. Yes, 5% or less would be ideal, but its not uncommon to see newer rebuilt motors in the 5 to 10% range either. A 12% and 16% leakdown could indicate some carbon build up in those cylinders. That alone could happen from lots of short driving trips or oil build up in the cylinder from sitting long periods at a time. If the compression numbers were showing a consistent pattern in those same cylinders, then yes....I would start considering my options. But if they are the same as the others and you can somewhat verify that the motor isnt burning oil above whats normal, I wouldnt be too concerned. I'll bet that there are a lot of 930 and 911's out there now that have a similiar condition and have been running without an issue for years. Is this the same car we talked about the other day? If it is.....I still say you can do better.

 

Hey Chet,

No a different car but variation between cylinders concerned my wrench and others enough to warrant a pass. The car was real nice but I'm comfortable with the decision. Still looking but right now htere doesn't seem to be much out there.