compression variance

terryb · 07-20-2003, 11:27 AM

Just got the results back from a PPI done by Callas Rennsport in Torrance, CA. Thanks to everybody for the shop recommendation--they seemed to do a very thorough job. It's an '88 coupe with 116k miles on it.

The first compression/leakdown test:

1: 185/4%
2: 125/55% <-- not good
3: 170/5%
4: 175/3%
5: 175/25% <-- not good
6: 175/5%

Cylinders 2 and 6 were not looking so good. Tony Callas thought it might be carbon buildup so he took it out for a spirited drive to see if he could blow things out. Since I wasn't present at the PPI (I'm not in LA) I don't know if he squirted something in the cylinders or not, and I forgot to ask. Here's the second test results:

1: 185/4%
2: 165/5% <-- much better
3: 170/5%
4: 175/3%
5: 175/8% <-- better
6: 175/5%

The numbers definitely got a lot better and Tony was satisfied.

My question is about the difference between the highest and lowest compression numbers. One of my buddies feels that a 20lb difference (185 - 165) is something to be concerned about.

Is this something to worry about? Would this be a deal breaker for you?

Thanks for any advice on this.

-Terry

masraum · 07-20-2003, 12:42 PM

What's weird is the 185. I thought 175 was the norm. Would 185 indicate a problem, poorly adjusted valves or lots of carbon built up in the combustion chamber?

Wayne 962 · Wayne 962's Garage

Tony is an absolute fanatic. I would take a guess that he wouldn't like most of the cars that come to him for a PPI. He's been a mechanic on many of the factory Le Mans sponsored teams. I can't quite think of anyone I know who seems to know more than Tony (maybe Jerry Woods and him could duke it out and it would be close).

Needless to say, if Tony gives it the thumbs up, then I would say it's got to be a good car. Remember that compression tests are only one measurement of the engine condition, and aren't always completely accurate. The fact that the numbers improved during tests proves this.

Nothing is set in stone, but if Tony says the car is okay, I would buy it (if the price is in your range).

-Wayne

Wayne 962 · Wayne 962's Garage

P.S. When I was looking at a 5-Series BMW for my wife, I took it to Tony to get a 2nd opinion. Looked good to me, but there were some suspicous things I wanted him to check out (brand new components front and rear). Him and his mechanics tore out a bunch of stuff in the trunk, and found that the rear 6 feet of the car had been replaced. I didn't see this, as I only checked in about four feet for weld lines and new paint. Likewise in the front, there were a bunch of things I couldn't see without putting it on a lift. The entire front had been replaced. Seems the car was in an accident from the rear, and then pushed into someone in the front. Tony said that the repairs and work seemed very high quality, and he said that this would be a good car, if the price reflected this previous damage. Needless to say, the price didn't reflect this.

-Wayne

82SC · 07-20-2003, 02:26 PM

hahaha...I took a car to tony once for a PPI..

and he looked at the car from 4 feet and said the roof line was off...by a hair...it looked like psychic magic...

he started going over the roofline with a magnet...and found a small defect

When I have money coming out my ears and no time to wrench myself, I'd probably take my 550 spyder and 356 speedster and 993 turboS to him...hahaha

MJ

terryb · 07-20-2003, 06:06 PM

I got the feeling while talking to Tony that he was a perfectionist, and I am extremely happy with the quality and scrutiny of the PPI his shop did. As an aside, it was only because he was recommended by the Pelican list that he agreed to take me as a customer. Thank you Wayne!

I'm asking the compression question because I'm curious if others have heard of a concern about a 20lb difference between highest and lowest compression numbers.

I have a call into Tony about this, but it's Sunday and hopefully he's cruising Highway 1--it's a lovely day in SoCal.

-Terry

Bill Douglas · 07-20-2003, 06:13 PM

It sounds like it may be a really nice car, and if one spirited drive cleaned it up by that much imagine what a dose of valve and injector cleaner (that Chevron product) will do plus a day at the track.

I drive my SC as it should be driven, lots of revs when it's warmed up etc. But after a day at the track it started running sooo much better and uses less gas. Gawd knows what happened?