View Full Version : 8V Compression

01-25-2002, 01:11 PM
Hello Gang:
Quick question:
What should the compression be per cylinder on a 83-84 VW 1.8L 8V GTI?
I just did (Jan. 2002)an old fashsion compression test (not leak down). Just pulled all plugs and inserted the compression gauge, cranked motor with starter. Recorded the highest value per cylinder.


For reference, preformed same test in June 2000 (approx. 8-10 races ago and few schools)and all cylinders were 135psi.

How bad are these numbers from ideal?

For you others that have been following some of my posts, this is the same motor that produces 1/2 quart oil in a weekend of races in the catch can.

Thanks in advance for your help.

Ron Vaughn

01-25-2002, 02:18 PM
What do you want us to tell you? You had a worn out motor 8 races ago, and now its still worn out. Darn, I hate when that happens. A good compression number is generally above 165 psi.

01-25-2002, 02:21 PM
Ron, my 1.8L JH engine with a dozen races on the rings run 165 to 170 on the cold test. Your readings are on the low end of the scale however the cylinder to cylinder is good. Have you used the compression tester before or on other engines? (maybe it reads low).

01-25-2002, 03:56 PM
No, I don't want you to tell me my motor is old and tired, I wanted you to tell me that stock compression should be 110psi.
But seriously, thanks for the info, I had no idea what it was suppose to be, now I do, bummer.
Hey, it still won it's last race.
Ok, time for rebuild, that will be a first for me.

Bill Miller
01-25-2002, 04:54 PM
I got 155 - 160 on my street car w/ over 150k miles on it.

MARRS #25 ITB Rabbit GTI

Vantage #51
01-28-2002, 11:08 PM
Our A-1 rabbit GTi will show 170-175 psi on a known good guage hot.This is close for an 8.5-1 motor in IT trim