[Rick_1950]

Hello,
Thank you for taking the time to read this post.
I have a 1999 2.0L 93 Turbo.
I toasted the head gasket and recently replaced it.
I have been having problems with hard starting and rough idle.
Today I brought the number 1 and 4 piston to top dead center and moved the cams to their markings on the block head.
I am going to do a compression check. Could you tell me what the usual good compression would be for this 2.0L engine. I have done some searching and have found that 150 P.S.I. is the magic number.
Any information will be appreciated.
Thank you.
Rick

 

[Presto]

Compression

Hi Rick,
According to the Haynes manual Saab do not give a specific figure for cylinder compression but the manual says it should be at least 10 bars (147psi) with no more than 10 pounds variation between cylinders. The manual says to get the engine to normal operating temperature, disconnect the DIC after removal, pull the fuse for the fuel pump and hold the accelerator to the floor whilst cranking. Make sure your battery is fully charged so the engine turns quickly enough. If the pressure in any cylinder is low pour a teaspoon of engine oil into the cylinder, if the reading temporarily increases it is rings or wear in the bore if no difference it is valves or head.

 

[Rick_1950]

Hi Presto,

Thank you very much for the information, I appreciate it very much.
I have the WIS CD ROM for the SAAB and can not find any information on that at all which pertains to cylinder compression.
Good Health
Rick

 

[PMI]

The compression can vary depending on a number of factors, but 150 +/- 10 is about right.

Normal engine wear and how warm the engine is at the time of the test are probably the most common things that cause differences reported by various people.

The main consideration is little variation between cylinders.

I have done a few compression tests on my car ('96 900SE) because of issues with the engine, and measured anywhere from mid-140's to a high of about 160. (cool engine, but NOT standing overnight or for hours).

Low compression on one cylinder on a single test is not necessarily an indication of anything. I had that, and after a couple cans of a valve clean product from Lubro-Moly, the numbers were perfectly consistent across all cylinders, despite some known problems with my engine.

http://www.geocities.com/ng900set/Engine/eng.html