The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support Fuel Injector Clinic
Please Support Morrison Fabrication

2.3 Stroker Compression Test Results

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

phunny

15+ Year Contributor
3,155
21
Feb 1, 2005
Pittsboro, Indiana
Hey guys I'm having a problem with oil in my coolant and I believe it's my oil cooler, but I just did a compression test just to make sure it wasn't an obvious HG failure.

Anyway, I did some searching to see if I could find some 2.3l 9:1 compression engine numbers and decided to make a thread so others have something to base theirs off of.

My results were 150psi +/- 2 across the board.
 
Hey guys I'm having a problem with oil in my coolant and I believe it's my oil cooler, but I just did a compression test just to make sure it wasn't an obvious HG failure.

Anyway, I did some searching to see if I could find some 2.3l 9:1 compression engine numbers and decided to make a thread so others have something to base theirs off of.

My results were 150psi +/- 2 across the board.

My 8.8:1 wiesco stroker motor is at 168-170psi at 15,000mi, just somthing for you to compare to.
 
2.3, 9.0CR pistons, 500miles on rings/bore,

180 180 150 145

I learned from kthackst that I probably need to bleed my lifters out better on the cylinders around 150.

150 isn't bad, but I'd say shoot for 180... apparently it's achievable.
 
Hey guys I'm having a problem with oil in my coolant and I believe it's my oil cooler, but I just did a compression test just to make sure it wasn't an obvious HG failure.

Anyway, I did some searching to see if I could find some 2.3l 9:1 compression engine numbers and decided to make a thread so others have something to base theirs off of.

My results were 150psi +/- 2 across the board.

What cams do you have? How are they timed? How much was cut off the head/block?

The fact that they are so close to each other points to your problem being elsewhere. But, anything is possible, with a dsm.
 
Can't believe I forgot an important piece of information. The car idled for maybe 2 minutes max, the temp gauge wasn't even at 1/4 when the test was done. Didn't really want to push all my oil in the cooling system and just wanted a real quick test to see if I had any obvious problems. This may account for the low numbers. :thumb:
 
The higher the CR the higher you want the numbers. On a stock 91 80K motor I got 149-151 across the board. I would assume with 9.1 you would want at the very least 170, especially on a newish motor.
 
The static compression ratio of a motor had little effect on a cranking compression test. Has a lot more to do with cam timing and ring seal.
 
I'm a bit confused, but would your compression readings not be very accurate without breaking in the motor first since the piston rings never had a chance to set?
I was told its common to get a little fuel in the oil on first oil change after rebuild because the rings aren't set and fuel may pass down the walls, same would go with compressed air!
Correct me if i'm wrong or mis-informed!
 
I'm a bit confused, but would your compression readings not be very accurate without breaking in the motor first since the piston rings never had a chance to set?
I was told its common to get a little fuel in the oil on first oil change after rebuild because the rings aren't set and fuel may pass down the walls, same would go with compressed air!
Correct me if i'm wrong or mis-informed!

You are correct:thumb:
 
here you go guys
 

Attachments

  • compression ratio.jpg
    compression ratio.jpg
    55.3 KB · Views: 441
Damn. . . So is something wrong with mine? I'm showing 110 105 105 110
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top