Mighty Shilling

What numbers should I look for when doing a compression check? 1987 944.

should I look to make sure that all are very similar across all 4? is there a specific number? thanks!

iloveporsches

IIRC it should be around 150 or 160 for the 2.5L NA engine. Look for uniformity across the cylinders too.

Mighty Shilling

Awesome. thanks Brandon!

Serge944

Anything around 160psi is very good compression for these cars. As Brandom said, do look for uniformity.

Mighty Shilling

thanks too Sergey!

Jason_86_951

180psi is what it should have been new.
The 84' engine I sold had 170ish accross all 4.

a.n.other

My 84 had about 180psi over all four cylinders when I tested it last year (but I dare say the gauge can make quite a difference)

Mighty Shilling

Ok. this car is consistant in all 4 cylinders around 150. runs smoothly, and leakdown (i didn't do an official test) is nice...I watched the compression go down on the gauge for 10 seconds, and it really did not move too much in all 4 cylinders...

So, my advice to my friend, BUY IT!!!!

fezz

my 187k original motor

178 to 184 across all four cylinders
used MAC Tool tester.
warmed engine for 4 minutes, airbox removed.

Yabo

So what is it, 180 or 160?

Mighty Shilling

Ok, our tester is a cheap little $5.00 thingy got at auto zone... so I'm not expecting accuracy, but it did read consistant throughout all four cylinders...

and that was on a cold engine with an airbox...

michaelathome

Best I was able to do was mid to high 160's across all 4 cold. I was told that warm I should get close to 170+. Haven't tried that yet. Still working on the '83..


Michael

User 41221

Anything in the 170 to 180 range is considered good on a 2.5 ltr NA engine. Anything under 140, and you probably start seeing oil usage and a loss of power. Inconsistencies between cylinders and you should do a real leakdown test (sorry, dude, but watching how fast the compression gauge goes down doesn't qualify! ) to determine what needs to be rebuilt.

Regards,

Mighty Shilling

Yeah, I know... but it held compression really well!

944_S_TYPE

So what should the compression be for the 16V motor "S" ??