Russ-R

Ive search but to no luck on finding the answer. What should the compression numbers be on a fresh rebuild with 0 miles. Im getting 40 on both faces and i dont think that is right. I have used housings and rotors.

snowball

seems like they are going to have to seet to get good compresion
especially with used rotors and housings
go drive 500 miles and re-test.

Russ-R

The thing is that the car isnt starting and i was thinking it was due to the low compression numbers. Is it possible to start with that low of a compression number?

2713ddddavid

iTrader: (1)

Push start in 2nd gear, key on using another car. get up to about 20 to 25 mph. I`ve seen this work on several differant 7s though I`m not sure if compression was that low. Also you can squirt a little fresh oil into both housings being sure to turn her over by hand so all faces get some. this will help bring up comp. a little.

ddub

Possible? Probably. Easy? Not usually.

Lowest compression motor I've seen started and driven first hand was one putting out low 60's on all faces of each rotor. It started OK, sometimes had issues, but oh wow did it lack power. Very slow, very hard to get going, not good at all.

Try squirting in some oil into the motor and then starting. The oil will take up space and help you get the motor started easier, or at least should. After it gets started keep it running by blipping the throttle if you have to. You'll want it to stay running for at least 30-60 minutes after initial startup of a fresh rebuild, especially with low compression. During that time you can check for leaks/etc if it will idle on its own, and then once everything looks good you can drive it. Driving and putting load on it will help everything seat better and hopefully will help compression go up. After that you can check again and see if it went up at all. Then check again every few hundred miles to make sure it goes up.

joeylyrech

iTrader: (11)

maybe its not sealing right and its flooded,install a fuel cutoff switch and try again.
on my rebuild with use housings my initial compression was 35 on all faces turning the motor a little bit at the time with the starter,i havent drived yet but it sat for a couple of days idiling in my shop and my com now its 90 on all faces but still getting flooded i think that it just need to run to get some decent comp