I'm about to do a compression test on my Mini Cooper S and I need to know if anyone knows what the stock compressions numbers should be at?

 

Not all engines will register similar numbers and number will vary depending on how many cranks overs you do per cylinder. However, each cylinder should be pretty close to eachother. Mine ran about 150s across each of the four.

 

Just firnished the compression test, here is the outcome:

When I tested them dry they read 149, 145, 149, 149.

When I tested them wet they read 152, 150, 152, 151.

The only one that seemed off was cylinder 2 when dry. We tested that one twice and got the same reading both times.

Let me know what you think...I am open for suggestions.

 

Those look fine. A little deviation is alright...when one is 15-20 psi lower, then you have a problem.

 

yeah, that is what I figured but I just wanted to make sure. Thanks for everything guys.

 

Hey, do you think you have a blown headgasket or possibly bad valve sealing issues also?

 

I am blowing alot of blue smoke when I come off the throttle but at the same time I feel no loss in power at all. One shop said it sounded like the motor was blown and to do a compression test. So far it seems that turned out okay by what other people are saying.

 

Sounds like you're burning oil but I don't know where the oil would be coming from...Do you only have blue smoke coming out right at the moment you're off throttle or the whole time you're decelerating using engine braking? Your compression #'s are good so rings are out.

Do the pressures hold when you do the compression test? If anything #2 might be an issue, but even that's pushing it. I'd try running a leak down to see if that shows anything on #2 cylinder.

 

Check your oil return line from the turbo...its possible its restricting the oil from leaving the turbo & pushing oil out through the compression seals. Also pull your intake line off to the throttle body & check for oil. I just ran into this issue myself & that seemed to help cure it. The other thing is to ck the routing of your crank case hoses. I capped both of mine off & tied the valve cover lines into my intake.

Which turbo are you running??

 

More likely the problem is worn valve guides. Blue smoke on throttle overrun
is a classic symptom. Do you also happen to get a bit of blue smoke when
coldstarting the engine?

Your compression readings look fine.

 

I pulled off all the intake plumbing and found only drops of oil inthe intake but nothing to serious. If the oil line leaving the turbo was to restrictive would this be a problem that would just accur out of no where? The car has been running great for one year and this just started to happen.
It is a Garrett GT2860r.

 

If the oil return line started to restrict flow then the oil will be pushed through the seals on the compressor side of the turbo.....its probably not it, since you would see a lot more smoke. Do check how your PCV valve is plumed. Alta told me that they ran into an issue with the pcv not holding pressure....I am still wondering how they mean it will burn oil....Since your in Jersey, I assume its a Helix kit?? Did you speak with Eric about it? It could be in the head itself as Pete mentioned. If thats the case, its a good time for a valve job...maybe P&P too! What psi are you running?

 

It is an SPI Kit which Hubie installed at his New Jersey location and trying to get in touch with Hubie is impossible. Trying to get in touch with anyone from SPI is impossible!

I have not checked on the pcv valve yet but will do.

22 psi.

 

If you check all the obvious stuff....and its not any of that, then it may be time to dive into the head. 22psi is probably the max on a stock engine, shorting the reliability of things like pistons/headgaskets/head bolts/valve seats. I would say pull the head and inspect it. Take it to a shop or send it out to have a going over. If everything checks out ok, then install stronger head bolts & of course a new headgasket. If the head has valve seat problems or other issues, address that then. You may want to consider replacing the pistons with aftermarket so you can have a bit of peace of mind or run even higher boost.

That is my plan anyways....I would do it rite away myself, but I already burned a larger pile of money then my trashcan holds at the moment..Keep us posted on what you find if you decide to remove the head.....

Good luck!

 

I hope everything turns out alright for your car, im going to get the alta kit in december, so let me know what happens with this. Heaven forbid you loose some power and i beat you on a 2,3,4 gear pull Btw, PM me and give me your email address, i gotta send you some funny stories about Sudanese refugees and other things... Cheers buddy