Author Topic: My Compression testtt (Read 5338 times)

E30_3I8I · « **on:** May 09, 2010, 12:16:19 PM »

hey everyone just want to start this thread on my new motor that i swapped into my car.

I took my car to a friend to see the compression on the motor. But at the beginning when i first got my motor i checked the plugs and it had oil all over it.. but I thought it was because of it being tilted and it was sitting for a while... so i changed the plugs and drove the car for over 1500 miles since i installed it.

Back to the story, when I took it to my friends shop he pulled the plugs and they were soaked in oil all four cylinders. and the compression showed 125 +1-2
across all cylinders, my friend told me its showing they are all the same but I the plugs arent a good signn, i mite need a head, and valve cover gasket replacement.

need some help on what to do at this point....

Thanks ,

Paul

KenC · « **Reply #1 on:** May 09, 2010, 04:39:26 PM »

I'm surprised it runs at 125... supposed to be 190+

Is there oil in the plug wells?

bmwman91 · « **Reply #2 on:** May 09, 2010, 05:29:27 PM »

Consistency is good, but 125 is super low. Both M42s I have owned have had ~210psi in the check.

E30_3I8I · « **Reply #3 on:** May 09, 2010, 08:29:47 PM »

well the person that i bought the motor from said that he bored it out and put hemispheric pistons and cams

E30_3I8I · « **Reply #4 on:** May 12, 2010, 09:45:38 AM »

bumpppp need help plzzzzz

dinu.negrean · « **Reply #5 on:** May 12, 2010, 10:45:43 AM »

Regarding the oil the problem il clear. You need new spark plugs an new valve cover gaskets.

Do youu have any numbers? Bored to what? what's the size of the piston? What thickness of headgasket did he use? You still have the original crank?

E30_3I8I · « **Reply #6 on:** May 12, 2010, 10:31:37 PM »

im going to dyno it later... i think its 1.9 or 2.0 with m44 crank... i didnt rebuild it .. but the person that did is a friend of mine so he knows more than i do.. haha

Romrog318is · « **Reply #7 on:** May 13, 2010, 09:31:51 PM »

mine was 210 across the board!

KenC · « **Reply #8 on:** May 13, 2010, 10:40:18 PM »

Is there oil in the plug wells?

E30_3I8I · « **Reply #9 on:** May 13, 2010, 11:12:32 PM »

yah there was oil all over spark plugs.. mainly #1 & #4

KenC · « **Reply #10 on:** May 13, 2010, 11:25:04 PM »

You need a new valve cover gasket then. There are little rings that go around the top of the plug wells. Also make sure that the screws by the plug wells are tightened down all the way... not too tight though, as it's an aluminum head.

Just to be clear, I'm talking about oil on top of the plugs, not the part that's in the combustion chamber.

E30_3I8I · « **Reply #11 on:** May 14, 2010, 09:47:15 AM »

oh its basically on both sides of the plug. is a 140 bucks for 3 pulls on a dyno worth it? not to me, i dont have anything too special, i just wanted to see what my stats are for my car.

KenC · « **Reply #12 on:** May 14, 2010, 12:49:29 PM »

You have wet oil on the spark producing mechanism of the plug?

E30_3I8I · « **Reply #13 on:** May 16, 2010, 10:32:36 AM »

Some Pics of the change in valve cover gasket and ........

the Old cosmolining valve cover

fresh timing belt=]

and what it looks now when I was all done

I love it hahaha

DesktopDave · « **Reply #14 on:** May 16, 2010, 10:38:03 AM »

Wow. That's clean. Love the radiator. I know it looks dumb, but putting that radiator funnel back on will help the fan do its job much better.

Now all you need is a COP kit & TB heater delete! Maybe a MarkD chip too?