My v50 2.4i overheated when I was driving it as a result of the coolant reservoir cracking on a road trip. The system lost pressure, coolant evaporated and the car overheated. I had the head checked, and it was warped but that's it. It did not blow a head gasket. I checked the compression before tear down and numbers were all over, some as low as 35. I just finished bolting the engine back together to the point where I could do a compression test. I got 95,80,65,65,120. I tried adding oil to the cylinders and it didnt make much of a difference. I replaced the head gasket, head bolts, used copper gasket spray, and cleaned everything very well. Will the compression even out and go up that much after I get it started and warm the engine? Thanks, any help is much appreciated.

 

Can I swap a older 2.4i from another chassis?

 

Presumeably you took the head into an engine reconditioners to have it checked for cracks,warping etc?

If warped they would need to have planed/skimmed the surface to enable you to refix it to the engine block successfully with a new specified head gasket.
New head bolts probably needed also.
The compressions you have now do not sound at all promising and vary way too much.
Another compression test again, after you get her started will tell the story???

 

You need to have the head straightened. When it warps it also puts the camshafts in a bind. Did you have a valve job done while the head was off? With compression that low it sounds like some of the valves are leaking or the head is not sealing in the middle. An engine shop can straighten that head. They bolt it to a thick plate and put it in an oven and heat it up.

 

Did you make sure the block wasn't cracked? I've seen that more than once.

 

When you over heat the motor, and the head warps, that = a blown head gasket.

You have gone this far you should finish the job and start the car to see how it runs.

 

If I may suggest, pull the timing gear off the crankshaft and carefully inspect it for sheared internal teeth. I have seen this before. The timing may look correct, but changes as the crank rotates, opening valves slightly, but not enough to hit the pistons. If not this, then I suspect bent valves. Perform a leakdown test before dismantling the engine again.