Have a lip on the bore of the block?

[urfy]

I have just stripped the head off a standard 325i sport and found a slight lip towards the top of the bores on piston 1 & 3.
Question what may have caused this and weather is it safe to just wack the head back on, if i did this would it be safe?

Thanks for any comments.

[Brianmoooore]

The only thing that can cause a lip (assuming it'snot just carbon on the surface) is a badly worn bore. Most unusual on a M20 - you can usually still expect to see the cross hatch honing marks on the bore.
You can "whack the head back on" if you like- it won't be any different than it was before,but you will be assembling a sick engine.
Have any mods. been made to the fuelling on this engine. The main cause of bore wear is a rich fuel mixture on the engines of those of you that still run them on petrol.

[urfy]

Its a standard 325i sport, as I said its a slight lip toward the top. Could it be worn rings? as a year ago I had the compression tested and the same pistons (1&3) had half the compression of what it should be.
If this is the case would this effect the head or gasket in the future?

Thanks.

[HairyScreech]

that would sound like a bore wear issue, especially considering the reduced compression in those cylinders.

you have three options, get the block honed and go oversize on the pistons and rings (read expensive), get a good sh bottom end (less expensive) or whack it back together and use it knowing full well it wont last forever and will slowly lose performance/economy.

all depends what your intentions for the car are.

[Brianmoooore]

The 'weak' point of the M20B25 engine is its cylinder head which tends to crack under and through the camshaft bearings.
For this reason, there is a surplus of short engines in excellent condition, which can be bought for very little money.
Your best plan of action, if you want to repair the car, is to get hold of one of these, attach your cylinder head to it, and swap it into your car.

[urfy]

Seems like a replacement bottom end.
Thanks for your comments.

[Jhonno]

Worthy of note perhaps, as a sport numbers matching is important to value, if it is a nice one..

[urfy]

Worthy of note perhaps, as a sport numbers matching is important to value, if it is a nice one..

are you reffering to the engine number?

[Jhonno]

Yes. Swapping the bottom end, will give you a different engine number.

[urfy]

I guess in that case i better spend the extra to get the original block sorted, better for the long term, as the car is in mint condition.