Diagnose this M10 - pics included.

[SA E30]

Ok, I have finally started pulling the motor apart for my turbo build and this is what I have come across so far. Opinions and information welcome.

Questions to come,

Symptoms: The car would smoke heavily on start up, lightly while driving, and heavily on the over run. Seemed lacking in power, and limited at RPM at 4600rpm (I think both those are down to the VW carb the previous owner fitted, not cool).

Anyways, the motor is being converted to EFI.









Ok, this is the bottom end, it seems to be in decent condition. The bores look like they might need a rebore as the cross hatching is gone.

What causes the brown ring at the top of the bores?

That head gasket looks like it's been around the park a few times! What is that coppery stuff, copper spray??







The bottom of the head, what are those marks at the very end? Looks like water channels have been welded closed or something, also there are some irregularities on some of the water galleries.













Here are some of the valves, and stem seals. I'm pretty sure this is what was causing the smoking, or am I wrong and it was blow by from the rings?

[SA E30]

Also is the always plugged on all M10's? This pipe off the oil gallery near too the chain.

[ttrousdell]

Did the smoke have a bluish tint. usually that's a sign of burning oil. Dont forget it could be leaking through the valve guides as well. Some of the valves look like their coated in a lot of carbon probably because the fuel/air was too rich.

[ttrousdell]

the "plugged pipe" near the timing chain is the chain tensioner housing. If you take that plug off you will find a spring and a few washers and at the end you will see the part that pushes into the plastic tensioner that the chain rides on. it is the same on the m30 too

[SA E30]

Sent the head in, and its just going to have a complete rebuild with slight porting, stiffer valve springs and a 292 regrind.

Seems the guides, and seals were shot.