M30 rebuild. What from the machine shop?

[Mastrcruse]

Hey guys,
I am still knee deep in the M30 swap project. Its going good and I will be removing the motor soon. I have found that there is milky liquid in the oil so I am going to replace the head gasket and all the gaskets top and bottom of the motor.

My question is,
What should I have done by a machine shop/engine building shop? It has 180K on the motor. I don't want to put a HUGE amount of money it in but have heard people getting the head redone for some where around $300.

The first things are going to be...
Have it cleaned
have it checked for cracks

and from there I need your help.

Thanks
DJ

[Mastrcruse]

Time to go to bed BUMP

[Mastrcruse]

ttt

[euroshark]

I got a head done for $180. That's all I'd have them do unless the cylinder bores are damaged.

[Mastrcruse]

What did you have done to the head? What about the block, should I have them do anything to that?

[PeaveyBassist]

Make sure you have the head pressure checked. M30 heads are known to crack after being overheated and that could be causing your coolant/oil mix issue. Also, the milky stuff could be from not changing the oil very often. Lots of new BMW's get the milky stuff on the oil cap and in the head by the valves because of the gay 15k oil service thing.

Will

[euroshark]

I went through two heads before I got a good one for my last 6er, but you can generally see the cracking. It's pretty easy to spot as it happens generally between the exhaust valve opening and the coolant passages on that half of the head.

I had the shop do a 3 angle valve job, nothing fancy... Also got new guides and seals installed, that's it. I reassembled the valve train at home. The motor ran so incredibly smooth after the valve job, it was unreal.

[Mastrcruse]

Great thanks. So should I do anything with the block then?

[euroshark]

Maybe just get some plasti-gauge (I think it's spelled like that?) and check the main and rod bearings. Also go ahead and do the rear main seal and the front crank seal if you can get that nut off AND back on again with the correct torque. Otherwise I wouldn't touch a thing. M30 bottom ends are tough as hell and should last a good 300,000 miles.

[Mastrcruse]

Alright, well I have a lower gasket set so hopefully I can get things figured out. The m30s blocks wouldn't crack though right? Just the heads+


EDIT: What about piston and things? Pistons are one thing that look damn expensive and would not be worth it too me to replace

[euroshark]

The blocks shouldn't crack, it would take something special to do that.

Rings can go, but as long as the cross hatching marks are still visible in the cylinders and the end gap in the rings isn't excessive, I wouldn't touch them. Pistons should be fine... If you feel like doing rings just to be safe, it's pretty affordable and easy to do though.

[Mastrcruse]

Alright thanks for the help. I will take a picture *better than camera phone quality* and get it up when I get the head off.

Thanks again!

[PeaveyBassist]

Do the rings if you're going to have the head apart. The rings arent THAT expensive, and its good insurance in case the others would go back in the next couple thousand miles. The crosshatch is probably still there, if it is just hand hone the block with a drill and one of those tools that goes in it. That way you wont take any material out of the walls and still be able to use standard size rings and the original pistons. The lower bearings MIGHT be ok too, but if you have the money I would go ahead and do them while you have all of this apart. It would be a HUGE hassle to do this all again because you didnt spend an extra couple bucks now.

Will