Used engine retailer recommendations

[george graves]

Someone tell me how wrong I am...or don't....

But really the most important part of any BMW I6 motor is the head. You can open up a 300k BMW motor, and still see the factory cylinder 45 degree honing on the cyclinder walls.
I have seem guys with older motors with some piston slap, so they knerl the pistons and re-set them.

If you're looking for a long block with everything attached, well....they pop up ever once in awhile with low rebuilt miles.

The other option is a swap. But if I wanted to stick with a m20, and I wanted a good motor, I'd get a head from someone like Mr325 at Bimmerheads. It's going to cost something, but again, it's all about the head (and oil pump - RNR that too - cheap to do! Make sure it good!)

[jeffnhiscars]

Someone tell me how wrong I am...or don't....

But really the most important part of any BMW I6 motor is the head. You can open up a 300k BMW motor, and still see the factory cylinder 45 degree honing on the cyclinder walls.
I have seem guys with older motors with some piston slap, so they knerl the pistons and re-set them.

If you're looking for a long block with everything attached, well....they pop up ever once in awhile with low rebuilt miles.

The other option is a swap. But if I wanted to stick with a m20, and I wanted a good motor, I'd get a head from someone like Mr325 at Bimmerheads. It's going to cost something, but again, it's all about the head (and oil pump - RNR that too - cheap to do! Make sure it good!)

They are all good options but not everyone can afford a bimmerheads head plus plus plus. I think this topic is more about a practical and affordable way get your car up and running after a blown motor.

I do agree that most motors absent serious damage can be revived with some head work and all the usual replacements and that that's a far better option than a questionable used engine. The upgrade path is a whole other conversation IMO

[ForcedFirebird]

Someone tell me how wrong I am...or don't....

But really the most important part of any BMW I6 motor is the head. You can open up a 300k BMW motor, and still see the factory cylinder 45 degree honing on the cyclinder walls.

I have seem guys with older motors with some piston slap, so they knerl the pistons and re-set them.

If you're looking for a long block with everything attached, well....they pop up ever once in awhile with low rebuilt miles.

The other option is a swap. But if I wanted to stick with a m20, and I wanted a good motor, I'd get a head from someone like Mr325 at Bimmerheads. It's going to cost something, but again, it's all about the head (and oil pump - RNR that too - cheap to do! Make sure it good!)

Yes, the head is where the power comes from. The rotating assembly is just a mechanical set of levers.

Perhaps an m20 10 years go was in excellent condition, but I have had several come through the shop lately that have severe ridges at the top of the block bores. ALWAYS do a leak-down prior to pulling the head.

In fact, I have almost dozen cracked 885 heads sitting on the shelf from HG jobbers over the years (two locals bought cracked used heads on the internats :/), so a coolant pressure test prior to removal is standard procedure before I even drain a drop of coolant. 885 heads crack down the cam valley, usually around cyl #5. I plan on creating a repair procedure (possibly preventative) that doesn't involve a lot of heat straightening from heavy welding.

Never knurl. That's a band-aid that maybe lasted back in he day when cars didn't see much more than 40mph on a regular basis. BMW has a very tight piston to wall clearance (on all models) compared to typical engine "standards". The m20 starts out at .02mm on a diameter (that's .01mm per side!) piston to wall clearance.

Now that the thought is rolling, not sure the last time I actually witnessed knurling, even for valve guides.

Modern equipment, carbide blade technology, and digital speed makes hand knurl/ream seem like rubbing sticks together to start a fire when you have a Bic lighter in your pocket.