started m30 build again

[jjdickm]

As some probably remember I was having the binging issue with my m30 engine I was using the same bearings and piston rings. I bought new rings and all new bearings. Basically have a box full of parts from the guy I had working the engine gave to me, rods and pistons and all not marked. Where should I start?

[Bin_jammin]

How about at the beginning? What's a binging issue, what happened to your engine, what parts did you get, and what are you doing with them?

[jjdickm]

everytime the engine goes together it seems to be extremely hard to turn over. also I don't know which pistons came from which cylinder, does it matter?

[Turbo Ready]

everytime the engine goes together it seems to be extremely hard to turn over. also I don't know which pistons came from which cylinder, does it matter?

It's always better to install the pistons in the order they came out from the block. Since you are changing the main bearings and rings it should not be a critical issue, however the pistons are directional as you probably know.

[jjdickm]

yeah I know that much. I have built a couple of these but never like this. It just I don't know why I was having binding before. I will try getting it back together and see if I have problems again.

[E34-520iSE]

Are you putting the bearings & caps in the right way round? 1 'reversed' bearing will lock the whole thing up. Install the pistons & con-rods into their cylinders, then lie the crank in place and bolt the con-rods to their journals using the correct bearings, and after each one is fitted try turning the crank. Keep adding pistons to the crank until you end up with all 6 and a free-turning crankshaft. Then start fitting the main bearings, one at a time until they all are fitted and the crank turns freely. All bearing caps should have some sort of mark on them for correct orientation.

HTH,

Shaun M

[Turbo Ready]

Are you putting the bearings & caps in the right way round? 1 'reversed' bearing will lock the whole thing up. Install the pistons & con-rods into their cylinders, then lie the crank in place and bolt the con-rods to their journals using the correct bearings, and after each one is fitted try turning the crank. Keep adding pistons to the crank until you end up with all 6 and a free-turning crankshaft. Then start fitting the main bearings, one at a time until they all are fitted and the crank turns freely. All bearing caps should have some sort of mark on them for correct orientation.

HTH,

Shaun M

Very good procedure to ensure its not the main bearings binding. If you wish, you can also check your clearances without pulling everything apart, compare them to specs using Plasti Guage like I did here on my m30

[E34-520iSE]

Thanks for that. Plastigage is the correct way to go - I deliberately never mentioned it as it may have complicated things a little, or made the post hard to follow for any newbie engine builders. The photo shows a lot of detail, much more than I could have described!

Cheers,

Shaun M

[Turbo Ready]

Thanks for that. Plastigage is the correct way to go - I deliberately never mentioned it as it may have complicated things a little, or made the post hard to follow for any newbie engine builders. The photo shows a lot of detail, much more than I could have described!

Cheers,

Shaun M

You are right Shaun, your procedure is simple and piratical, but if anyone wants to get a little insight as how the Plastigage is used, they can take a look at an m20 rebuild we have on my forums here http://bmw.turboready.com/phpbb2/viewtopic.php?t=102

[jjdickm]

okay, I have put a few engines together but this is the first one I've had issues with. And I was using the plastigauge. I was just concerned that I had put the pistons in the incorrect cylinders and if that would cause the binding. What is the clearance on the main bearings?