Crank swap...

[sjpgoalie]

Does anyone know how long it takes to swap an E46 or E36 crank in the six cylinders? I'm swapping the forged 328 crank into a 323 (2.5L) motor. It is a straight forward swap and would take the same amount of time to swap in another identical 2.5L crank as I'm sure most of you know. I just can't find out how many hours it takes to do one of these and it is driving me crazy. I'm sure a bunch of you have removed and installed cranks in these motors before...

TIA!

[milKt]

Are you looking for a "book rate" labour time?

[mike radowski]

Iis the motor in the car? Do you have different pistons to install as well? Your question is pretty vague. It is between 1-20hrs :D

[BavarianLove]

What the hell. You got two different strokes their bro. Gonna have to change pistons or rods for desired compression ratio.

[techno550]

a couple questions.
1. does this need to include time to remove and reinstall the motor? tear it down? machine shop time?

2. why are you swapping cranks?

[sjpgoalie]

What the hell. You got two different strokes their bro. Gonna have to change pistons or rods for desired compression ratio.

I know, bro. Same pistons, though. As far as I know. Thank you for taking the time to respond everyone.

It's a crank coming out of an m52tuB28 that is going into an m52tuB25. Same bore in each, 84mm. The head is junk in the b28, thus we are turning the b25 into a b28 as the cylinder heads are identical.

The b25 is ready to go in and a friend wants to swap the head over onto the existing b28 that is currently in the car. It wouldn't take as long to swap motors, but he wants the extra near non-existant power his 328 had in comparison to the 323 (2.5l e46). So, I began to wonder if it would actually take less time to do a straight forward crank swap, then put the "stroked" motor in. I'm 99% sure that the pistons are the same size. One may have the graphite coated ones, but they should still be the same size. They are identical motors other than the crank.

Sorry, I should have be more clear. I am typing from my phone. Thanks a lot for taking the time to read...I didn't think I'd get any responses. I went over to e46fanatics and was about to ask the same question....then I noticed there were about ten people viewing the mechanical section and over 200 viewing the gallery section...so I figured I couldn't even trust answers there. They didn't even know the cam profiles of each, which after research I've come to find are also the same (228I/244E/9.0 lift).

[BavarianLove]

Measure rod lengths and piston wrist pin height. Something will be different. Then you need to balance gl.

[techno550]

the pistons between the 2.8 and 2.5 are different. The rods in the 2.5 (M50TU and such) are 140mm, the rods in the 2.8 are 135mm.

[sjpgoalie]

Good to know. Thanks guys.

[Quicksilver328i]

Just swap the heads, way easier. You have to take the head off to change pistons and rods.

[sjpgoalie]

True. I should have thought of that.