Options when it comes to M52 strokers

[318isbmw]

nah, boreing doesn't add as much as power as you think.

and I bet most BMW less than 30 years old still have "crossmech" walls

I'm not saying for power, I'm saying for getting the crossmesh back. Yeah odds are their decent, but if your there, why not do the extra work, it aint that much just to be careful.

[Ray McCooney]

is that 3.0 starting from an m50 block or m52 block? or are they same? whats it take to get an m52 block to s52 spec?

The displacement of 3.0 liters is in reference to a stock M54 (E46, E39, etc.) rotating assembly, of which the head from another member of the M "class" family of motors could be bolted on to (such as an M52).

You would need the crankshaft from an S52 to be able to allow an M52 block to reach 3.2 liters of displacement.

[Jean]

I'm not saying for power, I'm saying for getting the crossmesh back. Yeah odds are their decent, but if your there, why not do the extra work, it aint that much just to be careful.

Once you drop the pistons to rehone the block wouldn't you need a new set of rings to seat the pistons properly for good wear?

Thanks.

[SpecM]

Once you drop the pistons to rehone the block wouldn't you need a new set of rings to seat the pistons properly for good wear?

Thanks.

-yes

And an s52b32 crank = m54b30 crank. Same thing, it's just that the 3.0 has a smaller (84mm) bore, therefore will drop into any m50/52 block

[hoveringuy]

I'm looking at purchasing an m54b30 motor that the PO had overheated. Classic e46 story.. the expansion tank failed and the temp gauge was too little, too late. He shut it off when "the valves got noisy". Once the car was towed home and topped off with fluids the car started and "had white smoke coming from the exhaust".

I would probably get the motor for around $300 and I'm sure at a MINIMUM the head gasket failed. I would expect the head to need attention and MAYBE I'd have a viable engine. Do the Al blocks tend to pull the threads??

Plan B (what I'm getting at) is strip the rotating components for an M50 3.0. So, what is the difference between S50 and M54 components?

Are the crankshafts identical? Connecting rods? Any lighter? Pistons?

[SpecM]

I'm looking at purchasing an m54b30 motor that the PO had overheated. Classic e46 story.. the expansion tank failed and the temp gauge was too little, too late. He shut it off when "the valves got noisy". Once the car was towed home and topped off with fluids the car started and "had white smoke coming from the exhaust".

I would probably get the motor for around $300 and I'm sure at a MINIMUM the head gasket failed. I would expect the head to need attention and MAYBE I'd have a viable engine. Do the Al blocks tend to pull the threads??

Plan B (what I'm getting at) is strip the rotating components for an M50 3.0. So, what is the difference between S50 and M54 components?

Are the crankshafts identical? Connecting rods? Any lighter? Pistons?

-yeah I've heard this one a lot too, typical e46!

-YES most m54 blocks "pull thread" once overheated, and the head itself is probably toast. They are junk, worth their weight in Al.

-m54b30 cranks are identical to s52b32 cranks. The pistons are smaller (84mm, like an m20,m50,m52 b25/28 ), as opposed to 86mm in the s50 and a little over 86mm in the s52. And the internals are WAY lighter and better-coated, too.

[hoveringuy]

-And the internals are WAY lighter and better-coated, too.

Lighter than S50? Cool!

So is this a plug-n-play "take M54 rotating assembly, drop into M50 block" recipe or are there clearance, compression and other "gotcha" issues that make it more difficult than that?

Also, has anyone ever tried an M54 OBD1 conversion? Realizing the obvious difference in the intake and VANOS I wonder if it would work better than standalone ecu.

[hugh jass]

don't forget you have to pass smog. don't spend all that $$ on a stroker motor that you can't pass smog with. always keep that in mind.
that's one of the benefits of going with a used s50/s52 - its a known quantity

[hoveringuy]

I have to pass smog?? I haven't done that in years. I'm military... I can pollute with impunity.

[SpecM]

I have to pass smog?? I haven't done that in years. I'm military... I can pollute with impunity.

+1 haha!

and yes they are drop-in...

... and how the heck is an inspector going to know if its an s50 or a stroked m50? Really now...

[Jean]

Not the inspector, but once the car is on a roller....

[hugh jass]

+1 haha!

and yes they are drop-in...

... and how the heck is an inspector going to know if its an s50 or a stroked m50? Really now...

where we live the car has to pass a tailpipe emissions test at a simulated 15 and 25 mph on a dyno smog machine. too rich or too lean and you won't pass no matter what the motor looks like from the outside.