What's everything I need? (stroker)

[619E30]

I'm starting to get into the process of doing a m50 swap into my 1990 alpineweiss 325i and was wondering what was everything I would need to make it into a stroker. I'm not too familiar with the m50 besides repairing a few head gaskets and other meticulous stuff. So first off, the engine will be coming off a salvaged 1993 325is (m50b25tu). The plans for the swap are m50b28 crank and rods while keeping the m50b25 pistons, then adding s50 cams. (Info came from this website http://www.rmeuropean.com/bmw-e30-m50-swap.aspx) .

Here are some off my questions:

Will the crankshaft and rods be as simple as just installing them in the block without having to "modify" anything?

And will the s50 cams fit directly in the stock trays or will I need s50 trays?

Last but not least, what will I be looking at compression wise, with just these mods?


Sorry if I am reposting, searched but could not find anything on this subject.

Thanks

[Van Westervelt]

I have s50 cams and an s52 crank if thats the direction you head.

[brokenbimmer533]

I went with s52 crank, 135mm rods, and low comp custom pistons. Stock pistons do not work as the wrist pin location is too far from the top of the pistons. For my setup.

I think you are referring to an m52b28. What is the stroke on the crank? The length of the stock rods? I thought s52 and m52 had the same stroke but not sure.
s52 stroke = 89.6mm


I believe you need to swap over trays and lifters as well. Not 100% sure as I have never researched it

[Uber E30]

A few useful facts that might help you:

1. All the vanos engines have the same size rods (135) so you dont need to change those
2. m50tu and m52 share the same size piston bore
3. No modification is needed to fit any of the vanos cranks in a vanos block (pistons are a different story)
4. S50/m50tu pistons have a different wristpin location then s52/m52


What the real question becomes is, do you want to spend money at the machine shop for a bore and go with s52 specs, or just toss in a 2.8 crank and m52 pistons and be done with it.

[619E30]

A few useful facts that might help you:

1. All the vanos engines have the same size rods (135) so you dont need to change those
2. m50tu and m52 share the same size piston bore
3. No modification is needed to fit any of the vanos cranks in a vanos block (pistons are a different story)
4. S50/m50tu pistons have a different wristpin location then s52/m52


What the real question becomes is, do you want to spend money at the machine shop for a bore and go with s52 specs, or just toss in a 2.8 crank and m52 pistons and be done with it.

I don't want to have to spend a lot of money, I just want to be able to make a little more horsepower without busting the bank, that's why I thought a 2.8 crank and rods would be perfect

[Uber E30]

Well at a minimum the right way to do it would be have the block honed and decked, throw in a 2.8 crank and m52 pistons with new rings and call it a day. But (IMO) the HP gain from that wouldnt be worth the price.

I read the link you gave and that wont cut it in CA unless you dont plan to smog it. The High CR will not cut it here, not to mention finding anything above 91 is pretty hard. My advice would be to leave the bottom end alone unless you are looking to spend 1k+ after all is said and done.


Mine was originally an s50 that i bored to s52 specs

[619E30]

Well at a minimum the right way to do it would be have the block honed and decked, throw in a 2.8 crank and m52 pistons with new rings and call it a day. But (IMO) the HP gain from that wouldnt be worth the price.

I read the link you gave and that wont cut it in CA unless you dont plan to smog it. The High CR will not cut it here, not to mention finding anything above 91 is pretty hard. My advice would be to leave the bottom end alone unless you are looking to spend 1k+ after all is said and done.


Mine was originally an s50 that i bored to s52 specs
[

And it passed smog I'm guessing?

[nando]

I don't really get M50 "strokers". Why not just buy an M52B28, swap over the OBD1 stuff, and call it good? it will probably run better while being cheaper at the same time.

It just seems like a lot of work to build a motor that you can buy just as easily.

[brokenbimmer533]

My reason is if I'm replacing the stock rods with forged rods and the pistons with low comp pistons, why would I go through the trouble of going from OBD2 to OBD1. When I can just use a M50 thats already OBD1. I realize with all the information out there now its not hard but thats just one more thing to add to the list. My M50 stroker will also be 3 L instead of 2.8 L. It would be way cheaper to throw in a M52 than stroking an M50. It all depends on your goals. I wanted to put a brand new engine in my e30 so I'm replacing everything while the engine is out. The price of rods, pistons and machine shop bill alone put me close to the price of an s52. Not including new cooling system, all gaskets, .08 MLS, 60lb injectors, and ems.

[Uber E30]

And it passed smog I'm guessing?

Its just an OBDI s52 at that point. When you mess with CR is where you will have issues with smog.

My reason is if I'm replacing the stock rods with forged rods and the pistons with low comp pistons, why would I go through the trouble of going from OBD2 to OBD1. When I can just use a M50 thats already OBD1. I realize with all the information out there now its not hard but thats just one more thing to add to the list. My M50 stroker will also be 3 L instead of 2.8 L. It would be way cheaper to throw in a M52 than stroking an M50. It all depends on your goals. I wanted to put a brand new engine in my e30 so I'm replacing everything while the engine is out. The price of rods, pistons and machine shop bill alone put me close to the price of an s52. Not including new cooling system, all gaskets, .08 MLS, 60lb injectors, and ems.

You're going FI, thats unrelated.

[George77]

A few useful facts that might help you:

1. All the vanos engines have the same size rods (135) so you dont need to change those
2. m50tu and m52 share the same size piston bore
3. No modification is needed to fit any of the vanos cranks in a vanos block (pistons are a different story)
4. S50/m50tu pistons have a different wristpin location then s52/m52


What the real question becomes is, do you want to spend money at the machine shop for a bore and go with s52 specs, or just toss in a 2.8 crank and m52 pistons and be done with it.

That is not entirely true.The m50TU has 140mm A shape con rods,similar with the ones from non vanos just that are 140mm .

[George77]

I'm starting to get into the process of doing a m50 swap into my 1990 alpineweiss 325i and was wondering what was everything I would need to make it into a stroker. I'm not too familiar with the m50 besides repairing a few head gaskets and other meticulous stuff. So first off, the engine will be coming off a salvaged 1993 325is (m50b25tu). The plans for the swap are m50b28 crank and rods while keeping the m50b25 pistons, then adding s50 cams. (Info came from this website http://www.rmeuropean.com/bmw-e30-m50-swap.aspx) .

Here are some off my questions:

Will the crankshaft and rods be as simple as just installing them in the block without having to "modify" anything?

And will the s50 cams fit directly in the stock trays or will I need s50 trays?

Last but not least, what will I be looking at compression wise, with just these mods?


Sorry if I am reposting, searched but could not find anything on this subject.

Thanks

The m50 tu pistons will seat 0.4mm higher the m52 pistons .I did not do the math but you gonna have a higher compression then 10.2(m52 compression ratio).so in looks like a good recipe .The S50 cams will fit no problem

[nando]

My reason is if I'm replacing the stock rods with forged rods and the pistons with low comp pistons, why would I go through the trouble of going from OBD2 to OBD1. When I can just use a M50 thats already OBD1. I realize with all the information out there now its not hard but thats just one more thing to add to the list. My M50 stroker will also be 3 L instead of 2.8 L. It would be way cheaper to throw in a M52 than stroking an M50. It all depends on your goals. I wanted to put a brand new engine in my e30 so I'm replacing everything while the engine is out. The price of rods, pistons and machine shop bill alone put me close to the price of an s52. Not including new cooling system, all gaskets, .08 MLS, 60lb injectors, and ems.

stock rods are forged. *ALL* rods are forged..

[brokenbimmer533]

stock rods are forged. *ALL* rods are forged..

Sorry, should have clarified, H-beam instead of I-beam.

[Uber E30]

That is not entirely true.The m50TU has 140mm A shape con rods,similar with the ones from non vanos just that are 140mm .

Oh thats right, the m50nv rods are 135 and for some reason the swapped the m50tu to 140 and then they all went back to 135. I was thinking it was the other way around.