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winfred
03-04-2007, 02:19 PM
i was playing around in the core pile at work yesterday and figured out you can combine on a m20 block a 325/528 crank with E rods and I short skirt pistons (skirts will need a couple mm notch to clear the counter weights on the crank) i ran the math last night on the rod length vs the stroke and it works out perfect, with a little more checking and playing around i may of found my motor combo 84mm bore 84mm stroke 168 cid 2753cc, anybody know if anybody sells just the required spacer for the front seal to ride on and space out the cam belt drive, i've seen them on the metric engines m20 page in the pictures of the stroker kits, just wondering if they or anybody else sells one outside of a overpriced kit, i can probably get the machine shop across the street from my shop bob the crank snout and maybe make the spacer if i can't buy one ready made

raimo_iX
03-04-2007, 02:36 PM
yes, the m52b28 cranck, eta rods and i pistons combo works. you might have to deck the block a bit and take off some material form the pistons. the piston skirt goes very close to the cranck counterweight.
take your stuff to a machine shop and let them make the cranck to fit.

-Agressor-
03-05-2007, 08:10 PM
sorry for my terrible english :)
I have a 325 1985 year, that's mean engine has 9,4:1 (or 9,7 ? ) comp ratio
I read about the m52b28 cranck in m20b25
Did anybody realize this project in practice?
If yes, so that, what parts i need to buy? m52 cranck, rods from 320/323/ eta, what else? And what i need do with the lip for oil seal?

thanks to all for help :)

-Agressor-
03-06-2007, 08:41 PM
Somebody! Help me, please!

winfred
03-06-2007, 09:29 PM
i haven't done it yet and it may be a few weeks till i get to it as i need to gather more parts and a decent scale to balance the rods and pistons, i am going to use 325e rods but any of the 130mm rods should work (not sure what all euro models run that size) and i haven't gotten to the seal bushing part yet but the snout on the m52 crank needs to shortened a little and that's a job that you can't do with normal equipment


ps you can probably find out more by searching around on the forum

Somebody! Help me, please!

Stevin
03-07-2007, 03:55 AM
I've got a M52B28 crank in my car...

any competent machine shop should be able to machine the collar on the nose of the crank.

-Agressor-
03-07-2007, 05:14 AM
Thanks.
rods are the same in 320, 323, 325e (130 mm)
I have uncertainty, that pistons can be uncorrectly fit in block (under or in block, but not in the same level)

it is not problem to modify the cranck

-Agressor-
03-10-2007, 09:29 AM
I have some problems with searching on forums in english language :)
Maybe you can give me a direct reference on posts with the same project?

klrskies
03-10-2007, 07:05 PM
I've got a M52B28 crank in my car...

any competent machine shop should be able to machine the collar on the nose of the crank.

So tell us what was required to make it fit. Give us the details!

winfred
03-10-2007, 09:29 PM
i was playing around with it some more today and i don't think the snout of the crank is going to need any shortening, (what made it look that way was the difference on the length of the crank bolts, what the difference really is they set the hole in the crank a good inch deeper) and i beleave i can make a collar out of the m52 hub by shortening it on my buddy's lathe to the length needed to space out the m20s cam belt drive to the proper position, and it's already the correct diameter for the seal to ride on

-Agressor-
03-12-2007, 06:44 AM
For what it is need to make crank more short?

modify the lip of crank:

http://r.foto.radikal.ru/0703/0cf79a6aa06b.jpg

http://www.elcats.ru/bmw/image.asp?imid=A5B0013F (cut off №5)

Stevin
03-12-2007, 07:48 AM
I've got a M52B28 crank in my car...

any competent machine shop should be able to machine the collar on the nose of the crank.

So tell us what was required to make it fit. Give us the details!

Machine a collar for the nose, so that it seals on the front of the block.

Otherwise it's a direct bolt on.

I've got 86mm pistons on std M20 325i rods, and M52B28 crank.

AFAIK, u can use a complete M52b28 crank rods and pistons in a M20 no problems... if I remember correctly, but I have feeling that u might need 2 take a little off the piston as the M52 block is longer.

klrskies
03-12-2007, 08:24 AM
I've got a M52B28 crank in my car...

any competent machine shop should be able to machine the collar on the nose of the crank.

So tell us what was required to make it fit. Give us the details!

Machine a collar for the nose, so that it seals on the front of the block.

Otherwise it's a direct bolt on.

I've got 86mm pistons on std M20 325i rods, and M52B28 crank.

AFAIK, u can use a complete M52b28 crank rods and pistons in a M20 no problems... if I remember correctly, but I have feeling that u might need 2 take a little off the piston as the M52 block is longer.


Thanks for the information!
WHat pistons did you use and what did your compression end up being?

Stevin
03-13-2007, 06:00 AM
I've got a M52B28 crank in my car...

any competent machine shop should be able to machine the collar on the nose of the crank.

So tell us what was required to make it fit. Give us the details!

Machine a collar for the nose, so that it seals on the front of the block.

Otherwise it's a direct bolt on.

I've got 86mm pistons on std M20 325i rods, and M52B28 crank.

AFAIK, u can use a complete M52b28 crank rods and pistons in a M20 no problems... if I remember correctly, but I have feeling that u might need 2 take a little off the piston as the M52 block is longer.


Thanks for the information!
WHat pistons did you use and what did your compression end up being?

Originally I used S50B30 Euro pistons, with about 1.5mm cut off the top. Now I've got forged pistons with a CR of 11.5:1

CR b4 if I remember correctly was about 10:1

klrskies
03-13-2007, 08:44 AM
Thanks Stevin,
Are you going to leave your C/R 11.5? How high do feel you can go on pump gas?

winfred
03-14-2007, 12:45 AM
i took the m50/52 balancer mounting hub and turned the end down on my buddys lathe, i took a little off the spacer that's just under the crank bolt too to keep things tight (it would of hit the end of the crank before tightening the cam drive), i measured the collar to need to be .710" long and the step on the spacer to need to be under .085 from it's .140

http://www.fileden.com/files/2006/11/26/427251/crank%20spacer%201.JPG
http://www.fileden.com/files/2006/11/26/427251/crank%20spacer%202.JPG
http://www.fileden.com/files/2006/11/26/427251/crank%20spacer%203.JPG
http://www.fileden.com/files/2006/11/26/427251/crank%20spacer%204.JPG
http://www.fileden.com/files/2006/11/26/427251/crank%20spacer%205.JPG

Stevin
03-14-2007, 11:04 AM
Thanks Stevin,
Are you going to leave your C/R 11.5? How high do feel you can go on pump gas?

Yes going to leave it at that... it runs fine, but the ignition timing is a bit retarded, with a piggyback chip. I could run more advance on the motor on race fuel... but that would mean it needs to be setup up.

A friend of mine runs his M42 2.0lt stroker with 11.8:1 on 95 Ron fuel... but then it does have knock sensors.

-Agressor-
03-24-2007, 08:37 PM
up

winfred
03-24-2007, 09:31 PM
ill post the build up and complete measurements when i build the short block, i have all of the hard and soft parts to build it but i want to get a little performance crank work done before i put it together

up

bme30
03-25-2007, 08:10 PM
funny I came across this. I am planning on building myself a 2.8 stroker using the m52 crank, 130mm eta rods, and late style 'i' pistons.

If you check out the magazine Total BMW I think its the march issue, which I have and first heard about this in, there is a " motor tech" section about 4 pages on the correct way to build a 2.7, and 2.8 using factory parts, with minimal machine shop time.

LEANE30
03-27-2007, 02:28 AM
anyone wanna post that article up in a PDF or somthin?

klrskies
03-27-2007, 08:54 AM
Second That!

MitchM
03-28-2007, 06:51 PM
Metric Mechanic sells everything you need to adapt the M52 crank to the M20.