stroking a m50 up to 2.8 advice

[wullie325i]

hi

i currently have a 1992 non vanos m50 in my e30 and i am getting hold of a m52 lump from a e39 5 series which is getting another engine so i am going to use the bottom end internals from the m52 and use them to stroke my m50 up to 2.8.

basically im just looking for some tips and advice about doing this as it will be my first engine rebuild.

is it as simple as using the m52 crank rods and pistons?

wullie

[DanThe]

In a word, yes

You will need a set of suitable piston rings though, also im not sure if the main bearing shells are different due to the oil squirters.

Another thing to consider is having the lot balanced before dropping it in.

[Laimis]

The main bearings are the same.

You have few options here:
Either use 2.8 internals in your current engine, or even whole 2.8 bottom end with 2.5i head and intake.
All parts are interchangable. We have here M50B25's with M52B28 or M54B30 internals.
M52B28 bottom + M50B25 top and etc.
Anyway, after such conversion your ECU needs to be remaped, to achieve full engine potencial.

[wullie325i]

thanks for the replys guys.

dan what exactly should i have balanced other than the crank and what rings can be used as i thought i could use the m52 ones?

i think the easiest thing to do here is use the complete m52 bottom end as it saves alot of time. laimis you said its all interchangable so i can just swap everything over from my m50 block onto the m52 and stick my head on and away i go?(that sounds so easy just writing it lol)

whats the opinion on this as to what way to go i.e m50 bottom with the m52 internals or m52 bottom with m50 head ect as there are a few options but what will see the best gains or will they be the same but in a different configuration as the outcome is the same?.

the m52 lump im getting has no starter alternator ect so will all the m50 stuff bolt straight on and will the sump fit on there(im sure they do but i better ask now before i start).

also once i have done this i know i will need a remap but can i use a 2.8 ecu chip in the m50 ecu to get me rolling or will it run on the 2.5 m50 setup

thanks

wullie

[Yaninnya]

basically im just looking for some tips and advice about doing this as it will be my first engine rebuild.

Go to http://www.e30.de and under "325i 24v" you can find "Hubraumerweiterung (Theorie)". It is in german but if you don't understand it at all, you can translate it by Babelfish.
Good source.
Jan

[march109]

If its your first rebuild too look up the nimbus engine uilder kit, it should have all the consumables you will need, spray lube, cam lube, engine assembly lube ect ect, £49.99. Thanks to PPC making idiots like me look like they know what they are talking about.

[Andyboy]

It depends on whether it's a Nikasil engine or not. Nikasil units have cast iron pads on the sides of the pistons which are NOT suitable for cast iron blocks. If the engine is a steel liner unit the pistons, rings, crank and rods all drop in. Don't use an M52 alloy block, they're nowhere near as good as the cast iron M50 blocks.

I have a genuine brand new M50/52 BMW bottom end gasket set with all the later bits - the steel sump gasket, timing cover gaskets, front and rear oil seats - yours for £30 posted. All you will need is a head gasket and head bolts. Also replace the timing chains whilst it's apart.

[wullie325i]

It depends on whether it's a Nikasil engine or not. Nikasil units have cast iron pads on the sides of the pistons which are NOT suitable for cast iron blocks. If the engine is a steel liner unit the pistons, rings, crank and rods all drop in. Don't use an M52 alloy block, they're nowhere near as good as the cast iron M50 blocks.

I have a genuine brand new M50/52 BMW bottom end gasket set with all the later bits - the steel sump gasket, timing cover gaskets, front and rear oil seats - yours for £30 posted. All you will need is a head gasket and head bolts. Also replace the timing chains whilst it's apart.

hi

i have no idea if its a nikasil block or not as i havent seen it yet but im sure the e39 is a r reg if the production years have any bearing on the nikasil issue.

i will get back to you about that bottom end set as i will need to see the m52 block before i know which way i will be going.

thanks

wullie

[wullie325i]

basically im just looking for some tips and advice about doing this as it will be my first engine rebuild.

Go to http://www.e30.de and under "325i 24v" you can find "Hubraumerweiterung (Theorie)". It is in german but if you don't understand it at all, you can translate it by Babelfish.
Good source.
Jan

thanks for that theres some great info on there

[wullie325i]

If its your first rebuild too look up the nimbus engine uilder kit, it should have all the consumables you will need, spray lube, cam lube, engine assembly lube ect ect, £49.99. Thanks to PPC making idiots like me look like they know what they are talking about.

when it comes time to rebuild i will only be doing the bottom end. the head will be sent out to my local engineers to be rebuilt and possibly ported and polished but that kit is still handy and it seems like a good price too.

wullie

[Gunni]

M50/M52 bottoms ends are all interchangable with M50/M52 heads.
resulting in pretty large sum of engine sizes and configurations.

The heads are interchangable because they have basically the same casting and do have same valve angles + chamber volume.

Also included in this are the US 3.0 and 3.2 M3 engines.

It´s pretty funny isn´t it

[wullie325i]

M50/M52 bottoms ends are all interchangable with M50/M52 heads.
resulting in pretty large sum of engine sizes and configurations.

The heads are interchangable because they have basically the same casting and do have same valve angles + chamber volume.

Also included in this are the US 3.0 and 3.2 M3 engines.

It´s pretty funny isn´t it

yeah its good that you have so many options to go for with these engines.

if the m52 im getting is not a nikasil lump im going to build everything into the m50 cast lump i have now as it seems the better long term plan.

using the complete m52 bottom end would be easier but the way i plan on doing it will leave me with a totaly rebuilt engine from top to bottom

wullie

[DanThe]

It depends on whether it's a Nikasil engine or not. Nikasil units have cast iron pads on the sides of the pistons which are NOT suitable for cast iron blocks.

Never seen these Andy, I have a set of 96 B28 and a set of 98 B23 here and neither have any iron pads.
The pistons from the steel liner blocks have a teflon sticker on the sides though.

If you want a quick sale of your gaskets/seals and wullie doesnt mind I have £30 burning a hole in my pocket

[g57yle]

Yes the 2.8 m52 internals fit straight in to the M50 2.5, i did thata while back and the alloy block was nakered, this is probably one of the best ways of doing it because the cast block is a lot stonger, but if you are using the m52 head with the standard exhaust you will find that one of the lambda/o2 sensors will hit the water drain bolt on the block, i just grinded it back slightly, and if you want to re-balance bits for a bit more refinement you can do so, i would start with the crankshaft but you can infact balance every moving part in the block. and if your balancing, maybe do the flywheel also.

Hope you project goes well Wullie

Gary

[wullie325i]

Yes the 2.8 m52 internals fit straight in to the M50 2.5, i did thata while back and the alloy block was nakered, this is probably one of the best ways of doing it because the cast block is a lot stonger, but if you are using the m52 head with the standard exhaust you will find that one of the lambda/o2 sensors will hit the water drain bolt on the block, i just grinded it back slightly, and if you want to re-balance bits for a bit more refinement you can do so, i would start with the crankshaft but you can infact balance every moving part in the block. and if your balancing, maybe do the flywheel also.

Hope you project goes well Wullie

Gary

im going to use the m50 head with the single lambda is that going to cause any issues?

[g57yle]

it will confuse the ecu, your better off using both as there is one per 3 cylinders, or try finding a shorter sensor, they are all the same, you could use a different manifold but i wouldnt as they are so well designed on the 328i

[wullie325i]

hi

if i keep the m50 ecu with the 1 lambda setup and have it remapped will that not get round the problem as theres only one on the m50 anyway?

wullie

[g57yle]

it will probably be fine, and just use a bung to block the other hole, but i cant say for definate because i have never tried it. but there is nothing from stopping you, but its not going to be the most accurate way

[Brianmoooore]

ECUs are easily fooled as regards lambda input - just feed them a 2Hz square wave and they are happy.
Some LPG ECUs have an output just for this purpose, if all else fails.
Can't see why one O2 sensor couldn't be used to feed two ECU inputs, if everything is working OK.

[wullie325i]

ECUs are easily fooled as regards lambda input - just feed them a 2Hz square wave and they are happy.
Some LPG ECUs have an output just for this purpose, if all else fails.
Can't see why one O2 sensor couldn't be used to feed two ECU inputs, if everything is working OK.

thanks brian

thats what i was getting at as the m50 is only running on one lambda anyway so my thought was that it shouldnt make too much of a difference on my setup if im using the same engine management.

yes - no ?

wullie

[wullie325i]

[Andyboy]

It depends on whether it's a Nikasil engine or not. Nikasil units have cast iron pads on the sides of the pistons which are NOT suitable for cast iron blocks.

Never seen these Andy, I have a set of 96 B28 and a set of 98 B23 here and neither have any iron pads.
The pistons from the steel liner blocks have a teflon sticker on the sides though.

Many years ago (1995) we did a 2.8 conversion on an early E36 320i. Six pistons and a crank from BMW ( can't remember about rods) and the pistons had black pads on the side which BMW tech said were cast iron. The pistons had to have the valve cut outs remachined so the 320i head would work. It was immenselt torquey with the 320i inlet and a remap. Given the number of old E36's still about, someone somewhere has a quick 320i.
I stripped a 2000 728i engine and Ant has all the guts of it, can't recall if it had the Teflon pads.

BMW sent 12 pistons for the price of 6. I sold them recently to a guy who built a Nikasil blocked 2.8 M52....non vanos. It went in a Compact, came out again and is in a Zoner's car.

Get the gaskets alright?

[DanThe]

Yeah got them, I even left you feedback!

Out of the 3 sets I have here, only one has anything but bare alloy sides

1996 B28 Nikasil from an E36 touring = bare alloy
1997 B28 steel lined from an E39 = Teflon stickers
1998 B23 Nikasil from an E36 cab = bare alloy

I cant remember any others ive had but im sure I would have noticed lumps of iron hanging out of the sides
I have a couple more to strip at some point though so I will keep an eye out

How much do you reckon I could safely have a Nikasil block bored out by and lined?
And how much at a guess would it cost?

[Andyboy]

Don't get involved with alloy blocks. They are almost a 'use once' block and you can run into trouble with head bolt threads pulling out. Just use an iron block, much better!

[DanThe]

What about some Rawl bolts?

How about an iron block then, whats the safe limit to bore to