m52 vs m50

[320ise]

what is the better engine i belive the m52 is more powerfull but has many problems with bore linings and if you over heat your engines dead etc , i have only ever had an m50 non vanos and it had done nearly 200k and was still tough and smooth. are the m50 stronger having not got the ally block?

[Morat]

Is the M52 any lighter?

[Ziggy]

The M50 does certainly seem to be a stronger lump. But it's heavier & less powerful (assuming we're talking M50B25 vs M52B28 here). Which is 'best' depends on your priorities...

[town325i]

they both have problems if they over heat its the head that are the weak point not the blocks but the alloy block is iirc 15kgs lighter than the cast block it may be more and the b28 is a shed load quicker than the m50b25

[Ziggy]

they both have problems if they over heat its the head that are the weak point not the blocks but the alloy block is iirc 15kgs lighter than the cast block it may be more and the b28 is a shed load quicker than the m50b25

The M52 block is certainly not a strong point.

[Jon_Bmw]

Nice headbolt threads!

[town325i]

they both have problems if they over heat its the head that are the weak point not the blocks but the alloy block is iirc 15kgs lighter than the cast block it may be more and the b28 is a shed load quicker than the m50b25

The M52 block is certainly not a strong point.

it is if you want to build a m20b28 cheap ish

[Ziggy]

Then you'll be throwing the block away! What are you talking about?

[JungleGus]

i don't really understand all this talk about the m52 block - I can understand it weakens if it's overheated - why just not overheat it? most of us keep a pretty close eye on temp gauges...i can't see it being that common a problem? they did come stock from BMW, they can't be that bad...and couldn't you use steel linings (i can't think of the term right now) if the threads stripped???

[Gibson]

Then you'll be throwing the block away! What are you talking about?

I believe he means the fact that blocks fail makes crankshafts readily available... hence it helps M20B28 makers.... but dont quote me on that,

Also its called Nikasil, its a bore lining that has a habit of failing (although not all do) and BMW replace alot of engines for ones with steel cylinders under warranty. i believe the problem was only M52 related not M50. plus am i right in thinking M50s normally dont have Vanos where as M52s normally do? great when its working in the car, but a sod if it goes wrong or is being wired into another car...

[Ziggy]

As I understand it, the alloy blocks can sink between the steel liners - exit one head gasket & then the threads'll strip when you try & put the head back on.

Yep, the crank's a very useful thing, but that doesn't make it a good block!
A combination of both: M52 rebuilt into an M50 iron block is the way forward.

[320ise]

how common is it for an m52 to die of sinking? just if overheated or is it inevitable?

[daimlerman]

Is M52 the same internal size as M50? Just longer stroke crank and shorter rods?

[bmpaul]

my old 525i has an m52 engine and when the water pump went it overheated a couple of times and suffered no problems as a result. its on 200,700 miles ang still pulling like a train. m52 all the way baby!

[Ziggy]

my old 525i has an m52 engine and when the water pump went it overheated a couple of times and suffered no problems as a result. its on 200,700 miles ang still pulling like a train. m52 all the way baby!

Not the E34 you mention in your sig? I thought they were all M50s?

I'd certainly rather have a m50b25 than a m52b25 anyway - significantly more power as well as less agro.

Is M52 the same internal size as M50? Just longer stroke crank and shorter rods?

Sounds likely, but DanThe is the expert on that one!

how common is it for an m52 to die of sinking? just if overheated or is it inevitable?

There are plenty healthy ones around still, so I wouldn't write the idea off - just trying to make you aware of the pros & cons between the two.

[Daf318is]

I think Dan pulled the internals from an M52 and built a 2.8 in to an M50 block - dont quote me on this because I'm not really sure, but it does seem like the best all rount solution if possible.

[town325i]

I think Dan pulled the internals from an M52 and built a 2.8 in to an M50 block - dont quote me on this because I'm not really sure, but it does seem like the best all rount solution if possible.

he did yes and fook me it went well alot better than the m50 that was in the car before had plenty of passenger rides on the way to work in it

[Daf318is]

I think Dan pulled the internals from an M52 and built a 2.8 in to an M50 block - dont quote me on this because I'm not really sure, but it does seem like the best all rount solution if possible.

he did yes and fook me it went well alot better than the m50 that was in the car before had plenty of passenger rides on the way to work in it

I wend for a ride in his more door white one too ! Great fun.

From my one passanger ride in it I would recomend it as a conversion!!

[zaust]

If you can find a good m50 you will be much better off in the long run. M52's I have killed a few and they are not worth repairing. The m50 is much more versitile and and easy fix in comparison.

[Gibson]

As I understand it, the alloy blocks can sink between the steel liners - exit one head gasket & then the threads'll strip when you try & put the head back on.

Yep, the crank's a very useful thing, but that doesn't make it a good block!
A combination of both: M52 rebuilt into an M50 iron block is the way forward.

I mean he is praising the block for being a failure, because it means cranks from cars that have failed are plentiful

[Fushion_Julz]

M50s came with no vanos and single vanos...Iron block and no nikisil issues

M52s came with either single vanos or double vanos and have alloy blocks...the early ones had nikisil bores (later ones were alusil) that can suffer from premature bore wear brought on by use of high-sulpher fuel (that is no longer sold in Europe).

All E34s (24v 520 and 525) had M50 blocks...early ones were non-vanos and later ones single vanos.

E36s had both M50 and M52 blocks depending on the age but AFAIK, non had double vanos.

[Omi]

Not Alusil. Common misconception... And the liners were iron, not steel in the revised lump. If the M52 ever went Alusil it would have been the M52B28TU3 which didn't arrive until the dual VANOS E46. I don't believe Alusil made it before the M54 though.

To answer the original question, the M52 is the better engine, being lighter, more modern, and much more powerful (de-restricted with a decent inlet).

However, this needs to be off-set against the risks of failure... Because the cooling systems on our old cars are old and feeble, and the engines may have been unloved before we got hold of them, there's a chance of air-locking, overheating, HG failure, and in the case of lined blocks complete bin-food-syndrome if the alloy sinks below the liners.

There's plenty of M52s on the road with hundreds of thousands of miles on the original engines, even Nikasil ones. - I think if you get a good one, the M52 is fantastic. - Then if it goes tits-up, spend £50 on an M50 scrapper and rebuild with the M52 internals.

Just watch your temperatures and spend some time and effort on your coolant system. - Best thing I ever did was fit a warning buzzer using the float switch on the expansion tank... Any issue with my coolant system will be highlighted either by temperature dial or a warning buzzer telling me something's wrong when the coolant level drops.

I may be biased. All-alloy boy here.

[Daf318is]

Is there any way of telling a nikisil engine from a non nikisil one? Did they stop using it after a certain engine number?

Might be worth knowing if you dont know the history of a potential engine purchase.

[Omi]

http://www.bmwowner.com/forum/viewtopic.php?f=6&t=1770

[Bob_S]

yes Dan did put the 2.8 internals into an iron block and boy did it go.. as a comparison a his old NV 2.5 with 1 man in struggled to keep up with it with 4 people in..

I'm all alloy now.. Dafs, want a pax ride again?

[DanThe]

yes Dan did put the 2.8 internals into an iron block and boy did it go.. as a comparison a his old NV 2.5 with 1 man in struggled to keep up with it with 4 people in..

I'm all alloy now.. Dafs, want a pax ride again?

You can take me for a spin on Friday, by 'spin' I dont mean 'spin off' or similar!

[Daf318is]

Is it going again now Bob? I'll have to call and see it now if you find another 2.8 going let me know.... allready I dont think the 2.5 is quick enough

just dont bust it on track tomorrow!!!!

[Daf318is]

yes Dan did put the 2.8 internals into an iron block and boy did it go.. as a comparison a his old NV 2.5 with 1 man in struggled to keep up with it with 4 people in..

I'm all alloy now.. Dafs, want a pax ride again?

You can take me for a spin on Friday, by 'spin' I dont mean 'spin off' or similar!

Got a death wish have you Dan??

[Bob_S]

Dan's been out in the m50 over the horseshoe pass with those touch and go brakes I had on! He knows the open diff is capable!!
Dafs I'll try not to, I have 2 support vehicles though

[Daf318is]

Ahh the horshoe pass, haven't been over that with the M50 yet - managed to spin a Rover 200 on one of the cattle grids though!

Please tell me that the "Astra of Doom" is not one of your support vehicles!

[Bob_S]

I would of been had I not sold that peach!

I have been for a run in the 2.8 today... sweet jesus!

[Daf318is]

Good stuff then yes? I just wish I was off tomorrow - I would have come to wach! I'll call in the next couple of weeks - I need a ride in that! I'm all ready on the lookout for a 2.8 - although I need to build up an engine for the missus car first

[Bob_S]

AGAIN!!! yeah sound mate no probs

[Daf318is]

It is a rover engine - you can't expect them to last THAT long!!!

[Bob_S]

true, true..

and for the record.. m52's faster thus better.