Hi All,
I am going to build a M52 engine using the crank, rods and pistons from an S50 3l. We know that we have to bore the block out 2 mm which means we are going to have stainless steel liners put into the block to make sure that nothing goes wrong. My question is what head should we use, an M54B30 or an M52B25/28?? We are also going to put cams into the head and maybe look at doing the valves depending on the flow. We are also looking at going ITB and megasquirt on the engine as its going to be too much for the standard ECU to handle.
Any advice would be great.
Any before you say just buy an S50B30 engine in Australia these are really rare and when they do come up for sale they about about 3000 pounds.
Thanks
Leigh
M52 Engine Build
Moderator: martauto
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march109
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If the S50 3L is that rare why not use a complete M54B30? or the M54 crank, rods and M54 pistons (with +2mm bore) or S50/M52 pistons with stock bore or a combination of the parts in the M52 block. Get the M52 head worked on and it should be a good engine, the M54B30 and M52B28 have the same bore iirc.
The S50B30 crank has less stroke than the M54B30 crank too. In fact my head is spinning with the possible options.
The S50B30 crank has less stroke than the M54B30 crank too. In fact my head is spinning with the possible options.
325i Tech 1 Touring, breaking.
2.5 high comp. M20, 3.64 LSD, Fully undersealed, Spax springs & Bilstein shocks, s/s exhaust, Alpina rep wheels and more.
2.5 high comp. M20, 3.64 LSD, Fully undersealed, Spax springs & Bilstein shocks, s/s exhaust, Alpina rep wheels and more.
I thought the B28 shared its bore with the B25?
I would say that if you can find a M50 iron block then use that, the M52 alloy blocks love to strip the headbolt threads out and there are cases where they have had liner's put in to combat nikasil issues, then the alloy around the liners has sunk, popping the head gasket.
I would say that if you can find a M50 iron block then use that, the M52 alloy blocks love to strip the headbolt threads out and there are cases where they have had liner's put in to combat nikasil issues, then the alloy around the liners has sunk, popping the head gasket.
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jaistanley
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Not sure you'll have much luck using the S50 crank either as I seem to recall the main bearings are larger diameter. You might be able to get the block line-bored if that is the case though. Unless you meant the american S50B30?
Thanks guys. The reason for using the S50 crank, rods and pistons, is that we already have them sitting on a bench not doing anything, along with a M52 alloy block. The refinement in the S50 crank compared with the standard M52/54 cranks is worth going that little bit further.
The reason for doing the stainless steel liners was to combat the problems of the nikasil along with refining the cooling system temperature controls which we tend to think are a bit high.
Yes the M52B25, M52B28 and M54B30 all use a bore of 84mm compared to the S50B30 bore of 86mm. The S50B30 engine is basical a square engine 86mm x 85.8mm so yes the stroke is longer using a M54B30 crank (89.6) but I doubt it would rev as well or as smoothly as a S50 crank.
The reason for doing the stainless steel liners was to combat the problems of the nikasil along with refining the cooling system temperature controls which we tend to think are a bit high.
Yes the M52B25, M52B28 and M54B30 all use a bore of 84mm compared to the S50B30 bore of 86mm. The S50B30 engine is basical a square engine 86mm x 85.8mm so yes the stroke is longer using a M54B30 crank (89.6) but I doubt it would rev as well or as smoothly as a S50 crank.
you'll have fun fitting the S50B30 crank in the M52 block........you need an S50B30US 85.8mm or S52B32/M54B30 89.6mm crank from the US in order to fit a bigger crank (without hassles) than what the M52 had these all fit in the M20 also.
Plus the M52 blocks are made from chocolate. Chances are you will pull the thread or two out of the block when you angle tighten the head bolts the final 90. These things aren't meant to be repaired. As for liners you will need the top hat type if you are looking to avoid sinkagebetween them (as suffered on steel liner factory blocks)
Iron blocks are the only way to go. The M54 head is useless on anything except an M54.
Euro M3 crank eh? How do you intend to get around the four bolt front pulley, the different lower chain sprocket, different front timing cover?
In short - forget it. You need M50, M52 or M54 bits to make it work.
Iron blocks are the only way to go. The M54 head is useless on anything except an M54.
Euro M3 crank eh? How do you intend to get around the four bolt front pulley, the different lower chain sprocket, different front timing cover?
In short - forget it. You need M50, M52 or M54 bits to make it work.
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jaistanley
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Looks as though you need to make a shopping list:
M50B25 non vanos full engine (very cheap, circa £150 around these parts)
M54B30 crank
Megasquirt
Don't know which pistons and con-rods you'll need. You might be able to use the S50 pistons you have but you'll need appropriate length ones to match.
I reccomend the non-vanos engine as they are the easiest to control with megasquirt. It's possible to run the basic (ie non S50) vanos with megasquirt but it's a bit more involved.
Good luck buddy...
M50B25 non vanos full engine (very cheap, circa £150 around these parts)
M54B30 crank
Megasquirt
Don't know which pistons and con-rods you'll need. You might be able to use the S50 pistons you have but you'll need appropriate length ones to match.
I reccomend the non-vanos engine as they are the easiest to control with megasquirt. It's possible to run the basic (ie non S50) vanos with megasquirt but it's a bit more involved.
Good luck buddy...