Parts cost E30 M42 to M50 swap?

[josephb983]

Ok, I'm wondering what it might cost to put in an M50 in a 318is. What parts can be reused? What parts would have to be upgraded/replaced?

So far, it looks like I'd need:
M50 engine
engine mounts
wiring harness
computer/ecu
brake booster
lower ratio differential
M50 exhaust header

Possibly:
bigger radiator
clutch/flywheel
E36 driveshaft

What else do I have to change/upgrade?

What would the total parts cost come to, when I get done with all the required upgrades? My budget is limited, if it can't be done very cheap I may just do an E36 M42 swap, as with that engine everything should transfer directly I believe.

Thanks.

[FredK]

If you retain your transmission and radiator, you can save a little money. If you went all used on all of the parts and got an engine from a 525i, you might be able to squeeze the swap out for like $900. But, you'd probably want to replace stuff like the waterpump and thermostat housing. I know it could be done for cheaper, but the market varies on all of the swap parts.

[josephb983]

If you retain your transmission and radiator, you can save a little money. If you went all used on all of the parts and got an engine from a 525i, you might be able to squeeze the swap out for like $900. But, you'd probably want to replace stuff like the waterpump and thermostat housing. I know it could be done for cheaper, but the market varies on all of the swap parts.

$900 is pretty cheap. really think I could get by that low?

Did I list any other parts above that I wouldn't have to change out? How much would the engine, ecu, and harness run?

[FredK]

You'd have to find the engine with the 525i oilpan, all accessories, and DME for cheap, like $600. I got my 325i M50 for $660 including transmission. I got the brake booster for $20 at the pick and pull. I got the 325i driveshaft for $20. I got the oilpan, pickup, and dipstick for $20.

I did end up at around $1400 for the complete swap, BUT, I did a lot of maintenance parts (OE waterpump, thermostat, rear main seal, VC gasket, steel/rubber oil pan gasket, very low mile clutch, new clutch slave, etc.), and I got a lower ratio limited slip diff, new center support bearing, throw out bearing, guibo, and E36 transmission. You don't NEED this stuff, though it'd be "nice to have."

You might need like another $200-300 to figure out an exhaust.

[josephb983]

What would I have to look out for on a used M50 engine? I mean, I know the timing chain is a big issue on M42's once they get miles, as the tensioners usually are not replaced in time. Anything like this on an M50?

What miles would a $600 M50 have on it would you think?

[FredK]

120-150K. It's hit-or-miss though, sometimes you'll be able to score it cheap, other times, not so much.

Timing chains aren't nearly as big an issue on M50 engines. I haven't heard of anyone's timing case disintegrating like on an M42. The tensioner can be easily replaced just like on the M42.

[kolunda]

you can re-use your brake booster and slot the holes, that will save you some $

[josephb983]

you can re-use your brake booster and slot the holes, that will save you some $

is that a booster-side modification, or engine-side?

[josephb983]

Looks like my parts list right now would be:
M50 engine
M50 exhaust header
525i oilpan
water pump
thermostat housing
engine mounts
wiring harness
computer/ecu
brake booster
lower ratio differential
e36 driveshaft

Would I need a different flywheel? What do they cost, if so?

What other parts am I missing from the above list?

[318isbmw]

Depends on what transmission you use for the flywheel. If you keep the same transmission then it would be e30 m20 flywheel and clutch assembly and then the 323 TOB to make it all work out correctly. I would do brake booster and don't slot the old one... Just find a cheap 735 being parted and pull the master cylinder from that and it works w/ the ix booster(same booster) and is the 25mm size so brakes are much firmer.

Good luck trying to do it on the cheap, Fred's right, it does very depend the market at the time. Mine I tried to do cheap and it kicked me in the end, so spend a few extra bucks and follow what everyone else does and it'll end up working out. Good luck, its much more fun than the m42, just finished the swap last week on mine.

[josephb983]

Good luck, its much more fun than the m42, just finished the swap last week on mine.

You swapped from an M42?

I would do brake booster and don't slot the old one... Just find a cheap 735 being parted and pull the master cylinder from that and it works w/ the ix booster(same booster) and is the 25mm size so brakes are much firmer.

Yeah, I'd like my brakes to be firmer. Would the brake booster from a 525i work as well?

[318isbmw]

You swapped from an M42?



Yeah, I'd like my brakes to be firmer. Would the brake booster from a 525i work as well?

Yes I swapped from the m42. The remnents of the m42 are laying in the garage still actually. No the 525i brakes will not work. Just look for a 735 brake setup, I got mine for 65 off craigslist and get the booster and master cylinder and you're good to go w/ a 25mm master cylinder rather than 23 I believe stock and then it is the same as the ix booster.

If you wanna see the tear down pics, jrhaile posted them under the the swap section of the forum on here as Brendan's swap or something like that. For any other pics or advice, hit me up, I've got tons on my facebook that my gf posted for me.