e34 engine conversions (525 to 535)

[kibosmith]

My 1991 525i jsut blew the head gasket and rather then fixing the gasket I am going to put in a new engine. I was wondering if it is possible to put a 535i engine in a 525i without too much extra work and cost?

[Hypr5]

My 1991 525i jsut blew the head gasket and rather then fixing the gasket I am going to put in a new engine. I was wondering if it is possible to put a 535i engine in a 525i without too much extra work and cost?

do you now have the m50 or m20? some 91's had an m20.

If you have an m20, it's probably not a bad idea, but will need a bigger radiator, relocate battery to backseat, etc. just mostly minor things. Tranny should bolt up, etc, etc.

If you have the m50 now, it's not even worth it. Sure theres an HP gain, but the technology is older and the loss in fuel economy, modern technology, etc just really isn't worth it. Try to get in a nice m52 if thats what your going for.

[kibosmith]

do you now have the m50 or m20? some 91's had an m20.

If you have an m20, it's probably not a bad idea, but will need a bigger radiator, relocate battery to backseat, etc. just mostly minor things. Tranny should bolt up, etc, etc.

If you have the m50 now, it's not even worth it. Sure theres an HP gain, but the technology is older and the loss in fuel economy, modern technology, etc just really isn't worth it. Try to get in a nice m52 if thats what your going for.

I have an m50, my mechanic says it will be cheaper to put in a new engine rather then repalce the head gasket. So since I have to get a new engine I figured it owuld be nice to get a better engine. But if the 535i engine is not as good I'll jsut stick with what I have.

Do you know if the m52 is significantly more expernsive to buy used, and if it will convert fairly easily. I don't really need a bigger engine but if its easy and not too expensive I figured i might as well.

[Kalevera]

The M52 is an OBDII motor, so unless your mechanic is a complete idiot, he's going to charge you a lot of money to stick one in there.

The M30 found in any US spec 535 won't bolt into an M50 powered 525; you'll need to replace most of the driveline, the engine bay harness, and address other small issues.

Why is the mechanic so averse to doing a head gasket on an M50? It sounds like he thinks something else is up with the head/block. Otherwise, it's $600 in labor versus something around two gees for a motor swap, if you're lucky (last one I did came in around 4 gees), and your car showed up at the wrong time of the business year. HHHHhhhmmm.

best, whit

[kibosmith]

Thanks for the help.
I am going to take the car to another shop to get a second opinion.
I think the head might be shot, but i hope not.
Thanks again!