E12 3.5 swop ?

[Paul02]

Hello , I have access to a good m535i E12 . Is it worth transplanting this older engine into my coupe or is it best to use an E28 535i. Is there much difference.
thanks Paul

 

[x_atlas0]

Actually, a combination of the two is pretty much the best. You see, the E12 M535 used a derivative of the M88 called the M90, which used the same bore/stroke configuration of the M88 with the M30 SOHC head. As such, it is a very oversquare engine, giving great torque and responsiveness. A common modification to these engines is to swap in the crank from a later M30, as it will give you an extra ~250 ccs of displacement, giving you a very cheap 3.7L M30. If you hunt around a lot and find the crank from a Bavaria 3.3, you can go up to 3.9L, but since those are difficult to find at best, 3.7L is much easier to come by. The only caveat is you will need to re-tune the engine, depending on your management type, so re-jetting the carbs or getting a new Motronic chip burned. I am unfamiliar with D-Jet, so I don't know how adaptive it is to the extra displacement.

 

[Bert-Ola]

Actually, a combination of the two is pretty much the best. You see, the E12 M535 used a derivative of the M88 called the M90, which used the same bore/stroke configuration of the M88 with the M30 SOHC head. As such, it is a very oversquare engine, giving great torque and responsiveness. A common modification to these engines is to swap in the crank from a later M30, as it will give you an extra ~250 ccs of displacement, giving you a very cheap 3.7L M30. If you hunt around a lot and find the crank from a Bavaria 3.3, you can go up to 3.9L, but since those are difficult to find at best, 3.7L is much easier to come by. The only caveat is you will need to re-tune the engine, depending on your management type, so re-jetting the carbs or getting a new Motronic chip burned. I am unfamiliar with D-Jet, so I don't know how adaptive it is to the extra displacement.

And new pistons :? ......I would wote for using the E12 535 engine as it is.

On the 3453cm³ M90 it's 9.3:1 in compression.
84 mm throw
135 mm conrod
217,5 mm deck height
93.4 mm bore
41 mm compression height (flat top)
1.7 mm head gasket
61 cm³ combustion chamber

With an 86 mm crank and VW pistons you get 3581 cm³ and 9.3:1 in compression.
86 mm throw
135 mm conrod
217,5 mm deck height
94 mm bore
39.6 mm compression height (flat top)
1.7 mm head gasket
61 cm³ combustion chamber

 

[MichaelP]

Waitaminnit, this is Pommyland we're talking about, not the US. What year is the E28 we're looking at? I'm not sure what motors were available which years over there, but it may be a 211bhp Motronic (Kat? I dunno) unit.

The only caveat is you will need to re-tune the engine, depending on your management type, so re-jetting the carbs or getting a new Motronic chip burned. I am unfamiliar with D-Jet, so I don't know how adaptive it is to the extra displacement.

Carbs? The E12 M535i was L-jet. Non-tuneable. Changing motor internals means going to Motronic or some other management like Megasquirt.

 

[DustyM]

I am unfamiliar with D-Jet, so I don't know how adaptive it is to the extra displacement.

From what I've read, its not really adaptable at all, to any sort of changes.

 

[de coupe]

Great advice

Great advice did the same conversion to a 3.7 works great

Now dont go with the 3.3 crank they are extreamly hard to find and you will be scatching your head till your hair falls out.. Rewelding ect ect..

 

[Paul02]

Thanks fellas E12 it is.
Paul