B21A to B200F Block swap
 

HI Guy
Just curious I have a 1984 240 that has been fitted with a fuel injected 93 B200F oil squirt etc engine, the whole lot,wiring loom, self diagnostics unit etc from a completely rotted out 93 Torslanda a couple of years back,

My question is this, the original engine came with the car (B21A carb model 1984) can I mate the original block to the 93 engine.

Purely Because I would like to put the original block back in but retain all the good bits from the 93 engine like the fuel injection system fuel injection head, oil squirters etc,

obviously this would entail a complete rebuild an awful lot of expense but it's not about economics as I would enjoy the challenge and the excuse to spend more time in the shed away from the family.

Please forgive my Naivety in asking the question as I'm sure that a 93 head on an old 84 block will not work as they must've changed the bolt pattern or something in that time

Regards Ned

There isn't much point really you have an engine fully matched with everything on it and working well there is no big differences to the B21A but there will be improvements and different details on it such as the piston oil squirt coolers . The B21 has extra capacity too which will increase the compression ration a bit but that would be welcome . The B21 has a forged steel crankshaft and connecting rods rather than cast iron ones . your best modification is to fit a B23E or B230E/F

It was more me wanting the original block that the car came with from the factory.

That is an unusual idea. Like Clan says, the two motors will be quite similar under the skin; there would be lots of detailed differences (like the distributor drive for instance) but I dare say it could be done if one had the will.

Unless you know the provenance of the B21a motor, you may find that it was changed out for a good reason: perhaps it isn't any good?

I'm struggling to see what possible advantage there might be in this venture - you might end up with the same engine number on the log book as the motor car had originally (and perhaps still has now, maybe no one told the DVLA it was changed), but otherwise it would be hard to see the difference.

Let us know if you decide to do this, it will be a long (and interesting I'm sure) project thread.

Alan

Hi
I can't add much to this discussion as I've never had an early block.
However, I do know there must have been a re-design of the cylinder head from the original silver one to the later black one which allows a distributor to be used at the back of the head.
I don't know how it relates to the head fitting on the block, but the cam cover of the earlier head is about 10mm longer than the later head, indicating that at least the tops of the two heads are different sizes.
If it is a problem you could probably use the old head too and just add the later FI inlet manifold and LH2.4 sensors etc.
Tim

The B19/21/23 family heads and B200/B230 heads can be swapped over however the timing belt covers will not swap over

I would rebuild the B21 complete but add the sensors for LH2.4 to the head. You also need to drill and tap the back of the block for the crank sensor


For info and to be clear the B200F should not have piston oil sprays. Not saying impossible but I have never seen one or any data to suggest they might have even been fitted with them. Only late turbo engines had them

Brilliant guys thank you,
The distributor is in the same place and the original B21A and the engine was fine when removed having only covered 80k and serviced, the owner was a tinkerer
And only put the B200F engine in because it was really low mileage and got the car for nothing so just had a play.
As for the oil squirted thing, I know nothing and thought I read it a forum so a case of hey I read and not hey I know, false knowledge from trawling not real experience again
Thank you guys👍🏻👍🏻👍🏻

A friend of mine did something similar, in that he converted a b21 engined car to turbo and 2.4lh but kept the original engine (the car is pretty early and he wanted to keep the original engine in it).

There’s no reason to change cylinderheads over, just drill and tap the back of the block on the B21a for a crank position sensor, drill and tap the block for a knock sensor and drill and tap the the cylinderhead for an ecu temp sensor then put it in the car complete. The inlet manifold with the injectors etc will bolt on, as will the exhaust manifold.

It might be a tiny bit more sprightly than the B200f as a result of 100cc of capacity and slightly higher compression ratio, although there won’t be much in it.

Cheers