CSL Bat

[jonathan49bat]

I have an issue with the 3.2l engine fitted in that at 3.5 revs when hot the engine reveals an unpleasant metallic rattle. I have two options available to have the original engine overhauled likely with new pistons which would have to be made especially.

On good authority the likely cause of noise is the shells spinning inside the con rods. If so the crankshaft could well be damaged and because of this I was offered and bought an early 3.5l engine, dog left 5 speed box and rear diff with propshaft from a 1978 635 which shared the same crankshaft as the 3.2.

So the options are either to use this crank in rebuilding the original engine or to remove the 3.2 and pack it away for originality and rebuild the 3.5 and have it mildly breathed on and fit this with the 5sp gearbox and diff from the 635, with the prop modified for length.

The 3.5 engine seems like the sensible option given that the 3.2 is rare and difficult to scource spare parts and the 3.5 will give some useful extra power and flexibility.

However my question is will the 3.2 fuel injection system work on the 3.5 without modification?

 

[DJSimca]

difficult questions .. :?

If I had a original Bat I would probably not put a 'non original' engine in the car ... however I must admit that I am a bit of a purist with these things

I would probably say it is 'OK' to put the bigger engine in there if you can make it look identical to the 3.0/3.2 engine, however I don't think the D-Jet would work on the 3.5 engine without modification... the 3.5 was born with what .. L-Jet ??

You mention that it is difficult to source parts for the 3.2 .. have you checked this with BMW, W&N, Sima etc.? As I understand it the only difference between the 3003cc engine and the 3152cc engine is the crankshaft. The bore is the same, the pistons and all other internal parts are identical. I am not an expert in these matters but I was told by a German engine tuner that I can convert my 3003cc engine into the 3.2l engine simply by replacing the crankshaft! If this is the case I would rebuild the 3.2l engine.

My 2 cents

 

[jonathan49bat]

bore

The pistons are larger...

 

[Malc]

I may be confusing the issue here but here is some info

3.0 designation engine is actually 2966cc effective
3.2 designation is actually 3188cc effective
and just to confuse the issue further
3.3 designation is 3277cc effective , fitted to the old 4 door 3.3L/LA/Li/LiA

now the 3.0 and the 3.2 and the 3.3 use the same size pistons - 88.97mm

The stroke is different

3.0 - 80.0mm
3.2 - 86.0mm
3.3 - 88.4mm

now the 3.5 engine (From the old E28) I believe is a M3/B34 or M30/B35M engine uses pistons that are 92.0mm in diameter.
Now I don't have the stoke numbers for this engine, but with a little math I work it out to be in the order 87.75mm working from a value of 3500cc
now this number is very close to the 3.3 engine with a published stroke of 88.4mm

Now a M30/B30M engine as used in a later E34 5-series (530i) happens to use pistons that are 88.97mm in diameter

Ok so whats the point?

Well I think an original CSL engine can be rebuilt to original specs using parts from various different engines that BMW use and still produce!

Will D-jet work with a 3.5 engine?
Yes it should because the delivery of the d-jet injectors compared to the L-Jet is pretty much the same. The difference in cc over six cylinders isn't that much either. I heard but cannot confirm the D-jet was used on cars up to 5 litres without modification.

I'll shut up now
Malc :roll:

 

[DJSimca]

I may be confusing the issue here but here is some info

3.0 designation engine is actually 2966cc effective
3.2 designation is actually 3188cc effective
and just to confuse the issue further
3.3 designation is 3277cc effective , fitted to the old 4 door 3.3L/LA/Li/LiA

now the 3.0 and the 3.2 and the 3.3 use the same size pistons - 88.97mm

The stroke is different

3.0 - 80.0mm
3.2 - 86.0mm
3.3 - 88.4mm

I did think the piston size was the same.
Just to add to what you said, I suppose 3.0 also refers to 3003cc effective which is the engine in the 2nd series CSL

 

[roundel]

Info re `Bat` engine.
The engine fitted to the CSL `Bats` are different to all other BMW engines. So you can`t make a `parts bin special` out of other bits. Reason is it used an 84mm stroke crank, so the gudgeon pin height in the piston must match the crank throw. If you fit normal 3;0 pistons they will stick out the bore by 2mm.
`Bat` engine is actually 3153cc whereas later so called `3;2` engines were with 86mm crank so were actually 3;3 litre (3266cc...)

Also `D` Jet will not work with 3;5 litres. It will just about work with 3;3 litres if everything is in good order. No way to get any more fuel out of it other that raising fuel pressure to silly level which ruins low down running.

Hope that helps..............

 

[jonathan49bat]

Bat stats

Roundel - for the record the stroke as you say is 84.00 and the bore is 89.25. I'm going away from the 3.5 idea with a dogleft 5 speed as the mountings have to be re fabricated..