3.5/D-Jetronic

[Henrik]

I will soon start on a CSL project which (unfortunately) has unoriginal engine block and cylinder head. The block comes from an E12 535i (VIN4148067) and the cylinder head is stamped M90 on the end. The cylinder head has however many cracks, which I think is caused by improper head gasket. I have managed to acquire a used M30 cylinder head (casted in 1978), without camshaft. I will pull the camshaft from the M90 cylinder head and use it in the M30 head. I do not know the origin of the camshaft, but it is possible that it is the original CSL shaft (Cam nose has two half-moon shaped prongs) All in all this will probably be a standard M30 3.5l engine with d-jetronic.
Does anyone have experience with this setup? Can D-Jetronic system to feed the engine with enough fuel? Upsides or downsides?

 

[DerSchwede]

Hi Henrik,

You can't use an early M30 head on an M90 block. See the tech section for details why not.

If you just bolt the D-jet to the 3.5 engine it will run rich on low revs and lean out on top according to the vacuum-based D-jet tech. Don't try to fiddle with the MAP-sensor, either it's good or dead. The risk is evident to break the membrane inside it if you try to tweak it - and then it's shot!

I tried to do the same thing with a later '85 based 535i engine but decided to go for a tripple Weber setup instead. This will definately cause a lot of tuning to get set right and it will not respond to altitude changes and run rich in the alpes but I chose to go that way for now.

Remember: there is no stock M30 setup superior to a bone stock D-jet 3 litre setup in terms of response, sound, mileage and driveability - and did I say sound!

The only reason trying the DCOE setup is that I have another E3 with a nice running D-jet....

Cheers
Anders

 

[Henrik]

Hi Anders!

If I understand you correctly, a setup with 3.5 engine and D-Jetronic mean that I get poor engine response at high speeds and poor combustion at low speeds. The question is whether this will be so noticeable that I should look around for a M30 3.0 block instead?
The car is equipped with D-Jetronic so I prefer to continue with this to keep it as original as possible, except for the engine block.

 

[DerSchwede]

Hi Henrik,
Yes, try to find a 3.0 block with corresponding Si-pistons. Send me a PN if you can't find one locally.
A

 

[Henrik]

Hi Henrik,
Yes, try to find a 3.0 block with corresponding Si-pistons. Send me a PN if you can't find one locally.
A

Are Si pistons different from the other e3 pistons? And is the cylinder volume similar to the other e3/e9 engines?

Henrik

 

[sfdon]

DerSchwede appears to be exactly correct- injected e9 and e3 pistons are unique.
Thanks for the info.


Part Cross-reference


Part 11251261972 (MAHLE PISTON) was found on the following vehicles:

E3: Details on E3
E3 3.0Si Sedan, Europe

E9: Details on E9
E9 3.0CSi Coupe, Europe
E9 3.0CSiL Coupe, Europe

 

[DerSchwede]

The CR for the D-jet pistons is 9.5:1

All other euro M30 verions for E3 and E9 had 9.0:1

 

[Henrik]

It will be a tough job to find such an engine block locally, but perhaps not as difficult as finding a 3003cm3 CSL engine block..................!

 

[DerSchwede]

It's the same block, only the pistons are +0.25mm bore for the 3003 cc engine. You can still buy new pistons from BMW and W&N.

 

[Henrik]

It's the same block, only the pistons are +0.25mm bore for the 3003 cc engine. You can still buy new pistons from BMW and W&N.

€262.40 each !! I think I stick to the standard 3.0i engine block. In fact it seems to be at least one not far away from where I live.

 

[DerSchwede]

No, €990 for the set of 6 pistons including rings.

The D-jet need the higher CR to work well. If you combine a normal 3.0 engine with the D-jet it will not perform better than the standard engine but it will generate a worse milage....

 

[Henrik]

I meant the standard CSI engine. It's probably nothing that separates them than displacement and pistons? Torque and power appears to be the same according to tech. info. Since it is a D-Jetronic it's probably not any quick solutions to achieve more power.