Thread: 10 bolt heads on 14 bolt block?

Yes, no problems AFAIK.

Injected heads have a cut out in the ports so be aware of that if running injection.

**Edit: of course you have injection on a D2.....

And please use a stud kit which ever way you go, the kit has all 14 studs so it'll work both ways.

You cannot use your late block timing case/oil pump as the crankshaft nose on an early block is shorter.
(90MM vs 70MM)
Of course you can do it the other way around ie early timing case on late engine using a spacer. All rover blocks are backward compatable but not forward compatable which is what you want to do as the engineers were not clairvoyant.
So this then AFAIK will stop you using your Disco 2 accessories.
Maybe you could make a packing piece to get the extra length on the short crank, but I wouldn't think the pulley would be very secure.

If the engine is a Vbelt engine and not "interim" you have another problem in that the keyway is too short for the oil pump and front pulley. to use a v belt crank on an interim engine the crank has to be removed and longer keyway groove made and longer keyway inserted.
All this is set out in detail in"How to Power Tune Rover V8 Engines"
Regards Philip A
If you want to use the early oil pump and timing case, I doubt very much whether the mounting points for accessories such as water pump, alternator, power steer, will be anything like the D11 ones.

Originally Posted by PhilipA

You cannot use your late block timing case/oil pump as the crankshaft nose on an early block is shorter.
(90MM vs 70MM)
Of course you can do it the other way around ie early timing case on late engine using a spacer. .

I cut the end off an old cranksaft pulley and machined the length down to the use as a spacer. One advantage was that it had a readymade and accurate keyway to slide over the crankshaft key.

If I swap the cranks will this help?

Also is the 4.6 a stroked version of the 4.0 or are the bores bigger as well?

Are the pistons the same for both.

If I need to change the crank I may as well go to to 4.6l

James

Ron, I think you are talking about an early timing case on a LATE block (ie upgrade from 3.9 to 4.6 ) which is not what the poster is on about. He is talking a LATE pulley on an early block.
The spacer you refer to goes behind the pulley , over the OD of the crank so that the pulley can be tightened and the belts line up.
I was (NOT) suggesting that it could be vaguely possible to place a spacer/extension on the nose of the crankshaft ( in the same OD as the crank and with a hole in the middle) so that if he placed a late multi belt pulley on an early crank the belts would line up.
He would also need a looong bolt, but it would be poor practice and NOT recommended, as a flying pulley would create havoc. A fan blade is bad enough!LOL
Regards Philip A

If I swap the cranks will this help?

No, the 4.0 and 4.6 cranks have a larger main bearing diameter than a 3.9 so will not fit.
The 4.6 has a longer stroke crank and different rods /pistons to a 4.0.
Regards Philip A

Originally Posted by PhilipA

Ron, I think you are talking about an early timing case on a LATE block (ie upgrade from 3.9 to 4.6 ) which is not what the poster is on about.

You are absolutely correct, Philip. Sorry I misread your post.