Thread: V8 Crankshaft interchangeability

If you can find a 4.2 crank, because they awere never sold in OZ, then AFAIK they are the only one.
4.6 has bigger mains and longer nose, but the nose is easily fixable with a spacer. and you have to grind off a dowel from the rear. The bigger mains are probably insurmountable.

There are probably some stroker kits still around. I know that Real steel still do a 5 litre
http://www.realsteel.co.uk/section1.pdf
Regards Philip A

Seconding what Philip A said...

4.2 cranks rods and pistons are hard to come by, and are the only ones that you fit into a 3.9 block (4.2 litre engines used 3.9 lblocks).

The 4.6 with its bigger mains along with the throw of the crank make fitment into a 3.9 block not possible.

Ron.

Originally Posted by nsgnomad

Can anyone shed some light on the crankshafts used in the 3.9 and later engines. I have a 3.9 (1996 D1 auto) and am thinking of replacing the crankshaft with one of a longer stroke (with suitable conrods and pistons). Which other crankshafts will fit the 3.9 engine without having to modify the pulley or flywheel ends? 4.2? 4.4(P76)? or 4.6?
Would be interested to hear comments from owners who have done this to their vehicles.
thanks
Roger

Well, someone on e-bay claims to have 3.5 block with 4.4 crank machined to fit, modified pistons

Range Rover 4.4 Stroker Motor - eBay, Other Car Parts, Accessories, Car Parts, Accessories, Cars, Bikes, Boats. (end time 06-Nov-09 16:14:48 AEDST)

without having to modify the pulley or flywheel ends

Regard s Philip A

Still an intesting combo,
4.4 stuffed into a 3.5

AFAIR a 4.4 has the same bore as a 3.5. The block decks were made higher as Rover considered the conrod angularity to be too extreme with the long stroke and short rods.

So the 4.4 crank should fit OK, using AFAIR Holden 253 rods and I forget which pistons.

However in the deep dark recesses of my memory I may remember that some machining was necessary in the rear seal area.

Good luck with finding a good one as it is now 32years since last production.

Regards Philip A

Originally Posted by PhilipA

AFAIR a 4.4 has the same bore as a 3.5. The block decks were made higher as Rover considered the conrod angularity to be too extreme with the long stroke and short rods.

So the 4.4 crank should fit OK, using AFAIR Holden 253 rods and I forget which pistons.

However in the deep dark recesses of my memory I may remember that some machining was necessary in the rear seal area.

Good luck with finding a good one as it is now 32years since last production.

Regards Philip A

I have a 4.4 in the shed, needs a rebuild, was told to put in 3.5 pistons (domed tops) bumping up the compression.
i also have a 3.5 bored out to 4.0 running.
Im wondering what size it would come to with a 4.4 crank (the bored out 4.0)
Sorry nsgnomad, i seemed to have hijacked your thread

I had a look at "How to power tune rover V8s' today and teh 4.4 has bigger main bearings than a 2 bolt 3.9, and a different and bigger rear crank flange with a different PCD on the holes.

This is not insurmountable but you would have to find rods and pistons to suit, which could be a challenge.


To roverv8

You could fit the 4.4 crank to your 4.0 or most probably 3.9. But the pistons would not be 3.9 as AFAIK they have a different gudgeon height. I guess you would end up with about 4.8 or so litres.You would have to be sure the motor is in good condition before you spent your money having the block line bored, particularly the main cap fitment to the block from beariing shuffle. Also you would have to be sure of the integrity of the sleeves.

Regards Philip A