Thread: 3.5 crank vs 3.9 crank

I have just been pulling my 3.5 V8 apart (original engine from my 10/87 build RRC). This engine was factory fitted with the V belt timing cover.

I have a stoker crank for this engine and I was intending to rebuild it as a stroker (approx 4.2).

However, while the 3.5 has been out of the RRC I have fitted an ex 96 Disco 3.9 (serpentine belt). I don't know for sure, but I believe the serpentine belt engines have a longer snout on the front of the crankshaft. I prefer the serpentine belt arrangement to the old V belt setup.

My question is this: If the 3.9 cranks are indeed longer, is it possible for me to fit the short snout stroker crank and retain the serpentine drive belt system?

[QUOTE=BigJon;1444092
My question is this: If the 3.9 cranks are indeed longer, is it possible for me to fit the short snout stroker crank and retain the serpentine drive belt system?[/QUOTE]

G`day ,

As you`ve found the length is the same .

Your problem with fitting the stroker crank and the serpentine gear is in the length of the keyway and key .

V belt cranks have the same length keys and serpentine cranks have the same length keys but the 2 don`t interchange .

The V belt set up doesn`t care about the key length but the serpentine set up does .

As you have the stroker crank out it means you can have the keyway lengthened and fit a longer key and then use the serpentine gear .

If you need the key length i have it somewhere .