Jp4 crank question

27th May 2015, 21:36

I'm just about to rebuild the engine back up and have a question about the crank fitment.

The engine is a jp4 however I am going to be running.

J4 cams, cam pulleys, springs, retainers etc
J4 cambelt kit with waterpump
J4 cambelt covers

Looking to find out is the crank fitment is the same on the jp4 as the j4 ?

Can I use the fitted jp4 crank pulley or will I need to change this to a j4 one ?

28th May 2015, 08:41

What I have managed to find out so far is the part numbers are the same for the pictured part above on the jp4 & j4 engine.

The only difference between the two is the vts j4 has a crankshaft spacer and the jp4 doesn't as its built in to the part.

From the parts diagram the difference is the 3 bolt crank pulley the vts j4 is 5 ribs and 138 diameter.

The newer jp4 is 6 ribs and a larger diameter 146 or 152 depending on alternator.

I know the part fitted is the earlier vts j4 part as it doesn't have the spacer part built in to it. With my engine being the newer jp4 it shouldn't be this part that's fitted on to the engine it should be the later one with the built in spacer.

This could be one of the reasons the belt has slipped and the valves bent. I'm going to fit a jp4 pulley with the built in spacer which should align everything better.

See photo from another thread below showing the difference.

Newer jp4 engine set up

Saxo vts j4 set up