AJP Crankshafts - 2 or 3 types ?
Discussion
Hi,
Are there 2 or 3 types of AJP Crankshafts
1) There is the early cast 4.2 small journal Crank fitted from 96 to 97(ish) - some have failed but a lot survive today.
2) There is the steel 4.5 larger journal crank fitted to all 4.5 and later 4.2 cars (not known to fail)
3) Was the 4.5 crank fitted to 4.2's from 98 or is there an improved 4.2 crank fitted from 98 to ??
Capacity difference is achieved via piston and liners not crank throw?
Hope the question is clear enough ?
David
Are there 2 or 3 types of AJP Crankshafts
1) There is the early cast 4.2 small journal Crank fitted from 96 to 97(ish) - some have failed but a lot survive today.
2) There is the steel 4.5 larger journal crank fitted to all 4.5 and later 4.2 cars (not known to fail)
3) Was the 4.5 crank fitted to 4.2's from 98 or is there an improved 4.2 crank fitted from 98 to ??
Capacity difference is achieved via piston and liners not crank throw?
Hope the question is clear enough ?
David
If you discount billet, then there is only two types I'm aware of, large and small journal both 86mm stroke. Change over between small/large was I think around 98, I'm sure someone like Andy @ APM or Paul @Austec could tell you exactly.
The only real difference between 4.2/4.5 was the bore which as some are finding out became the same 91mm for the later cars i.e. they were all 4.5's towards the end.
The 4.7, I understood it was a stroker, but APM has posted in the past it was achieved by bore only, I've neveer seen one, so again I'd defer to those that look at the internals of these lumps.
The only real difference between 4.2/4.5 was the bore which as some are finding out became the same 91mm for the later cars i.e. they were all 4.5's towards the end.
The 4.7, I understood it was a stroker, but APM has posted in the past it was achieved by bore only, I've neveer seen one, so again I'd defer to those that look at the internals of these lumps.
there are 3 tpyes if you want to be fussy.
the ealry 4.2 crank which gets hair line cracks and disintergrates
the late 1998 on iirc 4.2's which seem to be of better mouldings/qulaity of iron and dont seem to suffer from cracks etc
and the 4.5 steel crank which is "unbreakable".
this is what i read on here somewhere.
the ealry 4.2 crank which gets hair line cracks and disintergrates
the late 1998 on iirc 4.2's which seem to be of better mouldings/qulaity of iron and dont seem to suffer from cracks etc
and the 4.5 steel crank which is "unbreakable".
this is what i read on here somewhere.
I couldn't say for sure that this is always the case but a recent (98 or 99) "4.2" I stripped had the large journal steel crank and was in fact a 4.5
I suspect that on later cars the engines were all 4.5 and the only difference was the induction system.
What is a bit weird is that the rods were cast. I would have thought if you go to the trouble of putting a steel crank in an engine you would use forged rods too.
Jon
I suspect that on later cars the engines were all 4.5 and the only difference was the induction system.
What is a bit weird is that the rods were cast. I would have thought if you go to the trouble of putting a steel crank in an engine you would use forged rods too.
Jon
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