JowettTalk

Probably a question with an obvious answer...but...the engine number on my Javelin is R7289. This does not conform to usual engine numbering, so what's the explanation? The chassis number is E1PD19996D. Michael

Are you sure you are looking at the engine number, and not a casting number on it?

Engine no should be right on the front of the engine on the raised plinth:



You can just about make it out on the front of the engine, just above the engine mount. If that is where your R7289 number is, then I'll have to leave this one to the experts!

Jack.

Thanks Jack, yes the number is on the raised plinth, bit of a weird one! The R number is taken from the log book, the actual number on the engine plinth is N7957! Evan more curious!

R numbers on engine mean the engine was reconditioned at the factory. It is usually on a plate on the clutch housing.
The crankcase numbers should be the same on each half of the block.
No idea what the N prefix is.

The number R7289 signifies that it has been a factory reconditioned unit fitted with a square web crankshaft. There is usually a brass plate giving the crankshaft dimensions located above the starter motor hole. If this is missing, or one has never been fitted then the original number has been filed off and the N number stamped on. There should be a large number stamped on the front of each half crankcase and that can also tell a story. If it had a number prefixed RO........ then it was a factory reconditioned unit with an OVAL crankshaft. I notice from the photo that it still has the early Volkes oil filter casting and not the later Tecalemit unit.

An N before the number MAY signify that a nitrided shaft had been fitted but this code was not the standard. If you open up a Jowett engine then it makes sense to record exactly what the internals are.

Drummond

Thanks Admin and Drummond; the picture belongs to Jack, mine is in the car! Yes the engine was fitted with a square crank replaced by an oval one ( previous owner). Crankcase numbers normal, no letter prefix. Factory recon with square crank must be right and later oval crank must be nitrided.