Anybody know the size of the crank pulley bolt and the pitch of the threads ?

it looks like a 16mm bolt - 1.5 pitch on the threads.

 

19mm 1.5

 

Ok, if one were to buy a tap, which one would be correct ?

 

A 19 X 1.5mm

 

This is not correct. For anyone else that looks at this thread. 19 is too large

 

majestic shows its a 16x49 (49 mm being the bolt length). it doesn't list the thread pitch, however. IIRC, 19mm is the bolt head size.
darcy

 

There is no such thing as a 19 mm bolt. For that bolt in particular, probably even more important is the head style and grade.

 

OEM crank pulley bolt is 16mm x 1.5 tpm pitch.

It is 49mm long. However....it has a floating, non-removeable, 8mm thick washer, making it effectively a 41mm bolt.

If you were to get a 49mm bolt from the aftermarket without a washer, it would bottom out in the crankshaft.

So 41mm from the base of the washer to the end of the bolt.

 

Some people refer to bolts by the metric size of the head, hence the 19mm which is the socket size. But the threaded bolt sizes are correctly noted by Darcy. I take it that the end of the crankshaft is stripped and needs repair ?

 

People typically do that only when referring to the tools needed to remove it. As in diy instructions. For example, ...then remove the 19mm crankshaft bolt.

It that context, the real bolt specs, diameter, thread pitch, length, are not important, as you're typically going to reuse the original fastener. So in that scenario you only care about what tool to use on it. Its incorrect vernacular, but its acceptable as everyone realizes you are referring to the tool, not the fastener specs.

When REPLACING a bolt, you HAVE to refer to the actual bolt specs. Diameter, pitch, length. Anyone that refers to the bolt head size instead of the bolt diameter when spec'ing a bolt is simply doing it wrong.