The crank pulley bolt on a BMC A-series engine is 5/8" 16 TPI. I can't seem
to match that to any thread series. Is it a custom truly non-standard
thread, or is there a hope of finding a source for a 1.5" long bolt in that
thread?

Thanks, Brian

Brian wrote in article
...
The crank pulley bolt on a BMC A-series engine is 5/8" 16 TPI. I can't
seem
to match that to any thread series. Is it a custom truly non-standard
thread, or is there a hope of finding a source for a 1.5" long bolt in
that
thread?

Thanks, Brian




If the "B" in BMC stands for "British", and the machine is older, it's
quite possible that you have a Whitworth bolt - a unique creature unto
itself.


Bob Paulin - R.A.C.E.
Racing Chassis Analysis Services

Machinerys handbook lists it as 5/8 -16 UN between UNC and UNF. From my
experience with the A series it uses unified threads and not BSW / BSF.
Are you doing something special with the engine or do you just require a
replacement.

Brian wrote:

The crank pulley bolt on a BMC A-series engine is 5/8" 16 TPI. I can't seem
to match that to any thread series. Is it a custom truly non-standard
thread, or is there a hope of finding a source for a 1.5" long bolt in that
thread?

Thanks, Brian

I should have looked in Machinery's myself, rather than relying on a
new-fangled Google search! thanks!

I am dry-sumping the engine, and need to drive a minimum 1/2" wide gilmer
pulley for the oil pump in addition to the normal crank damper and water
pump pulley. One design would work better if I could get a longer bolt to
hold the pulleys on with. It's British Motor Company (British Leyland,
etc.) and the engine is a 1071cc Formula Junior engine for a 1960's Cooper.

Brian


"David Billington" wrote in message
...
Machinerys handbook lists it as 5/8 -16 UN between UNC and UNF. From my
experience with the A series it uses unified threads and not BSW / BSF.
Are you doing something special with the engine or do you just require a
replacement.

Brian wrote:

The crank pulley bolt on a BMC A-series engine is 5/8" 16 TPI. I can't
seem
to match that to any thread series. Is it a custom truly non-standard
thread, or is there a hope of finding a source for a 1.5" long bolt in
that
thread?

Thanks, Brian

I think you may have to resort to thread cutting a special.

Brian wrote:

I should have looked in Machinery's myself, rather than relying on a
new-fangled Google search! thanks!

I am dry-sumping the engine, and need to drive a minimum 1/2" wide gilmer
pulley for the oil pump in addition to the normal crank damper and water
pump pulley. One design would work better if I could get a longer bolt to
hold the pulleys on with. It's British Motor Company (British Leyland,
etc.) and the engine is a 1071cc Formula Junior engine for a 1960's Cooper.

Brian


"David Billington" wrote in message
k...

Machinerys handbook lists it as 5/8 -16 UN between UNC and UNF. From my
experience with the A series it uses unified threads and not BSW / BSF.
Are you doing something special with the engine or do you just require a
replacement.

Brian wrote:

The crank pulley bolt on a BMC A-series engine is 5/8" 16 TPI. I can't

seem

to match that to any thread series. Is it a custom truly non-standard
thread, or is there a hope of finding a source for a 1.5" long bolt in

that

thread?

Thanks, Brian