Fan pulley assembly.

[Chris KC]

The thread is actually Whitworth but 2BA is a very close alternative.

I wonder if that could be why mine continually wriggle loose?

[Reckless Rat]

With the cost of a radiator re-core being what it is, a few drops of Loctite are a very worthwhile investment!

[Chris KC]

With the cost of a radiator re-core being what it is, a few drops of Loctite are a very worthwhile investment!

Good thought Reckless!

[AustinWood]

Working loose might well be caused by the fan being out of balance.

[Chris KC]

Working loose might well be caused by the fan being out of balance.

Yes Jim, see above. If anyone has a nice cheap, simple way of balancing the fan properly I'd be interested to hear about it.

[jansens]

I am assuming the flat washer that goes on first should but up hard against the flat of the shaft bracket? On mine the hole in the washer is the same diameter as the shaft so it won't go fully home as the shaft itself has a curved fillet on the base.

This is all assembled form mismatched second hand parts so I am not sure the ones I have are correct.

I have an old 2 blade fan with traces of red on it. Not sure that's original though,

Simon

[Bill Sheehan]

I am assuming the flat washer that goes on first should but up hard against the flat of the shaft bracket? On mine the hole in the washer is the same diameter as the shaft so it won't go fully home as the shaft itself has a curved fillet on the base.

This is all assembled form mismatched second hand parts so I am not sure the ones I have are correct.

I have an old 2 blade fan with traces of red on it. Not sure that's original though,

Simon

To follow on re the colour - this was discussed at length once before on the Forum.  My understanding was Austin didn't paint them until the 4-bladed type came into being, but because as jansens said, the two-bladed ones that  are red may not be original, we'll probably never know for sure.  I've worked on dozens of vintage Sevens and never found traces of red paint on any of the fans.  There would have to be instances where the first owner painted them themselves?   Cheers,l  Bill in Oz

[Mark Dymond]

The thread is actually Whitworth but 2BA is a very close alternative.

There are several types of fan pulley all of which are different lengths - can you post a photo of yours?

Thats good to know, remeasured the bolts on mine and they are 2BA - but all different so not original. A 2 BA tap runs down the holes fine but I have no bsf or other to compare.

Pics below of the pulley setup, I assume its standard, perhaps someone with a speedy engine can confirm. I have always assumed the problem stems from the body position on the chassis. Its an Arrow and has a few "hand built" attributes

[Ruairidh Dunford]

Sports fan pulleys are internally wider but I would need to check one of mine against a standard to tell you if this affects the total length.

Your flitch plates are somewhat different from factory (I presume Arrow made) and this may affect the position of your rad. With some careful file work in the mounting holes you should be able to move the rad forward slightly but your bonnet may then end up a less snug fit.

[Mark Dymond]

Sports fan pulleys are internally wider but I would need to check one of mine against a standard to tell you if this affects the total length.

Your flitch plates are somewhat different from factory (I presume Arrow made) and this may affect the position of your rad.    With some careful file work in the mounting holes you should be able to move the rad forward slightly but your bonnet may then end up a less snug fit.

Ruairidh, ive had the whole body off to try to move things forward (and failed), the bonnets a bad enough fit with the radiator in the current position! I think with recessed socket head screws I'll be OK, how confident are you that the thread is imperial (3/16 BSF I presume)

Cheers, Mark