Adjustments on distributor drive housing

[ukmax]

I have to rectify a severe oil leak on my LM SS from the fan belt drive pulley shaft seal and I notice what appears to be three adjustment slots, two at the end of the top two bolts holding the generator on and the other a little lower down behind the fan pulley. Will somebody please tell me what these adjustments are for.

I have only recently discovered that these cars were not fitted with fans as standard so I assume that the protruding end of the distributor shaft was covered in some way, maybe similar to the dome used to cover a starter bendix? - are such covers available? I intend replacing my fan with an electric one.

Many thanks
David

[nth]

Hi David
My '33 nine sports has a factory fitted SS engine which has a fan. Can you post a picture of the oil leak location?

[nth]

late 33 SS engine

late 33 SS engine

[Peter McKercher]

Sounds like your oil thrower (Mexican Hat) is either worn or missing.

[ukmax]

Thank you Neil, what I said about the fan was only an assumption based on me reading an article that mentioned the fan followed by the words "if fitted".

The leak only occurs when the engine is running and looking from underneath with a small mirror, I can see the oil running down the cover from behind the pulley and there is no oil leak apparent above the pulley. I'll post a photo later.

Thank you Peter,. I did suspect the "Mexican hat" thrower but as the leak is a fairly recent event, I assumed the thrower is present however I didn't know it could wear or indeed how it could wear so it seems I'll have to investigate that.

From what I can make out from the relatively small diagrams I have, it seems that the thrower has no key way so it must only be pinched between the pulley and chain drive sprocket so I'm now wondering if the pulley bolt has become loose. I'll check the bolt when I go up to my workshop later today.

[Peter McKercher]

Yes they do wear. Mine was actually missing entirely though and causing a substantial leak.

[ukmax]

Thank you Peter, I actually found and downloaded those very photographs during a recent search of the forum! I now have a greater knowledge of the subject! The remaining mystery is - how do I adjust the fan belt please?

David

[ukmax]

Image as requested. The leak is below the place I am pointing at with the screwdriver. The frayed fan belt is another investigation required!

[Peter McKercher]

The remaining mystery is - how do I adjust the fan belt please?

David

The fan mounting bracket (red in your photo) is adustable

[ukmax]

Ahh, I see now - thank you

I was confused by your reply at first, then I realised you were referring to Neil's photographs.

I've had the Singer for over 15 years but it has had little use and thus I have not needed to carry out any meaningful work on it until now so I'm on a steep learning curve, especially as this is my only pre-war classic car.

[ukmax]

Just to update and close the topic.

There was no "Mexican hat" thrower fitted but the previous owner who was a competent engineer, had made a new cover and incorporated lipped nitrile rubber seal (24x35x7 mm) which had worn. The engine was rebuilt about 20/25 years ago and whilst I've done very little mileage in it, the PO did several thousand miles, so the seal has lasted well and probably suffered more from lack pf use than it did from use!

However, I don't think that this is really a suitable arrangement because of the need for more precision when centring the cover after generator chain adjustment, therefore, the seal is almost certainly going to be squeezed more on one side.

When I have the time, I shall remove the front cover and fit an oil thrower but also leave the seal in place, meanwhile I shall simply replace the seal, but with a steel bodied, double lipped one.

[jeans_old_man]

Hardwick's are showing item 107 Oil thrower (mexican hat) in stock at £17.50. Counter intuitive but probably a better solution than an oil seal - I've never had a problem with mine.

[ukmax]

Thank you Brian, I'm on the case.

I prepared for a bit of a battle to get the seal out of the cover only to find it to be a very loose fit, which surprised me given the PO did the job! so it could be that oil was leaking past the outer edge of the seal - I'll never know now. I'll use I light smear of sealant when I fit the new seal.

There is more oil than usual in this area because I have a small bore feed pipe to drip feed a small amount of extra oil on to the distributor drive gears.

[ukmax]

I thought I'd closed the topic but there is another development.

It seems that the only problem with using an oil seal in the on the dynamo pulley shaft is keeping the shaft dead centre (within 10/15 thou for the seal I used). I therefore made a tool (see picture) to centre the cover on the shaft before refitting the pulley. There was no need to put a keyway in, I just ran a 6mm end mill down the edge to clear the woodruff key. The smaller diameter of the tool is less than the oil seal so the seal does not interfere, the cover actually centres on the short (1.5mm) larger diameter.

After adjusting the drive chain, it's a pretty simple job to remove the pulley and recenter the shaft.