1275 a series with a Shorrock

[ColinChandler]

Hello everyone,
Just a quick question to see if anyone else has had the same problem when fitting a Shorrock supercharger to a 1275 Midget engine. As you can see, the timing chain cover oil separator gets in the way of the belt path. I know good breathing is important on A series engines to avoid leaking oil through the rear crank scroll so I'd be pleased to hear advice from anyone who has overcome this problem with a cunning plan.
Many thanks, Colin.[frame][/frame]

[bmcecosse]

You'll need to use a standard flat face timing cover - and a rocker cover with breather connection.

[philthehill]

As bmc says use a flat timing cover.
Has your twin belt crankshaft pulley for driving the supercharger been fitted yet? It does not look like it! If not do not do anything until that has been fitted and the alignment/clearances re-checked. The crankshaft pulley has three grooves - two for driving the supercharger and one for driving the water pump and dynamo/alternator. The supercharger drive belts should be a matched pair otherwise you will have one of the belts doing all the drive work and it will soon fail.
See: http://www.shorrocksuperchargers.co.uk/ ... x?DocID=66 for details. Also elsewhere on that web link you will find the full instructions for fitting a Shorrocks Supercharger to an 'A' series and all the information you could want relating to the Shorrocks Supercharger including what additional parts you may require to fit the supercharger sucessfully.
Note the spare dynamo belt fitted behind the supercharger drive belts
If you must have a crankcase breather you can tap into the side of the crankcase where the blanked hole for a mechanical fuel pump would have been fitted. A useful mod fitted to many comp engines.

[bmcecosse]

2nd vote for using the mechanical fuel pump opening - or drilling it through if not present. It is very 'low' on the engine and likely to pick up oil droplets- so a good long vertical wide area section (possibly even filled with copper pot scrubber mesh) will be needed to act as an oil/fume separator, before connecting to the carb inlet.

[ColinChandler]

Hello again and thanks for the superb advice – especially the link to the installation photo.
My first thoughts were to take a “flat” timing cover and weld in a separator can so it points towards the supercharger i.e. being in the gap of the supercharger belt. There’s not much clearance if the belts flap and I wasn’t sure if moving the can to a shallower angle would make a difference to how well the oil separates/drains back. Therefore for ease, if you think a flat timing cover and a rocker cover connected to the carb would be fine, then that’ll be my first attempt. Would you use a vented or a plain filler cap in the rocker cover?
Yes, that photo was taken mainly to see what the supercharger looked like in the engine bay and it did give me a bit of an “eyes on stalks” moment when I stepped back to have a look. Since then the 3 groove pulley has been fitted and the car used conventionally whilst I’ve been busy on other areas but I can’t see any other clearance problems now I’ve now fitted an electric fan in front of the radiator.
I have made sure too that the belts are a matched pair so they both do equal work. That’s a very good point to be aware of and it wasn’t the case with the first pair I bought. I had a quick scuttle back to swap them for some that matched. I like the spare alternator/dynamo belt stowed away too and thought it’s a brilliant idea. Belts never break in the comfort of the garage so anything that makes fitting a new one at the side of the road is all to the good.
Thanks again for your help. It’s much appreciated.
Best wishes, Colin.

[bmcecosse]

I would use a non-vented cap. The extra belt tucked in is a standard 'rally' trick. Trouble is - when you go to use it in 3 years time it's been contaminated with oil - and subject to considerable heat - and therefore of dubious use.. But better than nothing when stuck in a dark forest!!