Half time spindle

Previously marcus_bloomfield wrote:

Hello, probably not important but, where would one position the hole on the intermediate spindle? top middle or bottom, too paraphrase the vernacular, I dont want any hot spots through poor oil flow, what is a hot spot? not a good spot, too p the v again..

Hello I do think you need to elaborate a bit more do you mean the half timing gear spindle is situated in the centre of the timing chest so to say, have a nice time yours anna j

The small hole in the spindle that holds the intermediate gear that seems to always come loose faces downwards. At the back of the spindle there is a circlip that stops the spindle going into the inner part of the crankcase. There is also a hardened washer between the crankcase and the gear to stop the gear from chewing up the inner part of the crankcase. I have never had any problems with this part of the engine even when that spindle came loose and I have had Norton twins since the late 1960's.

Oddly, Anthony - I've had problems here. My spindle spins freely, and when I take the timing cover off it has been known to come partly out with the cover - thus allowing that hardened washer to drop down. That's then a nasty job with bits of bent wire to hold it in place when putting the spindle back in - either that or removing the sprockets to remove the chains etc etc.

So next time the cover comes off I've promised myself to Loctite the spindle back into the hole. Then the question is - which Loctite etc etc.? Or maybe stake the surround?! Until then,I'm leaving well alone.

Hole at the bottom to allow oil to lube the gear ,otherwise the oil would just not go anywhere usefull.

It is the bellows effect of the oily gas mixinside the engine that helps to lubricate the half time pinion. Along with the timing chains, followers and camshaft. As the pistons descend themix is pushed through the circlip end of the spindle and out through the hole midway alongthe spindle. These gases cannot pass all the way through the spindle due tothe timing cover blocking off the far end.It is best for the midway hole to be pointing downwards.

This is yet another piece of the Norton Twin cylinder engine that was designed to self lubricate. But.......peopleadding extra holes and breathers to the engine actually mess up the former and can end up causing premature wear. A similar issue can occur, to some extent,with camshaft followers.

Interesting observation from Anthony. I have always resisted putting extra breathers in engines on the grounds that if you need extra breathers you probably need a rebore. Good to know there are other valid reasons for leaving well alone.