Midget Distributer

Post by **Matt** » Sun Nov 16, 2008 11:48 am

HI Guys

I have a midget (okay spridget) engine im about to put in the minor, its a goldseal unit and appears to have only done a few thousand miles. It was in a car that was taken off the road in 83/84. The car itself has about 120,000 miles.

Anyway the dizzy on it (which appears to be the one that was on it when reconditioned) doesnt have a vacuum advance unit! Has anyone noticed this before?

Post by **WPR678B** » Sun Nov 16, 2008 12:36 pm

The Marina engine i had in the red pick up didn't have a vacuum advance on it either and it worked fine mate

Post by **bmcecosse** » Sun Nov 16, 2008 1:31 pm

Original Cooper S dizzy had no vac advance. Thinking nowadays is - you NEED a vacuum advance for best running and economy. I would suggest you simply swap the bob weights and springs into a dizzy with a vacuum advance - and use that.
On the other hand - people seem to pay daft money on ebay for these original S dizzys - so may be worth cleaning and selling! What number is on the body - I can't remember S number - but something like 40811 ??
Second thoughts - maybe it's 40819 ??

Post by **Kevin** » Tue Nov 18, 2008 3:55 pm

The Marina one was produced to stop crank rumble, with the dizzy with advance unit this was a problem with the earlier Marina engines.

Post by **Alec** » Tue Nov 18, 2008 5:31 pm

Hello BMCE,

you only need a vacuum advance unit if you drive sedately, presumably BMC thought that economy was the last thing on an 'S' buyer's mind so tuned it for performance?
My Triumph 2.5 P.I. doesn't have a vacuum advance unit either, but that only has about 7" HG at idle so not much vacuum at all anyway.

Alec

Post by **bmcecosse** » Tue Nov 18, 2008 7:19 pm

I hear you Alec! The vacuum advance though allows a very slight static advance to be set for easy starting - and then when the engine starts and idles - the vacuum (even 7"Hg) pulls the timing up to give a nice smooth idle. Cooper S were often set with 10 BTDC static - and were a bu99er to start in cold weather - especially if the CR was increased. The engine would kick like mad against the starter. So - my vote is very much FOR vacuum advance. Like your PI - many TR7s had strange vacuum arrangements (must have been a Triumph 'thing') - especially for export - they actually had a vacuum RETARD sytem fitted to cheat the emissions tests. They go very much better when kitted out with a proper UK style vacuum advance dizzy.
And I've never been able to understand how no vacuum unit was supposed to help 'crank rumble' - either the cranks were a good fit in their bearings - or they weren't - just don't see how timing would help any rumble! And this 'idea' seemed to be unique to Marinas - certainly not to Mini or Metro units!