vacuum advance

[horrace]

hiiiiiiiiiii everybody. going to try and adjust the timing tomorrow but feeel i ought to check the vacuum advance is working ok..... how do i check that the vacuum advance is working

[les]

If you suck on the attached tube it should cause the mechanism to turn slightly.

[bmcecosse]

If when you suck there is no resistance ie you can't make a vacuum, then the diaphragm has failed - if you can make a vacuum but the plate in the dizzy doesn't move then either the plate is seized (so try release oil) , or the vacuum unit is seized........ Any which way - you will need a new one! They rarely work if over 20 years old.....

[horrace]

Ok thanks and where's the plate in thanks distribbutor thing

[bmcecosse]

Oh dear......it's obvious when you take the cap off..............

[horrace]

as you say its obvious, i just checked and to my amazement it seems to work fine. its a 25d distributor, now i intend to advance the timing as discussed in a previous thread as we have the 12g940 head on, i tried to advance it on the knurled knob but it was already right forward, what sort of increments should i be advancing by, 1mm 5mm 25mm! and i assume i just mark where i start and then go from there or are there some marks on it already?
got a tiny oil leak since fitting the 12g940 head at the corner nearest the front exhaust manifold if anyone is interested? its only just visible so i guess not to worry abooooot!

[bmcecosse]

Just turn the dizzy a couple of mm clockwise - then you can wind back the knurled knob slightly to mid-stroke and play about from there.

[horrace]

ok, thanks if i can wangle it past the mrs ill get it done tommorrow, gonna try and do the brakes as well...

[horrace]

well i managed to wangle it and got the brakes done and did the 1st adjustment on the dizzy, i marked it up and twisted clockwise about 3mm.. i think it has worked as it has now lost its 'turbo lag' on acceleration and ive never haed it before but i think it is pinking... to me it sounds like hitting a piece of copper tube against a bit of metal. Its only apparent when i put in 4th and try to accelerate when its doing about 10 - 20mph. difficult to hear over noise of exhaust tho!

[MarkyB]

That's pinking, try retarding it on the knurled nut till it stops.

[horrace]

thanks will try to do this eve, not driving in the mean time tho

[bmcecosse]

My engine pinks very slightly just as I start to slog it - then it quiets down. Certainly don't run it with continuous pinking!

[katy]

Its only apparent when I put in 4th and try to accelerate when its doing about 10 - 20mph.

You shouldn't be lugging it that hard, no wonder it's pinging.

[horrace]

i dont normally, it was just to see.......... you know like touching paint to see if its dry even thought you know its wet!

[katy]

Aah so