MGB Register Forum

Hi The “click “ on my distributor vernier is very in distinct. Does anyone know how many degrees of adjustment one turn of the wheel is equivalent to?

I 'm fairly certain 10 clicks = 1 degree. Count the clicks from one end to the other and centralise it first. I think there are 50 clicks equating to 5 degrees.

I think its 11 clicks to the degree (crank)

Thanks for your reply. The problem is that I can’t distinguish an individual click on the wheel so I can’t count how many clicks when I am turning the wheel in either direction. Need to know how many degrees or clicks equals one complete revolution of the wheel then I can work out how many revolutions or part revolution to know how many degrees . Thanks

Geoff.

When moving the Vernier wheel you should be able to feel the clicks rather than hear them. If you are wearing work gloves, try this without them on! I can't recall hearing the clicks but always adjust by feel.

It seems to me that if you really are not getting any ratchet like setting, then there may be nothing to hold the Vernier in place, and it may well move away from any setting chosen?

Ian F

Hi Ian. I have been adjusting the vernier with bare hands but not achieving any ratcheting feeling. It feels like the wheel is detached from the ratchet but there is still resistance and an occasional click. I have been offered the old distributor by the previous owner maybe I should check this out and if it’s ok transfer the internals of the one currently fitted and do a swap

Thanks Geoff. It seems very likely that the distributor is faulty, and that it wouldn't be possible to reliably adjust the spark by using the Vernier. I'm sure it could be repaired and come back as good as new (Distributor Doctor) and that may be your best course of action.

I didn't bother too much with distributors for many years - they still work even if completely worn out! However, after getting mine rebuilt/restored it transformed the performance.

Two of the problems are;

Worn shaft/bearings causing a lot of scatter

Weak and worn out advance springs causing the mechanic to set the static advance incorrectly leading to inadequate advance at higher revs.

Ian F

Hi Thanks for all your input but does anyone know the answer to my original question -How many degrees of adjustment is one full turn of the vernier ‘nut’ equivalent to?’ Or put another way how many clicks are equivalent to one full turn accepting that 10 clicks equals one degree. Thanks

Geoff, not sure how to actually measure this? From memory I think the Vernier wheel moves a rod (connected to the diaphragm? That rod is marked with the degrees I believe. There is no base mark to measure against because the starting point for the timing depends on the rotational setting of the distributor in the block itself.

If you can see those markings - I believe each represents one degree - you should be able to determine what you require.

Does this help?

Ian F

Hi Ian. Contacted Distributor Doctor and they weren’t much help -surprisingly. Will get the distributor out some time and have a play around- see what I can find with a close up inspection