Morris Minor Owners Club

and minimum movement any tighter and you risk both dynamo and water pump

And don't use the 'cogged' belt.......

Wots wrong with the cogged belt?

They have a greater tendency to snap apparently. But if it is correctly adjusted I cannot see the problem.

Wots wrong with the cogged belt?

I have been using them since I fitted an alternator 40 years ago - they are better for wrapping round the small alternator pulley. I now use a larger alternator pulley to slow it down slightly, but never had any problem of any kind - I do replace it about once every 5 years or ~20,000 miles.

The other easier option to stop the impeller fouling is to fit another or thicker gasket.
.6 of 1mm spacing is all that is required to get the impeller to run free.
I fitted an additional .6mm thick paper gasket.

I just grinded a little off the impeller. It Didnt need much off it.

Adding another gasket is not a sensible option - because it puts the pulleys out of line.........

I dont think half a mill' will do any damage at all,
and not just a matter of opinion BMC, in practice on mine it hasnt, at the end of the day its a minor,not an RB211.

True, it's not a lot but being right -----it's an engineering thing. I do sometime wonder how well the original setup lines up though!

Its not about being right in theory,it is in this instance what is right in practice.
The right "engineering" solution is to fit the correct pump with impellers that dont foul.
However given the options I opted not to grind the impeller, because without something akin to a surface grinder (which of course is not practical) only a casual agricultural finish can be achieved, with say an angle grinder,probably the only option open to the hobbyist.
Also there is the danger of getting miniscule bits of steel washing round the cooling system.
As someone who is not a time served motor mechanic but a time served mechanical fitter, I always bow to superiority vis a vis the internal combustion engine, but having fitted this option, I can confirm it not only works but doesnt even wear the belt unevenly.
It is a small, perhaps even insignificant point, but something that should be tattooed on every apprentices torso should be the words
"Don't test the temperature of the water when your'e up to your backside in crocodiles".

I wasn't talking theory. Incidentally I've never seen an impeller with other than a rough finish. However a fine finish is quite feasible with an angle grinder, if you go lightly.

les wrote:I wasn't talking theory. Incidentally I've never seen an impeller with other than a rough finish. However a fine finish is quite feasible with an angle grinder, if you go lightly.

Ok Les, but if you have fitted an additional gasket, then in practice you have completed the exercise and can through the experiment prove the theory.
If however you have not, then it remains a point in theory.
Pedantic? me? how dare you sir?