Water pump won't fit!

[rogerowen]

Water pump on my 1960 948 was beginning to get a bit noisy - so decided to replace. 1960 saw a modification to the block which incurred an increase in size of the impellor. Both earlier short impellor and later long impellor versions are available, and as I intended to use the car right up to replacement - I ordered both types, and when the old one was removed I could easily see that it was the long type. However - when I went to fit the new pump the impellor hits the ridge inside the block. Using a depth gauge the new impellor stands 15.5 mm from flange face whereas the old one is 13 mm. Using same gasket goo on the impeller face I can determine where it's making contact.

My first thought was that I should be fitting the short impellor version (maybe a previous owner had modified a 'long' pump to fit whereas my engine originally had a 'short' one) But, then a short pump will obviously not perform as well as the long one - possibly leading to overheating problems.

What I'm thinking of doing is to attack the ridge inside the block with a die grinder to allow a good clearance for the impellor - also taking into account the fact that there will of course be some heat expansion to consider.

Any thoughts?

[rogerowen]

THE PICTURE! [frame][/frame]

[bmcecosse]

Short impeller is correct for the 948 engine. Plenty of circulation...

[ian.mcdougall]

if you grind away will you weaken the cylinder bore

[rogerowen]

Right chaps - many thanks, small impellor pump it is then! All done. [frame][/frame]

[bmcecosse]

BUT - oh dear = that's the very unreliable bypass hose on there!!! Take it off and fit a 'solid' hose before you box it all up.

[rogerowen]

BUT - oh dear = that's the very unreliable bypass hose on there!!! Take it off and fit a 'solid' hose before you box it all up.

Tell me more, please.

[bmcecosse]

The convoluted bypass hoses are very unreliable - far better to fit a 'solid wall' hose which will last 'for ever'. See item #16.... and note the convoluted hose ( # 17) is described as the 'repair' option........ http://www.moss-europe.co.uk/Shop/ViewP ... exID=17143

[rogerowen]

OK, thanks. Don't think BM stock the straight type - will order from M.

[bmcecosse]

Carry the conv hose in your spares kit (along with the head gasket and dizzy and fuel pump) - so you can help fix other Minors stopped at the side of the road!

[DAVIDMCCULLOUGH]

A piece of the 1/2' heater hose it the same, you can get it from any car shop.

[rogerowen]

A piece of the 1/2' heater hose it the same, you can get it from any car shop.

Thanks, think I might have some lying around.

[bmcecosse]

As long as it's good thick wall!