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MG MGA - Water pump pulley size

Trying to sort out what pump/pulley I have and which one I need.

1960 MGA with 18GB-U-H engine

The crankshaft pulley and the generator pulley line up perfectly but the water pump pulley is about 1/2 to 3/4 of an inch too far forward. This explains why the PO had a spare belt in the boot! Do I have an MGA pump on my MGB engine? Or possibly an MGB pump but an MGA pulley and fan?

Has anyone got a measurement for the length of the pump and/or fan pulley?
Thanks,
Dave



David Evans

David, Try for another pulley. I have found there are several pulleys, of various depths, from a variety of cars and models, not just MG's. The one from my Mk11 measures 110mm diameter across the vee, and 40mm from the fan mounting face to the centre of the vee. It is 50mm from the fan mount face to the back edge of the vee. Hope that makes sense!
Barry
BM Gannon

I had a similar problem where the PO had mixed an MGB (so I was told later) fan pulley with an 'A' pump and dynamo. The MGB fan pulley (see picture) has a longer nose by about your 1/2 - 3/4" and the PO had partially packed it out with a thick spacer between the water pump and pulley. Scaling from your photo it looks like you have an 'A' pulley which has a pulley width of 18mm and nose depth of 34 mm approx.
mike


m.j. moore

Dave, The fan on your car is not an MGA fan, probably an MGB unit. The cutout on the edge of the blade is not on the MGA. Also, your fan is indstalled backwards. There is a slight cup to the fan blades. The concave side should be towards the engine. It makes the fan slightly more efficient. Since you are working on this area anyway, I suggest reversing its orientation. I run an MGB fan on mine and have not seen any ill effects.

It looks like your water pump is a cast iron original style unit. I think it is likely that the pump, pulley and fan are from the MGB engine and not MGA issue. I assume that you are sporting an MBG crank pulley too.

As to the proper pulley to use, I'll leave that up to the others to sort out.

Chuck
C Schaefer

Looks like I have an MGA pulley and MGB fan (backwards!) Thanks for spotting that one Chuck. I would be some upset to find out after I got everything put back together.

I am thinking that I have an MGA pump too. The lubrication screw on the top of the pump matches the location on the pump in my MGA manual. It looks like the MGB had the lube point on the side based on the picture in the Victoria British catalogue. Is it right that the MGB pump is shorter than the MGA? I can buy a new MGB pump as they are not too expensive but will have to get a pulley somehow. Does anyone know a source?

The crank pulley is definitely MGB.

Thanks guys,
Dave
David Evans

What other pulleys will work with the water pump? I know that some of the Datsun 240z pulleys will work are there any others?

Thanks
Gordon
G Masor

The 3-main bearing and 5-main bearing water pumps are not interchangeable, even though they have the same bolt pattern. The 5-main pump has slightly different rotation axis and larger impellor, as well as being slightly longer. You need the MGB pulley to match the MGB pump. You may also need to shim the radiator forward about 1/4 inch to clear the fan. A less desirable alternative might be to machine almost 1/4 inch off the front of the 5-main water pump hub flange and use the MGA pulley.
Barney Gaylord

Dave, I know someone close to me who deals in s/h 'A' and 'B' parts so, if you can't find anyone nearer to you, I could ask if he has a 'B' pulley. New 'A' pulleys are no longer available but I would have thought 'B' pulleys are easier to come by. I paid this same guy £20 for an 'A' pulley a couple of years ago but only got £5 for my 'B' pulley on Ebay! mike
m.j. moore

A pulleys are available
dominic clancy

As Barney notes, there are at least two different "B" water pumps. My "B" engine came with the wrong one, and no selection of alternate pulleys would make it line up with the crankshaft pulley. I had to buy a different pump.

Ken
k v morton

I have used the "short" version of the 5 main water pump and the later pulley found on the 18V engine. It is designed for two pulleys and the rear one lines up perfectly.
Thomas Lennon

A follow-up to Barney's info. The water pump pulley for the MGA is 2" from back to nose. The 3 main MGB 1800 is 2.25" to account for the greater forward protrusion of the 3 main 1800 water pump shaft. To accommodate for the 3 main 1800 water pump, the radiator has to move forward for fan clearance. In the case of my MGA the radiator moved forward by .5". This was accomplished by .5" plywood cut to shape using the original spacer/insulator that fits between the radiator and mounting flange as a template. Painted black the plywood part looks as if it belongs. .5" longer bolts are then needed to mount the radiator. There's no problem with bonnet/radiator clearance.

-Martin Straka
Martin Straka

This thread was discussed between 04/02/2008 and 09/02/2008

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