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MG Midget and Sprite Technical - 1500 Water Pumps

Recently bought a '78 midget with the 1500 engine. The fan clutch is making a horrible noise. It's got to be replaced along with the water pump. Can anyone tell me if the water pump prior '74 (no clutch, solid fan) will bolt up to my engine? I would prefer a no clutch, continuously spinning fan due to climate conditions here in the Southeast (very hot!).

Any help would be appreciated!
DL Rhine

The water pump prior to 74 was for a different style of engine. It was for an A series Midget and not the triumph engined water pump that you will need.
Robert (Bob) Midget Turbo

Thanks for the info, I had been browsing a spitfire engine catalog and noticed that the '74 and '75 pumps had a similar looking bolt pattern. I'll just order the proper original parts.

Thanks again!
DL Rhine

But Bob, he has a Spitfire engine, so he needs an earlier Spitfire pump, which he seems to have figured out.
I've switched pumps, no problem, no fan clutch. Actually I think maybe all Spitfire, GT6 and TR6 may be interchangeable. Can't exactly recall the details, but some, possibly GT6-TR6, have different pulleys (comes on pump), so different speeds and belts. But last one (77 Spit) I did, I just used a 75 Spit I think.
Call up TRF and check.

FRM
FR Millmore

< It's got to be replaced along with the water pump >

The fan clutch is press-fit onto the water pump, it's not required to replace both at the same time. Be sure to press it completely upon the pump spindle or you may find fitment issues between the fan and the radiator, as in "The D**mn fan belt won't fit in! Don't ask... Not a problem if you're dumping it.

Anyone want to say what is the function of the fan clutch? I've always assumed it slips at high RPM to limit fan speed. Not a clue really. Wouldn't mind dumping mine in favor of a fixed fan, less weight, less to break, classier look.

R
Richard 79 1500 with a Type 9 in the garage

Richard-
Clutch contains a viscous silicon fluid, that gets thicker when hot (some descriptions claim there is also a bimetallic thermostat in there, but I don't think so - never autopsied one). So, the fan freewheels until the hot air thickens the fluid, which couples the fan to the shaft until it cools off enough to get slippish again. Theoretically, the thing is sized to only transmit the power required to drive the fan at the top efficiency of the fan, so it does slip at higher engine speeds even when hot, saving power and noise. Elegant and simple, until the bearing goes out and lets the magic juice depart.

FRM
FR Millmore

You could well be correct FRM, I took pre 74 to mean a pre 74 model Midget (I did wonder that it ought to say pre 75 :-) ?? ) Having no experience of earlier triumph engines I could not say whether or not the pre viscous coupled water pump fan would fit a Midget or not.
Robert (Bob) Midget Turbo

The UK 1500 Midget uses the same water pump as the equivalent Spitfire. The water pump has a simple plastic bladed fan that rotates all the time - no fancy clutches here!
Hope this helps.

Les
l snowdon

The Spitfire pump will work. I had my clutch go out and started looking at replacement cost. $189.95 for the clutch from Victoria British but for a Spit water pump and fan combination, only $117.90 combined. I went with the cheaper option.
Tim Michnay

Thanks fellows...looks like the Spitfire pump & solid fan will work, will order soon. On to the next problem: ominous vibration in the drive train at 45 mph and above. Just pulled the drive shaft out to install new u-joints...could see and feel they were going out, but just don't think they were bad enough to cause my vibration problem...I'll see.
DL Rhine

Thanks Tim, I looked at the Victoria British catalog over the weekend and it sure looked, by the pictures, that the Spitfire pump would work. Thanks for the feedback. I live down here in the Southeast and it gets mighty hot! Would prefer a fan that continuously spins, and the cost savings sounds good too.
DL Rhine

This thread was discussed between 05/07/2009 and 06/07/2009

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