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Water pumps and overheating

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Water pumps and overheating #1
tadge44 David Clark High Wycombe, Buckinghamshire, UK Sign in to contact 1956 MG Magnette ZA 1957 Austin A35 2003 Mazda MX-5 NB 2010 Ford Focus	Topic Creator (OP) Nov 23, 2014 02:36 AM Joined 9 years ago 323 Posts

My ZA with a 1622cc engine gets rather warm if I push it over 65 for very long - and it gets so hot in stationary traffic that it starts to stumble and misfire.

The latter is almost certainly fuel vaporisation as I don,t currently have the heat shields, but it should not overheat in the above circumstances normally, surely ?

I have read some where that if the wrong water pump is fitted to the 1600 this could be the problem 0-anyone tell me how I can check this before I remove rad and pump to find out, please ?

I can live with a highish temp reading when cruising fast because it stabilises but if we then get into traffic it starts to rise again(the alternative is to stay below 60, which does not appeal) and it then becomes uncertain whether it will keep running.

All advice gratefully received

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Re: Water pumps and overheating #2
racedriver Andrew McGee Holmfirth, UK Sign in to contact 1957 MG Magnette ZB Varitone 1966 MG MGB GT 1967 MG Midget MkIII 1969 MG Midget MkIII & more	Nov 23, 2014 03:47 AM Joined 12 years ago 683 Posts

We've found (on the race car) that the best type of water pump are the ones with a complete circular impellor and not the bladed type which can cavitate at higher revolutions. Ironically the ones from QH aren't as good as the Moss sourced repro ones.

I'd also suggested that you give the radiator a really good flush out if you can.

Andrew

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Re: Water pumps and overheating #3
Luv Em Old Brian Radich Auckland, Auckland, New Zealand Sign in to contact 1958 MG Magnette ZB Varitone 1966 Jaguar E-Type 2+2 1974 Ferrari Dino GT4	Dec 2, 2014 02:24 PM Joined 10 years ago 228 Posts

My ZB has an 1800 engine and always ran quite hot. When I took the water pump off (it started leaking) I saw that the impeller was too small for the cavity. I had a 1500 water pump on a 1800 block. The guy who fixed my pump used a 1800 impeller on a slightly shorter shaft than the 1800 one. That cured the over heating.

It's possible that you might have a 1500 pump on the 1600 engine and if there is a difference between the impeller and the cavity, it may be running inefficiently like mine was.

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Re: Water pumps and overheating #4
tadge44 David Clark High Wycombe, Buckinghamshire, UK Sign in to contact 1956 MG Magnette ZA 1957 Austin A35 2003 Mazda MX-5 NB 2010 Ford Focus	Topic Creator (OP) Dec 5, 2014 03:05 AM Joined 9 years ago 323 Posts

Sorry for the delay in responding. Thank you gentlemen for your suggestions.

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Re: Water pumps and overheating #5
B-racer Jeff Schlemmer Shakopee, MN, USA Sign in to contact 1950 Willys Jeep Pickup "Ratrod" 1964 Land Rover Series IIA 1971 MG MGB	Dec 5, 2014 07:24 AM Top Contributor Joined 17 years ago 20,012 Posts

I ran a very high compression 1800 in my Magnette with no overheating issues. Hot engines are usually caused by lean fuel mixture or retarded timing. Try 12 degrees BTDC at idle, set with the vac disconnected and richen your fuel mixture. Check all fuel lines for air leaks, as you could find cracked fuel lines or a cracked line at/in the tank. Vacuum leaks also cause a lean mixture and overheating.

jeff@advanceddistributors.com

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Re: Water pumps and overheating #6
tadge44 David Clark High Wycombe, Buckinghamshire, UK Sign in to contact 1956 MG Magnette ZA 1957 Austin A35 2003 Mazda MX-5 NB 2010 Ford Focus	Topic Creator (OP) Dec 5, 2014 02:05 PM Joined 9 years ago 323 Posts

Thank you Jeff - as I have mentioned before, all comment is gratefully received.

Winter has now reached us so workshop time will now be curtailed as I hate working in the cold, but, rest assured, the Magnette will be flying around the southern half of England next spring !

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