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MG TD TF 1500 - Td Water pump Question

Hello All
working on a 53 td with a overheating problem. It will sit and idle at 85 but on the road (45 to 50 mph) slowly creeps up to 95 plus. I am rebuilding the water pump and testing the thermostat.
Is there a spec for the gap between the impeller and pump body? I have about .040 and about .020 free play. The manual I have says to tighten the pulley "just firm" TIS Tom
T S Matsoukas

Tom,

You aren't overheating unless you are boiling. I run at about 87 at about 65 mph on the road, the ambient temperature also has a huge effect.

Some comments:
1) Water has a much better heat transfer coefficient than a 50/50 mix of Water/Antifreeze. In helping a fellow TDer over the weekend his car ran a full seven degrees C cooler with water than with the 50/50. In your location, a 75/25 mix will work and cool better (more water)

2) How do you know you are at 95 plus? Try removing the temperature bulb from the radiator and set in a pan of water next to the car. Heat the pan with a torch until it is boiling. The gauge should read 100 at this point. Adjust the needle on the gauge (you will need to remove the chrome ring, lift the glass, pry the needle up with a dinner fork, and reposition it.)

3) The radiator may need cleaning/recoring. A clean radiator with a pump with the clearances you mention should work fine. There isn't enough flow in the system to erode the blades or the body of the pump. If you paint a radiator use a very thin layer of flat black. Glossy paint may be too thick to aford good heat transfer.

4) Any load is going to increase the temperature on the gauge. You should be able to watch the needle drop when you slow down and rise when you speed up a hill.

5) The header tank on the radiator must be full as well, although it will constantly try to empty itself through the overflow. It will find its level, but need to be topped off once in a while.

6) With aluminum replacement parts available, corrosion is a potential big problem. Run Ethylene Glycol (the green stuff) in a system with brass, aluminum and iron in it. Change the coolent every two years if you have aluminum in your system.

7) On the belt's longest run you should be able to depress the belt a full inch. This will protect the bearings in the water pump and the generator. Use a segmented belt. I use a Goodyear 15AV0990 belt.

Hope this helps,
dave

Dave Braun

i thought the 1 inch deflection is on the SHORT run of the belt.
in regard to water-coolant level/topping off. i have just gotten back from a trip to michigan...week BEFORE GOF...darn..interstate all the way running 70 mph, 95 degree outside temps with an hour of staop and go traffic on I80 and a total of 1500 miles and the coolant is at the same level it was after my first run after changing the coolant. as dave says it will find it's own level and mine has not changed in the following 1500 miles. i still take a peek prior to every drive...old habit. regards, tom
tom peterson

Thanks Dave, and Tom
Good advice, I just bored it to .060 over and put in new bottom end bearings, and a moss rear seal. I flushed and tested the flow of the rad when it was off the car and repainted it flat black. The temp gage had not worked for as long as I can remember (possibly since the frame off we did in 1972) when I saw a article on bustedknukles.com
about diy repairs of the capillary tube. I was able to repair mine and I tested and calibrated it when I had it out. I am using an IR thermometer and was able to read the top of the rad at 85 while at idle ( bottom at 75) and the probe a 100 in the boiling water on my stove. So I am ok with the indications from the resurrected gage. I it has been boiling twice as I pull into the garage after the 7 mile drive from work. So, I pulled the pump and t-stat. I found the impellers on the pump rusted, ragged and mis-shapen. So I dug out an old impeller and put it on. If .040 gap with .020 end play is good I should be fine. Time to grill some brats, turn on the ac in the garage and put it back together.. Thanks again Tom
T S Matsoukas

T S
"and painted it flat black"

This may be your problem, a coat of "ordinary" paint may be enough to inhibit the heat transfer to the air,

My old radiator repair guy told me to "never use car paints on your radiator, they go on too thick".
He used a special thin black paint after removing all old paint and dirt n his hot tank.

Also use "Water Wetter" in your coolant. Drops the temp by as much as 20 degrees F.
Don Harmer

All

I got a chance to drive the td friday and it still exhibits the same symptoms. I found an article on tuning the carbs and it showed the timing should be set at 8btc? My wsm shows tdc and that is were I set it after the rebuild. I'm going to retime it to 8btc.
Don- I did not know that and I used hi temp flat black. I am using a wetter (royal purple brand).

More as I tinker this weekend. Family in this week from Denver.

Tom
T S Matsoukas

Where are you in Florida? You may have found the problem- the factory TDC timing was for the available super-low octane gas in England in the 50s. Search the archives also, there is a ton on overheating in there. George
George Butz

George,
i'm in the panhandle - Gulf Breeze - I will check the archives Thanks Tom
T S Matsoukas

Seems you are about a 7 or 8 hour drive from me, or I would pop over. Let us know if the timing advance fixes also.
George Butz

Hey Tom, my mother and sister live in Gulf Breeze, been looking for T car folks for years when I go down there. Would like to see your car sometime when I am there. Going to be there in Feb=March next year. Wish I could bring mine down there but leaving here with 2 ft of snow on the ground does not make for good or comfortable driving conditions. Is there a local club in that area? Tom
Tom Maine (TD8105)

Tom,

No guts - no glory !!

Gord Clark
Rockburn, Qué.
Gordon A Clark

Tom, I had very similar coolant problems to those that you describe but not quite as severe. Someone suggested years ago that I check the number of vertical tubes in the radiator. I had a "two row" radiator and had it recored with a "three row" model. Remove the radiator cap and peek into the tank to see how many rows (front to back) that you have. Just something easy to check. It cured my worry about overheating.
Jim Merz

I concur with the 3 row advice, I did that this spring and it dropped my temp from 100c to 85c. Also make sure you are not running your carbs too lean as that will cause the engine to run hotter.

Regards,
Jim
James Neel

George. I did retard the timing. You say advance it? I did not see any significant change. Am I going the wrong way?

Tom. I would love to get together next year. I am not active with the british club here, but see that they hold events on Pensacola beach. I will check the rad for row count. Plugs show rich side on the mixture. Good idea. Thanks again to all. Still searching. Maybe it's just a tight new motor thing. Tom
T S Matsoukas

Retarded timing often increases temperature. Try advancing so you can run at 3500 RPM at about 32 degrees (about 1.05 inches past the pointer).

warmly,
dave
Dave Braun

Tom, e mail me off line with your e mail and I will give a holler when I get down there. t maine 51 @ yahoo.com. all one word. Would love to visit and maybe have a cold one at Peg leg petes on the beach..
Tom Maine (TD8105)

Hey all, I reset the timing to 32 at 3500, and noticed the timing only varied about half that between idle and 3500 or approx. 16 of advance at idle.... I wonder if the advance weights need some attention. The rad is a two row. So that may be a solution if I don't find the problem elsewhere. Historically the car ran at 85 to 90 (185 to 190 on the old SW gage).

I don't want to hijack my own thread but, as I was setting the timing with my digital clamp on tach, I noticed the new cable I put on the dash tach has it reading about 500 rpms high??? I thought when I changed it was reading higher. I printed ttalk's chart for rpm/mph/rear end ratio and see my car was dead on the numbers for a 5.25 rearend before the tach cable change. Any thoughts? thanks again Tom
T S Matsoukas

Hey All, problems solved..
1. changed water pump-- all better 85-90 again
2. put on wider fan belt. pulleys turn slower
Thanks for your input and directions. Tom
T S Matsoukas

Tom,
Where did the pump come from???
SPW
STEVE WINCZE

This thread was discussed between 04/08/2011 and 18/08/2011

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