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Triumph TR6 - Overheating Problems - Part II

I first posted about suddeb overheating problems 3-4 weeks ago. The head had to be pulled anyway (broken inner valve springs) so that got crack checked - no problem found. Put everything back together, and STILL have overheating problem. Rats. Not as bad as before, but it still wants to go beyond the 3/4 mark.

Checked for collapsed hoses - none. Timing is fine. Radiator, block, & head all recently cleaned. Even removed the paint from the radiator fins while the head was shopped. Acceptable cooling is only obtained when running without a thermostat, so that tells me it's a circulation problem.

I decided to check out the water pump, and it appears ok as well (though I did order a new one). I found 2 things that should improve flow:
1) The 3 studs that hold the pump in the housing protrude into the discharge volute. I haven't done exact measurements, but it looks like they block about 1/3 of the area which would certainly interfere with flow. The plan is to lop off about 3/8" to make them flush with the volute wall.
2) There's a recirculation hole about 3/8" dia in the thermostat housing. That sucker gets plugged tonight with an allen screw & epoxy! A 1/8" minimum flow hole will be drilled in the thermostat.

I'll let you know if it works....
Brent B

One thing on recores and replacement rads that has always been overlooked is the flow speed and volume in the rad itself.

The coolant requires time in the rad to be cooled if the passages are too large and fewer very common on recores. The flow time in rad is too short for proper cooling?

In many cases when new rads or high volume water pumps have been added to resolve problems. Temperature goes up?

TR did not have a great rad area in the first place. Back pressure is also strong due to engine cavity design.

Bill

Bill Brayford

A fan shroud behind the air duct would certainly help I would think. I too had overheating problems that went away after the original rad was recored with a "modern" core (whatever that is).

Rick O.
Rick Orthen

Hi Brent,
Overheating could be due to increased static ignition advance - while often a good thing for performance it can raise the temp. If your rad is old it just may not be up to spec. Changing to an electric fan will make up for an inefficient rad and free up some horsepower - it would be less expensive than replacing the rad. If you do intend to change the rad get a good one! Unless your a stickler for originality you can probably find a performance aluminum rad that that you can make fit with a little work for less than or the same as the shoddy OE.
Hope that helps!
Mike

Thanks to all. The radiator was boiled out last year when I had the engine out. And I have an electric fan. It ran without problems last year, but suddenly started to overheat when the temp here hit 85F or so.

I did the work outlined in the first post last night. Only 2 of the studs needed to be shortened - the third was in solid metal. And the by-pass hole got plugged with a 3/8" allen screw. The new water pump should be here by the weekend.
Brent B

This may dispell a myth. I live in a warm climate and run a 30 year old radiator and nothing I can do will make the gage read even 1/2. I retained the engine driven fan and all is well at long idle, punching up the 10,000 ft mountain, stuck in traffic, and all this with an engine which is not even broken in yet and I was warned by the rebuilder would run hot at first.This is my first TR experience so have nothing else to judge by. Peter
Peter Gooch

After 2 says of driving I think it's safe to declare the overheating problem solved. Did the 2 modifications, and also throttled back on a ball valve in the intake manifold heater line, which is another radiator by-pass. The temperature has yet to get above the mid point.
Brent B

This thread was discussed between 13/05/2003 and 20/05/2003

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