Cooling System Questions

[40 Bud]

Has anyone contacted Evans about there cooling systems for use in GT40? It sounds interesting because of the low pressure maintained in the system and the corrosion protection granted. They apparently make special water pumps and aluminum radiators to fit your application. Iwould be interested in any info on these systems.

[Howard Jones]

So as to add some information to the discussion, I would like to say that my GTD has always been marginal in it's cooling capacity. So I have tried a few things that I believed were cost effective.

1. Moved the left hand radiator nipple to the top of the tank from the bottom.

2. Plumed the motor with a self bleed system from the rear of the intake(both sides) back to the temp sensor bung and then on to the surge tank.

3. Plumed the radiator so that both bleed ports now return back to the surge tank.

4. Removed the thermostat and put in its place a alum disk with a 5/8" hole in it.

5. I am using a victor junior edelbrock alum water pump.

6. Oil system has 7 quarts in it with a fairly large cooler. Oil temp runs at about 180ish on a hot day (100F)

One of the posts in the current discussion mentioned that the thermostat presented a fairly large percentage of the pressure drop. It's interesting to note that replacing the thermostat with a simple disk has worked quite well. I thought that the thermostat was causing air to form in the system due to its close proximity to the tight turn the system makes to water flow at the thermostat housing but it may well be it simply reduces pressure drop?

I think I have developed the stock GTD radiator/cooling system as far as it will go without a new radiator. My car seams to run cooler and also seams to return to a manageable temp after a surge in heat. Read put my foot into it.

I looks like I can expect about 180F on a hot day (100F) if driven at speed limits and without a lot of stop and go. I get a spike to about 200F with my foot in it, but it seams to recover back to 180F or so in a few Min's of speed limit driving.

The engine makes about 360ish hp.

[Howard Jones]

As sort of a follow up of the previous post. I drove my car to Sacramento Calif yesterday and hottest day I've ever been out in my car.

I left in the morning about 8am air-temp in San Ramon was about 77F water temp after car warmed up on freeway @ 80MPH was 170F. Drove to Sacramento and arrived at 9:30AM water temp 175F.

Left Roseville near Sacramento at 5PM with air temp about 106F. I did a couple runs through the gears up to about a 100MPH then turned car off for about ten Min's to let it heat soke just prior to getting on freeway. Water temp climbed to 205F and remained at 200-205 for first hour, As air temp came down as I neared the cooler bay area, mid 90s F, the water temp dropped down to 190F and remained there until I pulled it into the garage. Air temp inside my garage was 94F @ 6:45PM.

I "tested" cooling system several times during run home with runs up to approx 100MPH on the way home. Water temp did not spike and remained right at 200-205F.

Inside air temp (cockpit) in excess of 110F all the way home. Bag of ice on chest lasted 15 Min's. Next project get AC working.

[Jim c]

Well that is a lot of info & to many numbers for me.
I noticed a lot talk about top & bottom outlets.
I have made a couple of radiators & to get the spouts on the bottom with single pass I put an internal tube to the top inside one tank.
It has the same effect as a top spout but keeps the plumbing at the bottom.

I did read in this thread a radiator expert said it wont make any difference but it makes me feel better.

Never had a problem.

[Howard Jones]

Moving the nipple on the left of the radiator to the top was worth about 4-7F lower overall water temp. I think what happens is with both nipples on the bottom all the water flow is across the bottom half of the radiator. This reduces the heat rejection capacity by quite a lot. Moving the nipple requires the water flow to at least start at the top of the radiator before it flow across to the bottom nipple. The stock GTD radiator does not have a internal pipe to divert the flow to the top.

Now at least if I buy a aluminum radiator I will get the full effectiveness from it as the rest of the system is as optimum as I can make it.

This whole process has really proved to me how important is is to get all the air out of the system and then keep it out. If you do that these cars can be made to run reliably cool .