drilling holes in water pumps

[4tford]

A fellow showed me this water pump yesterday. Says drilling the big hole in the center is supposed to help cooling. Seems weird. Any thoughts???

[J Franklin]

Seems real weird.

[51 MERC-CT]

If the hole in the block is bigger then it would help in eliminating some restriction, but help in running cooler? That would only be proven by documenting before and after with the results.

[40cpe]

Here's my take on it: The pump gets cool water from the bottom of the radiator fed through the pump to the impeller. This hole cut in the pump will allow warm water from inside the block to dilute the radiator-cooled water. I think it will hurt cooling.

[4tford]

I suggested to him he only change one side and then compare the difference in temps.

[flatheadmurre]

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I was thinking about if the flow from the pump could draw some additional water passing by the hole...
Probably just wishfull thinking and a downgrade to the original.

[40cpe]

If the impeller pressurizes the water to force it to the rear of the block, the pressure is greatest near the pump and would force heated water into the big hole/incoming water and reduce the pressure to the rear of the block. Some of the water pumped would be going in a circle. Think about the results.

[G.M.]

DON"T DO IT. Skip received a few sets of pumps that people drilled like that and the flow was way down. He welded the holes closed. G.M.

[J Franklin]

Outguessing the engineers? Doesn't usually work.

[Graeme / New Zealand]

DON"T DO IT. Skip received a few sets of pumps that people drilled like that and the flow was way down. He welded the holes closed. G.M.


Probably the most sound advice on this subject considering the reverence Skip is held on this site.

GB

[TJ]

Originally Posted by J Franklin

Outguessing the engineers? Doesn't usually work.

Amen to that.

[MGG]

My first thought on this is that if Henry had thought this was a good idea, look at how much money he would have saved on steel by building them that way.

[A bones]

Pressure versus volume: Increase the the volume you decrease the pressure. Henry and Skip got it right.

[JAKEFORD]

The only thing I remember doing was to drill some small holes in the impeller blades to slow the coolant flow. This reduced flow seemed to help cooling.
I don't remember the size of the holes but maybe 3/16.

[G.M.]

Originally Posted by JAKEFORD

The only thing I remember doing was to drill some small holes in the impeller blades to slow the coolant flow. This reduced flow seemed to help cooling.
I don't remember the size of the holes but maybe 3/16.

Another joke. These engines need MORE coolant flow not less. The only
thing this did was slow the flow of coolant so not quite as much went out the over flow. Less coolant flowed through the engine but a LITTLE more coolant remained in the system because the flow was reduced so now you had a VERY SLIGHT IMPROVMENT in cooling. This is where the pressure cap came into use, not to pressurize the system but to stop coolant from going out the overflow. With the over flow sort of plugged with the pressure cap the engine now has more coolant and a lot more flow of coolant. The problem with posts like this and the large holes in the 39 type
pumps is that people read this and some think it is an improvement and as can be seen by some of answers believe it. G.M.

[JAKEFORD]

I can only report what worked for me. It may not work for you as Mr G.M. has stated very clearly.

But I did have a screw in thermometer in both the top and bottom and I remember the differential temperature increasing which indicated more cooling in the rad. This was done during my university days when I was taking Engineering. I reasoned that this was due to less flow in the rad and more time to get rid of the heat. I believe its a fine line as more time in the rad losing heat means more time in the engine gaining heat.

I am not sure the Ford engineers had the answer with more vanes, etc as these things were still prone to overheating.

A change to a truck rad later on really helped as it had more rows of tubes. Also made sure that the baffles were in place to direct as much air flow through the rad as possible and kept the fan belts in good shape.

In winter the reverse was true and often need cardboard to heat things up!

[rotorwrench]

It took FoMoCo a while to even figure out that pumping hot coolant to the radiator at the top of the heads was not a good design but they stuck with it for 10-years. The pumps worked a lot better when they relocated it more toward the bottom of the cooling system and then pumped cooled water solution from the bottom up through the block. Those ports allow water to flow into the block better when filling the system. They also prevent cavitation of the pump but there is a limit on how big they can be or they will just start to reduce coolant pressure and flow under normal operation.

[JAKEFORD]

At highway speeds with high engine rpm the coolant flow is high as the pump speed is high. Airflow through the rad is also high so cooling should be good. But why did my old 53 run hot?

Played with the thermostats, experimented with the pumps and reasoned that the coolant flow was too high and the water temp entering the block was too high. Slowing the coolant flow definitely helped cool the water entering the block and dropped engine temperature. My car spend at least 70% of its time at highway speeds at that time.

So I don't believe high water flow is the answer in all situations but a lot of experimenting was necessary. I remember doing a lot of calculations on heat transfer and one of my Profs was a huge help. I was going to do my graduation thesis on this topic but changed it to Automotive Engine Lubrication at the last minute.

Lot of fun at the time!

[rotorwrench]

Engines can run hot from several causes. Radiator tubes with muck build up in them can be a cause. Rodding the radiator out generally fixes that. Stuck thermostats can also be a problem. Too much casting sand and wire in the block can be a problem. Ignition timing out of specs is another cause for overheating. Leaks anywhere in the system including small leaks between cylinder and water jackets due to a leaky head gasket and weeping water pump seals can also cause overheating. Flathead Fords were not problematic with overheating until they had been in service for a while. Twin cooling systems worked well until stuff started to leak, clog, or get out of tune. I don't remember many overheating problems when I was a kid and these motors were still numerous in operation unless something finally wore out or clogged up. Fix the problem and go on down the road for many more miles. My Pop had big trucks, cars, and pickups with flathead V8s and we didn't have any more problems with them than you would have with a modern vehicle.

[russcc]

That concept is in Thunder Road Flathead by Bill Sinclair, page 56. The purpose is to move coolant to that back of the block low, to avoid the heat and restriction of the exhaust passages. Bill is a seat of the pants engineer, and tests everything rather than throwing out bunch of unproven theories. Barney Navarro used a similar concept to get coolant to the back of the block. Both the early and late blocks have the corresponding hole in them. Bill tested this mod. on both a street car and a stock car for years Actual results speak louder than words. It is only one part of the equation.