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TR2/3/3A Water pumps/head cooling

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TFB

Jedi Knight
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Im putting motor back together after blowing head gasket at rear between cyjinders 3&4.
I have not had the pump off before so I am going to pull it for inspection although the car has never overheated or indicated over temp on gauge.

I think the pump is an original.It has a grease fitting,three studs,and the original type pulley which was removed and fit with Moss thin belt pulley that fit just right.
I want to order a replacement spare.The price difference between 4 or 5 vane is not much.

Most important is original size shaft and key so the thin belt pulley installs correctly.Improved head cooling would be a plus.

ALso,I am thinking that leaving the heater valve open would improve circulation in the rear of the head .I realize this loop bypass the radiator but Im not concerned as I have the heater on lots of time in the summer but this year had it turned off.
Any thought or recommendations appreciated.
Tom
 
Piump is out .Bronze type 4 vane bronze impeller,one bottom bolt.
Is this a oem pump?
Thanks
Tom
 
Make sure that the keyway in the new pump is the same width as that in the pulley you want to use. My last pump came with a metric keyway in the shaft. A new shaft slot can be machined, BY A MACHINE SHOP to SAE, but if you put a metric key in the shaft and you have an SAE groove in the pulley, you will destroy the pulley in short order and then have a time getting the pulley off as the keyway in the pulley will be widened, leaving a shoulder behind the key. Do not try to machine the key itself so the bottom is metric and the top SAE.
Bob
 
Thanks for reply Bob.I just ordered a Moss upgraded five vane "for use with original pulley" but its backordered.
I also ordered some pump to housing gaskets.The moss head gasket kit came with housing to block gasket by no pump gasket.
I have read some old posts about shaft and key/keyway issues which is why I mentioned The the most important thing is the shaft and keyway being as original.
I have a milling machine and broaching tools and I am not getting into modifying parts.Luckily my current pump is ok andI feel better that I checked it.
Also, I had a bolt on the of pump so I ordered a stud.
Tom
 
TFB said:
Thanks for reply Bob.I just ordered a Moss upgraded five vane "for use with original pulley" but its backordered.
I also ordered some pump to housing gaskets.The moss head gasket kit came with housing to block gasket by no pump gasket.
I have read some old posts about shaft and key/keyway issues which is why I mentioned The the most important thing is the shaft and keyway being as original.
I have a milling machine and broaching tools and I am not getting into modifying parts.Luckily my current pump is ok andI feel better that I checked it.
Also, I had a bolt on the of pump so I ordered a stud.
Tom
Click to expand...
The original set up is to have two studs and one bolt for the water pump. Changing to 3 studs means that you can mount the pulley on the bench before putting assembly on the car. Much better idea, I think.
Charley
 
Fitting a high-flow water pump could result in overheating because the water doesn't have time to be cooled by the radiator. I think you are better off staying with the original setup.

Graham
 
Thanks Graham
charleyf said:
The original set up is to have two studs and one bolt for the water pump. Changing to 3 studs means that you can mount the pulley on the bench before putting assembly on the car. Much better idea, I think.
Charley
Click to expand...
Thanks charley,the pump came off witht the bolt captive because the pulleys on and I ordered the stud.But I may need to actualy keep the bolt because my electric fan is right in front of tne pump and pulley and barely came out with the bolt.So I may not have room to mount over an in place stud.
Tom
 
Graham H said:
Fitting a high-flow water pump could result in overheating because the water doesn't have time to be cooled by the radiator. I think you are better off staying with the original setup.

Graham
Click to expand...
Thanks Graham,I think the issue is laminar flow vs.turbulence and turbulence is not good for heat transfer.
I just removed the pump for inspection and it looks new and is going back in.
I think if you could increase flow to get more uniform head temp that would be good but like you said ,to fast could be a problem.
I wonder if you had another sensor at the rear of the head what kind of temp differences would you see.
I think I will take some infared readings when im done.
Thanks
Tom
 
TFB said:
Thanks Graham

Thanks charley,the pump came off witht the bolt captive because the pulleys on and I ordered the stud.But I may need to actualy keep the bolt because my electric fan is right in front of tne pump and pulley and barely came out with the bolt.So I may not have room to mount over an in place stud.
Tom
Click to expand...
Actually the stud once in place should be the same height as the other two studs.
Charley
 
I will never use another of those five-vane pumps. Here is my experience with one, not atypical:


If the cooling system is in good condition, the original pump should be fine.

Don't overthink this. Yes, the rear of the engine is probably a little hotter, but what will you do about it if it is? As long as the cooling system is in good shape, it is doing what it was designed to do. If it isn't, best thing is a good flush with some radiator-flush stuff from your local auto parts store. Maybe get the radiator boiled out, if you think it needs it.

I have to disagree with the idea that high flow rate means poorer cooling. The amount of heat removed from the coolant depends on the coolant temperature in the radiator, the air flow, and air temperature; not the rate of flow. If the flow is low, there will be a greater gradient of temperature between the radiator's input and output. The greater the flow, the less the gradient. That's the only difference.
 
^^^^ Good reading there, Steve!
 
It has been said that leaving the heater valve open will facilitate circulation of water thru the back of the head. Seems quite plausible to me and it certainly can't hurt.
Bob
 
With regard to the flow rate issue, Randall Young would have pointed out that the laws of thermodynamics preclude that being a factor.
Bob
 
Sarastro said:
I will never use another of those five-vane pumps. Here is my experience with one, not atypical:


If the cooling system is in good condition, the original pump should be fine.
Click to expand...
For exactly these reasons, I sent my original pump to the Flying Dutchman for a rebuild. Have not gotten it back, much less used it, so I can't speak for the quality, however the interwebs rate the place highly.
 
Thanks Steve ,I have no cooling issues but blew a gasket,most likely from not being torqued after startup.I would think more flow would reduce the tempature variations in the block and head.
What didnt you like about the 5 vane pump?
Tom
 
Thanks Steve ,I missed the link about your build and the pump.
I was not aware the fittment issues were with this 5 vane pump.I would image these issues are still the same.
Advertised as fitting with stock pulley and then the keyway size issues I wouldnt be happy,especially if it sat on my shelf for years until I needed it and then found out.
Thanks Mike for FlyingDuchman lead for rebuild.

So the question is what is the best replacement pump that the oem pulley fits with no issues for shaft or keyway?
Do the Moss classic gold and their aftermarket pumps have the same issues?
Or is rebuild an original the only option?
Thanks
Tom
 
I rebuilt a second engine, which came with my car, and used the original-type, four-vane pump. It was Lucas-branded. As I remember, it went together uneventfully. I can't comment on the Moss "classic gold" thing, but I can't imagine how it would be significantly better.

We aging aerospace geeks have a saying; "better" is the enemy of "good enough."
 
You just need to verify current dimensions with Moss. When I bought mine 5 or more years ago, the keyway in the shaft was 3mm. Needs to be 1/8" to fit pulley.
Bob
 
Last edited:
charleyf said:
Actually the stud once in place should be the same height as the other two studs.
Charley
Click to expand...
The Moss water pump stud came and is short,like the top 2.
The bottom bolt on my pump is 2 5/8".That means the stud needed to replace would be 27/8-3" long.
So the bolt goes in for now.Do I have unique serup?Ithink Moss only lists one stud.
Tom
 
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