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TR2/3/3A TR3 Cooling

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MGTF1250Dave

MGTF1250Dave

Jedi Knight
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Aloha All,

In December there was a very thorough discussion of the TR3 cooling system and techniques to maximize its efficiency. One item discussed was blocking or partial blocking of the by pass hose from the thermostat housing to the water pump. This was suggest if not using the original sleeved thermostat. My question is, what are suggested methods of blocking this hose?

Safety Fast,
Dave
 
I used a piece of broomstick years ago to block the bypass on the TR3A. Later I think I put a big nut in the bypass in the TR4 because I heard some theorize that you need to let a bit of water move thru there so the head doesn't get hot spots while waiting for the thermostat to open.

Almost anything round with a 1/4" or so hole it in that is small enough to get in the hose yet to big to go into the tstat head or waterpump housing should work.

Note: there is not universal opinion that this is a good way to go, though I have had no problems, even with that broomstick.
 
Aloha George,

Thanks for the suggestions.

Regarding the need for the by pass, I notice that my MG does not have one.

Safety Fast,
Dave

P.S. That is a nice brace of Triumphs you have.
 
The broomstick idea worked very well for me. Had a huge over heating problem especially in traffic. What also helped my problem was a fan from a GT6. 6 steel blades that move lots of air. Best of all it bolted right up with no adaptations. Looks like the proper fan too and rarely does anyone picks up on it. Those two items fixed the problem.
Larry
 
Dave,(mahalo)my advise is that the original fan is junk. Little known fact, there was an optional 6 blade fan(good luck finding this hens tooth). you need more air flow, and the thickness of the stock radiator is the problem. Get a modern plastic fan,adapt it to the hub. Use the factory air ducts too and you will never heat up(leave the heater cock partialy open....
MD(mad dog)
 
Re: TR3 Cooling-- 6 blade?

So-- I'd like to give the 6 blade a try-- anybody got one they wanna sell? My TR3 does fine running around for a while but on a hot day in city traffic, starts to overheat.
 
Re: TR3 Cooling-- 6 blade?

Hi Dave I have replaced both original fans on the 2 TR2's I have owned with Flexi-Fans. There is a 12 or 13 inch one that basically bolts on. I think I had to slightly grind out the ID to fit over the crank bolt. You can get them at most auto parts stores. Blades flatten out at high revs so very little drag. The old one has been on the car for about 20 years..
Best of luck
Brian /ubbthreads/images/graemlins/canpatriot.GIF
 
Re: TR3 Cooling-- 6 blade?

I saw on a Roadster Factory web specials catalog not too long ago 6 bladed plastic yellow fans for about $15. They were marketing directly for TR2-4 applications, so I would think that modifications should be minimal. Don't quote me on that though, I don't have hands-on experience with it.
 
Re: TR3 Cooling-- 6 blade?

Aloha,

I've found my plug, a tubeless tire valve stem. I sawed it down to about 1 inch high and removed the brass core. It has about a 1/4 inch bore in it. The valve stem wedges nicely into the water pump by pass orifice and the lip on the valve stem will make sure it stays in place.

I agree that the shroud to direct air through the radiator is a key component of the cooling system. Further more, the original fan is junk. I tried to fit a "yellow" TR6 fan, but I didn't have enough clearance between radiator and fan. I have an electric, thermosatically controlled fan that works great in keeping water temperature in the normal range in stop and go traffic. I also have a Flexifan as backup, as I recall it has either 6 or 8 blades and moves more air than the original. My original radiator works fine for me. Mahalo (Thank you) to all of you for your replies and suggestions.

Safety fast,
Dave
 
Re: TR3 Cooling-- 6 blade?

Hi all,

I think the 6-blade metal fan you are thinking about is the same as an optional "Tropical" fan offered with the TR4, intended for use on cars destined for hot climates. It is not listed in the TR4 parts catalogue, however. It is extremely rare.

Regarding Flexi-fans, I've got a 6-blade one I was considering using on my TR4. I did find it would foul on the cross brace between the front shock towers, so carefully trimmed a little off the rear edge of the stainless steel blades. I also had to enlarge the center hole to get it to fit. Still, I'm concerned because it is quite heavy compared to the stock fans. It probably should be balanced, too. There is no doubt this fan would move a lot more air than the original 4-bladed and possibly the Tropical fan, too.

I've also got an early TR6 7-blade plastic fan I might use. Originally it was pale yellow, but the one I have is painted black. I think there was a white version, quite similar, used on the TR250/5. It bolts up easily, directly to the hub, using the original hardware, doesn't require any balancing and is very lightweight. It is considerably smaller diameter and smaller blades than the Flexi-fan, so would surely move less air. But, I think it would out-perform the original 4-blade metal fan.

The item available from TRF and some other vendors is an 8-blade plastic fan, a replica of the one used on later mid-production TR6. It's also quite lightweight, requires no balancing, and bolts right onto the extension hub with the same hardware as the original metal 4-blade fan. The larger diameter and square-end blades will also move quite a bit of air. It is also yellow, a bit brighter color than the earlier 7-blade plastic fan.

There might be some other fans out in the junk yards of the world that would do, too. All in all, it's not difficult to find an improved fan, and there is always the option of using an electric fan.

Cheers!

Alan
 
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