TR2/3/3A TR3 pulley conversion

[prb51]

I'm going to have the nose off to replace the rediator (no crank hole) and was thinking about the pully conversion to normal fan belt width. Is there a crank pulley available where you can retain the fan (I want to put a TR6 fan in place)? I have an electric fan now but have heard the TR6 fan does as good if not better. I live in Az and drive in 100+ weather so this is a key issue. Is the pulley conversion worth the effort?

 

[Alan_Myers]

Hi,

The most commonly available TR6 7- or 8-blade yellow fan definitely will pull more air than the original TR3 4-bladed metal fan, but may or may not pull as much as an electric fan.

The TR6 yellow plastic fan doesn't need balancing, like the original 4-blade did, and is more durable and less likely to throw off a blade than the metal fan.

It's not mandatory to change to a thin belt to install the TR6 fan. You can simply bolt the plastic fan up to the TR3 fan extension, and continue using the wider original belt if you wish.

Is your electric fan a pusher or puller? If it's a pusher (in front of the radiator), it could be used in conjunction with a TR6 fan. If a puller (behind the radiator), it would need to be removed to fit the TR6 fan.

I doubt a TR6 fan alone will pull more air than a good electric fan, if you are thinking of removing the electric fan. There are a variety of sizes and designs of electric fans, some are highly efficient. Generally a puller electric fan (behind the radiator) is most efficient. Some 14-16" fans can keep a V6 or small V8 comfortably cool, so are more than enough to keep a 2 liter 4-cylinder engine cool. Most electric fans incorporate some sort of housing or shrouding that helps make them more efficient.

An electric fan only comes on when needed, and is more efficient overall, doesn't drag on the engine at highway speeds (when no fan is needed) like a crank-mounted fan will. A thin belt will also be a little more efficient and is gentler on the water pump and alternator/generator bearings (the original 3/4" belt could easily be over-tightened and damage those bearings).

Do you have an alternator installed? Usually it's needed with an electric fan, larger ones can pull upwards of 10-12 amps and the original generator was only good for about 17 amps.

Yes, there are pulleys to convert to a "thin belt" available:
1. For use with the original generator. This means replacing 3 pulleys.
2. For use with an alternator. Most alternators are already set up to use a thinner belt, so only the water pump and crankshaft pulleys would need to be replaced.
3. For use with electric fan only, in which case the crankshaft pulley is best replaced with a harmonic balancer/thin-belt pulley combination.

While you have the radiator out being worked on to remove the starter handle hole (which will increase rad efficiency some 150-20%), you might ask the shop doing the work for other suggestions to improve the radiator's capacity and efficiency. I'd bet that Arizona radiator shops are pretty expert at making radiator improvements!

Hope this helps with your decisions.

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[prb51]

Alan, I always appreciate your responses. I believe I'll try the new radiator, thin belt conversion, and retain the fan/fan ext using the TR6 fan. I rarely used the electric unit even in our weather because the engine innards are clean and the radiator was recored (but with the starter hole). My new unit is without the starter hole. If this isn't sat I can always add the fan (pusher) later.
Revington carries the ally crank pulley. Check out the oil cooler thread.

 

[TR3Mod]

Hey, I guess I'm building up a little reputation as a TR3 modification guy (widening a TR3 body four inches...), so I'll tell you what I did to get my other '57 TR3 to run cool. I decided to update the very ineffeciant (hole or no hole) radiator. I used a Chevy Monza cross-flow triple-row type and had it narrowed to fit in the original location. The cross-flow design and number of rows makes this so much better than the stock unit. Behind this I mounted an after-market electric fan. These are great units and spin very fact and move alot of air. The 'cool' thing to do is mount a temp sensor in-line somewhere to modulate the fan on/off. I just have a manual switch. These fans mount easy with straps pulled through the rad core itself. After this I was now able to machine off the heavy lump of original fan extension from the front pulley assembly. If I remember I was able to use the original starter crank center bolt by simply cutting it to it's new length and threading the cut end to match the crank. I run a Chevy 180 F degree themostat, which is an unbelievable perfect fit. I thought I would also use another pulley on the water pump to get it to turn faster, but this proved not to be needed. I live on the West coast of Canada, and although nowhere near the temps you get, we get up there in the summer. I can sit in stuck traffic for hours and the temp. guage sits at 185 F. It has worked out very well for me, and although not stock, in a TR3, it's hard to even find the radiator! Oh, I run a 15 lb pressure cap and an over-flow bottle, which is mounted behind the rad, where I can top up coolant, if needed, without having to open the rad. itself. If you can stand the idea of an American part under the hood, this will keep your car cool. I'm even more disadvantaged because I've got the 'small mouth' grille, and my motor is tweaked- 2.2 litre, cam, headers, etc... Good luck!