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Electric Fan

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mylesw

Jedi Hopeful
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Hello

I want to convert my TR4 to an electric fan. My plan is to buy a lower cooling pipe with the boss for a thermostat, and an electric fan and a short bolt to replace the long bolt and fan extension. Whilst I have seen these kits in the UK, I have yet to find a US supplier. Does anyone know if anyone can supply these items in the US?

Thanks for your help.

Myles
 
Myles, Kit for all or part. The bolt you can do your self and take the rad. to a shop and have them weld a bung in the bottom for a thermostat.
 
Myles,
Buy your fan first as many don't have a 'wet' thermostat anymore. The one I have has a tube that's placed between the fins of the radiator with a wire lead to the unit.
Some are preset to a temp and some are adjustable, my unit is adjustable from 160 to 190 degrees.
They work well and you can save the modification for something else.
 
Myles, check out spalusa.com. You won't regret it. The best fans you can buy, in every conceivable size and configuration. Installing the fan in the lower pipe is the way to go, short of installing it in the bottom tank of your rad. Try to avoid installing in the cooling fins if you can. Spal makes a very high quality, stainless sensor.
 
Myles-

You may want to take a look at the lower return pipe from Moss UK - it is a nice stainless setup which has the bung for the thermostat built into it. I have one in that pile of stuff I showed you if you want to inspect before hand. I've not seen those pipes for sale over here. I also picked up a Kenlowe fan for that but it awaits installation along with the other bits, but I've also heard very good things about the Spal fan.

As to a short bolt assembly, here is one option:
alloy crank nose

No experience on this, you may also get opinions if this is not sufficient as a dampener to avoid crank damage.

The other more expensive option is a harmonic dampener setup, I think Moss as well as British Frame and Engine carry those.



Randy
 
TR4nut said:
Myles-

As to a short bolt assembly, here is one option:
alloy crank nose

No experience on this, you may also get opinions if this is not sufficient as a dampener to avoid crank damage.

The other more expensive option is a harmonic dampener setup, I think Moss as well as British Frame and Engine carry those.
Randy
Click to expand...

The original fan extension and rubber mounted fan act as a harmonic dampener on the TR3-4A engines.

I think the consensus on the non-dampening plate was that if you keep your revs under 5k, no prolonged high-revs to keep from reaching the crankshaft harmonics (supposedly one @2800rpm and another just over 5Krpm), then the simple aluminum plate will be OK. If you race, it is insufficient to keep the crank from breaking at the front.
 
/bcforum/images/%%GRAEMLIN_URL%%/iagree.gifI've run a whole lot of miles on several different TR3 engines (since about 1976) without any dampener and never had a problem with the crank breaking. That includes several lengthy runs near redline and near WOT (amazing what you can get away with on desert roads at night).

However, when they do snap, it's typically at the rear instead of at the front. One of the local racers brought part of his broken crank to show and tell at a meeting, and it was just the rear main journal & flange. Likely it's the sum of the (increased) engine's torque and resonant vibration that does them in.
 
Thanks for all your comments. In my many years of TR ownership I've seen the damped vs undamped argument surface many times and there seems to be no right answer. However, having bought an undamped pulley set I am using the attached link Revington Advice to justify going undamped.

Myles
 
TR6BILL said:
Is this or can this be an issue with the TR6 crank??
Click to expand...
I don't think so, Bill. The TR6 never used the fan bushings for dampening, so that's not a problem.
And from what I've read, getting a TR6 motor to hang together at significantly over factory redline takes much more than a simple damper on the crank. So just stay mostly below redline and all should be fine.
 
Its something like the second and third harmonics that are bad on the TR6. The first is around 3000rpm, the second one is at about 6300rpm. Below that is fine. I don't think the racers even hit the third. I've hit 6K a few times with my TR6, suprised the heck out of a Quattro TT. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif My current set up makes peak HP at about 5,600rpm according to the dyno.
 
Kas Kastner once wrote that he measured over 1/2" deflection of the flywheel, at 6200 rpm, due to crank flex. It kind of explained why they were having a hard time keeping the flywheel attached !
 
Thats the second harmonic range I was referring to. Which is why the current racers add four more bolts holding the flywheel to the Billet crankshafts they also use for those bursts past 7500rpm.
/bcforum/images/%%GRAEMLIN_URL%%/driving.gif

Way way overkill for a street engine though.
 
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