View Full Version : electric cooling fan

05-17-2005, 06:00 PM
Seeking thoughts, experiences and opinions of installing an electric cooling fan in a TR6 in place of the old mechanical yellow fan. If you are using an electric fan tell me what brand/model you are running and how you like it. Also, how do those things mount; hard mounts or some suspect snap-in feature? Thanks as always, comments are helping me complete my rebuild....wait did I say complete?

Geo Hahn
05-17-2005, 06:46 PM
I used a 12" fan available at a local auto parts store (Checker) and mounted using the mounting tabs and some clamping bolts I fashioned. I am only using it as a 'pusher' auxillary (still have the stock fan) but perhaps the mounting method will give you some ideas...


05-17-2005, 07:02 PM
You will get two opinions on using an electric fan in a TR6.
I am of the opinion that, "it ain't worth it." I had an overheating problem, tried a pusher fan, and took it off. Instead, I added a shroud (Vicky Brit catalog) and revamped my radiator to make it a 4-row. Heating is never a problem. Now, if you are **** bent on doing the fan, for performance reasons, you will want a puller fan, remove the stock fan and shorten the shaft that held it on. Don't remove it as it is part of the balance of the crank. Just go with the best quality fan you can find and bolt it to the radiator shell, not through the cooling fins. Wire it so that you can run off a thermostat or an overrider switch.
Again, I think that an electric fan on a TR6 just doesn't work that well.


05-17-2005, 07:37 PM
I have to respectively disagree, I think an electric cooling fan is great on a TR6, but it ain't easy. Bill is right, never mount it on the cooling fins, it will eventually destroy your radiator, I had a local radiator shop fabricate some mounts for me, along with installing a drain. I picked a Perma cool 16" fan that blows over 2200cfm and it works great, It turns on and off with a sensor in the radiator or using a manual override that I use in heavy traffic. Oddly enough it's only came on once or twice, so the radiator by itself does a pretty darned good job of cooling the motor.

Is it worth it? Hmmmm a tough call. I really didn't do the conversion for horsepower but for sound... I hated how loud the stock fan was. With the new electric unit, I can barely hear it, so for me I achieved my goal. For horsepower gains, I have no idea, but following other cars I'd say it's good for 4-5 hp, more if you put the Permacool sticker on the window.

As for the crank extension, I bought a machined aluminum piece that replaced it from this guy:

I had the rotating assembley balanced with the new bolt to eliminate any balance issues.

I got the instructions for the whole process from this guy:

I pretty much followed his instructions to the letter. I bought the relays and switches from Summit Racing. Let me know if you need any part numbers.

CAUTION, please measure the distance between the radiator and the cross member support. Even though the author of the how-to said it would fit, the fan that I got was a 1/2" too tall, so I had to "fix" the support to accomodate the fan. So I would wait until you have most everything put back together so you can get accurate measurements.

Good luck,

05-17-2005, 07:39 PM
Geo, I just saw your radiator mounts... cool idea. I wish I had thought of that. I think my fabricated mounts were the reason I had fitting issues.


05-18-2005, 07:41 AM

If you decide to go to an electric fan and do away with the old fan, you might want to consider removing the fan extension and replacing it with a harmonic balancer. This is a must on a TR4, I'm not sure how critical it is with TR6.

Yes, Geo, that's a neat, simple mounting method! Wish I'd thought of it before I mounted the 14" fan on my TR4 (Mr. Gasket brand).

My main motivation installing an electric fan was just to not have to worry about it. The original 4-blade metal fan and long-neck radiator had done the job without fail for years, even at high altitude on 100 degree days, with Webers, increased compression, headers and a few other performance modifications.

Still, I had visions of a blade flying off and skewering the radiator! After all, the same 4-blade fans put 2 out of 3 TRs out of LeMans the first time Triumph entered. They pitted and removed the fan from the third, to prevent a three-pete. A fan wasn't really needed at an average speed of 114 mph anyway! (Salt in the wounds of the two cars retired by it.) But the third car DNFed for some other mechanical reasons anyway.

A 12" or even a 10" fan is probably adequate for most TRs, and is what the TR vendors sell. But on my car it's also pulling air through the oil cooler, so I opted for slightly larger (1700 cfm is overkill for a 2.4 liter engine). 14" hangs over the sides slightly, but shouldn't present any problem.

One of the trickiest things was finding a fan assembly that was thin enough to fit behind the radiator on a TR4. I've got less than half an inch to spare. Better measure on your car to see how much room you have, and watch that dimension on any fans you consider.

In my opinion, a puller fan and a thermoswitch to control it are the only way to go. The kit I bought is a reversible fan, can be changed to use as a pusher or puller, and came with good wiring, connectors, a relay and a self-resetting circuit breaker in case of overload (no fuse to worry about). The thermoswitch was a separate item (on at 180 F, off at 170 F) and came with a weld-in bung to fit it. It's now installed in the lower hose pipe of the car.

Another thing to watch out for when adding an electric fan is whether or not your alternator (or generator) is adequate. Bigger, high volume fans can draw upwards of 10 or 12 amps, by themselves. My car's generator was only good for about 17 or 18 amps, but I was changing to an alternator and thin belt system/harmonic balancer anyway.

Summit Racing has a huge selection of fans and competitive prices. The Delco #7127 alternator I picked up at a local parts store (rated at 60 amps, but tested at 76... time to beef up the wiring!). The thin belt conversion/harmonic balancer came from British Frame and Engine, not sure if one is offered (or necessary) for a TR6.



Geo Hahn
05-18-2005, 11:54 AM
The thermoswitch... now installed in the lower hose pipe of the car.

[/ QUOTE ]

This is a point missed by many (maybe most) of the electric fan installations I have seen. The thermoswitch is often installed up top, possibly because that's a bit easier but it is the temperature of coolant leaving the radiator that is relevant in determining whether the fan should be on.

Simon TR4a
05-18-2005, 02:10 PM
Not much to add here but I was using a 12 inch Hayden, mounted as a pusher for space reasons on a TR4a. Also radiator recored with an extra row, fine pitch fins, shroud, oil cooler and manual switch.
Mine was mounted to the fins with a soft plastic mount, no problems in 5 years; I agree with Alan's point about current draw, and I like Geo's mounts.
I don't drive much in heavy traffic but this setup worked very well, and was quiet.

Rick O.
05-19-2005, 10:09 AM
I installed a 16" Perma-Cool puller fan with a T-stat relay wired directly to the battery via fused wiring. Also have a manual override switch in the cockpit (never have had to use that after 2 years of use though). Eliminated the heavy mechanical fan extension with the machined aluminun donut/shortened crank bolt that others have mentioned. This mod, in conjunction with recoring the rad to modern specs, is well worth the peace of mind it provides. Except for the crank donut/bolt, I bought all the bits from Jeg's.

Rick O.
05-19-2005, 10:12 AM
This mod, in conjunction with recoring the rad to modern specs,

[/ QUOTE ]Forgot to add that I also replaced the stock Delco alternator with the 60-amp Bosch unit to handle the increase in combined loads.

05-19-2005, 11:50 AM
Hey Geo - are you still using the stock generator with that fan?

05-19-2005, 01:05 PM
Just to add to the discussion, I put an electric pusher fan (mounted between the grill and the radiator) on my 70 TR-6 many years ago. I found the fan at a junkyard; it came out of an old Volvo station wagon. We custom made brackets to fit onto the radiator mounting points and it worked like a champ for 40 thousand miles. I put in a thermocouple controlled temp bulb in the lower radiator hose, and wired it direct to the battery with a heavy duty fuse. It is an option to use a pusher fan, and I never had any overheating problems, even in 100 plus weather. I'm hoping my frame off including a total engine rebuild and new radiator will eliminate the need for this set up. I sold it on Ebay last month!!