View Full Version : Temp. range for electric fan ?

11-24-2008, 03:58 PM
I need input before ordering my parts. Since I added a hotter cam among other things, my car is running hotter than it likes making my idle a little unstable in heavy traffic. I will be adding a 16" puller fan with a thermostat switch. But don't really know if I should use a 185 degree (0n 185 and off at 165) or 195 ( on 195 and off at 175), if anyone can supply input, please chime in I don't want to use the wrong temperature loop with an electric fan and maybe create myself another problem. Thanks,
By the way I have always used a 160 thermostat in the engine as I live in Florida.

11-24-2008, 04:15 PM

I have 9.5 to 1 compression, a hotter cam, headers and triple carbs. Mine is fine with the 185/165 on/off settings, but I am using a Spal 16" puller fan on an aluminum radiator.

11-24-2008, 04:17 PM
The word i got from Gareth Thomas directly for my Tr4 was do not go over(hotter than) 70 degrees celcius or 160 degrees F. 10:1 comp. ratio. 290 deg cam, etc.
ps- no one makes themostats at this range(that i know of) so a manual switch is the best bet. When you know you will be standing still you can flick it on BEFORE you get hot.

11-24-2008, 05:04 PM
Why not get an adjustable thermostat, then you can tweak it later?

Eg, https://www.derale.com/adjust-fan-controller.html

11-24-2008, 05:22 PM
When you know you will be standing still you can flick it on BEFORE you get hot.

That's good advice. Comes in handy when you are adjusting carbs or tweeking the timing.
You can install both a thermostat switch, and a manual overide switch.

11-24-2008, 06:23 PM
You might consider buying Dan Masters' most excellent book on TR6 electricals. Answers every question you could possibly ask about electrical systems, fans and fan wiring too. Dan will show you how to effectively wire your electric fan to both run on a heat sensing thermostat and a manual bypass switch, as Poolboy suggests. When wiring a fan, overkill on wiring quality and protection (relays and fuses) is paramount. As Brosky suggests, a Spal fan is the best choice (their harnesses are the best!) www.spalusa.com (https://www.spalusa.com)

11-24-2008, 06:53 PM
Thanks Guys, I received a lot of good advice as usual. I have the fan eliminator kit from Rick Patton, the fan is a 16" Spal to replace the factory red fan and also the 12" pusher that seems to not do much in the cooling area, I will order the Spal wiring kit and hook it up with the indicator light as suggested by Dan Masters in one of his articles, and overkill is always the way to go in these cars to keep you from doing repairs to prior installations. My concern was with establishing the right on/off temp. loop and I will go with the 185/165 suggestion. will keep you posted...Thanks

11-24-2008, 07:20 PM
I used the interior dimmer light switch located right in front of the shifter lever to turn my fan on manually. (Like really, who ever DIMS their Triumph interior lights on purpose???) The pull switch is convenient and wires well to dead-short the fan motor. I also installed an LED light next to the switch to tell me when the fan is on. Beware, the light will glow at speed because the fan will act as an electric generator to the light and make the LED light glow at speed when the air current makes the fan blades turn and generate some juice. Now, if I can only get a really long extension cord and sell some of this power back to the electric company. :wink:

11-24-2008, 09:22 PM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]the fan is a 16" Spal to replace the factory red fan[/QUOTE]

So far, so good Mike.

Now how are you planning to mount it? Are you using the stock radiator? Has it ever been cleaned out or re-cored?

11-25-2008, 11:38 AM
Paul, Thanks for your input. It, a stock radiator (replaced new 15yrs ago) and I just had it cleaned 6 months ago, to the radiator I had a heavy screen welded across the rear to protect it from the plastic fan deflecting into it and cutting it up, I actually had this happen driving across a flooded parking lot 30 yrs ago. I'm going to try and attach it with stainless steel cable ties onto the radiator screen and paint the straps black so it wont show much.
I now have a small switch and a matching pilot light on the console under the radio for the small fan I had in front of the radiator, and the pilot light I will use on the new fan with the light to monitor use and the switch probably for an interior light under the glove box, Bill as to the light being powered by the spinning fan, if that happens maybe I will just add a diode to avoid back-feeding, can't sell the extra electricity! the extension cord in Miami will get stolen for sure. Bill, I put a bridge on my dimmer decades ago for full brightness (whatever that is?) It was a true Lucas...on/off/flicker and also dim.

11-25-2008, 10:14 PM

Just be careful of vibrations in the mounting that will wear a hole in the radiator faster than you can ever imagine.

I can show you how to make those dash lights bright again too.

Bright Dash Lights (https://www.74tr6.com/gauges.htm)

11-26-2008, 01:30 PM
Paul, a little late on the dash lights, I totally cleaned all my gauges and put them back in prior to your redoing your dash, they are impeccable but a shame that they are not as bright as yours, maybe next time (in 20yrs).
re: the fan I would never use the thru the radiator straps, I will try flat stainless steel cable straps I bought at Harbor Freight to the grill I have welded solidly to the radiator frame.

11-26-2008, 01:48 PM
I am using the Dan Master's instructions to the letter. I love the 16" Perma Cool fan. You do have to line it up to clear the tube crossmember. I do not have the remote control switch in the cockpit but not needed yet. The cool auto control switch works just fine. I found a cooler thermoelectric switch at NAPA and installed it at the top hose using the late stock tee in the hose.

I got my Electric fan conversion kit from my buddy Rick Patton.

My temp gauge gets to mid way and the fan comes on. This occurs only in hot weather stop and go traffic. The fan never comes on when the car is in motion. My temp gauge needle is normally just on the white line above cold.

Happy and cool..

11-26-2008, 08:47 PM
Hi Al,

We are on the same track, I bought the kit from Rick Patton also, and I will wire according to the same Dan Masters article, except that I think 185/165 on the temp switch will make me feel safer and it's the only thing that I'm now buying since I have had the 16" Spal fan saved away for over a year just in case and I figured that the curved blades might be quieter?, have had no basis to compare with having never heard either on a TR6.
Before I installed the cam and raised compression my temp. never went passed 1/4 on the gauge, now in traffic it sneaks passed the middle and my idle stars to suffer even tho it runs amazing otherwise. My wife says it will never be perfect enough for me and she accepts it as a constant work in progress, we have been married 32yrs, and I have also been married to the car for 34yrs.

11-27-2008, 01:35 PM
I have those great temp numbers with 10.0:1 compression and the GP2 cam. As a matter of fact, neither this motor nor the old one ever ran hot. I am using another cooler therm switch (can't remember which one) and a 165 degree therm.

I would like a temp gauge that shows degrees instead of just a range. I am considering a new gauge program. I will keep the fuel, amp and oil pressure but I would like to change the water temp range to a degree and add a oil temp and O2 sensor. I have a chrome 2 gauge holder that will be mounted under the dash over the radio location (I don't have a radio) or I will cut holes in the dash support. That is later.

Congrats on the 32 years of marriage. We must count our blessings. The car puts up with us regardless but a good marriage is another thread.

11-27-2008, 08:55 PM

Give Erik at Her Majesty's a call. I think that he has a proper size new Smiths temp gauge with numerical degrees.

11-27-2008, 09:04 PM
one thing i found while searching fans was there are many,many different flow rates/capacities for the same size fans. I have seen ranges of 1800 scfm to 3600 scfm. For those that don't understand that, it's the amount of air that they move. Makes a huge difference.

11-27-2008, 10:11 PM
That's true, Rob, and another factor to consider is the maximum draw. Of course you will be using a relay, so the wiring from that to the fan motor will be adequate for the amperage. But with a 36 amp alternator and factory wiring harness you need to consider the maximum draw at fan start up.
I have a fan rated for 10 amp max draw with a 36 amp alternator and factory wiring except for the wiring harness that came with the fan, and for the interval of a blink of an eye, at idle with lights on, I can tell that the fan came on. Other than that, I can't tell unless I hear the fan running.

11-28-2008, 01:01 AM
Thanks Paul. Will do. I need to yell at Erik any way.

11-28-2008, 01:19 AM
Same with me. I have the GM 55 amp alt. and the stock harness. When that 9.0 amp fan kicks on at idle the motor looses about 200 rpm. I think with all the electric add ons, I will need to go to a wiring harness upgrade. I can match the new loads with a larger alt but if the juice can't be delivered thru the exiting wiring, I have to get a bigger boat. Big supply and big demand on a thin wire results in a bad equation.

I have had one general electric failure corrected by rebuilding the wiper motor and switch, replacing the fuses and fuse boxes, and redistributing the circuit loads from the fuse box. The dreaded wiring task will be addressed in the future. I have BobbyD to guide me thru the wiring upgrade.

11-28-2008, 09:53 AM

I am also using a 55 amp Bosch alternator. No dimming of the lights or heater fan when the cooling fan comes on.

11-28-2008, 10:36 AM
I just took a look at your site to see if you had recorded the wiring harness up grade. Not sure if you did.

While I was there, I noticed that you had visited the dyno. Did you ever get your AFR corrected? What did your car produce for HP? I am at 118 HP at 5200 with the torque at 120 ftlbs. running very rich. At 2600 I go to WOT and the AFR drops to 11.0. At 3000 RPM the AFR goes to 11.5 and slowly improves to 12.25. That is very rich. I did not do a cruising read but my gas mileage is excellent and the plugs read very nice. If I were to do this again, I would get the SUs just because there is very little performance difference in the carbs but the SUs have a ton of affordable needles to tune with. Not so with the Zs.

Did not intend on bending the thread. We can talk about this someplace else.

11-28-2008, 03:38 PM

I have the Masters upgraded wiring harness &amp; relay pack for the headlamps, as well as the Spal harness and relay package for the fan.

I did not get enough miles on the engine prior to the accident to get the dyno tests run. What you saw there was old stuff.

And yes, my A/F seems to be fine now, but the dyno will tell next spring.

11-28-2008, 05:54 PM
Al, as far as the alternator is concerned 3yrs ago I replaced the factory lucas with a Delco 100 amp polished unit and reinforced the wiring with an additional HD marine cable all the way to the battery, by leaving the original cable running thru the ammeter it reads in the middle all the time, I did this because I once had an A/C unit that I installed with the help of a friend who knew what he was doing and after a few performance upgrades I removed it, also used the headlight wiring upgrade from VB along with Hela headlights and it's a pleasure to drive it at night.