TR2/3/3A Stock TR3 Fan mounting

[CraigLandrum]

We are about to mount a stock 4-bladed fan on a TR3 (in back of a brand new radiator). Any wisdom the forum can impart will be most welcome. I've read places that state that the fan and method of mounting help balance the crank, etc and that has me a bit worried. Should I be?

 

[MGTF1250Dave]

Aloha Craig,

The fan and the fan hub extension should have a small hole that was drilled through them somewhere between the fan mounting bolt holes. Line these up and you should have the fan blade in the correct location relative to the hub extension when it was originally balanced. The crank bolt locking plate is not a piece to forget. It prevents a back fire or dieseling on engine shut down (reverse rotation) from loosen that bolt. From personal experience, a loose crank bolt can act as a auger and bore a large hole in the radiator. Renew the rubber bushings and use the lock tab plates fan mounting bolts to keep them in place. The rubber bushings allow the fan to flex a bit even with the bolts tightened.

If you have balancing pieces and know where they go you can reuse them. When I remounted my fan, I didn't add balance pieces since I didn't have any reference points and it does not seem to have been a problem. I'm sure there are others who can comment on this also.

 

[tinman58]

IWhen I installed the fan on my 3 I was in the same position. So I just installed it the way the manual said, except that I left the balence plate out. There seemed to be no ill effects. No vibration at all. But after driving the car around for a couple hundred miles I noticed that the temp would rise when going slow or at idle. New engine and all new parts (waterpump, raditor etc.)
At speed the temp went down to 185. Since I had to rebuild the steering box I ordered the TR6 8 blade fan up grade from Moss.I also got the radiator duct, don't like the card board one that Moss sent so I am going to use it as a pattern to make one out of alum. After I put the car back together and starded the engine the air flow is 100% better thru the raditor.
I know it is not orginal but I think it is something to look into. I also installed a pusher fan with a manual switch, just in case. We do get somedays here that hit well over 100 degrees for weeks at a time. I do not want to remove the front apron again.
Dan
P.S. did you go thru your steering box?

 

[PeterK]

If you have a lawn mower blade balancer - cone shaped piece for static balance - it will suffice. Often, parts are swapped through the years and the fan and hub might be from different cars. So it's always good to check. Line up the tiny hole (as above) then check them on a blade balancer.

 

[CraigLandrum]

Thanks for all the great advice. The fan is likely not the original but is stock. I have the fan mounting kit from Moss with all the weights/locking tabs/bushings so should have the parts to use as suggested. The lawn mower blade balancer is a nice suggestion and I'll look at picking one up before we start on the job.

I also got the radiator duct from Moss, but probably won't remake in aluminum unless it falls apart on installation. I'll likely give it a quick rattle can spray coat to protect it from the elements before installation and hope for the best

I also have a brand new pusher electric fan that will get mounted on the radiator front which I plan to connect to a switch under the dash - just in case.

 

[Mkutz]

I've been wondering about a similar issue -- and a strong desire not to see the crank bolt and extension fly through the radiator travelling at full speed. Would it be OK to use a impact wrench to tighten the bolt solid? How else would you tighten it; putting the trans in gear or chocking the flywheel?

 

[MDCanaday]

As I have stated in the past,the stock fan is NOT good enough for general use in America,Probably OK in England.Cut off the "paddles" and mount a tr7 13 blade unit to the center hub, and you will never have a heat problem, and balance is not an issue with plastic....dont forget the loctite on the center bolt...
MD(mad dog)

 

[sp53]

Craig save yourself the pain and get a yellow multi-blade tr3 replacement fan from TRF and paint it black. It will bolt right up and I do not believe it will have any ill effects on the vibration damping of the engine. Moreover, it will cool the engine. I am afraid if you do not, you will end up taking the apron back off and do something different than the original design anyway.

 

[sp53]

Craig save yourself the pain and get a yellow multi-blade tr3 replacement fan from TRF and paint it black. It will bolt right up and I do not believe it will have any ill effects on the vibration damping of the engine. Moreover, it will cool the engine. I am afraid if you do not, you will end up taking the apron back off and do something different than the original design anyway.

 

[TR3driver]

I've been wondering about a similar issue -- and a strong desire not to see the crank bolt and extension fly through the radiator travelling at full speed. Would it be OK to use a impact wrench to tighten the bolt solid? How else would you tighten it; putting the trans in gear or chocking the flywheel?

Impact wrench should be fine. That's basically what I do, but if I don't have an air gun handy, I use a box-end wrench and tap on the handle with a BFH.

My Dad has an interesting theory, which is that the stock fan loses pitch over the years and hence becomes less effective. He tweaked his to give a little more pitch and claims that works fine. And the fan on TS13571L does look like it has more pitch than I recall the one from TS39781LO having. Now if I could just find that old fan for comparison ...

Another thing that I know happens sometimes : the radiator tubes lose thermal contact with the fins. The radiator holds water and flows just fine, but has lousy thermal efficiency. If your temperature creeps up at freeway speeds, this might be the problem.

Speaking of which, the fan is really only for low speeds and stopped. Above 20-30 mph it isn't needed. I once drove a TR3A to work every day through an entire Indiana summer with no fan at all, just by shutting the engine off at every stop light (and avoiding stop and go traffic).