Fitting fans to radiator

[TrevS]

Hi all

I've fitted the radiator to my car today and am looking at how to fix the fans to the radiator. It seems there are 4 brackets that fit to the corners of the fan and then a plastic threaded tie seems to pass through the radiator to the brackets and are then secured using a cap.

What I want to check is how the plastic ties pass through the radiator. Do you push them through the fins in the radiator as there isn't enough room for them to pass through without bending the fins in the radiator.

As always any advice always appreciated

Thanks

 

[Randy V]

I chose to not connect the fans directly to the core of the radiator.

Those connectors that you show needed to be forced through the fins carefully if you choose to go that route. Yes the fins will be bent in the process, just be careful to not mess up the tubes..

Instead I made a shroud ( note that I have not yet added my rubber flap valves that will allow the higher pressure from high speed road use to pass through without going through the fans )..

http://www.gt40s.com/forum/gt40-tec...0519-gt40-radiator-fan-shroud.html#post284336

 

[Andy Sheldon]

Trevor

Just push them through the core. It will be fine.

Thanks

Andy

 

[Bill Cooke]

Trevor, I used a different push thru that was a little bigger in dia' but still passed thru the core with no problem. If you space the fans right you can hold the AC condenser the same way.
Bill

 

[Ian Bissett]

Trev,
As Bill says, space them out right and you can get the a/c rad in on the same tabs.
Ian

 

[Dave Lindemann]

Trevor -

My recommendation - DO NOT use the through core mounting method! I installed fans using that method on my Esprit and after a season of driving (and vibrations) the plastic zip tie wore through the core and I had leaks all over the place. Use a structural mount to the frame of the radiator - don't run anything through the fins.

Just my .02.

Dave L

 

[Terry Oxandale]

I was wondering if anybody would say that. The whole idea of mounting something hard onto a radiator core with zip-ties just doen't pass muster to me...but I've been wrong before (many times). My second thought though is to mount a piece of foam padding between the two pieces (fan mount/radiator core...perhaps those used for furniture with a hole punched in the middle?

 

[Seymour Snerd]

...after a season of driving (and vibrations) the plastic zip tie wore through the core and I had leaks all over the place

I've heard that story elsewhere and so wonder why the fan mfrs still promote that method.

One way to mitigate the conflicting requirements of low-speed fan vs high-speed unassisted airflow is to fit fans of the maximum size. For example, see below Steve C's P2125 which I believe is the current standard fitment for SPF GT40s:



The fraction of total radiator area that is "in the shadow" of the shroud is small enough that I doubt it affects high-speed unassisted air flow much, especially given the much higher resistance provided by the radiator core itself.

In any event, Trevor, if you acquired fans of a dimension comparable to the height of the radiator it would also place their mounting lugs in a position that would make direct fastening to some framework much easier, would reduce parasitic loss when under unassisted airflow, would give you more fan volume when fan assisted and (ahem) would cost more money.

The 11" fan in the picture is here:

http://www.spalusa.com/store/main.aspx?p=itemdetail&item=30102054

(BTW just to put a number on the size of that "shadow", it's 1-pi/4 or about 22% for a radiator exactly one fan diameter tall and two diameters wide.)

 

[Andy Sheldon]

We have mounted our fans using this method for the last 25 years without any problems.
You must pull the mounts tight

Thanks

Andy

 

[Dave Lindemann]

I've heard that story elsewhere and so wonder why the fan mfrs still promote that method.

The fan manufacturers may promote it but the radiator manufacturers sure don't - at least the one that manufactured the aluminum replacement for my Lotus didn't.

Dave L

 

[Dimi Terleckyj]

Hi Trevor

This is just my opinion but under no circumstances should the fan be mounted directly on the radiator in that way.

1. The fan will only draw air through the area in front of the fan and not use the whole area of the radiator which will drastically effect the efficiency of the cooling system and with such a small radiator as these you need all the cooling possible.

2. The fan should be mounted on a shroud to allow the whole surface of the radiator to function correctly.

3. The core of the radiator is not designed to carry this extra weight and with the inevitable vibration issues will cause the radiator to fail in the long term.

4. If servicing of the fan or radiator is required by having the two of these mounted together it increases the chances of the radiator being damaged as they are seperated and reassembled, possibly a number of times.

The fan manufacturers recommend it because it is cheap, quick, and easy and saves the purchaser from having to fit a shroud which would have to be custom made.

For what it's worth mount it correctly on a shroud and save yourself the long term grief.

Dimi.

 

[Micke Lvov]

I have done like this !

 

[David]

IMO those fans are too small.

For a road car for best cooling when stationary/in slow traffic the fans *must* pull through all of the radiator. This means that the fans should be as large as possible and the radiator that isn't covered by the fans themselves should be shrouded to force the air to be pulled through.

It's a bit different in a race car where you're going to be stationary/in slow traffic for a very small amount of time and you can make the (reasonable) assumption that it's always going to be moving. This reaches the 'ultimate' in F1 (and similar) where they have external removable fans for the grid etc.

I would take a suitable sized piece of aluminium, bend the edges to leave a small gap between it and the radiator (with something suitable soft between it and the radiator to prevent wear) and then mount the fans to that. Not 100% sure where is best on yours to mount it to, I've seen other 'GT40' radiators with tabs top and bottom but yours appears not to so maybe from the main radiator mountings.

 

[David Briggs]

I never use the push thru pins, always make a shroud.
It is very easy to fold the edges so that it will attach to the frame of the radiator and will be far more efficient then just sticking the fans to the core.
Very important to seal around the edge of the radiator to the car, that way all of the air entering the front of the car is forced thru the radiator.

 

[TrevS]

As always, cheers for the responses guys

I think I might hold off fitting these until I get the AC rad now then so I can use the same cords. Alternatively I like the idea of making some mounts for the fans so I'll take a look tonight to see how this might work

 

[Stephen Tonks]

Hi Trev

I mounted my fans by passing the threads through the radiator. Lasted for 16 years, before springing a leak, and needing a new core. Not bad I suppose. I have now built a bracket that mounts at the back of the radiator, for the fans, with nothing passing through the radiator.

Regards

Stephen

 

[Jim Cowden]

16 years it needed a new one anyway.

jim

 

[TrevS]

16 years seems good enough for me

 

[SteveB]

There have been threads re ali radiators not being as robust as traditional copper items so it may be better to mount fans and a/c rad independently to avoid extra loading on the radiator.
You could consider soft mounting the rad to avoid stressing or flex of the ali rad core.

Steve

 

[Bob Putnam]

We make a frame that spans across the core to carry the weight of the fans.