MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - Rad - Crank Clearance

I am doing a Rover 3.5 - MGB and have arrived at the cooling system.
I have located a fan which puts out 3000CFM which is 4" thick at the fan motor.
The question is that I have 4 1/8" - 4 1/16" between the rad and the crank pulley and with a 4" fan this would only leave 1/8" - 3/16" clearance.
This would a great fan to get but I am concerned there might be some movement forward and aft of the motor through normal driving and the clearance would not be enough.
The next fan I have been able to locate is 3 3/8 thick and would provide 5/8" clearance between the fan motor and the crank pulley, but it only puts out 2350CFM

Bruce
Bruce

It should read I have 4 1/8" - 4 3/16" clearance between the rad and crank pulley

Bruce
Bruce

You can machine the extra sheaves off for extra clearance if you have a multi-sheave pulley. Early Buick water pumps were about 3/4 inch shorter than later ones, not sure if they fit the Rover. This could give additional clearance in center.
George B.

Bruce,
Are you using the buick 300 waterpump as it's shorter and widely used.Jim Stuart recommends a chevy pulley then just drilling new holes to fit the rover..........
greg phillips

I am using the shorter Buick water pump but there is lots of room there.
Where the fan motor will be located (center of rad) is right in line with the crank pulley which I taken apart and remove the extra pulley's. I would like to use this fan as it is rated for 3000CFM but I am concerned about the clearance. Will 1/8" - 3"16" be enough of a clearance between the fan motor and the crank pulley. If not then I would have to step down to 2350CFM which 3 3/8" wide at the fan motor and would give me a clearance of @ 5/8".
I am not sure if there is going to be any forward movement of the engine. If there isn't then I am okay, but if there is then I would have to go with the smaller unit.

Bruce
Bruce

Bruce,

The best place for the fan is covering the top right of the rad where the hot water comes in. This might help with alignment...

My gut feel is that if your brakes are any good you might well be able to entice the engine forward a few mm when you stand on them which will push your fan through your rad.

I also would guess that the rad and mount would bow very slightly when it had the full force of the wind running through it. The fan starting would have the opposite effect so you have some interesting forces playing around within your low tolerance area.

You dont want a push fan? I put a larger push fan in after making a couple of mods to the front crossmember and strengthening. Works fine and allows room to work on the rad/fan/engine.

Frank
frank swinton

Frank
I too have been thinking about this a lot. The fan as I said is 3000CFM. Huge puller out put. I did talk to the fellows supplying the fan and he said no problem.
You do raise some interesting thoughts. Will the engine move forward? ? The tranny is bolted to the cross member and in turn to the frame. The tranny and the motor are securely bolted together. There might be a slight movement on the rubber motor mounts? But being bolted to the tranny, crossmember and then frame would it move? Just talking out loud here, I suppose there is only one way to tell. Buy it and mount it.
The rad which is from a 63 Ford Falcon does stick down quite low (as low as the oil cooler) but I have stiffened it up with supports bolted to the frame in addition to the newly welded rad supports so that shouldn't move.
The fan when it is running (as long as the force of the incoming air pressure is less than that being pulled) is trying to pull itself through the rad (puller) so how much will the fan flex once I exceed this pressure. Again lacking an engineering degree I suppose the best thing to do is to give it a try.
The puller fan is suppose to be 20% more efficient than the pusher and with the puller fan I would be able to cover almost the whole rad (16" puller) with pusher fans I would only get in (maybe) 2 8" fans.

Thanks all for your input

Bruce
Bruce

I am afraid my comment on this thread will be of no use to you at all, but with a fan this powerful, why bother with a V8? With a decent battery it'll pull itself down the road on the fan! Incidentally, I put my fan ( 14" american fan of unknown make ) in front of the rad and found it to be a good solution. Most conversions seem to want to look stock and that prevents them from using what is a really sensible answer to the problem.
David Daw

I used an engine driven flexi blade fan in the early days. To make this fit I moved the rad. about 3/4" foreward & lower.I drilled extra holes in the rad. mounting plates & used spacers to move the rad. foreward. I can't remember if I had to alter the lower plate in front of the rad.or not.Even so it was not a difficult task. The fan worked well & kept the car cool, but I always had visions of those steel blades converting someone's fingers into hamburger mince, may be mine ! HTHs Barrie E
begerton@froggy.com.au

David
Thanks for the laugh. "but with a fan this powerful, why bother with a V8? With a decent battery it'll pull itself down the road on the fan.

Barrie
I originally purchased a 15" crank drive fan. But I had to raise the engine to clear the oil pump on the steering rack and the headers/steering shaft. So of course the fan came up and just touched the bonnet. The next problem was I wanted to get a shroud to cover this fan. I could just see a couple of guys hanging over the engine having a beer and point to something only to loose a finger or worse. But to cut the fan down (or to buy a new one) and then buy a shroud, it started to look cheaper to buy a new fan. Especially considering I gained a little horse power, greatly increase air flow, and my new Delco Alternator will deal nicely with the load
I am unable to (now) move the rad any further forward because of the panel in front of it. The engine bay is painted, engine is in just need a few oil lines, rad hose's etc and I can fire it up.

Bruce
Bruce

This thread was discussed between 18/02/2001 and 23/02/2001

MG MGB GT V8 Factory Originals Technical index

This thread is from the archives. Join the live MG MGB GT V8 Factory Originals Technical BBS now