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MG Midget and Sprite Technical - Fitting a new radiator

Chaps

Noting the attached photo - you will see my present radiatior arrangement on the modified Migdet. The original radiator is retained, brass expansion tank with winged cap is shown, electric fan fitted, and the top of the radiator is about level with the top of the head. Fairly sure it constitutes a sealed system - feel free to comment on that by the by - and so far so good. It works.

However, given I have now fitted bike carbs to the Zetec unit, and in an effort to increase the cooling capacity, I am thinking of installing a slighly larger radiator from a Westfield. I was also thinking of lowering the height of the radiator by about 6 inches or so to make better use of the airflow from the lowered bonnet orifice and to fit it up on the vertical members at the front of the car rather than it sitting on the cross member.

Essentially then, would lowering the radiator by 6 inches or so have a detrimental effect - air locks etc? I think if it is a sealed system, then I'm OK, but all comments very welcome as ever.



Oggers

Where would you be filling the system from?

I would imagine you'd need the filler to be at the highest point.
Dave O'Neill 2

Dave

Previously filled from the brass plug atop the radiator, but if the brass expansion tank is fiited at the highest piont, then I could fill from there? it has never really needed topping up either...
Oggers

There's a large gap between the present rad and cooling fan I'd try temporarily filling the gap or fixing the fan unit to rad to see if that gives enough improvement, a lot less work and retains a system that has proven to work already.
Nigel Atkins

My radiator is a standard 1275 crossflow (aluminium) but is fitted a lot lower and further forward so it fits under the slam panel. The expansion tank is fitted next to the wiper motor so is a lot higher than the rad. I fill the rad from empty by disconnecting the top hose and then any top ups are done from the header tank. Seems to work well and not had any problems with air locks or overflowing etc.




John Payne

John

Good to know. That is pretty much where I want to position the rad. I think the key is to put the expansion tank at the highest point. I can fill the rad using the brass plug, and top up as you do from the expansion tank. Any entrained air will escape into the tank.
Oggers

Oggers

Have you thought of getting a thicker core fitted to your existing radiator?

You could also consider put an expansion tank with filler cap at a high point in the engine bay. Such as atop the passenger footwell box/bulkhead?

There is also the option of using a thermostat housing that has a filler cap or special water rail, for example from Burton: https://www.burtonpower.com/parts-by-fitment-type/parts-by-engine-ford/ford-zetec-e.html?product_area=589 (if you were still using an A Series engine or a Ford Crossflow, Xtra Special Svens sell nice swirlpots that fit on where a thermostat hosting went: http://www.xtraspecialsevens.co.uk/swirlpot.html). Westfield radiator might have inlet pipe side that would suit such swirlpots.

Cheers
Mike
M Wood

At one time, I think the it was a Peugeot 106 variant, required the use of an extension piece fitted to the radiator filler neck when filling, in order to purge air from the system. You fitted the service extension tube, filled it to the brim and opened an air bleed valve at the highest point in the system - a heater pipe. You then closed the valve, removed the extension (spillage) and fitted the rad cap. I forget what it was, but a domestic plastic bottle with the base cut off served very well as the extension tube, sealing nicely when fitted to the rad filler orifice.
GuyW

Gents

The first thing to establish is whether I have a sealed system - just like any other modern car. I think I have. Therefore, like any other modern car, the expansion tank is located at the high point. I can raise the height of the tank without much bother and thus not worry about air locks.

I would like to use the Westfield rad. It is larger, thicker and in far better condition internally. It does however require some manipulation, grinding and drilling to get it in place, but I think it will perform very well. I also have a home made air defelector up front. Bascially some plywood wings sitting at 45 deg outwards which channel more airflow to the rad from the bonnet orifice. It worked very well with the old rad - lowering the running temperature quite markedly. Electric fan will also of course be replaced. Couldn't do without it at traffic lights.

Oggers

Oggers

Sounds like good plan.

I did wonder if you would want to get a swirl pot with filler and outlet to radiator down the front of the block, using one of these Redline water rails for Zetecs: https://www.burtonpower.com/water-rail-raceline-ford-zetec-e-rwd-conversion-fz470.html in conjunction with a Crossflow swirlpot which has a filler (see links at foot of that link). Pity the cost is way high as would make for a neat installation for radiator connection to a Westfield rad plus make filling with coolant and removing air simple.

Cheers
Mike
M Wood

Mike

Bit OTT for my simple needs. As John suggests, I can easily fill from the top hose, then top up via the expnansion tank
Oggers

Oggers

Have you seen this Zetec midget for sale with bike carbs - maybe some useful info/pics?

https://www.ebay.co.uk/itm/Mg-midget-zetec-/174475979861?_trksid=p2385738.m4383.l4275.c10

Cheers
Mike
M Wood

Oggers

Good point about keeping it simple.

When I was seeing whether Redline water rails for Zetecs were still available (memory from years ago reading CCC for folk putting Zetecs in Escorts) I did stumble on what might be a more cost effective but elegantly simple option from a fabrication company in Horsham (Neil Dunne):
https://www.engineere.com/GB/Horsham/837598526293793/Neil-Dunne-Welding-%26-Fabrication pictures on LocostBuilders forum: https://www.locostbuilders.co.uk/viewthread.php?tid=217556 (I have a Locost 7 project on the back burner that I am slowly collecting parts for and a Zetec is an option and a Neil Dunner water rail looks ideal).

Cheers
Mike
M Wood

This thread was discussed between 17/10/2020 and 21/10/2020

MG Midget and Sprite Technical index

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