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MG Midget and Sprite Technical - Expansion tank for vertical flow radiator

Has anyone done this modification? If so did you use modern type cap that can suck coolant back in and where did you get the cap? Or is pressurised expansion tank better? Thanks Andy.
Andy Potter

What do you mean?

Afaik you replace the cap on the rad with a non sprung one.
Then connect the expansion tank to the overflow pipe.
Now the pressure comes from the cap that came with the expansion tank.

Never fitted one
My vert flow keeps my engine just the right temp.
Only in hot summer traffic it gets a bit warm and after that I have to remember to top up.
Onno K

Onno, the system I have read about allows coolant to escape as normal into a container, the tube is into the bottom of the bottle so always in the fluid. The cap has a one valve that is sucked open by the drop in pressure caused by cooling thus drawing the fluid back into the radiator. The expansion tank is therefore not at system pressure. :)
Andy Potter

Andy, funny you should mention this. I added an expansion tank, purely for the recovery function, only last week.

Here's a pic.

I retained the functioning 7lb cap on the vertical rad. There is a built in valve to allow suction under the vaccum formed as the rad cools, in all modern caps, and all those fitted to Spridgets.

I used and old 7lb pressure cap for the expansion tank. I removed the spring and seal, so that all it does is function as a cap to keep the water from splashing out.

It won't directly improve cooling but does save the hassle, if you can call it that, of checking the water level in the rad.

See David dubois website for a full description of this. http://homepages.donobi.net/sufuelpumps/othertecharticles.html

Scroll down for the piece on cooling and radiators.


Lawrence Slater

I did this mod on my MGA for reasons of water recovery, this will never help with cooling.

The cap on the radiator I took the spring and seal off and just used a rubber seal on the op of the cap to seal the rad. Then the overflow pipe connection (that is now directly connected to the pressure in the rad) is then piped to a modern midget expansion tank that acts now as the pressure cap.

System works grat and the expansion tank can be mounted below the top of the original radiator without issues.
Robert (Bob) Midget Turbo

Andy and Lawrence,
Not to be pedantic about terminology, but what you are describing is an overflow catch tank (non-pressurized).


vertical radiators have a large tank on top, so they only need an overflow catch tank (as the coolant reduces in volume when cold, its level still easily remains above the top of the matrix)

horizontal radiators lack a tank on top, so if they prefer an expansion tank (pressurized) as the top of the matrix would be left exposed to air during warm up if the radiator was not able to be kept tip-top full when cold


Theoretically, either type would work to do that, but a pressurized expansion tank is more dependable for the radiator type that really needs it (horizontal ones). A well functioning vertical radiator doesn't really need any kind of a catch tank, but fitting an overflow catch tank is nice for the environment.


Norm "pedants of the world unite, we've nothing to lose but our sense of proportion!" Kerr

Norm Kerr

Thanks all for your input. Catch tank is exactly what I was thinking of, thanks for the photo Lawrence it helps a lot.
Andy Potter

is that BL/Rover windscreen washer bottle you got there L?
Nigel Atkins

Yup it is Nigel. Been there as long as I can remember, and the motor is still going strong.

Norm, not to be too pedantic, but in actuality, mine is an expansion tank. It's not used for that purpose, as I described, but it is nonetheless, an expansion tank.

If you use and old bean tin as a flower pot, it will remain an old bean tin, just with an adapted use. :)

Also, it is more than a catchment tank. It's a recovery tank. :)
Lawrence Slater

grin

:O)
Norm Kerr

Is that a pair of spare underpants tucked in the engine bay, Lawrence? O_o
P Dodd

My car when I bought it had an unpresseurised cap on the radiator with the overflow going to a tank with a pressure cap on. Not sure whether that helps or not attached a picture if its of any use.

Mike


m fairclough

Yup P Dodd, they saw good service keeping my nuts in place, and now keep my tools clean. :) LOL.

Mike, was it still at 7lb and did you keep it like that?

I wasn't sure if I could get a decent enough seal on the neck spout to handle pressure so I just went for recovery.

Lawrence Slater

Yes Lawrence it was a 7lb cap on the additional tank, but like you I was never quite happy with the jubilee clip on the hose on the overflow under the rad cap as there wasn't much to push the hose on to. I did do a couple of races like that however, I then reverted to a crossflow radiator that I had lying around and I do plan to put the vertical flow back on at some point.
The copper pipe attached to the top hose incidentally went to a heater core mounted adjacent to the radiator as additional cooling, could be an idea if your struggling with yours.
Not sure if any of this is helping Andy !
m fairclough

Yes all useful background info although I'm not having cooling problems just thought it would be nice to catch the overflow. :) BTW Mike where in West Mids are you?
I too noticed the pants Lawrence but thought they were there incase you had scary moment whilst driving. :)
Andy Potter

Hi thanks Mike.
The only time I overheated was in traffic jams in Spain and Greece. In the UK I don't have a problem. I just fitted the extra tank so that I no longer have to top up the radiator. Just getting lazier and lazier with age. :)
Lawrence Slater

Lawrence,
don't damage or loose the washer motor/lid as I think a replacement cost me £26 or more 6/7 years ago

as for the underpants, I believe Next is some sort of fashion label I never had you down as the pretty boy sort, every 4/5 years I buy half a dozen from Tesco whether I need them or not and each time I seem to go up a size
Nigel Atkins

I'm amazed it's lasted as long as it has Nigel. I didn't think you could still get spares for it either.

As for the Next, they were bought for me, I don't waste money on lables, and nor are my trousers around my ar*e so I can show 'em off, in the bizarre fashion that kids follow these days. Very peculiar.
Lawrence Slater

On the back of the tank there should be a moulded in lug at the bottom. When the tank is mounted to a flat panel, that lug should touch the panel to prevent the tank from rocking up and down and snapping off the legs or, worse, the pipe spigot.

I notice you have a spacer under one of the legs- presumably because the panel you've mounted it to isn't flat. I'm hoping you also have a spacer behind that middle lug to take the weight and stop the tank rocking.

Oh and I respect any man that needs to keep spare underpants in the car. Drum brakes, I presume?
Growler

There are some very observant people on here.:)

I do indeed have a support under the lugs, as I figured it should really be mounted on a flat. The top support extends down to the lower lug. Being lazy and not wanting to move my cable and washer pipes or my washer bottle, I did as you observe, and used spacers under the legs. Not the most elegant solutuion, but that's a charge that has never been able to stick to me. :)
Lawrence Slater

Lawrence,
I found a chap who had a stock of 70s NOS Rover/BL parts stored in some sheds that he occassionaly advertised

as for the sloppy jeans - I saw a TV program which said the fashion started because in the US prisons the young skinny prisoners got the same trousers/jeans to wear as the more mature prisoners so they hung low

once out of prison to show how hard they were by going to prison they continued to wear oversized

then of course they wanted to show the 'label' of even there underpants by showing off the 'label' on the waist band

a whole generation was taught the price of everything but value of nothing - could go off on a political rant here but I wont
Nigel Atkins

That makes sense Nigel. All these kids wandering around with their jeans around their ar*es, without even knowing why. lol. But even if I did know why, I still can't think of a single reason that it looks cool to walk around with your underpants showing out of the top. Some of them even pull the underpants down, so they display the typical builders crack.

What make me laugh so derisively though, is the way they have to walk to stop them falling down. Legs parted and strained against the outsides of the jeans at pocket level, they walk like penguins or charley chaplin.

Do you remember when if your jeans were too baggy at the back, you were called cement bags or the like? Times changed I suppose, and now it's cool to look like a nerd if your a kid. Funny that.
Lawrence Slater

This thread was discussed between 14/07/2012 and 17/07/2012

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