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MG Midget and Sprite Technical - Heater Query

Hi all,
1274 Mk III
Have replaced the old mini heater control valve which fell apart ( thanks PO!),with a decent brass one from Sussex Classics.
It's at a funny angle, hard by the rocker cover and makes the water hose angle to the heater box rather acute.
my question is , its just a car for bimbling about & having fun in, its NOT a hot rod. So, IF I close the heater tap off & blank off the tap outlet, what else do I need to do to close off the system.
If I just blank off the water return FROM the heater box, is that enough?
If I " dispose" of the heater system, which I never use anyway, am I going to cause myself any more problems?
Thanks all again
Cheers colin
colin frowen

Have you got the right heater hose? The correct one is moulded to look a bit like a question mark. I leave mine connected as an insurance policy against overheating in the summer
Bob Beaumont

If you'd asked the question before buying a new tap, you could have saved some money. The easiest way to blank off the heater is to fit a blanking plate to the head and block off the stub on the bottom rad hose.

You won't cause any problems by removing the heater, other than not having any fresh air entering the car...unless you open the window.

If you do remove the heater completely, blank off the hole under where the heater was, so you don't get fumes entering the car.
Dave O'Neill 2

I'm not sure if I'm missing something but I always leave my heater tap fully open and just open or close the air flap to determine whether or not the heat actually comes into the cockpit.
Does anyone else do this?
Glynn
Glynn (1275RWA) Williams

>>>It's at a funny angle, hard by the rocker cover and makes the water hose angle to the heater box rather acute.

Can't you adjust the angle by adding an extra washer or two under the tap?

Jim
J Smith

I also leave my water tap open and control heating via the flaps, both before the heater and into the car. If it starts to overheat its very simple to open flaps and get rid of some heat, never a problem as I very rarely have the hood up - its a fine and dry weather car!
Colin
C Martin

The proper heater tap is in two parts, with the body of the tap screwed into the base plate that attaches to the head. It is therefore possible to alter the angle of the tap outlet relative to the two attaching studs. If turning it causes it to leak, then unscrew it completely and wind a few turns of PTFE tape around the threads before reassembling, just tightening it to the correct angle.
Guy W

My tap isn't on a tapered thread as I recall Guy; it is tightened down onto (and sealed) with a fibre washer:

https://www.ukmgparts.com/product/mga-midcat-9-mga21-steering-rack/heater-valve-washer-midget-aaa836

Jim
J Smith

No Jim, I don't think the thread is tapered, but it can still be slackened off and adjusted if PTFE tape is used to seal it as I suggested
Guy W

im still running with out the heater matrix in mine. I jst ran a rubber heater hose off the tap in the head to the top of the radiator hose

That way there is water.running thur the head and keeping the #4 piston band valve assmbly cool

I drilled a couple 1/8inch holes in the stat for circulation bypass ...so far no trouble

Prop and the Blackhole Midget

Colin do you have the early heater (square box & separate blower) or late one all in one casing? The hose from the tap is different and the tap angle is adjusted by shims, see parts 11 and 41 here:
http://www.moss-europe.co.uk/shop-by-model/mg/midget/heating-ventilation/heaters-vents-fittings/heater-systems-1275-1500cc.html
David Smith

On A-series engines, I've read that if you are going to do away with a heater, or even turn if off, you should really send the water from the rear of the head, back to the top of the radiator.

If you blank off tap at the rear of the head, the back of the head around number 4, can overheat.

If you plumb the heater tap directly back to the bottom hose, that too can cause overheating on very hot days, because hot water is being circulated directly back into the engine.

Hence, this is the correct way to do away with the heater.



Lawrence Slater

PS. I just read Prop's post, describing what I just said.

Ideally, if you wanted to control the water, some kind of T tap coud be employed. How about a couple of 12Volt motorsised valves? One to open a bi-pass to the rad, and one to close off the flow to the heater matrix.
Lawrence Slater

Hi all,
Thanks for all your help.
I think I will try the PTFE tape trick first.
( D'Oh! why didn't I think of that ?? )
Cheers
Colin
colin frowen

I am thinking of fitting one of these on my 1500 think it will fit on the original bracket with a adaptor plate and pipes come out the right way.

http://www.ebay.co.uk/itm/BMW-E46-3-SERIES-ENGINE-BAY-WATER-HEATER-CONTROL-VALVE-SOLENOID-8369805-GENUINE-/351630480232?hash=item51decf5368:g:9IIAAOSwpRRWmOn0


mark 1500 on the road Preston Lancs

The hose diameters might be different sizes.

Our LBC's have .5 inch dia. heater hoses. Don't know what BMW uses.

J Bubela

When I go to the South of France Spain or Italy in summer. I disconnect the heater. I connect the tab with with the other heater tube. So there is waterflow on cylinder no 4.

Flip
Flip Brühl

FAO Guy W.
Guy, the PTFE wheeze you suggested above worked really well. Thanks very much for the suggestion- cheers buddy!
colin frowen

Just so you know, A-engined cars sent to tropical regions of S. America in the 1970s had no heater and the tap port was blanked with a plate. The heater was obviously not intended to be part of the engine's cooling system.
Glenn Mallory

This thread was discussed between 16/01/2016 and 20/01/2016

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