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MG Midget and Sprite Technical - bypass hose

I've just changed a leaking bypass hose on my midget. Was a little surprised when I removed the old one as it wasn't a hose, it was two blanking rubbers!
I know the car was raced years ago, anyone got any ideas as to why this would be done?
Would it bypass the thermostat so water is always flowing?
Photo attached.



Mallorcaben

I don't think the by-pass serves any purpose in practice and in later A-series heads it is missing. I have an MG Metro head that is very similar to the Midget head except it has no by-pass. I had to blank off the water pump to match. I have had no problems with cooling and, if anything, the cooling is better than before. It is, however, wise to put a couple of small (1/8th in) holes in the thermostat to allow some water to flow before it opens. There was a thread on this BB recently about just this matter.
Chris
Chris H (1970 Midget 1275)

The by-pass hose provides cooling to the front part of the engine during the warm-up phase at least. On standard engines a couple of small holes in the thermostat can work.

On our 1380, I had considerable problems with localised overheating after removing the by-pass and drilling a couple of holes in the stat, so have replaced it. No problems of any description since. After that experience I would not remove the by-pass from any A-Series engine, but I know many have had no problems after doing so.

Later A-Series applications do not run without a by-pass. The head to water pump by-pass is not used, but there is a permanent by-pass from underneath the thermostat that runs through the heater and back.
Richard Wale

A permanent by-pass! Well I learn something every day. I never knew that.
Chris H (1970 Midget 1275)

Double thickness of thermostat housing on Metros has the lower branch dedicated to water bypassing

The stat sits under the top housing, it's a two part doofer. If used the heater hose off the bottom hose needs blanking off instead. I didn't bother, just poppped a hole in the stat plate and saved an extra stat gasket...

The picture was filched from my little "Boy's Book for Austin-Rover Metro Mechanics" and shows the second half of the stat housing with its by-pass

hope it helps explain


Bill

Morning peeps

Having looked through various threads in the archives, I'm still looking for suggestions.

I have a metro turbo head, metro pump with no by-pass port on my turbo engine.

I also have the metro sandwich thermostat plate under the std midget thermostat housing and a outlet where the heater tap would have been.

My question is does the thermostat housing set up clear the bonnet??
Or do I do as many have done and do away with sandwich plate and just drill a couple of holes in the thermostat?
M Slater

Really no one????
M Slater

Hi mate

Yes I have a turbo but I have the metro thermostat housing without the sandwich plate as you refer to it.

I have piped my heater using the connection on top of the pump with a rubber elbow and the other connection to the heater is from the rear of the head. On turbo heads this can be simply drilled out if not already done so.

So regarding the clearence I have no direct knowledge although I would be very surprised if there was any clearence issues
Bob Turbo Midget England

ok cheers Bob, I guess I will just have to wait until the bonnet is back from the painters to see if it will clear.

If it dosn't at least there are options for plumbing.......
M Slater

This thread was discussed between 11/11/2008 and 20/03/2012

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.