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MG TD TF 1500 - 51TD current water hose setup

I'm thinking about my heater rebuild project as the next step. Looking at my current heater hose setup, I realize, I've never seen what it originally looked like. In the picture below you can make out (if you peer long enough) the branch pipe and heater hoses snaking in the front of the engine.
My question is it looks to me like my branch pipe is in backwards... does anyone have a picture of an unmodified original setup? Seems to me like someone reversed it to make an easier flow to the heater hoses, but as I said, I've got nothing to work with, it just looks wrong to me.
I'm thinking I should drain the system, remove the heater and the hoses, and set the system back up the way before the heater was installed, and I just want to make sure that I can do that.

Geoffrey M Baker

This is from my TF.



Frank Cronin

Geoffrey, based on my '53 TD, I'm pretty sure that your branch pipe is in backwards, probably for the reason you guessed.
Jud

J K Chapin

Thanks Jud that is very helpful and looks like I guessed right. Great - I can proceed to remove the hoses and set it back to the original setup. Then I can spend some time stripping and cleaning the heater and reinstall when I'm ready!
Geoffrey M Baker

Geof,
What you have is perfectly adequate- there's nothing wrong with it, and it's better than a lot of others.

Frank,
It appears you have an originall Arnolt fitting in your radiator return hose. Not only are you diverting cool water to your heater, you've choked off you whole cooling system. Are you experiencing overheating in the warm weather? Check the archives for tapping the thermostat housing for hot heater water.

Jud,
Yours doesn't have a heater, does it? All I see is the bypass hose from the thermostat housing back to the radiator return.
JRN JIM

JRN
There may be nothing wrong with my setup (except that hot water is drawn from the back of the engine) but it's time to strip down and rebuild the heater... So I need to take all the hoses out and temporarily plumb it as a heaterless system.
Geoffrey M Baker

Geof,
You say the water is drawn from the back of the engine. That photo gives the impression the top hose is coming off the bypass fitting on the thermostat housing.
Which is it?
I like the little bracket holding the floatbowl vent tubes.
JRN JIM

Jim, you're right. I do not have heater. I was trying to show what I think is the "stock" branch pipe installation. Lately building a heater using perhaps an oil or transmission cooler and a couple of computer fans has crossed my mind but truthfully around here a heater is only needed for about 3 months out of the year and then only about half the time so the project is more idle musing that an actual plan. Jud
J K Chapin

Jim, if you follow the top hose down, it ends in a T. One side of the T connects to the rear engine block, one goes to the heater. The other heater hose goes from the heater to the branch pipe. Here's a diagram.
I want to restore the heater (it hasn't been touched in 60 years) and I want to get rid of this hose mess!

Geoffrey M Baker

Good news and bad news...
I drained the system and took out the heater, hoses and branch pipe. Good news: the Arnolt core looks surprisingly good. The fan more or less works, although I probably need to disassemble and clean it and repaint the blades. The housing needs stripping and repainting.
But the bad news: that isn't a branch pipe reversed. It's a home made branch pipe, which won't work any way but the way its set up. I'll probably have to braze on a new fitting to the top of it to make it connect to the thermostat housing. Probably not worth buying a proper branch pipe (which I would need to braze a fitting onto anyway).
But the downside was that I had hoped or expected that after a couple of hours work, I could reverse the branch pipe, hook everything back up minus the heater, and still be able to take the car for a spin.
That isn't going to happen. I'll have to block off the back of the engine block and braze a new fitting onto the handmade branchpipe that I have and make a cap to fit the heater return connection, before I can drive her again.
Live and learn!

Geoffrey M Baker

Here's a closeup of the handmade branchpipe

Geoffrey M Baker

Geoffrey, in the interim your welcome to use this one. It's ugly but it didn't leak when I replaced it last fall. I can drop it in the mail tomorrow and you can reimburse me for the postage. If you want it post your address or send me a note at jchapin3 at aol dot com. Jud

J K Chapin

Jud, I'm trying to braze mine now. If I can get it done tomorrow I'm all set - otherwise if I run into trouble I will take you up on your generous offer!
Geoffrey M Baker

Unless you are just trying to change the angle on the branch pipe to maybe reinstall the bypass, or feed the heater return differently, it would work just fine.

Don't bother trying to reinstall or reenginer a bypass circuit from the bypass fitting to the branch pipe. All the replacement thermostats fail to block the bypass once the engine is hot. The old ones cut off the bypass and thus curtailed circulation through the heater. You just can't win with the bypass.

What you need to do is get rid of that worthless Y pipe to the back of the head and blank off cover plate. It does need feed water to the block, it pulls warm water out and mixes it with hotter water from the stat housing. Your coolant is circulating from both ends of the higher pressure in the head, through the heater, to the low pressure of the pump suction inlet. It serves no useful purpose.

One other question I have, now that your system is drained, do you know the precise location of your thermostat within the housing, or if there even is one? If it a later replacement, it could be installed before or after the bypass port. If it is installed in front of the bypass, you won't get any coolant circulation to the heater while the stat is closed, when you need it most. Sometimes, our thermostat doesn't even open on a cold day with the heater on.
JRN JIM

Jim, I have checked and tested the thermostat and it works fine. My goal is to run the bypass by teeing into the thermostat elbow (beneath the thermostat) for the hottest water while not disturbing the thermostat bypass loop, and returning water to the branch pipe by brazing another fitting there.
I do plan on closing off the heater takeoff at the rear of the engine.
I agree, whoever set up the system I just removed had not really thought the process through.
Currently, I'm having all kinds of trouble with the branch pipe. Mine, which is steel and homemade (by, I assume, the person who installed the heater), just isn't giving me a leak-free result. I've tried brazing it (no good, my MAPP torch just doesn't get hot enough) and welding it (no good, endless pinhole leaks). I'm wondering whether I should just solder the outside surface to waterproof it, as I have a good strong (but not leak-free) weld for the takeoff.
Geoffrey M Baker

I *think* I've got a leakfree braze on the branch pipe now, will try to figure out how to water test it!
Geoffrey M Baker

OK I installed my new branch tube with extra connection. I also decided to turn the connection on the rear of the engine into a tap/drain to allow me to open the system at the high point of the system to make sure whole system drains properly (and fills properly). I put a brass plug on the branch tube extra connection for now, so that I can run around in the car while I rebuild the heater :)
We'll see if it's all leak free tomorrow!
Geoffrey M Baker

Here's the new valve at the back of the engine block.

Geoffrey M Baker

This thread was discussed between 21/01/2015 and 25/01/2015

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