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MG TD TF 1500 - heater system tubing

I'm in the process of installing a Mojave heater in my '54 TF. I'm using copper tubing for the most part except where rubber hose connecting is necessary.

Question: Will braising the copper tubes to copper elbows be sufficient for the water pressure that will travel through the system, especially when closed? Or, is there a better way to secure copper to copper?

TIA -- John
John Brickell

How high will the pressure be? A 14 PSI (=1 bar) cap will give just a little pressure?

The pressure in hot water systems at home can get higher, I presume. There brazing is perfectly acceptable.
Willem van der Veer

Why not solder..the radiators themselves are just soldered. Regards, tom
tm peterson

Sweat the fittings just like you would for plumbing in a house. That's how Laverne did his (1/2" plumbing). Just make sure you have a wet rag to get the excess solder off the pipe so you have a clean finish.

Personally, I'd prefer to do bent pipe on mandrels as I don't like the raised hubs found on fittings. However, that is a bit more effort than just doing up some fittings from the hardware store. The bent pipe wont move the water any better either. It will just look cooler... to me.

Alex
Alex Waugh

Alex is back :-) Thought about you the other day when I saw some new dancing on youtube...salsa and something else mixed in...lotta sweat going on when the finished.


Yep I sweated the fittings together. Bent would be nice but that won't happen with ridged pipe. Go to tubing if you want to go that route.
MG LaVerne

Thanks all for the input. Much appreciated and very helpful. Yes, very good to see Alex back on the board. Besides being a TF "hotroder", the undisputed salsa king.
John Brickell

Yes... I did take a break for a bit. I'm building out a basement apartment at my new place and it is taking all my time. I do go out in the TF and terrorize the new neighborhood now and again. If you don't exercise them, they require more maintenance! Go drive em boys!

Alex
Alex Waugh

Hey John,

Good to see you're still kicking. I won't forget our breakfasts in Reno ('way back in 2011, can you believe?).

I have used copper tubing on my heater. The ideal method is to butt-braise the ends, but better still, is to first slide a sleeve over a free length of the tube, then solder it in place over the joint. This is neigh-impossible to do with the heater in place - best done before installation.

Pre-make all the runs you can before installing the heater.

In all cases, easily said, but not so easily done!

Gord Clark
Rockburn, Qué.
Gord Clark

Hey there Gord -- Good to hear from you and thanks for the suggestions on securing copper tubing. Yes, the breakfast in Reno, and the entire Reno event, although a few years ago, I recall with good memories. Especially your MG history test during breakfast. Nicely done.

Cheers -- John
John Brickell

I used thinwall 5/8 OD stainless steel tubing (larger volume water capacity and stronger) but it can still be soldered directly to 1/2 fittings (with a little filing). I also bought 5/8 brass compression sleeves and slid them on then soldered them, like Gordon did, to get good connections for the hoses.
I strongly recommend you use good quality use silver bearing flux!
Geoffrey M Baker

My heater pipes before final fitting. PJ



Paul S Jennings

Geoffrey, thanks for your input and suggesting the use of silver bearing flux. Hadn't known of it, but will look into it. This is another one of those areas where I'm in a learning mode.

Paul, that is a very clean looking system, and one that Alex would certainly be proud of, but I'll stick with my pieced together copper tubing since I have all of the pieces cut and ready to be brazed, and connected to the heater.

John Brickell

I ran my piping UNDER the manifold, as I think it gives me the 'cleanest' install. Before you get around to soldering, look up the archives, there is plenty of good information on how to achieve a perfect join.
Here's a pic of my installation:

Geoffrey M Baker

By the way, John, when I was planning my system and practicing brazing and soldering, I read that technically, the only difference between brazing and soldering is that brazing takes place at a higher temperature. I used alpha fry flo-temp lead free acid core silver bearing wire and silver bearing alpha fry plumbing solder flux. As this melts at 430 degrees, it is so far above any safe engine temperatures that you don't have to worry about it - your engine will have blown up long before the pipe joints fail :)
Geoffrey M Baker

Geoffrey -- The specificity of products used is very helpful and much appreciated. Now, on to find such.
John Brickell

John, Paul and others,

The below has been published several times, including in the TSO. However I ran only one line under the manifold, with the return going into the rear of the head.

Anybody considering flow dynamics, will quickly realize that the flow through the rear of the cylinder head and the normal flow coming from the front, now come into 'conflict' somewhere in the middle of the head, and some will argue that this will cause a hot spot.

To the contrary, all flow goes from the head, down into the block, irrespective of source.

The benefits of using this arrangement are:-
* It is neat - minimizes hoses running through the engine compartment
* The copper pipe running under the exhaust manifold, picks up more heat for the heater

I installed this system in 1957 and have probably put on 200,000 miles with it, including driving back from Sebring in 1959 in bitterly cold weather. I was as warm as the proverbial "bug-in-a rug".

The below pic is a composite of two images, with the centre of the engine not shown. The dotted lines show the copper pipe running under the exh. manifold.

Gord Clark

Please ignore all the compound dust etc, cars filthy, but here's how I routed my lines through a Triumph fitting to accommodate how my heater pipes are situated. PJ



Paul S Jennings

If anyone has followed my threads on my heater installation, you will know that I ran both my heater lines under the manifold. Like Gordon, I did mine mostly because it gives the engine compartment a less cluttered look. Unlike Gordon, I tapped into the hotter area near the thermostat for maximum heat; as we know, the difference is minimal; but as long as I had it all apart I thought I would do it that way.

As I have the engine out and am working on other projects (right now I have disassembled and desoldered the radiator and am "rodding" the radiator and repainting the frame) I am considering one final step... to cut two new holes in the firewall (pretty much directly beneath the existing holes) so that the hose lines do not have to rise and make a 180 degree turn to enter the passenger compartment. I believe, done right, I could then be able to run a gravity drain system for both pipes, so that opening up the radiator drain would completely drain the heater lines as well. The holes would allow for me to make a straight run to the heater, which if plumbed correctly, would drain perfectly. I think it would be a small but very pleasant improvement, in that it would greatly simplify removing the heater and all related work in that area (when accessing the bellhousing and gearbox, etc etc).
Has anybody thought about this?
Geoffrey M Baker

This thread was discussed between 07/04/2015 and 11/04/2015

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