bypassing heater matrix

[troydeon]

Living in southern Texas I can see that the heat coming from the heater matrix is going to be a problem.
Would like to bypass it with valves so that I can turn it on on rainy days to defog or if I do travel north...
Has anyone set this up?
Are there kits available?
Any recommendations will be appreciated.
I do have AC but haven't had it looked at yet, but even once I get it working I think that the residual heat from the matrix will be a problem here...

Troy
1980 TR7 DHC

[nick]

There is no kit that I have heard of. But it seems pretty simple. There are two hoses at the the firewall, one inlet, one outlet. The coolant circulates through them. A valve could be placed there and turned on and off at will.

[img][IMG]http://i615.photobucket.com/albums/tt234/nickmi/TR7%201975/Yellow.jpg[/img]
nick
'79 TR7 DHC
'76 TR7 FHC

[trickyx12000]

the engine will probably run hotter if you do..

[FI Spyder]

If I'm not mistaken the factory A/C heater unit turns off the water flow to the heater matrix when heat is shut off (unlike a regular heater where the flow through is constant). Therefore you don't get any loss of efficiency. Obviously with no flow through of coolant you don't get any appreciable loss of cooling as my car runs as cool as a cucumber (although it is said FI cars run cooler or perhaps more accurately tend not to overheat as easily.)

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[troydeon]

I thought that it was the other way around... AC always had the coolant flowing through and non AC could actually shut it off...

Going to do some research, I did find some easy solutions if I do need to do it...

Troy
1980 TR7 DHC

[Hasbeen]

Turning off the flow of water from the back of the head in an 8V engine will probably cook the rear of the cylinder head. The cooling system is deigned to return the hot water, & thus the heat, from the back of the engine, via the heater to the water pump.

It is a 5 minute job to swap the heater outlet pipe, which runs to the water pump, to the cylinder head outlet, which is all that's required.

I suppose you could design a fancy switching system that allowed the flow to go either way, I would expect suitable things exist.

It may be possible for the head gasket, & head, to survive a hot pocket at the rear of the engine, in some climates. If you do run this way, please let us know if it is OK, as the advice I've had here in hot Oz is it is a problem.

Hasbeen

[john 215]

Hi,

A similar question asked a while ago -

http://www.forum.triumphtr7.com/topic.a ... hTerms=800

Cheers John


LIVE LIFE A QUARTER OF A MILE AT A TIME!

1976 Speke FHC Beauty

1979 3.5 FHC(STATUS PENDING!!)

1982 2.0 DHC NOW A 4.6,ON THE ROAD NOW KICKING AR5E !!!!

[KFSullivan]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Hasbeen</i>

Turning off the flow of water from the back of the head in an 8V engine will probably cook the rear of the cylinder head. The cooling system is deigned to return the hot water, & thus the heat, from the back of the engine, via the heater to the water pump.

It is a 5 minute job to swap the heater outlet pipe, which runs to the water pump, to the cylinder head outlet, which is all that's required.

I suppose you could design a fancy switching system that allowed the flow to go either way, I would expect suitable things exist.

It may be possible for the head gasket, & head, to survive a hot pocket at the rear of the engine, in some climates. If you do run this way, please let us know if it is OK, as the advice I've had here in hot Oz is it is a problem.

Hasbeen
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Hasbeen -

I've seen you post a comment similar to this a few times. Any chance you can post a diagram or photos to show how this can be done? Much thanks!

1980 DHC Pagaent Blue

[nick]

I think the US and UK cars are different in how the water is plumbed to the heater. On my US car the outlet from the back of the head is blocked. Notice the capped hose in the picture.



[img][IMG]http://i615.photobucket.com/albums/tt234/nickmi/TR7%201975/Yellow.jpg[/img]
nick
'79 TR7 DHC
'76 TR7 FHC

[Last TR]

I believe my heater connection is from the back of the intake manifold, and only the water passages at the front of the heads are connected to the manifold. Can't see where shutting the water off would matter to the back of the heads. Is there a difference in the heater connection between the TR8 engine and TR7s with later Rover V8s?.

Ken Morton
Anchorage, Alaska

1980 TR8, 1973 TR6, 1965 Volvo PV544, 1958 MGA, Jeep Cherokees

[Hasbeen]

Sorry KFSullivan, I don't even own a camera.

On every 7 I have seen, including ZS carb models, as were most Oz cars, the heater is supplied by a pipe attached to the back of the head. This is just a few inches long.

The outlet from the heater comes out beside the inlet, & connected by a hose pipe arrangement running from their under the inlet manifold/carbs, to the back of the heater.

In a couple of my 7s this pipework had rusted out, & been replaced by a full length hose, which could easily be rerouted to the head outlet. The short hose was left in place connected to the heater.

In the one that still hade the pipework required the rear hose connection on the pipe adjusted, so the curve designed to go onto the heater could get it to the head outlet.

The first time I did this took some hours, to make sure everything was OK. The last time about 10 minutes.

Ken you may be right about shutting off the coolant flow in your frigid far north, but it would be a brave man who did it in our much warmer climates. If that flow was not required, I very much doubt that the all powerful bean counters at Triumph would have sprung for the more expensive system, particularly the valve required in the air conditioned cars, when a simple on/off cock would suffice.

Hasbeen

[Last TR]

I guess I need to read more carefully. I thought we were talking about a TR7 V8, but I see now it's a TR7 8V. I'll crawl back into my snowdrift and wait until spring...

Ken Morton
Anchorage, Alaska

1980 TR8, 1973 TR6, 1965 Volvo PV544, 1958 MGA, Jeep Cherokees

[Hasbeen]

Ah, now I understand. My 8 has a simple on/off cock in the heater/air con plumbing. This eliminates the cost of that valve, [$600] in Oz] to control t6he flow in the air conditioned cars.

Bypassing the heater in the 7 also eliminated the requirement for that valve. Just as well, it cost a kings ransom to have the air con fitted as it was.

Any room in that snow drift? It's still a bit hot here.

Hasbeen

[nick]

In this drawing from the Victoria British catalog the heater hoses for 1979-'81 TR7 show two pipes from the heater core. One is a return to the water pump and the other is the supply from the intake manifold. With this setup the pipe at the back of the head is blocked. This is the set up I show in my previous post. Both of my cars are set up this way and run nice and cool.

http://www.victoriabritish.com/icatalog ... px?Page=50

[img][IMG]http://i615.photobucket.com/albums/tt234/nickmi/TR7%201975/Yellow.jpg[/img]
nick
'79 TR7 DHC
'76 TR7 FHC

[troydeon]

In reading the manual that I have the flow is supposed to shut off based on temperture and where you have the temperture slider. Mine doesn't seem to do that...

I have seen some simple valves on amazon, that have four connections and provide for bypass flow, I am thinking of fitting one of those and then perhaps looking into the temperture controled valve down the road.

Down here in south Texas come summer I want as little heat as possible slipping into the cabin area. It is a convertible and that helps, but something is definately not working right with the heater. I drove in with the top down this morning and could feel heat coming from the system even though it was a cooler morning and I had it sit on the ocldest...

Troy
1980 TR7 DHC