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MG TD TF 1500 - TD heater plumbing photo
| So much discussion lately about the Arnolt heater plumbing, that I thought I would go ahead and post the piping and valve that I made.... I tried to duplicate the Arnolt valve, as best I could from discriptions, here on the forum.... Tested all today, and it works great. As you can see from the photo, it is installed on the bypass pipe ('52 TD), and , I found that it gets plenty hot enough for our area (mountains of N.E. Georgia)...We get cold Winters, but nothing like the folks in the North East, or Mid-West.... I had tested the temperatures with my laser thermometer, and the bypass hose easily reached 165 degrees...Plenty warm enough for my purposes. I have construction photos of the way I made the valve, if anyone would like them. Edward  |
| E.B. Wesson |
| Edward, Thanks for the picture. I am still working on a similar revision and would appreciate any photos of the area around the bypass. Something from a slightly different angle to better see the "T" connection and others. You can post here or send them e-mail. Thanks, Mort |
| Mort TD 1851 |
| Had the chance , today , to actually drive the car, with the heat off, and the heat on.... I did place the Arnolt heater closer to the firewall, so all the heat is at my feet, and lower legs. Drove about 10 miles, with no apparent issues. Edward |
| E.B. Wesson |
| Edward, what sort of thermostat arrangement are you using, if I may ask? Bud |
| Bud Krueger (TD10855) |
| Ed, Thanks for the photos. I need some plumbing work done at my house and I want to hire you. Great job. I do have a question about the water flow. I have been thinking about this for awhile. The enclosed sketch shows my interpretation of your system. Did I get it right? With the thermostat closed water flows down towards the bypass to return to the engine. Along your downspout you have two branches that feed the heater. Which is feed and which is return? It seems that there is no substantial flow thru the heater. Am I seeing this wrong? In the summer position with your valve closed the flow looks just like the standard MG bypass system. Since there is deliberately no flow to the heater there is no issue.  |
| Mort TD 1851 |
| Mort, the Arnolt adapter is a diverter, not a 'T'. The water is coming from the thermostat housing is diverted to the piping that leads to the heater. After passing through the heater the water returns to the line leading to the radiator return. Bud |
| Bud Krueger (TD10855) |
| AHA! Bud, I have never seen one of these adapters and did not understand there construction. By diverter I understand that there is a blockage between the two branches. If I understand what you mean correctly that resolves this issue in my mind. Have I got the schematic correct this time? Thanks, Mort  |
| Mort TD 1851 |
| ....that 'blockage' does have a small hole in it to allow some water to circulate....it looks like a washer..... Remember, if you are using the original thermostat, that the bypass gets closed off when the thermostat opens.....that shiny bit is a brass sleeve attached to the main part of the therm.....  |
| gblawson(gordon- TD27667) |
| Thank you Gordon. This is getting clearer by the posting. Do I have this right yet? With the original thermostat With the original thermostat open and the bypass closed, what happens around the diverter? Also, with the original thermostat, do I understand that the water flow direction changes thru the heater?  |
| Mort TD 1851 |
| No... they didn't use the bypass hose for the heater supply....they used the bottom rad hose (which has never made sense to me cause its colder)....anyway...you won't have water through your heater if you have an original thermostat.... The Arnolt bypass tube replaced the lower tube going up to the water pump....  |
| gblawson(gordon- TD27667) |
| Mort There is a restrictive washer between the two "elbows"... With the "replacement" style thermostat, a certain amount of water will flow into the bypass, even with the thermostat open... The washer that I made has a 5/16" hole...If you make a model of the thing, and just run it under a faucet, you will see that some water is diverted , by the washer, into the upper elbow, the rest of the water goes through the washer, in a normal flow... Virtually all the water that goes through the washer, passes the lower (return) pipe, which also helps draw water out of the return pipe.... I know that isn't very scientific, but all I care about is that it works. The narrow area in the photo , attached, is where one pipe is forced into the other pipe, with the washer trapped in-between the two. Edward  |
| E.B. Wesson |
| Checking the temp of the lower radiator hose, as it goes into the pump, it is at least 20 degrees cooler than the water in the bypass hose.... In addition, you would have to eliminate most of the lower pipe to the pump to make this happen.... My existing hoses on this pipe, are not more than 4 inches long.... IMHO, that would not be a good place to put a restrictor, as you will be restricting the "cold" supply to the block... While the original Arnolt valve, may be on the lower pipe,(I don't know for sure), my setup isn't. It just causes the thermostat to open sooner. The main "cold" supply is full volume to the pump, from the bottom of the radiator. Again, since it works, I have no other proof. Edward |
| E.B. Wesson |
| Just checked the Archive, and the original Arnolt manual pictures the "valve" on the bypass hose, not the lower hose. Edward |
| E.B. Wesson |
| Rmember as well ( I think you have)...that you have to have an on/off valve going to the heater...you do not want hot water in it in the summer.....One 80 degree day and you will roast..... |
| gblawson(gordon- TD27667) |
| Thanks Edward, Mort and Gordon for photos plans & comments. You've laid out a clear plan, for me anyway. Peter |
| Peter Pope |
| This is the subject that won't end. I was going to wait until I built this before posting but since we are discussing it I will post it now. I would also welcome any comments now before I begin. This main component is a three port valve which acts as a diverter. In the summer position the flow to the heater is cut off. The valve acts as a bypass until the thermostat opens. Initially in the winter position all flow thru the engine and heater are in series resulting in maximum heat to the heater. Once the thermostat is open the main flow to the engine is thru the radiator and the auxiliary flow is to the heater. I have located a perfect three port valve because any port can be the input. This lends flexibility to the physical construction. My next project. Please post comments. TIA, Mort  |
| Mort TD 1851 |
| Mort I like the idea of a "bypass for the bypass", but I'm not sure how much space you will have for the extra "T", and hoses, plus clamps. The heater hoses are very heavy walled...You may end up really close to the fan... I was trying to keep the extra plumbing to a minimum. I would be interested in seeing the valve, when you have a photo. Edward |
| E.B. Wesson |
I want the modern convinience of a valve I can operate from the drivers seat. Have one on both the TF and the TD. Think its a Toyota. Less than $10.00 from NAPA.
 |
| LaVerne |
And on the TD.
 |
| LaVerne |
| Mort, The 3-way valve would be interesting, but make sure the branch diverting right back into the pump inlet has a tiny hole, you don't want to pump a large % of your hot coolant right back into a hot engine on a hot day! You know, a tiny hole in the thermostat would do what you are trying to achieve, a bit of circulation while thermostat is closed. |
| Jim Northrup |
| LaVerne Here I am driving a motorized Conestoga wagon, and you're talking about modern conveniences! That's really funny (LOL). Nice installation, too! Edward |
| E.B. Wesson |
| I have a heater in my newly purchased td but it barely puts out any heat. The temp gauge has never gone over 60 degrees f so I assumed there was no thermostat or it was always open. You have be curious now. Thanks |
| cj schmit |
| Temperature in my TD is typically between 80 and 85 degrees "C", right now....I would imagine that it will run hotter in mid summer... Some people think leaving the thermostat out will allow a car to run cooler, but that's a mistake.... If the oil doesn't get up to temp, it may not properly lubricate.... Edward |
| E.B. Wesson |
| cj, I'd suggest that you unscrew your temperature sensor bulb from the radiator top tank and place it into a pan of boiling water. I suspect that it's not going to read 212F, 100C. Bud |
| Bud Krueger (TD10855) |
| cj, Post pictures on where your heater hoses are attached around the engine. You'll wind up with a whole host of conflicting recommendations to mull over. |
| Jim Northrup |
| Jim Your comment about "conflicting recommendations", is spot-on.... What the reader must do , is sift through all the talk, and then make a committment to do it his own way...(Kind of like Burger King..."Have it your way"). Worst case scenario, is, it doesn't work, and you can re-do the whole thing....Been there, done that! Edward |
| E.B. Wesson |
| Ooopps! Got my units mixed up. My temp reads 60 deg "C" Still a ways to go befor 100 deg boiling, but it's still springtime in Calif too! And i'm in Santa Cruz where it's always cooler... Will post a photo tomorrow. |
| cj schmit |
| cj, I'd still suggest the calibration of your meter. Bud |
| Bud Krueger (TD10855) |
This thread was discussed between 11/05/2011 and 24/05/2011
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