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MG TD TF 1500 - Radiator temp and tuneup

Along with the brakes I had the lower hose tube crack on the TF and so it came out as I was doing the brakes. I had had a bit of a problem before the crack with the temperatures climbing in AZ if I had to climb a long hill on a warm day. The radiator shop boiled out the radiator and got it a little cleaner but he said it was pretty clean to start with. I also did a minor tune and found the timing advanced about 3/16" on the lower part of the distributor, I don't know how many degrees that might be. In addition I had picked up a MGA six bladed fan that I mounted. I filled the system with a 50/50 antifreeze mix and went for a test drive.

Before on my test hill the temp would climb from the just under 85 mark where it normally sits to just above the intermediate mark, about halfway between that and the 110 (last) mark. Yesterday under the same conditions the rise was from just under 85 to halfway or three quarters to the intermediate mark but still a definite rise that seemed to stabilize below the intermediate mark. I'm pleased that progress has been made. How much can be attributed to each of the changes is now open to speculation. I do have some Water Wetter and will put that in and go for another test today. Stay tuned.
D Clark

The MGA 6-bladed metal fan is probably not as good as the much lighter MGB 6-bladed fan which by now, most T-Series owners have realised to be an inexpensive and effective solution.

I made the mistake of getting very fancy - an electric "pull" fan between the rad and the water pump, let in (brazed) a VW Golf thermostat into the rad header tank, and added an "auto-off-manual" switch under the dash. While this all works just tickety-boo, it was overkill, and to do it again, I would simply add the MGB fan and some Water Wetter (for the summer months only, here!).

Gord Clark
Rockburn, Qué.
Gordon A. Clark

I too have a TD that runs hot on long hills and hot days. Several times I have had the temperature gage go past the first 100 and stop at the second! The largest improvment came when I blocked the thermostat bypass. Queastion; has anyone fitted a fan shroud to a TD? I know that is a regular fix for hot running MGA's. Regards, Tom
Tom McNamara

Have you checked your ignition timing?

Mark Sherman
mrkshrmn@hotmail.com
Mark Sherman

In this fall (?) weather mine is pegged at 70/75 and has been since Sept.... in the summer it is at 80/85 unless i'm stuck in traffic on really hot days then it might go 90
Have had the rad dipped and flushed...flushed out the block myself for an hour or so (with some kind of prestone flush stuff). I could use a bit more temp to keep the heater hotter...
gordon lawson - TD 27667

Test drove it again yesterday doing the same climb this time with my wife aboard and after I added Water Wetter. There was a noticeable improvement but less than 5 degrees. Maybe the extra load of my wife caused it to work harder so the test might not be valid. I did the metal fan because I just couldn't bring myself to put a plastic one on the car.

Gordon, here in AZ I could use an A/C unit by the foot pedals! That firewall gets pretty warm even with normal engine temps.
D Clark

Hey Mark Sherman, yes, I have water wetter, 6 blade plastic fan, new radiater core, flushed engine, new water pump, new thermistat and blocked bypass. I have reduced the overheating problem to hot days and long hills, but it is always in the back of my mind. I have a petronix ignition, hardened valve seats and aheater plumbing also. Some hot days find me running the heater to reduce engine temp. Not my favorite thing! I am loath to re-adjust the timing as I had one heck of a time getting it to where it is. The car really runs good. I keep thinking that the gage is incorrect? On a 70 or 80 degree (F) day the car runs about 85 (C). BTW, the fact that it runs hot does not seem to do any harm so far. I am thinking that a coolant recovery system may be my next step but I can't bring myself to it. Regards, Tom
Tom McNamara

I have brought this up several times on this BBS ...but I'm still a believer! (Check archives under "operating temprature") Many of you have seen the before & after pictures. Looks great, and so far I have done it to 5 cars now. What can I say ..it works!
http://www.jet-hot.com/pages/techinfo.html
Cheers,
David 55 TF1500 #7427
David Sheward

Tom:
Did you use a five row radiator core or find a three row stock one? If you used a five row can you get me a part number and source? I hear you about the coolant recovery system. It would also keep the mess off the underneath. I suggest you check the timing even though you find it difficult. Is it the Petronix that makes it difficult because the stock system static timing method is easy to the extreme.

David S.
My 460 Ford van has a notorious problem with cracking exhaust manifolds. Especially towing a heavy trailer. I just bought a new RH side and had it Jet Hot coated. In fact it went on yesterday. I believe that will greatly extend the life of the manifold and reduce the temperatures dramatically. Besides, it looks jewel like with the silver coating, not that you can see it on the van but it would be a nice look on the MG. Except for the purist it would not look quite like the stock alumanized finish. I wonder if the factory did that as an attempt to control temperature? Anyway David how much cooling help in degrees would you estimate you get from the Jet Hot coating?
D Clark

Hey Dave, thanks for the Jet hot info. If I ever get my TC to stop eating my budget, I will get the TD's exhaust manifold done. Tom
Tom McNamara

Mr. Clark,

I chose the slightly more expensive grey coating for my TD manifold (the silver coating is stock) from Jet Hot. I won't have my TD on the road again until early summer, but I'm looking forward to the results. I picked the grey because I'm not doing anything particularly shiney under the hood.

Personally, because of the very short lived nature of the factory coating, I think it was strictly for sales appeal. I also wonder if the higher octane (more power, more energy, more heat) then the old 'pool petrol' which was available when the XPAG installation was designed causes our cooling systems to underperform, along with the crud and scale which has built up over the years. The original cooling system was probably marginal. In 25 years of driving my TD I've always found that around town driving at sub 50 mph speeds was ok in almost any temperature. I also felt that if the water wasn't boiling, I was OK, and would sometimes see 95C+ on my temp gauge on the freeway. I chose to run with the bypass blocked, always with antifreeze, and always with a thermostat. Changing any of those things made my car overheat.

On my rebuild which I am just completing, I flushed the head and the block, and drilled the extra water passage in the cooling jacket. I will probably recore, and install a new waterpump, and see how I do.

Warmly (or not)
dave
Dave Braun

Tom, the pertronix system acts just like points for setting static timing. You might want to take a look at http://www.ttalk.info/Tech/pertronix_igniters.htm
For a coolant recovery system you might want to take a look at http://www.ttalk.info/Tech/Overflow_tank.html
Bud Krueger

"how much cooling help in degrees would you estimate you get from the Jet Hot coating?"
That's a hard one to pin down because I have always done this at same time I have made other changes to my cars...but I would guess at least 20/30 degrees at the gauge. I run a mix of distilled H20 / Antifreeze & water-wetter.
Cheers, David 55 TF1500 #7427
David Sheward

Any chance your carbs are set too lean? You could lower each jet by 1 flat and take a test run.

Might be worth a try. Cheaper than a radiator re-core.
Evan Ford - TD 27621

I guess I should have asked which needle you are running as well?
Evan Ford - TD 27621

"I would guess at least 20/30 degrees at the gauge. I run a mix of distilled H20 / Antifreeze & water-wetter. "

Wow that's a lot! I guess I should give that a try too but when the weather gets nasty here so I don't miss driving it. Hey mine is #7477!!

Evan, my car is at 5000ft and is actually running a bit rich. I'll be digging into the carbs to do a rebuild at some point soon because the jet adjustment seems to be stuck on both carbs and I'm sure all the gaskets are dried out.
D Clark

Before somebody ask...cost was aprx $100.00 and turnaround was about a week.
If you check the archives under "operating temprature" you will find the whole story on the TF.
I have also done this to a TR7 and an Opel GT. Hard to say on the TR because I also removed the air-cond from that one. (The condensor in front of the radiator was larger than the radiator and the ele "fans" were in-op on the TR....gee wonder why it was overheating!) The Opel hasn't been fired up yet...but it sure looks nice in there. Other 2 cars I have done are Mits 3000 GT's ...with all the computer regulation going on in those I did not notice a big change in temp ...but definetly an improvement in preformance.
The big differance in Jet-Hot over other treatments is that they treat the "inside" of the manifold as well as outside. This makes for a very "slippery" exhaust so the hot air leaves the engine compartment quicker. I would be curious to hear what the differance in an XPAG/XPEG engine would be if somebody does this without making ANY OTHER changes at the same time.
Cheers,
David 55 TF1500 #7427
PS Neat ##7477...you a 1250 or a 1500?
David Sheward

David S, I'm a 1500. I'll go do a search for your thread. Thanks.
Dave C
D Clark

Hey Tom McNamara!
Why can't you bring yourself to a coolant recovery system? It is without a doubt the simplest "modification" you can possibly do!
Just take an empty plastic quart of oil (rectangular-style) and stick it in the cavity above the frame, forward of the footwell (next to where the copper fuel line emerges).
Drill a hole in the cap and place a copper tube in snugly, allowing it to reach the bottom of the quart bottle. (Good idea to cut the bottom of the tube on an angle so it will draw effectively.
Then remove the tube that connects to the radiator overflow. Use a piece of vinyl tubing to connect it to the copper tube inthe quart bottle. You are done!

Mark Sherman
mrkshrmn@hotmail.com

Mark Sherman

Hey Mark Sherman, sounds interesting. Please explain where you attached the vinyl tubing to the rediater overflow. At the bottom of the radiater? What tube do I remove? Thanks, Tom
Tom McNamara

Dave C,
You can see before /durring / after pics
of my exhaust header here:
http://www.ttalk.info/picture_this.htm
Cheers,
David 55 TF1500 #7427
David Sheward

OBTW...
Unless I am wrong here....TD is not a pressurized system?....TF IS pressurized for sure!
Something you would defintley what to take into account before making an overflow system!
Cheers,
David 55 TF1500 #7427
David Sheward

This thread was discussed between 23/10/2005 and 31/10/2005

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