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TR4/4A "Smokin" hot TR4

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thechileman

thechileman

Jedi Hopeful
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"Smokin" hot TR4

OK, this Sunday, my wife and I took the 64 out for the longest drive so far. It was a typical hot NM day. About 90 minutes in, we began to smell smoke. The Temp guage said engine was not overheated, so I thought maybe wiring. Pulled over, and looked at everything. It all seemed fine. It appeared that the exhaust got the cardboard transmission tunnel hot enough that the oil that had soaked into it over the years started to smoke a bit. Not actually catch on fire, just smoke.

So questions. Is this a fairly normal occurrence? The Transmission was fairly hot as well, still shifted smoothly, no funny noises. I will check the tranny oil, but I don't think this was the problem. Any other thoughts?? Anything I should check? I already have a new Transmission tunnel in the parts pile, so I will be swapping out the old one either way..

thanks!
Chris
 
Re: "Smokin" hot TR4

I'll show my ignorance here. Aren't the cardboard tunnels on these cars insulated on the underside? They are on the "small car" range (Herald, Spitfire, etc.), with some sort of batting in plastic. Of course, that also gets covered with oil and road grime through the years, and the same problem could occur....
 
Re: "Smokin" hot TR4

Interesting... I haven't looked that close, but I don't think there is any insulation on the underside of my tunnel.
 
Re: "Smokin" hot TR4

I have a friend with a TR4 that he took club racing one day. What he didn't notice, but everyone watching did was that the heat of the exhaust actually caught the carpet on fire. He noticed it when he slowed down at the end of the race, though!
I certainly get a lovely smell of burning oil from my TR3 a few miles into a journey. One of the numerous oil leaks obviously is above the exhaust somewhere and it burns off when it gets up to temperature. I think it is all part of the experience!
It is surprising how hot an exhaust can get and it is always wise to check that it is not routed too close to anything that could be considered flammable.
 
Re: "Smokin" hot TR4

thechileman said:
Interesting... I haven't looked that close, but I don't think there is any insulation on the underside of my tunnel.
Click to expand...
Nothing under the cardboard but cardboard, oil, grease, and whatever else splattered up there.
 
Re: "Smokin" hot TR4

Back in the mid '60s, I had a friend that had an MGA. We were booking along the Long Island Expressway, when the distinct odor of burning wood started to waft into the cockpit. Sure enough, one of the wooden floorboards had started to smolder on the passenger side...where I was sitting! :sick: Yep, exhaust pipe too close to the floorboards! :laugh:
 
Re: "Smokin" hot TR4

Well, maybe I'll let it cook off a bit.. Sounds like a fairly normal LBC problem. The car has been running great! I was pushing it a bit when it started smoking... I'll just keep an eye on it. Thanks for the input!

Chris :thankyousign:
 
Re: "Smokin" hot TR4

And carry a fire extinguisher, I hope!

I've had a similar experience riding in a friend's MGA; but that oil-soaked cardboard is going to go up a whole lot faster than old wet (from being left in the rain) plywood.
 
Re: "Smokin" hot TR4

I think Ozzy Osbourne said there are no absolute truths, but I wouldn't accept as expected, usual or normal any smoking in the TR4 underside. I'd get to the bottom of it.

My transmission never gets hot. I'd suggest you definitely check both the differential and the transmission fluid levels, leaks, and make sure nothing is burning up.

If the transmission tunnel is in contact with the exhaust, I'd get that fixed, and I'd check the exhaust manifold gasket. I'd also verify that none of the generator wires is touching the manifold and burning at that location. The generator wires can get close.

Finally, burning wires sometimes can only be found by close examination and touching them. I'd run the car awhile, then pull over and touch the wires at several locations: ammeter gauge, fuse box, heater and under the instrument panel. I'd check your voltage stabilizer (which is the culprit behind a number of electrical issues) above the passenger footwell and the wires to the key/ignition. Make sure they're not hot.

If the only problem is old oil on the cardboard, that would be great, but for it to be damp and to smoke would indicate either a recent leak and one darn hot arrangement.

Just me probably being overly concerned. Good luck.
 
Re: "Smokin" hot TR4

TR631-1.jpg
 
Re: "Smokin" hot TR4

I suggest you get a fiberglass or aluminum trans cover and then cover that with some heat and sound insulation.

Kool Mat

I plan on applying Kool Mat to the inside of the entire tub as well as the inside of the door panels. It's supposed to really make a tremendous difference in both heat and sound suppression.
 
Re: "Smokin" hot TR4

Thanks for all the input! Tabcon, I like the Kool Mat idea. But I am also going to take a look at the exhaust manifold, where the exhaust pipe flange meets the manifold. I had a heck of a time getting all that to line up when I put the new exhaust system on, So maybe I have a leak there. That would cause things to heat up in the Trans area. I'll retorgue everything to make sure it is tight...
 
Re: "Smokin" hot TR4

Chris, did you ever get to the bottom of this? I've had something similar just happen on a fairly long (150 mile) Thanksgiving run. I stopped and topped up the tranny oil which was a little low, but the smoke and heat continued for a good while afterwards.

Now, after about 45 minutes of running after topping up everything suddenly cooled down. Would it really take that long for the oil to get round everything in the transmission and reduce the friction so that everything cools down?
 
Re: "Smokin" hot TR4

you can go to the auto parts store and get some fiberglass muffler wrap and wrap your exhaust thats near the transmission and tunnel, that stuff works really well, I wrapped my exhaust manifold and down past the tunnel, keeps the under hood temps down and the floor doesn get as hot

Hondo
 
Re: "Smokin" hot TR4

I actually figured out what it was in my case. My overdrive solonoid was in the process of burning itself up. It wasn't adjusted quite right, and was getting hot because too much current was running through it all the time. I actually burnt up a second one before I got it adjusted right.. (I hope.) Those things are expensive!
 
Re: "Smokin" hot TR4

thechileman said:
My overdrive solonoid was in the process of burning itself up. It wasn't adjusted quite right, and was getting hot because too much current was running through it all the time. I actually burnt up a second one before I got it adjusted right.. (I hope.) Those things are expensive!
Click to expand...
Which is exactly my rationale for adding a fuse to that circuit! Choosing a fuse that will blow if the cutout contacts don't open will save the solenoid.

I used a MDL-8 just because that was what I had on hand, but I believe even an AGC-5 would work. The normal short burst of high current (approx 20 amps but only milliseconds long) isn't enough for the fuse element to get hot.
 
Re: "Smokin" hot TR4

I almost installed the fuse, I even have the parts on hand. I tend to get stubborn about making something work the way it is supposed to. I promised myself if I burn up another solenoid, the fuse goes in. So far so good!
 
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