Hot Gas Tank

[Glenn French]

Last October, driving from Laughlin, NV to Long Beach, CA, several of us from the Long Beach Model T Club climbed a long hill from Amboy to 29 Palms. The grade was hard for the Model T's and went for at least 20 minutes. It was in the upper 80's temp wise. At the top of the hill we stopped. When I checked my gas level I found the tank was so hot you could not hold your hand on it. Shortly after that the car nearly stopped running, kicking, bucking and barely moving. Adjusting the carburetor made little or no improvement. We got to 29 Palms and filled it with gas (cool from the underground tank). The car was fine after that. It is a 15 Touring, stock tank under the seat. It has no engine splash pans. Has anyone experienced anything like this?

[Scott_Conger]

Glenn

Rather than go into the specifics of HOW things went awry, I'm going to address the specifics of WHY they went awry...and address your failure to run issue directly - that means addressing the "stopping on the hill issue": NEVER stop after a really hard pull with a T! !

There is a tremendous amount of heat gain in the entire system which is being kept in check by the cooling system while moving through air. Upon stopping, the heat previously generated is now free to flow into every part and device attached to the engine. Things which were previously staying at a nominal operating temperature will now skyrocket. While the engine is working, the carb is cool or even cold...stop that vaporization of fuel within the carb, and the cooking engine is now able to soak the intake manifold and carb with tons of heat. The conditions that existed when you turned off the key were ideal for running and when you switched the key "on" the conditions at the carb were just as bad as could possibly exist.

The best example of this was when I was on a tour with a very heavy hack with no extra gearing, on a terrific but brutal tour through So. Dakota...it seemed like everyone but myself had a T with a Ruckstell PLUS a Warford (or equivalent). As I chugged up each hill (with a brand new, tight engine!) in low gear, I was passed by lots of impatient and sometimes very rude people who were not shy about expressing their displeasure of my sedate pace with me...having the audacity to drive a car which they later told me "was not fit for touring". At each crest, my motometer was in the red and I continued past them and within a mile, after heading down hill at an idle, the engine was back to "cool", having rested and cooled off during the descent.

What were those other folks doing while I passed them at the crest? The wives were enjoying the view and the drivers were looking for cell service as nearly everyone of them blew like a geyser after they shut down "to take a rest". That was a valuable lesson to learn early in my T touring days.

You learned, too, but just not as spectacularly.

For me, the upshot was, my dad's freshly built engine was fully broken in, completed every inch of the tour, and has since given him many many years of reliable touring. Many of those folks whose cars WERE fit for touring spent lots of time on trouble trucks and as I recall, the local Model "A" club members that supplied the trouble trucks said that they cumulatively accrued around 900 miles of towing. So much for the expert tourists. Their cars may have been Tour Ready, but they themselves were clearly not.

[DanTreace]

Haven't had that heated up tank before that caused any fuel line to carb issues. But image it could happen if the fuel line is rather close to the exhaust pipe.

The pipe where the fuel line is draped under with the factory bends, is hot, this thermal image shows the exhaust pipe area under the floorboards to be around 120 F., maybe more. (The thermal image is front right hand drive T)

365368.jpg (51.34 KiB) Viewed 1167 times

If the fuel line is routed like stock, the curve keeps it rather away, min. 2" clearance, from the exhaust pipe to keep the gasoline in the steel fuel line a comfortable temp. FYI, if it makes any difference, I do run engine pans on all my Ts, could help a bit with some forced circulation of air from the radiator fan, but likely negligible. From the description of the hill climb, could have been one of those '3 gallon' hills, that need a least that much gas in the tank to gravity flow.

[mtntee20]

Quick Answer: Heat from the engine and exhaust flowing under the tank/body heated the fuel. The poor running was from Vapor Lock. Meaning, the fuel was boiling in the fuel line or carburetor causing flow and vaporization issues.

As Scott said, NEVER STOP on top of a hill. Dive right off on the downhill side. This increases the air flow, reduces the load on the engine, and allows everything to cool off after the long, hot, climb up the hill. This practice is widely know here in Colorado. Always funny seeing tourists stop on the summit to take photos and then try to get going again.

Things that may help: Purchase some high quality exhaust pipe wrap and wrap your exhaust pipe from manifold to muffler. Build and install a "heat shield" between your exhaust pipe and everything above your exhaust pipe. I use muffler clamps placed on the exhaust pipe, with threads/nuts facing up, where I plan to mount the shield. These are easy to apply where needed, inexpensive, and moveable. Cutting plain sheet metal such as tin ducting used for home heating systems, allows you to make pieces as large or small as you need. Flatten and cut to desired length and width. Fold over about 1/4" along the edges to prevent bleeding when working under the car in the future. I cut mine to 4" wide, with 1/4" folded on each side make the shield 3 1/2" finished width. Take a piece, place it over the pre-installed muffler clamp and tap gently with a hammer to mark where to drill holes. I place a washer on top of the muffler clamp nut, sheet metal heat shield, washer on top, lastly the nut to hold it all in place on the muffler clamp (2 nuts 2 washers on each leg of the clamp). I did 2 holes for one clamp, then putting the shield on that clamp without nuts or washers, was able to hammer tap the second muffler clamp for holes. Once 4 holes were drilled, I mounted the whole thing. So far, has worked great to prevent roasting my wife's feet and legs as she rides along.

As for the vapor locking problem: A quick, easy, inexpensive, and reversible answer: Crumpled aluminum foil. Take a piece about the same length as a bare section of fuel line, crumple it up into a "log" (lengthwise), un-crumple enough to get it wrapped around the bare fuel line section. Once it's on, crimp it just enough to keep it in place. The foil will shield some heat but moreover will radiate heat OUT of the line and fuel to prevent fuel from boiling (Vapor Lock). A bunch of people praise using standard clothes pins in the same way. I've never tried this but there are too many people recommending it for all of them to be crazy.

Good Luck

[George House]

Several very good and new to me ideas in this thread. Thanks guys for answering and Gene for asking

[Bryant]

I had a gas tractor running stationary for a long period of time in high heat. The tractor started acting up. Turns out the gas tank was hot and poorly vented. This caused the fuel pressure to spike. It was a gravity system. Cracking the gas cap remedied the problem by Alleviating the pressure. Cleaning the caps vent solved the issue. Not sure if this is your issue but it reminded me of that tractor.
Bryant

[Glenn French]

Thank you for the comments. I do have the exhaust pipe wrapped where it is near the fuel line and the fuel line routed as far as possible from the exhaust. I did not know to not stop after the long haul, so that may have been where I errored. We pulled over to let the long line of Moderns pass us and regroup. It sounds like I should have kept moving. Again thanks for the good advice.

[tdump]

After seeing and helping put out the floor boards on a Peirce Arrow 1 time because of a hole in the muffler heating up wood, there is exhaust wrap on my T pickup exhaust and is already on the speedster and it is not even finished. I weren't going to take a chance. Just be sure to run it outside for awhile as the wrap stinks the first time it gets hot