Stage 2: Tank heater.
A tank heater was designed using a 60" long gas appliance connector. The connector is inserted into the tank and coiled around the fuel pickup screen. Hot coolant is run though the connector, thus heating the fuel pickup and melting congealed SVO on sub-zero mornings.
Removing the old tank. Installation is the reverse of removal.
Tank after the hole was cut and heater inserted. Notice the vent pipe near the top of the hole! It was only through sheer luck that the vent pipe was not cut with the angle grinder.
Close up of inside the tank. The heater is coiled around the fuel pickup. I think a 72" long connector would have been more ideal as it could have been coiled around the pickup more times, but they are hard to find due to longer uncoated appliance connectors being against building codes. I ordered this one on ebay.
The large hole was sealed using a cork gasket and lots of "gasoline/oil resistant" formagasket. The smaller hole where the ends of the connector protrude the tank was overlaid with metal strips, covered in formagasket, and then covered in JB weld (for rigidity)
The large hole seems to leak ever so slightly, the small one not at all. If I had re-installed the carpeted panel that covers the tank it would have never been noticed.
A $10 inside / outside temperature sensing unit was acquired. The external probe was installed in the engine compartment (at the moment it is taped to one of the fuel injector lines.) The unit also contained an internal temperature sensor. This sensor was taken out, attacked to a long wire, and JB-welded to a magnet and dropped into the fuel tank right near the fuel pickup.
Direct link to temperature sensor of similar quality from Harbor Freight. They only read up to 158 Degrees Fahrenheit. but for this purpose it will work just fine.
Main tank coversion
You might be interested to know that Frigidaire had the 72" coils in stock. I was pleased with that. $21 each. Very good customer service.
I have a 1983 300SD. I'm concerned about coolant hose routing and being able to get to the top of the tank. I may have to leave out the rear deck trays. Do you have any pictures of the tank in place with coolant hoses run?
When you cut out the holes did you worry about metal shavings? Golden Fuels (Greasel) recommended using slight grind followed up by a metal chisel. Any thoughts? Did you wipe inside clean after grinding?
In hindsight, is there any reason to go with brazing over JB Weld? I had the tank cleaned by a radiator shop and they can do the brazing for me.
Also, upon reflection, any need for being able to keep the cover removable as an inspection whole?
I think I'm going to make sure there is a gap between wraps so it flows through but acts like a baffle.
I appreciate your thorough details. I'll let you know how my project goes, if you're interested.
re: Main tank coversion
>> You might be interested to know that Frigidaire had the 72" coils in stock. I was pleased with that. $21 each. Very good customer service.
Great! I thought those hoses had been discontinued for safety reasons, all I could find in hardware stores were hoses coated with plastic, which I felt would impede thermal transfer. Do you have a link to the hose, or did you just call them up?
>> I'm concerned about coolant hose routing and being able to get to the top of the tank. I may have to leave out the rear deck trays. Do you have any pictures of the tank in place with coolant hoses run?
It was very tight, but with the right angle NPT connectors it managed to fit. I ended up having to remove the vacuum reservoir which on my car was located directly on top of the fuel tank. I bet if your range hose was even longer it could be run down the side of the tank or something.
>> When you cut out the holes did you worry about metal shavings? Golden Fuels (Greasel) recommended using slight grind followed up by a metal chisel. Any thoughts? Did you wipe inside clean after grinding?
I worried a little bit, but ultimately figured that the metal shavings would just get caught in the filters the same as french fry bits. I probably rinsed the tank out with biosdiesl after drilling into it. Other people have suggested pressurizing the tank with compressed air so that as you drill, all the shavings are blown outward.
>> In hindsight, is there any reason to go with brazing over JB Weld? I had the tank cleaned by a radiator shop and they can do the brazing for me.
I wouldn't braze *over* JB weld, JB Weld is an epoxy and I doubt it would hold up to the heat of brazing.. I would suggest doing either brazing, OR JB weld, but not both. I'm not sure how the range hose would like being brazed either.
>>> Also, upon reflection, any need for being able to keep the cover removable as an inspection whole?
I wouldn't worry about it. If you ever want to inspect the tank you can always just pop off the first aid box and unscrew the fuel sending unit.
>> I appreciate your thorough details. I'll let you know how my project goes, if you're interested.
Great! Thanks for the feedback. I'd love to hear about your project, send pics!
-Jay
re: item discontinued
Sweet, thanks.. Yeah any cheapo temperature sensor will work. Especially if you are going to take it apart and chuck part ot it into the fuel tank.. :-)
Recently I replaced the under-hood sensor with a Thermaltake CL-W0033 which was around $25 on ebay. Its installed in the fuel line right before the injection pump. The sensor is much more responsive than the indoor/outdoor one.
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