Vapor lock

Hey guys,

A question about vapor lock. I am certain we have all dealt with this before. I have had this happen a couple of times recently. I recently put a new gasket on my sending unit due to gas leaking out the top of my tank if I filled up. It is sealed better now and it is no longer leaking.
I am running an electric fuel pump that is mounted next to the gas tank. I put one of those glass see through in line filters accessable from the doghouse. I am still running the original carter yf carb, after a couple of rebuilds, of course. The bulk of my driving is in town. I am guessing that it is happening now due to the new seal, as I do not smell fumes any more which was most likely helping vent the system better before and, of course not being as much of a danger to someone flicking a cigarette butt close to the back of the van and causing the obvious.
My real worry here is that Bonnaroo is coming up, and there are long lines of idling in hot weather most likely a couple of hours of inching along until inside the festival grounds. No way my van is going to survive it considering the last couple of times. Any one have suggestions.


Rerouting fuel lines? Some way of insulation the lines? A better system of venting back into the tank?

How about an awesome fuel injection system for this old six? ...Or a gm/chevy inline with factory fuel injection?

I'm no expert but,I'd check the gas cap first.It may not be venting.Replacing seal fixed leak but might have been the only air tank was getting.As a foot note,I never been a fan of those glass type fuel filters.Scared they might develop a leak.The stamped out metal ones worked just fine.

i have the problem of hard starting after a hot run. it has to do with heat on the fuel line. get a nasty vapor lock which takes a lot of cranking to overcome. i rerouted and insulated the fuel line, i routed the line to pass through where the fan will blow on it, and off the block completely. i also put in a spacer to help with the build up of heat in the carb which helped for a while but now that it is hotter i need to reroute the line. even though i'm in canada we live in the only canadian desert which can be very warm up to 41 degrees celsius for weeks at its worst. otherwise just the placement of the engines in these vans causes most of the grief, i had a 1982 toyota van that was difficult to maintain in the summer as well.

Please replace that filter! As a tech, I've had many cars with those that had drivability issues, and have heard of others that had them break and cause fires!!!
After that, drive it with the cap off and see if that helps. At that point, try to reduce heat as Donivan65 says.

Thanks guys,

I will give it a few tests throughout next week and see how things go.

I agree with the prior note that it is more likely the residual heat from the way these have the exhaust and intake manifolds connected--boiling gas in the carb bowl... Am thinking about a way to exhaust heat and fumes out of my doghouse. Am planning a little blower system like those found in inboard motor boats. Best would be something that would run for 10 or 15 minutes after shutdown. Of course I'm cheap so it will be something cobbled together out of stuff laying around. Another thing is I plan on removing my heat riser as I've found them, over the years, to be a lot more trouble than they are worth. And, when they get stuck or the cooked, rusty spring fails they just don't work anyway. Now, if anybody knows a way to remove my heat riser (the butterfly valve in the exhaust manifold) without removing the manifold I'd really appreciate the response. Not to steal this thread yet I think both could have a relationship to overheated intake/carb boil over.

Thanks and happy motoring, Mark

probably best just to leave it in and make sure it fails in the hot position instead of the cold (cooking the intake/carb). There is a special heat rizer lube but once they (usually the spring fails) they tend to get stuck easy.

Thanks much for the heads up, Mark

Just a question guys. What about those Langdon Stovebolt cast iron headers? How would they work with an original yf carb setup?... considering this issue. Would they have any effect. Positive or negative or not at all? I still have not gotten around to running all of these tests yet. Thank you all for the discussion... it is interesting. I have had no issues in the last few days, however it has been cooler and my trips have been short... only a couple of miles each, and very little traffic. I have driven a thirty minute interstate trip with no problems. This is my only vehicle by the way... well other than my bicycle.

donivan65 wrote:I would not leave home without my Hamburger Fan. It has an on/off switch as well as a 60 minute wind up ceiling fan timer on it. it takes care of all the fumes in the doghouse, any boil over in the carb and even lets me sit in LA traffic without overheating,,,,,,,,,,

Dude... That's sweet! That may be all I need. I still have the original belly pan installed. I am assuming that was an easy attachment. So as far as driving around... how often do you turn it on?

donivan65 wrote:I turn it on if I see my temperature gauge go up over 200 on hot days or going up mountain roads. But mostly for Hamburgers,,,,,I don't like to go and get my food and bring it back in my van and have eat it with gas fumes and a hot doghouse,,,,,,,so I turn the fan on to cool it down,,,,,if I forget and leave the fan on,,,,,the engine will start bucking because the coolant gets too cold and I have to pull the choke out ,,,,,when I make a long high speed run and stop at a light, I turn it on because the temp starts rising,,,,,, it never overheats, but I like it below 200,,,,,,,and after I get home and put it in the garage,,,,,I run the fan to cool the engine so I can work in the garage without the heat and fumes,,,,,and that timer is great ,set it and forget it,,,,,nothing worst than stopping somewhere having people all around and cranking a heat soaked , gas soaked, flooded out engine ,,,,,that sure spoils the moment,,,,,,I just turn the fan on and have none of that drama,,,,,and those fans are just laying on the ground in Pick a Part,,,,,probably $30,,,,they only want the radiators,,,,,,,,,and it is just bolted to my floor,,,,hanging there on long carriage bolts,,,,,you could bolt it to the bellypan in the same manner ,,,,

Dude... There is a Pull-A-Part near here. That will be a fun addition. Thanks for the run down. I'll give a heads up when I get this installed. It should be an easy install.