hey all...i have a 77 F-250 with a 429 and a 750 edelbrock carb and this weekend i was down on the beach, drove it hard on the sand for about an hour (i mean real hard like a souped up truck should be drove) but i got it back home with no problems, turned it off and let it rest about ten minutes...

got back in it, fired it up and took back off down the road to the store, stepped on it once, turned a corner and stepped on it again, then it POP'ed (sounding like a normal backfire because i havent timed it right yet) and then died,

i coasted to the side of the road and tried to fire it...no joy, waited about 5 min, tried again and nothing, but i could smell excessive amounts of gas, anyway, i got it towed home and in the front yard, while cranking, pure white smoke was rolling out of the tailpipes. finally we all gave up and went ate dinner, came back out about an hour later, choked it, and it fired up like nothing had ever happened...?

so a few people suggested this was just vapor lock because it had been driven so hard right before that happened....any suggestions on that or has anyone ever had that happen to them?

----also on the side, when it gets run hard and the heat comes up to about 220 (which by all rights is normal, but hot for this truck that runs about 195) it shifts real hard, and takes a lot of rpm's to engage 1st gear from a dead stop. it's got the C6 with 2500 stall and shift kit. some guy said this is the torque converter because also when u put a heavy load on the vehicle it vibrates and chimmy's the whole truck,

sorry for the long post,
-Thanks for the help!
-James

 

Sounds more like your ignition died of heat stroke.

 

Maybe the ignition but also in my experience anything over 200 can lead to vapor lock. 220 will ruin your oil and from the sound of it your tranny fluid. If the oil is 220 the tranny fluid could be a lot higher. One affects the other in the radiator.

 

All,
The high stall torque converter can cause alot of this excess heat. The additional slip results in an efficiency loss/transfer which results in heat transfer/generation to the tranny fluid. There are some measures to eliminate this type of vapor lock:
1. You've evidently got a hot rod. Have you blocked the manifold port that transfer exhaust gas under the manifold? Generally, the Mr. gasket kits provide a block-off plate for this.
2. What kind of spacer are you running between the manifold and carb? Get a plastic one and space it up an inch, or more, if possible.
3. What kind of exhaust do you have? Headers? If so, wrap them.
Manifolds? Ensure that the heat riser is removed. Additional measures may be required to ensure equal back pressure in the exhaust, (i.e. cross over pipe).
4. Fan? What kind of fan are you running? This is crucial.
Consider it,
KingFisher

 

This might sound stupid, but in the 50's lots of cars got vapor lock. One cure was to attach a bunch of clothes pins to the fuel line. They must have acted like some kind of heat-sink. Just thought I'd pass it along.

MR

 

Vapor lock falls under the general automotive forum because it can happen with ANY vehicle.

 

Yup....the fuel would get so hot that it would "boil" in the fuel lines running on top of the engine. The clothes pins (wooden) would take a lot of the heat out of the fuel.

 

I had a Jeep (Heep as they're known in S. Texas) a few years ago that had a bad case of vapor lock. Turned out the t-stat was bad and not fully opening. The thing overheated one day while idling for just a few minutes. I replaced the old part with a new 180 degree stat and the vapor lock never returned.

Rubber fuel lines at the top of your engine will also help, although there might be a bit of a safety concern....some claim in wreck, these would be more prone to rupture than a steel line.

If you have headers, I wouldn't recommend wrapping them. All that does is trap more heat inside and will ultimately cause worse problems.

 

Actually to make headers perform better you WANT to keep the heat in them. That is one reason the ceramic coater headers work so well.

You can always use the "hot fuel return" system that Ford used on some of it's 460 Vans and others in the 80's.

 

1) i have blocked the manifold port
2) i'm running an aluminum 1" 4-hole spacer between the carb and the manifold
3) i have a set of the L&L Lifetime Ultraflow headers, and no, they are not wrapped
4) as for the fan, it's just a fan running off the pulley, but it also has a 3" body lift where the radiator has been relocated.... (this might be a little problem?)

i think this also could have been an issue....it's the MSD 6AL ignition box, but its mounted about 6 inches to the left of the radiator on the engine wall.. could this be a problem just like a vapor lock situation?

also, the tranny cooler is pretty small, and is just mounted in front of the main radiator off to the left... it looks pretty stock

--any thoughts on any of this?--
~James

 

In my old trucks ('74 and '78) I would keep a gallon jug of water to cool off the fuel pump or ignition module. Not a permanant fix, just got me going.