Vapor Lock?

[Diggie]

Hello there! I have a 69 Road Runner, with a 440, single carb, and a 727 transmission. I just recently tore the car down, and rebuilt the engine. The other day, I was driving and the car just shut off while driving down the road. (not ignition) I pulled over, and tried to restart it, and it was very hard to crank, but finally started up. Drove for about 3 miles, and it did the same thing. Could this be vapor lock? I checked the MSD box, and all seems ok. It never did this before the rebuild, even during our texas winters. Since I've never experienced this, I am baffled as to what it could be, so I thought I'd ask the experts Any suggestions?

Thank you!

 

[Ski 61701]

Make sure your gas cap is vented properly is what I would first check.

 

[khryslerkid]

As soon as it quits on you, jump out, look into the carb, pull back on the linkage and see if you have any gas squirting out the squirters. If not your carb is dry.

If you have gas squirting, then pull the coil wire, touch to ground, have someone crank it or have a remote button to clip on the starter relay (with the key on) and see if there's spark.

After just installing your new engine, check all of your connections. Start the car and start pulling on connectors and see if there isn't a loose one. Coil, ballast, relay, bulkhead connection ect.

Good luck

 

[beanhead]

As soon as it quits on you, jump out, look into the carb, pull back on the linkage and see if you have any gas squirting out the squirters. If not your carb is dry.

If you have gas squirting, then pull the coil wire, touch to ground, have someone crank it or have a remote button to clip on the starter relay (with the key on) and see if there's spark.

After just installing your new engine, check all of your connections. Start the car and start pulling on connectors and see if there isn't a loose one. Coil, ballast, relay, bulkhead connection ect.

Good luck

Yessir give 'em the old wiggle test!

 

[Ranger16]

I don't know what part of Texas you are in, but I doubt any part is too hot this time of year. Hard to believe it got hot enough to vapor lock, especially while moving. Do you have a temp gauge in the car? If so what did it say?

 

[PurpleBeeper]

The guys above are right on cue. Maybe replace the fuel filter too (& brass carb insert filter if you have one).

 

[mopar 3 B]

Rebuilt engine. What was used for pistons and what was the clearance?

 

[SublimeSixpack]

Just for the record a '69 Road Runner should not have a vented gas cap. The tank should have two internal vent tubes that vent to the outside.

 

[twecomm]

Have you checked the fuel pump pushrod length? Did you put a new one in with the rebuild? If it's worn it won't move fuel and can exhibit the problem you describe.

 

[Diggie]

Thanks for all of the help! The car's temp was 185, and I will check all of the electrical connections this weekend. I did check the carb after it happened, and there was fuel squirting.

 

[WileE]

Make sure your ignition module and/ or Msd module have a good, solid ground.

 

[Ranger16]

At 185 I would think you could rule out vapor lock.
Exactly where was the fuel squirting from? Carb vents? If so, I think you need to readjust the float levels or maybe replace the float valve seats.

 

[Diggie]

The fuel was squirting from the jets. Unfortunately, it's been a while since I farted with a carb, so I'm a little rusty. The more I think about it, I don't think it is vapor lock. The car has set for a couple of days, and is very hard to start, which it wasn't when I put the motor back in. Something is telling me the carb might be the culprit.

After the motor was put in, I drove the car about 300 miles, without any issues at all. That's what is puzzling me.

 

[oldbee]

How old is the fuel in gas tank && how old is the tank? Maybe pulling crap from the tank?

 

[Ranger16]

The fuel was squirting from the jets.

The jets are inside the float bowl. How can you see fuel squirting from them? Fuel goes INTO the jets, much like water into your sink drain. If fuel was squirting back out, you'd have to be pressurizing the intake manifold as opposed to having a vacuum in it. Color me confused.

The car has set for a couple of days, and is very hard to start, which it wasn't when I put the motor back in. Something is telling me the carb might be the culprit.

Choke set properly?

 

[Johnpat]

Where is the coil?? Might be getting hot and shutting
down.
I would also check ballast ressistor,if you drove it
300 miles with no problems,check simple things
first.
Ive learned from my experience you jump to
conclusion,and look for really big problems
& in the end it was simple things that caused it.

 

[khryslerkid]

A bad pickup coil in the distributor will fail when it gets hot. Once it cools down it will start again. Just something to keep in mind since you know you have gas in the carb. Like stated above, think simple things first!

 

[Johnpat]

A bad pickup coil in the distributor will fail when it gets hot. Once it cools down it will start again. Just something to keep in mind since you know you have gas in the carb. Like stated above, think simple things first!

View attachment 579851

 

[Johnpat]

Hey kid is that a 62 Polara 500?
Had one back in 65 ,kicked butt street
racing with it.Loved that car!!!!

 

[Diggie]

Thanks guys. I'll report back what I find.