Vapor Lock
 

I know some don't believe in it but I'm looking for some input on an issue I'm having.
My coupe has an OLD rebuilt motor there is a date of 060945 stamped on the block. I have rebuilt the water pump, distributor, and rewired the car. I used "modern" points and a B profile distributor cam because the price was right(free). Both Snyders parts.
It has a stock Tilotson X model that was also refurbished by yours truly. I say refurbished because I didn't drill out the plugs and replace them. I did however thoroughly and cautiously clean all the jets and passages as well as check the float level and mating surfaces. I have the yellow Tillotson book as my guide.
OK now that the back story is done
The car starts and runs great. The Temp comes up to about 145 and stays right there. I can let the car sit and idle for extended periods without issue. The problem comes when I shut it down, say at the gas station like yesterday. Fill her up and get ready to leave, she barely runs. Coughing and choking I'm barely able to get her going. As I try to drive away its as if I'm on a bucking Bronco not in a 31 Ford. After about 10 minutes of driving all is well again.
Anyone have any insight?
I'm thinking vapor lock but isn't that not a problem with Tillotsons?

Is it time for clothes pins on the fuel line?:D:rolleyes::D:rolleyes::D:rolleyes:

As always thanks in adavance

Re: Vapor Lock
 

Do you know if your tank is very clean inside? It may be that adding fuel to the tank stirred up any deposits you have at the bottom of the tank which could interrupt the fuel flow when you go to take off.

Re: Vapor Lock
 

The tank is not perfect but not a rusty mess. I forgot to ad that I have also just replaced the tank shut off and fuel line as well as put a pencil filter in the tank. This was a problem before I did these things though

Re: Vapor Lock
 

What is the exterior temperature this time of year??

Re: Vapor Lock
 

62-72 but it did it on a 38 degree day a couple weeks ago

Re: Vapor Lock
 

Forget the clothespins, you need to tape magnets to the fuel line to set up correct fuel molecular polarity.:D:p

Seriously, it sounds just like my car when I used the crap gas.
What kind of fuel are you using?
I had problems in the upper 70's and above, but below that I never had a problem, so you mentioned a problem in the 38* range and that's hard to explain.:confused:

Re: Vapor Lock
 

Tom
All we get is crap gas in California 10% Ethonal. It's driving me nuts. If I had hair I'd be pulling it out by now.

Re: Vapor Lock
 

I think it would be impossible to get vapor lock at 38 degrees .

Normally vapor lock starts with cutting off at low idle .

Re: Vapor Lock
 

Maybe vapor lock is the wrong term. It only happens after it is shut down for a short period of time. Less than say 15 minutes. Would heat sinking be a better description maybe?

Re: Vapor Lock
 

It isn't the gas, there are thousands of A's running it in CO without issues.

Re: Vapor Lock
 

What the heck?
No thoughts or opinions fellas?
No talking dogs offering advice?
You guys are slipping.
No one has even derailed the thread saying Vapor Lock doesn't exist!!!

Re: Vapor Lock
 

Tiny - I have never experienced vapor lock. If I did, I didn't know it; I always looked for another solution to the problem. I might add that as long as I have been a member of our local Model A Club, I have never know or heard of anyone experiencing vapor lock. Thus, I won't have a solution for it.

However, I can offer one solution that worked after experiencing the same problem as you (engine not running right after short shutdown). After running the car long enough to thoroughly warm up the engine; when I stopped for a short time then restarted, it did not run well. I originally thought it was the carburetor. I completely cleaned and rebuilt it; all new parts, confirmed all passageways were open, repaired loose throttle shaft, etc. The engine continued to do the same thing.

Then I changed the distributor (using the club's spare we take along on tours), and all was well. I rebuilt mine from the ground up, and the engine has continued to run fine ever sense.

I am not sure which component of the distributor was causing the problem; as I didn't take the time to replace one part at a time. But I thought I would pass along my experience.

As they state: if you think it is an electrical problem, work on the carburetor; if you think if is a fuel problem, work on the electrical system.

Good luck.

Re: Vapor Lock
 

Ok , it barely runs after shutdown ,

Will it rev up ???

Check to see if its firing all four plugs ,

When it does this do you move the spark ???

When you stopped for gas , do you close the fuel shut off ???

You must test to determine if its fuel or spark .

Re: Vapor Lock
 

OK now were getting somewhere :)
yes it revs up, in fact I set the idle higher with the hand throttle to help it stay alive, but its still runs rough.
Advancing the spark changes the conditions very little.
Yes if the motor isn't running the fuel is shut off.

Re: Vapor Lock
 

I know I am bucking a lot of smarter fellows here, but 1. you restored the Tilly. Tillotsons have a nasty reputation of warpage of the white metal body that will cause issues of fuel mixture. 2. re check the float level. You may have a leak down of fuel into the carb while sitting. That will cause a rich mix upon restart( short time). It might be possible to crank the engine with the throttle wide open to restart. But, I would swap another carb that is known to run well. See what happens.

Re: Vapor Lock
 

Is it predictable enough so you can "make it happen" ? Will it happen in your own dooryard, or do you have to drive a distance first ? What happens if you drive to the Gas station, but do not stop and drive back home? Will it do it then? Sometimes you have to rule out Enviromental issues, which you have started to do by acknowledging that it happens over a range of temps. Might not be fuel, Could be a hot condenser. If you can make it happen in your shop you could do some electrical checks.

Re: Vapor Lock
 

So when it runs rough , it will still rev up .

Next time it does this put you hand on the coil and see how hot it is .

I would change the condenser if the coil is ok .

Re: Vapor Lock
 

Ron I'm doubting its a warped carb but that cannot be ruled out yet maybe this weekend. I have a new gasket set on my bench.
QGolden Your line of thinking is a road I have been thinking about also. The plates, points, and condenser as I said were freebies but I believe were purchased from Snyders. They were new in the package, given to me by a hot rodder friend who said "your gonna need these, they came with a car I bought and sold a few years ago".
The other factor is:
Last spring I rebuilt the water pump. I left the hood off for most of the summer, as its a pain to put back on by oneself and it just seemed to never happen. I don't remember this being an issue before when it was off.

Re: Vapor Lock
 

Hick
Yes still revs up
I check the coil temp next time I start it. Hopefully in the morning
I may just change the condenser to eliminate it

Re: Vapor Lock
 

I bet it is ignition-either coil or condenser.