Fuel boiling at fuel pump

[Seth Swoboda]

Originally Posted by Tinker

I'm going to make a very uneducated assumption. So octane is around 89-91 now. In the 30's around 50-60? How much could that make a difference to it's stability?



Non Eth has been good to me however.

Tinker,

You have a valid and important observation. Our engines, at least in a flathead Ford 1953 and older, have relatively low compression. The fuels we use now have higher octane ratings. The flathead will run on and was designed for lower octane fuel. I mentioned before that I was reading some AACA forums on this topic of vapor lock and lower boiling points in gasoline today. Some of these guys who were driving prewar Cadillac's and Packard's were adding a 5% kerosene blend to a tank full of 87 octane gasoline to increase the gasoline boiling point. They found that because of the lower compression ratios their engines were able to run on the 5% blend of kerosene without experiencing engine knock. Some of these guys claimed it helped reduce or eliminate their vapor lock issues.

[tubman]

Originally Posted by VeryTangled

Hi Seth, On days when I'm concenred about vapor lock, I park with the hood open when I know I'm going to be moving again soon.

I used to do that too, before I got my Optima battery, and it worked. People would walk up and look in expecting to see some chromed over monster engine with lots of finned aluminum parts. They'd walk away with an odd look on their faces.

[ford38v8]

Originally Posted by Seth Swoboda

Tinker,

You have a valid and important observation. Our engines, at least in a flathead Ford 1953 and older, have relatively low compression. The fuels we use now have higher octane ratings. The flathead will run on and was designed for lower octane fuel. I mentioned before that I was reading some AACA forums on this topic of vapor lock and higher boiling points in gasoline today. Some of these guys who were driving prewar Cadillac's and Packard's were adding a 5% kerosene blend to a tank full of 87 octane gasoline to reduce the gasoline boiling point. They found that because of the lower compression ratios their engines were able to run on the 5% blend of kerosene without experiencing engine knock. Some of these guys claimed it helped reduce or eliminate their vapor lock issues.

Seth, with all due respect, I think you have it backwards about the boiling point of gasoline. Today's gas is highly volatile, which means that it vaporizes (boils) at a lower temperature. I hadn't heard of adding kerosene to affect the volatility, but it does sound like it might help that issue, but what does it do to the octane?

[Seth Swoboda]

Originally Posted by ford38v8

Seth, with all due respect, I think you have it backwards about the boiling point of gasoline. Today's gas is highly volatile, which means that it vaporizes (boils) at a lower temperature. I hadn't heard of adding kerosene to affect the volatility, but it does sound like it might help that issue, but what does it do to the octane?

LOL, yes I did and I corrected it. I was inhaling too many gasoline fumes I guess

Adding kerosene will lower the octane rating, slightly. I don't know how to quantify the reduction in octane rating adding a 5% blend of kerosene to say 10 gallon of gasoline. Obviously that is 2 quarts of kerosene in 10 gallon of gas. It was the observation of the AACA guys that it did not cause engine knock. Their thought was it lowered octane to perhaps 85.

[revkev6]

I just went and looked at the msds sheet for lucas top end lubricant and guess what, it's listed as 60-100% paraffin aka kerosene.... so...

[Seth Swoboda]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by revkev6

I just went and looked at the msds sheet for lucas top end lubricant and guess what, it's listed as 60-100% paraffin aka kerosene.... so...

Well that is interesting. Now, how does the price of the Lucas top end lubricant compare per quart to straight kerosene?

[revkev6]

Originally Posted by Seth Swoboda

Well that is interesting. Now, how does the price of the Lucas top end lubricant compare per quart to straight kerosene?

not well

[G.M.]

I put a small fuel return back to the tank right after the pump. I used
if I remember about a 1/16" orfice hole to restrict the amount returned.
To much return will starve the engine at high speeds. The return allows
cool fuel to flow through the pump at idle cooling the pump. One picture
shows parts to have a temperature controlled fan blow air on the pump.
The other picture shows the return line into the filler neck. The return
line has been on for a number of years and still works. I tried 4 times
and pictures didn't upload, will try to add them later. G.M.

[NealinCA]

Bringing this up, as I experienced this yesterday. I drove 40 freeway miles with no problem, then drove through town, stop light to stop light, then pulled into the In-N-Out Burger drive through line. Idled for 10 minutes, engine temp got up to 200 and it shut down, would not restart. I rolled into a parking spot, pulled the line at the carb, cranked it over and no fuel out of the pump. Let it sit for 30 minutes with the hood open and it fired right up like nothing was wrong. This is the 2nd time I've experienced the problem, but 1st time I've pinpointed no fuel from the pump to carb.

It's a 59AB, with the glass fuel bowl style pump, 2 97's with 1/4 phenolic spacers on an Edelbrock regular hi-rise intake, with the heat risers plugged.

Has anyone come up with a magic solution? I didn't think about taking the ice out of my drink and cooling the pump, but there has got to be a better way...

Thanks,

Neal

[Tim Ayers]

Originally Posted by NealinCA

Bringing this up, as I experienced this yesterday. I drove 40 freeway miles with no problem, then drove through town, stop light to stop light, then pulled into the In-N-Out Burger drive through line. Idled for 10 minutes, engine temp got up to 200 and it shut down, would not restart. I rolled into a parking spot, pulled the line at the carb, cranked it over and no fuel out of the pump. Let it sit for 30 minutes with the hood open and it fired right up like nothing was wrong. This is the 2nd time I've experienced the problem, but 1st time I've pinpointed no fuel from the pump to carb.

It's a 59AB, with the glass fuel bowl style pump, 2 97's with 1/4 phenolic spacers on an Edelbrock regular hi-rise intake, with the heat risers plugged.

Has anyone come up with a magic solution? I didn't think about taking the ice out of my drink and cooling the pump, but there has got to be a better way...

Thanks,

Neal

Neal:

There was fuel in the glass bowl when it wasn't coming out of the line?

Tim

[hotrodart]

The magic solution is to not use ethanol laced fuel......it has a low boiling point compared to real gasoline. Also, my understanding is that fuel in your area is particularly poor in quality.......at least according to folks who live there.

[NealinCA]

Originally Posted by Tim Ayers

Neal:

There was fuel in the glass bowl when it wasn't coming out of the line?

Tim

Yes, fuel bowl was full. And tank was filled 20 miles prior.

[1931 flamingo]

Put in an elec pump (flow thru) near the tank and use it to prime the fuel pump.
Paul in CT Interesting that it got that hot idling in the food line??

[Aarongriffey]

I had horrible vapor lock problems on my ‘46 V8. Especially in stop and go traffic on hot days.
I went back to single exhaust and never had the problem again.
This week I am installing a new gas line on a ‘46 Mercury with dual exhaust system.
The fuel line was two inches from the left exhaust pipe and the electric pump was four inches from the rear of the left muffler.
I am putting the new fuel line on the OUTSIDE of the left frame rail to lessen the chance of heating the fuel and vapor locking.

[shoe box Jack]

cloth pins worked for me. Jack.

[shoe box Jack]

clothes pins worked for me. Jack.

[demingboy]

Many years ago vapor lock was caused by moisture in the gas tank. Only way to cure it was remove tank. Drain all fuel and let it dry. Probalby not the same problem but back in the late 60,s it worked for me.

[ford38v8]

Originally Posted by 1931 flamingo

Put in an elec pump (flow thru) near the tank and use it to prime the fuel pump.
Paul in CT Interesting that it got that hot idling in the food line??

This is precisely when it gets that hot, when the flow of fresh air under the hood slows to allow temperatures to rise. Compare your temperature gauge while on the highway to when you exit and wait at a traffic signal.

[Ken Henry]

I have had issues in the past depending on where a fuel filter is installed, with inadequate delivery when the filter was between the mechanical pump and the fuel tank. I think that the pump has an easier time pushing fuel through a filter than pulling it through... Ken