Vaporlock ideas? Help please?

Ok. I have a really rough 59 caddy flat top sedan. LOVE the piece of junk, but its constantly giving me fuel issues. I put a 350 chev in it. I didnt want and didnt have the time to take an extra few days to cut the frame for the fuel pump, so I just did a quick check online and found a pump that would fit my extremely limited space. I have 1/4 inch clearance now with a solid mounted motor. It's a powerflow piston style fuel pump that can put out 55 psi. I have the drop head style regulator (per instructions) installed and everything seems to work fine. Im running 7psi to my carb. It has worked for a couple years this way WITH the occasional vaporlock issue. I thought it was the pump, so i sent it back and they replaced it. Then It turned out to be my temporary rat exhaust. Thats ok cause I didnt want to keep it that way anyway. Im running an old ramhorns on that side now. still does it but in a different place. I header-taped the exhaust dump near the pump. Did some checking with my "scientifically accurate temperature gauge shaped like my hand". The heat is NOT coming from the exhaust anymore. This vaporlock problem keeps happening, and I keep eliminating one cause only to have the problem change to a new reason. My motor runs at 160-180 temp. NOW the problem is heat saturation. If I drive it anywhere, I need to let it cool for an hour cause radiant heat FROM THE BLOCK heats up the aluminum pump and boils the gas IN the pump. It runs from the carb till empty, then dead. Again.

Is there something I can do or put between the block and pump to kill the heat saturation? This problem has had different causes but has been plaguing me for two years! This is the only thing I see that's left. If the car ran any cooler then the oil wouldn't pump!

Any ideas, suggestions, opinions GREATLY appreciated. -GothY-

 

Put an electric pump at the rear of the car near the gas tank. Electric pumps are supposed to push not pull.

 

GOTHBOY...It would help if you could take a few pics. of the pump in relation to the exaust. because your engine isn't hot enough to cause vapor lock. and are you running a metal gas line from pump to carb. man a PICTURE realy is worth a thousand words...POP.

 

Holeshot, GREAT IDEA! Ok. (duh ) I'll take a couple pics tonight.The powerflow is a mechanical style that bolts to the block in the normal place, so its not electric. My fuel lines are temporary because I keep having to re rout them due to this issue. They are rubber front to back. HotRod40 are you suggesting I put a secondary pump inline? Like an electric fuel pump inline near the tank? I was thinking of doing this because I cant think of anything else. But that would merely be a patch and not a fix. :/ -GothY-

 

It's obviously not happy being downgraded with a chevy engine

 

it's a fix if it works isn't it? i run them on all my cars. screw that vapor lock.

 

I've never had vapor lock running electric pumps at the rear of the car. Be safe with the fuel lines, please, gasoline is not a toy!

 

you sure your carb is not leaking gas into intake after shut off, making it hard to start again

 

As said before....an electric pump at the rear will solve the problem...If it's vapor lock.

 

Try this,thought mine was vapor lock but it wasn't.

 

if it turns out to be carb perk, you can block the manifold heat passages with a thin piece of metal, like tin can thickness. loosen the intake nuts, pry up a bit and slip it in. you don't really need it in warm climates.

 

Fuel line looks a little close to that exhaust, to me.

 

Ok. You guys rock number 1. The picture with the rat exhaust is no longer accurate. I FINALLY found the correct stock exhaust manifold for this application, allowing me to get rid of my temporary rat exhaust. That's why I didn't post that pic. Here's some right now pics.

Henry29 it was actually further away than it looked, but with that exhaust it didnt matter, cause it was cooking my coil too. Its now running a new exhaust with a Gm Hei. No more ignition problems. Fuel line is currently 9 inches away from the exhaust at closest point.

Electric fuel pumps. Ive had tons of problems with them dying on me over the years, I will use them as a back up, but not a primary pump anymore. That's another reason I went out of my way to find a really good mechanical pump. (Note, it's not hitting the frame) Last night, I installed my spare electric pump right at the tank, so currently I'm running two pumps. I'll have to see how that goes over the next few days. Once I get this all sorted out and it runs good then I'll make some metal fuel lines and run it done.

Shaggy, that same thought has crossed my mind too.

TwoChops, thanks Ill look into gettin' one of those soon.

61Chevy, Im NOT sure its not just leaking down into the manifold, however, it doesnt seem hard to start when "its doing it". instead it just seems to not be pumping fuel until the pump cools down. It runs great til the carb bowl runs dry. Can you fill me in on how to check for this?

Thanks again for any further ideas. wood fiber gasket sounds good, I'll look into gettin' one, and the heat passages will be blocked off this weekend per your guys suggestions. Here's the current pics so you can see all the room around everything. It REALLY is mind boggling me to no end. -GothY-

 

This may sound a bit simplistic, but why not just cut/modify the frame so that a stock pump will fit? Sure, it should have been done earlier, but it's not too late to do it now.

Then run a steel line from pump to carburetor, and use a heat-block style gasket or phrenolic spacer. These two steps will most likely eliminate any fuel leakage into the manifold after the engine has been shut off.

This rig should run fine without using an electric fuel pump as a band-aid fix. And, as has been mentioned earlier, any electric fuel pump application should use ONLY steel lines between the pump and the carburetor. A pinhole "leak" in a rubber hose will spray gasoline in a very impressive manner when pressurized by an electric pump!

And a fire of this sort happens so fast you won't know it until the car is already toast!

Just my $.02. Good luck!

 

Just thought I would mention , I think 7 psi on a stock style needle and seat in any carb is pushing the limit. Try running 3-5 psi. ( I know what your going to say) But trust me , You don't need that much fuel pressure with that pump.

I have the pump your using on a 331 SBC in my race car , only runs 3 1/2 psi and feeds an 850 Holley at 7500 rpm. (9.70's at 135 MPH)

Its an easy try just set the pressure lower and see what happens.

Desert

 

MissysDad1, you're 100% right about that, I cant have the car down right now though, no garage, street sweeping BS, etc. The next time I can have it down I'm going to cut the frame. I watch VERY VERY closely for ANY leaks of any kind in the fuel system. I had a good scare years ago with a rust pinhole in a steel line, and now I'm paranoid about that. Thank you.

Desert1957, The pressure issue. When I get home tonight I'll re-check fuel press. I am not 100% sure that it's 7 but that's the number that sticks out. You say "trust me". I DO, otherwise I would not have asked here. I will check and re-set it for 3-5

I'll do some suggested things tonight, and see how it runs in the next few days. Thank you all for your help so far. -GothY-

 

This is not pump-related, but does your car have "sock"-type filter on the pick-up/sending unit in the tank? They can get real nasty and clog up.

 

Do you positively know that it is a vapor lock or does it just quit and then start an run fine after it sets a while?

I and a lot of others have had problems with gas caps being non vented when these older cars need a vented gas cap. You drive four or five miles and the car dies, It sits a half hour or so (about the time it takes to walk to the gas station and back) and it willfire right up and go again for another four or five miles or until the fuel pump sucks the sides of the tank in to where it creates a vacuum and the pump won't pump fuel. Next time it quits walk around and slowly open the gas cap and see if you don't hear a rush of air and the sides of the tank pop back out.

Belair's idea on the sock on the pickup being plugged is a good one too as that happens a lot on cars, especially ones that may have been sitting for a long period of time.

 

One other minor thing that I have had problems with in the past is those glass see-through fuel filters like the one you have there. Wrap it in some header wrap or replace it with a plastic one. The metal end caps wick heat into the fuel (the glass doesnt help either) and cause the fuel to vapor there or just downstream. The plastic ones look horrible, but don't transfer heat as well. Also, you really can't see how full of crap they are until you take them apart and clean them, no matter what the package says. Good luck.

 

try changing the ignition coil. see if that helps.

 

I have identical problem of "vapor lock"

We have to use the 10% ethanol blend of gasoline which I believe is the culprit.

If I run race gas or a 50/50 blend of race gas, I have no problem.

A return line to the tank should solve your problem.

 

Also, concerning the electric pumps...The little square Puralator style ones usually are the ones that go bad. There are two kinds of them, one being crap, and the other being fine. I can't remember the differences, but it is on the web. I have one of the good ones, and have never had any problems with it.

They make really nice ones as well....I think MBL might have a Holley that is real nice, and quiet.