fuel gas pump piping

peter e mark · Post by **peter e mark** » Mon Apr 21, 2008 10:24 am

Well folks, it happened to me ! After letting my M37 idle for 40 minutes and "warm up" on a 70* day in New York, It got real warm I guess and I think I experienced what is called VAPOR LOCK ! Drat ! The tow truck pulled me along in 3 rd gear and it started again. And now I'm buying a fuel pump, regulator with guage , and would like to ask KNATTRASS these questions , but the State Police tells me he's presently hiding under his truck: 1. Do I keep the mechanical pump in the circuit and go 100% electric? Shall I mount the regulator on the firewall ( it has a guage , 4 PSI , right ) . Sure appreciate it . peter mark

knattrass · Post by **knattrass** » Mon Apr 21, 2008 5:18 pm

I told you bad things happen when you leave the island!

I had my mech pump rebuilt by T&N and properly installed the heat shield. I find it hard to believe but someone told me that VL can occur in the fuel line between the pump and the carb under extreme heat conditions and that a heat shield on the line would help (anyone want to confirm?).

Next, I was told to crank with the throttle cracked so that the idle and throttle jets are pumping but don't pump. The other recommendatio was to hold the pedal to the floor. (anyone?)

Finally, I was told that the VL causes the bowl to go dry, and that if you had a cold weather primer kit installed, you could give the engine a shot of fuel using the mech primer

Lifer · Post by **Lifer** » Mon Apr 21, 2008 5:26 pm

Confirmed! The fuel line has to pass the exhaust manifold between the fuel pump and the carb. An engine builds up a LOT of heat under the hood when idling for a while, and it heats the fuel in the line to boiling point. This results in vapor lock. The only cure is to allow the engine to cool down. Correct installation of the heat shield will protect the fuel line from excessive temperatures (to a point) and will dramatically reduce the frequency of vapor lock instances. Note, however, that it will not completely eliminate the possibility of it happening.

I grew up with old flathead Fords, which were infamous for vapor locking. On more than one occasion I resorted to reaching into the cooler for a bottle of beer which I poured over the fuel line in order to get back on the road a little quicker. Talk about alcohol abuse!

knattrass · Post by **knattrass** » Mon Apr 21, 2008 5:27 pm

The other solution was to get a low psi 24v pump (4psi). I looked all over and only found one via Saturn Surplus but it was 7psi. That meant buying a regulator to step the psi down to 4psi. The set-up recommended was near the fuel tank for the filter-pump-regulator all in one mounting.

For safety, you should install a oil psi switch by installing a Tee off the oil sender and install the Ballkamp 4 psi oil switch. This gets wired in series to the fuel pump, such that the oil sender switch closes and then supplies power to the pump. No psi. no fuel.

For a primer feature, Charles recommended a push button switch wired in parallel that would send fuel when the primer button was pushed. I found a heavy duty silver contact Cole-Hersey switch from the marine store.

When i decided to get my mech pump rebuilt, I decided to stay mech. I could never find the right electric pump.

peter e mark · Post by **peter e mark** » Mon Apr 21, 2008 7:12 pm

First of all, congratulations on your promotion, to E-6 , knattrass. And thank you Lifer and all for ,your input. I followed most of it , and an old timer told me just today to insulate the mechanical fuel pump to carberator line with an asbestos lining, which will solve the problem of the vapor lock. I will look at my engine to see if I have a heat shield too. And do I understand the purpose of a 4 PSI switch in the oil line to prove that the engine is running before the fuel pump can run, so as to prevent inadvertant use of the fuel pump and a possible leak ? And one last question:There are two shielded lines going over and into the tank top, a thinner one and a thicker one., Which one is the line to the mechanical fuel ,pump? Thank You all.

Nickathome · Post by **Nickathome** » Tue Apr 22, 2008 8:03 am

Lifer wrote:Confirmed! The fuel line has to pass the exhaust manifold between the fuel pump and the carb. An engine builds up a LOT of heat under the hood when idling for a while, and it heats the fuel in the line to boiling point. This results in vapor lock. The only cure is to allow the engine to cool down. Correct installation of the heat shield will protect the fuel line from excessive temperatures (to a point) and will dramatically reduce the frequency of vapor lock instances. Note, however, that it will not completely eliminate the possibility of it happening.

I grew up with old flathead Fords, which were infamous for vapor locking. On more than one occasion I resorted to reaching into the cooler for a bottle of beer which I poured over the fuel line in order to get back on the road a little quicker. Talk about alcohol abuse!

You can reroute the fuel line os it stays away from the manifold. Al lyou need do is install a slightly longer hose and run it up and away from the manifold and use a tie wrap or hose clamp to secure it to the inside of the fender, then up to the carb. My truck's got an industrial engine which has the fuel pump mounted in the rear of the block, real close to the down tube of the exhaust. I first wrapped that part of my downtube with that wrapping material they use on motorcycle exhausts(summitracing.com) and then ran the fuel line up along the fendr as previously mentioned. So far, no problems.

knattrass · Post by **knattrass** » Tue Apr 22, 2008 12:13 pm

The fat boy = fuel, the small one is the vent. Mine lines were toast so I got a kit from John B at MWM. The vent required a ton of cleaning and repair - you may want to check yours.

[/img]

peter e mark · Post by **peter e mark** » Tue Apr 22, 2008 4:18 pm

Hey Knattrass, I hate to tell you this, but most of what is the rear of your vehicle is missing ! Just funnin ... So far I re routed my 5/16" line away from the header, and fastened about 20 wooden clothes pins. Looks real profesional; ( e gads ! ) Also John B suggested I tighten the fittings at all points in the line, which I did , save for the tank, as he is sending me a new in-tank filterWell then, and thank you Knattrass for this picture, you know what Confuscious says about pictures : " Get your M37 parts from John B at MWM"

Lifer · Post by **Lifer** » Tue Apr 22, 2008 5:28 pm

Looks like quite a bit of the front part is missing, too. What's visible in the pic sure is pretty, though!

peter e mark · Post by **peter e mark** » Wed Apr 23, 2008 4:53 pm

Gentlemen, As I look thru the 50,000 pages of my M37 CD, I do not find the fuel line size dimention/diameter at or near the gas tank. Any input will be apprciated as I am going to go forward with my "inline" electric fuel pump, and spin on filter, and regulator, and pressure guage and shut off valve ! Peter

greeno · Post by **greeno** » Wed Sep 12, 2012 9:29 am

Guys - looks like Peter's question never got answered, and I'd like to know the same. I plan on bending up my own metal lines.

nortonscustoms · Post by **nortonscustoms** » Thu Sep 13, 2012 7:21 pm

The steel fuel line from the tank to the pump is 5/16"

Norton

Wayne64 · Post by **Wayne64** » Fri Sep 14, 2012 5:09 pm

Peter, drive on over to Levittown and see for yourself how I handled the 24v pump install . BTW, I didn't bother with a regulator, just the right sized pump. A Regulator in my mind is just one more thing to buy and one more thing to fail. JMO
Wayne

fuel gas pump piping

fuel gas pump piping

Mechanical Pump

Fuel lines

Re: fuel gas pump piping

Re: fuel gas pump piping

Re: fuel gas pump piping