The Stovebolt Site Forums The Shop Area Engine Shop Electric Boost pump and oil pressure switch

OK I have a 235 with all of Langdons goodies on it and I have a what I believe is a fuel vapor lock issue. I'd like to install a fuel boost pump and oil pressure switch. Has anyone any suggestions on what I need to accomplish this. I was thinking a pump near the inline filter 5/16 fittings I believe. What have ya'll done?

Thanks

Before you go adding an electric pump, you really need to find out why you have a vapor lock problem. Check the line routing, make sure it is well away from heat sources, and possibly even insulate it if it has to run near them. You should also check the mechanical pump for proper operation. The stock pump should be plenty to feed the webber designed carbs that the Langdon setup uses.
If you do decide to run an elecric pump, you may want to consider using it as the main feed, rather than a "booster". You'll need to have a regulator, and possibly a return line as well. Mount the pump as close to the tank as possible, as electric pumps are better pushers than pullers (that's why modern cars have them in the tank). You will also want to have a pre-filter (sock) on the pickup tube in the tank to prevent any debris from damaging the pump.

I agree with longbox. As far as a external mounted pump goes, look for a solenoid type pump and not a vane type. A solenoid pump will actually be able to suck the fuel just like the mechanical type pump you have now. I bought a solenoid pump for my tbi conversion and it works very well. No problems sucking fuel uphill.

Where is your fuel filter located?

What carburetor(s) are you using (Langdon sells a few in his list of "goodies"),
and what intake manifold,
and how are you heating the intake manifold?

Where is you fuel line running near enough to something hot enough to cause vapor lock?

Have you discussed your set up and your problems with Tom? He is quite knowledgeable and helpful.

Not to sound like a broken record but......I've had the same vapor lock symptoms since we switched over to E10 fuel. I tried both an electric pump as a primary source and also in series with the mechanical pump.

After shutting the engine down (without opening the hood) it would crank and run until the bowls in my C/W's emptied and then it would die. My fuel pressure gauge, which normally reads 4-1/2psi would read zero. The electric pump both as the primary source and also as a supplimental pump made no difference. The problem is that E10 fuel has a "phase seperation" point of about 128 degrees.....and the engine compartment reaches well above that within minutes of shutting down.

In duplicating the problem I discovered that a wet rag laid on the metal fuel line right at the corner of the valve cover, where the line starts back to the carbs, immediately restored fuel pressure. I tried insulating the line between the valve cover and the thermostat housing to no avail. At this point I switched back to the mechanical pump as the primary source of pressure.

The process to correct the problem has had me fabricating an aluminum heat shield that I thought might deflect enough of the heat soak to correct the problem. It didn't. Popping the hood after shutting down the engine allows enough heat to escape so that the problem corrects itself in 15-20 minutes. I've also resorted to running my supplimental a/c pusher fan for 5 minutes after shutting down which seems to work okay. I have a strong hunch that my creative metal fuel line setup is a major contributing factor but I never once had this problem until my first tank of E10 fuel after a year and a half of driving. (a full tank a week) My next corrective action attempt will be to change out the metal line to E10 rated rubber hose and see if I can't reduce the 150 degree temperature, after shutdown, in the metal line.

Before you invest in an electric pump try applying a wet rag to the line that runs up from the pump to the carbs. If you're experiencing the same issues as mine your engine should pick back up and run normally. I'll also add that the "wet rag" has proven to be a quick fix at several of our shows where a vehicle drove in just fine, and wouldn't run after their float bowl emptied. If allowed to cool down, the vehicle will start and run fine but will repeat the process if allowed to sit after shutting down for a short period of time.

I'm not saying that your issue is the same as mine but adding an electric pump didn't correct my situation.

Dave

Dave, this sounds very familiar. I'll take your experiences into much consideration. I'm going to put an electric fan to supplement the engine cooling anyway, so maybe I'll do this first and see if it helps my problem. I'll insulate the lines as well.

Thanks to everyone for their suggestions I'll use a little bit of all of them to solve this problem.