There is a huge amount of misinformation on vapor lock leading to wrapping the line to carb, all that . First ---fuel in that line is under pressure . Vapor lock ( gas becoming vapor) only can happen under vacuum . If it boiled under the 5 psi pressure in the carb line, think about it , the pump then just pushes the vapor/ gas and fluid out at carb when float drops till the liquid comes . Cannot stop that flow with a "bubble". It CAN vapor lock inside fuel pump due to vacuum there ( suction on tank line) if pump itself is hot .the Pump valve in inlet cannot work in the gas of the vapor. Flow stops. Or feed line to pump is near exhaust . Some older cars had sheet metal shields around pump , going between pump and block, extending out . Like Fins . That is right . But even better is pressurize whole line with E pump in back . And be sure whole line is ok for pressure .new hoses and tight clamps But I would not ever pump through a fuel pump . Inlet is not designed for pressure and a ruptured or pulled out of The seam diaphragm will pour gas into crankcase or out of pump all over the underside of your car . Risk of becoming a toasted critter or explosion way too high . This will not stop many from wrapping carb lines in tin foil and then saying it fixed it . "Worked for me"--- like leaving spark Plugs in full moon -- that worked for me too. Be sure air vent into tank is open too .including on some cars the gas cap . If you hear sucking sound opening tank that is a problem .. And a common one . Stops car After 5-10 miles . Someone will pipe up " vapor lock" and wrap fuel line and drives off . Because the vacuum in tank dissipated. John Sent from my iPhone
I have learned the hard way that old style pumps in perfect condition have a hard time sucking today’s fuels. I am blaming 90% of vapor lock problems on the fuel. This combined with cold cranking concerns and the fact my cars may not get driven for weeks, I am converting to electric pumps near the tank and dummy fuel pumps on the block where the fuel is just routed straight thru. The first car I did this on 5 years ago is 6v and slow cranking, now – one pump of the pedal and it starts right away, every time. …Jack ---------- Original Message ----------
From: "RON WATERS ronbo97@xxxxxxxxxxx [Chrysler300]" <Chrysler300-noreply@xxxxxxxxxxxxxxx>
To: "Carlton Schroeder' schroe99@xxxxxxxxxxxx [Chrysler300]" <Chrysler300-noreply@xxxxxxxxxxxxxxx>
Cc: chrysler300@xxxxxxxxxxxxxxx
Date: July 5, 2017 at 1:28 PM
Subject: RE: [Chrysler300] ethanol-eaten fuel pumps
So from reading this lengthy thread, there seems to be two problems: the main one being that fuel pumps were leaking due to gasket/diaphragm failure and a second problem being vapor lock. Rather than jury-rigging one or more electric fuel pumps, I would suggest rebuilding the original Carter fuel pump with modern gaskets from Then and Now. To solve the vapor lock issue, I would wrap the fuel line in some heat shielding material. Ron On July 5, 2017 at 11:18 AM "'Carlton Schroeder' schroe99@xxxxxxxxxxxx [Chrysler300]" <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:
Good morning, Another approach (but it will not get by the concours judges) that works for the 1st generation Hemi is to install a spacer / adaptor that allows 273 - 360 size block fuel pumps to be installed. Those fuel pumps are readily available at auto parts stores. Hot Heads (for one) sells the spacer. That approach has worked fine for me, although we are also fortunate to have ethanol-free gas readily available in this area (northern Wisconsin). Carlton I love it! Got those concours judges..didn’t you?! Have a Happy and Safe 4th! Rob Sent: Tuesday, July 04, 2017 7:50 PM Subject: RE: [Chrysler300] ethanol-eaten fuel pumps Rob, When I revised my 300H, I did the same thing you did. I carried it one step further by “modifying” my mechanical fuel pump. I removed the pump, removed the pump arm, and filled the inside area where the pump arm pivots with PC7 (two-part epoxy mixture). I made a gasket to cover the whole pump where it seats on the block, and re-installed the pump. I connected the fuel lines to the “dummy” fuel pump to make it look original. It never gave me any problems. Mark
ANATHEMA!! I gave my 300C fuel pump that worked swell to John Begian for his C project for the cost of shipping and replaced it with a 5 psi electric pump from Hemi Hot Heads. It is a non-racing pump that is engineered for dual carb hemis. I located it on the frame rail where I had my electric priming pump in front of the passenger rear wheel with a stone guard beneath it. I insulated it from the frame rail with a rubber pad so it doesn’t make a racket like a woodpecker on the roof. The major reason was vapor lock. The 392 mechanical pump is just beneath the exhaust manifold and the metal lines go right next to it on the rise to the front fuel bowel and hug the water pump area for the upper radiator hose connection. I am fortunate to purchase ethanol free unleaded 91 octane easily in Lawton, Oklahoma. Still modern fuels burn up to 200 degrees F hotter than the ones formulated back in the time of the early letter Cars. There is a reason that fuel pumps I now realize are in gas tanks or away from the engine compartment . Probably the vapor reclamation (EGR?) circuit in modern vehicles has something to do with the location also. Soooo.... the engine starts up immediately since the pump turns on when ignition key turned to on before engaging the starter, pure gas, no diaphragms to fail (near and dear to a soon to retire gyn, 27 days to go), and smooth driving at all speeds and all temperatures without any hiccups. You purists can do your thing, but here is a solution that works well but is not concours correct. Rob Kern Sent: Tuesday, July 04, 2017 1:46 PM Subject: Re: [Chrysler300] ethanol-eaten fuel pumps Maybe I'm just lucky. I've been dealing with fuel system adversities for more than 50 years and I don't find things to be a great deal worse now than in the past. I've not checked the alcohol content in local fuels in a long time now, but I suspect that here in Florida we still have less of it than in many parts of the country. Between 1995 and about 2004 I never saw local content to be greater than about 6percent (measured with a rather crude test device, careful monitoring required because of 2-stroke sensitivity). My sense of smell is not very acute, but it seems that now we have less ethanol than at some times in the past because I hardly smell it at all now most of the time. A few months ago I disassembled the fuel pump on my C300 just to make certain that it was still in good shape before driving to Wisconsin. What I found was no noticeable deterioration of the diaphragms and it remained clean and corrosion free internally. The pump was a new Airtec from Carquest in 2008. I drive the car a little bit almost every day, refuel it about once a month, and have now accumulated just over 21,000 miles since I started driving it. There's little for me to complain about. ---------------Marshall Goodknight
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Posted by: John Grady <jkg@xxxxxxxxxxxxxxxxx>
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