fuel line insulation, 38 & 40 La S

[Rhino 21150]

Is the steel fuel line from the fuel pump to the carburetor on the 322 engine supposed to be insulated? My Dads has clothes pins on it to prevent vapor lock. I told him it broke up the hot air flow around the line and kept the temp just a little lower. Then I said the line should be insulated to fix the problem. As per the norm he disagrees. Have we both got our heads dislocated?

[Brad Ipsen CLC#737]

I got parts from a 12,000 mile car being hot rodded to restore my 1940 60S.  On this car the line you refer to was insulated with the black heavy primary wire loom material as sold by YnZs and others.  It was definitely original since the size was smaller than the ends.  The material was installed before the flared ends were made. This line should not be nearly as critical as the suction side of the pump since the discharge is under pressure but then again it is in a much hotter area of the car.

[Doug ouston]

I agree with brad. I havent seen an insulated line on all of the Cadillacs Ive seen from back in the forties, but that means nothing anyhow. It would be good to insulate the line with a soft, flexible fiberglass tubing. It may be possible to get some tubing that can be opened up enough to slip over the fittings. Another approach would be to make a completely new pipe, and have insulating tubing on it before the last fitting goes on.

One bad mistake Ive seen is where someone installed an in-line fuel filter in this pipe. The extra surface to heat up just makes vapor lock even worse.  

[Bruce Reynolds # 18992]

One thing that really works for me is the fibreglass or asbestos heatproofing tubing that Ford installs on their polution tube that runs from the exhaust manifold to the EGR valve on an inline 6 cyl.

Once it is slipped over the hose, or pipe, then it can be pulled tight to take up any slack, and secured at each end with heatproof tape.

Bruce,
The Tassie Devil(le),
60 CDV

[Barry M. Wheeler #2189]

Mine is simple in the extreme. A length of grey foam insulating tubing cut to length and just slipped over the line. It can be readily removed for judging.

[Art#22010]

On my 49 I used a razor and cut a slit in vacuum hose and popped it on. Looks great and works great. Email direct if you want a picture.  Art

[Fred Garfield 22310]

You beat me to it, Barry. The slit foam is what Ive used for such problems in the past, although Ive secured it with 1/4-inch plastic pull ties instead of tape. Ive heard of auxiliary pumps being installed at the tank but to my mind, its overkill.

[Rhino 21150]

Obviously this is an essential part that was left off at the factory! I had similar insulation on my Fairlane, Galaxie, Corvair, Dodge van and now my La Salle. The Corvair had the fiberglass kit sold by a speed shop and looked really good next to all that chrome!
On the La Salles my dad and I have it is obvious that hot air from the radiator is blown directly onto the fuel line. On the other vehicles above, they all just ran too hot because of modifications.
Just out of curiousity: did the FACTORY ever recommend or install this fix? I have seen insulation on dozens of cars.
I am going to recommend to my doubting dad that he get the fancy kit. It will look good to him and will feel right. This is very important and he certainly couldnt care less about the $15 at Whitney.
http://www.jcwhitney.com/autoparts/Product/showCustom-0/Pr-p_Product.CATENTRY_ID:2005764/c-10101/Nty-1/p-2005764/Ntx-modematchallpartial/N-10101/tf-Browse/s-10101/Ntk-AllTextSearchGroup?Ntt=fuel20line20insulation TARGET=_blank>http://www.jcwhitney.com/autoparts/Product/showCustom-0/Pr-p_Product.CATENTRY_ID:2005764/c-10101/Nty-1/p-
(Search for fuel line insulation.)

[Bill Ingler #7799]

I get the impression from the above threads that since there was no fuel line insulation on the fuel line from the pump to the carb on 40s flat head as it left the factory, then if we insulate that line now, the vapor lock problem is gone.Please go back and read Brad Ipsens comment on pressure on the output side of the pump verses the intake side of the pump. The most unlikely place for a lock to occur is on the pressure side of the fuel pump, the line to the carb. An inline electric aux pump uses pressure to push out a lock. The most likely place for fuel to lock from the heat plus low pressure is from the intake stroke  of the fuel pump in the pump. The harder that pump works to bring fuel to the intake side of the pump, ie sucking fuel from the tank through an inline pulse pump, an inline filter, then toss in a heat and you have a possible vapor lock. The pressure discharge side of the pump needs gas to send under pressure to the carb but can`t get the fuel because the lock is in the pump, not the pressure line to the carb.Insulate that line might make you feel better but finding a better way to cool the fuel pump, raise the flash point of today`s fuels or make it easier for the engine pump to suck fuel from the tank, all this would make for a better solution.  

[Brad Ipsen CLC#737]

Maybe I wasnt clear in the note above.  The discharge line from the fuel pump was insulated originally from the factory with the material noted.  I got the entire running gear from this 12,000 mile car and most all was like new.  The material noted showed some wear from 65 plus years but it was original.  I put new on the old line by re-flaring one end.  The material was about 4 inches shorter than the line.