54 New Yorker hard starting

I have a 54 with the 331 hemi, 6 volt system. When cold the first few cranks are a bit slow but then gets up to about normal cranking speed and it starts. When hot it cranks slower and it seems to have a vapor lock type of symptom. I was wondering if the hot coolant flowing thru the carb base could be the cause. Anyone have a solution?

Check the timing.

Symptoms seem similar to the ones I have had with my 55, which are not vapor-lock related. Renewed large size cables and overhauled starter plus a good (Optima) battery will help.

You may also want to check the starter

these 6 volt systems crank slow and we often think something is wrong. even though they crank slow they have no problem starting a properly tuned car. your problem definitely sounds battery cable related, and check the ground cable from the engine to the frame. grounds get bad on these old cars and when cleaned up make a big difference. cables need to be a size 1 or bigger. if someone put cables for a 12 volt system on they cannot carry the proper amps for starting. skyler

Thanks to everyone who responded. I believe I found most of the problem, the starter quit working, took it out and had it rebuilt, seems to be working nicely now. The cables are the correct size and the battery is new. Also re-checked the ground connection.

As far as the vapor lock type condition, I found that the gas cap (which appears to be original) was not vented. Went to put gas in the car and the cap about blew out of my hand! Compared it to another cap from a 54 and found no vent holes in mine. Drilled a few small holes and all is better. Still might have a slight carb issue but that remains to be seen, need to put more miles on it to find that out.

Some gas caps will let pressure build up but will let air in when the level goes down.

Personally I dont like the pressure thing so vented both ways on these old cars is best.

the tank is vented from a small hose that connects to the gas fill tube near the cap. look under the car, not too far from the cap itself. that small hose closes up with age , so just replace it and the tank will vent fine. hope the small holes you drilled do not let the tank leak thru them when full. i have spare caps if you need one. skyler

Had trouble with my 55 Desoto hemi with hot starting. Redid all the ground wires to the battery and generator and starter and no more trouble. A regular 6 volt battery should do fine if all your electrical connections are good and the engine is tuned up and has good compression.

Martin Lum

55 Desoto

The key to making these 6 volt systems work properly are (1) correct battery cables, 6 volt is much heavier than 12 volt which are usually the replacment for those not knowing. Point gap, timing and general condition of the distributor. Starters can play into is as well.

For years I fought this stuff, ran one of the 6-12 batteries and then a friend made me see the light. Once he checked and replaced the necessary items my cars start everytime. Yes 6 volts will crank slower than 12, but they will start if all is well.

a bit late....but.....my 51 in winter was very, very slow cranking.....took and had the starter rebuilt.....replaced it, same problem.

took the starter back, checked out okay, reinstalled it.  then. for some reason (!) I changed my oil from 30W to 10W30, and

that was the end of my "slow turnover"........stay safe.......thanks......G*u