39 Buick - Vapor Lock Problems

[WHSEWARD]

RONs49,

Diesel is one of the products distilled in a refinery from crude oil. In order of increasing average boiling point, the order is gasoline, kerosene, then diesel, then fuel oil. The heavier you get, the lower the vapor pressure, but the more high-boiling-temperature compounds there are in the mixture (each of these products is a mixture of many individual hydrocarbon compounds). Kerosene is only slightly heavier than gasoline so I would choose it first over diesel, but I don't know what specific problems diesel would cause, especially now that ultra-low-sulfur diesel is mandated for road vehicles. Would BP have comments on that?

BTW, I bought 2-1/2 gallons of kerosene at my local (non-chain) hardware store for just about $10 a gallon, BUT the owner said if I bring the container back he can refill it out of his bulk drum for $6.50 per gallon. Maybe you guys buying kero can work the same kind of deal.

Has anyone tried to buy jet fuel at the local airport? That's kerosene, I think. I thought I heard that you need a permit to do that, though.

Finished wrapping my fuel lines and my test drive showed about a 20 degree drop in fuel line surface temperature from the unwrapped condition. Texas Tour is next week - will let you know how it goes.

[rons49]

Thanks Bill, I wouldn't think the sulfur removal is a problem for our uses, but any comments would be appreciated. Bill, what and how did you wrap the lines. Can the wrap be easially removed for judging?

[WHSEWARD]

I wrapped the lines with a two-layer wrap, aluminized on the outside and woven fiberglass inside. Is is made by (among others, I'm sure) by DEI, and is sold at Advance Auto Parts, etc. It's actually sold as a tube so I cut it to fit rather than disconnect my fuel lines. Outside of all I wrapped it with Cool Tape, also by DEI, and then added hose clamps at certain intervals to prevent too much unraveling. It's NOT a beautiful job, and I do not plan to remove it for shows. If someone wants to knock off points, so be it - my car is original and will never be a 100-point car anyway. I thought about using a roll of self-adhesive exhaust wrap, but the way my fuel line is configured it would have been even more of a nightmare to wrap the fuel lines with that.

To make a wrap that could be removed for judging perhaps one could use some sort of tubing like heater hose cut lengthwise, fitted onto the fuel line, wrapped with the CoolTape, then secured with hose clamps. That way when it was removed it might be sufficiently preserved to be re-installed for the Tour.

[rons49]

Bill, I used to use header wrap and fastened it with small cable ties. I would cut the ties and remove the wrap for a judged event once a year or so. But, the idea did not do enough to cool the steel gas lines enough. Once the lines got hot, they stayed hot.

Cold war, There is a slight risk that fuel could be pumped into the crankcase with an electric pump in line with a working mechanical pump. Ok for priming or "emergency" use, but IMO not to use as a prime source, unless a. a bypass fuel line is used (still a chance of fuel leakage).b. the mech pump is removed from the line( or blocked off) and a electric is the only pump used ( this would usually require a pressure regulator). The later has one problem. Without a device to shut off in a serious incident, the elec pump( still drawing current) will continue to run until the tank is empty. This is not good!

[Owen_Dyneto]

Agree fully with "rons49" comments. More than one engine has been ruined and more than one nice car burned to a crisp from an electric pump used for anything other than priming after long inactive periods.

The question you have to ask yourself when wrapping underhood fuel lines is, "am I insulating overheated fuel from being cooled by the draft of the fan, or am I insulating cool fuel from the hot under-hood temperatures?"

[rons49]

RE, the pressure switch at Summit. Is the switch that you prefer the 3 terminal Carter, GA 68301. Is that switch OK for 6 volt?

[Guest Julian]

Buy a sack of grapefruit or oranges from a roadside stand or grocery. Cut one in half with your jack knife. Smush one half on the fuel pump. Eat the other half. Drive around until your car vapor locks again, should be several days or a week. When the orange or grapefruit dries out you will get another vapor lock. Just throw away the old one and put on a new one. Hope this is clear.

Now THATS an answer !!..love it

[rons49]

I have a question re. the Holley 12-810. Will I still be able to prime the carb with the engine not running, so as to not crank and crank until the fuel fills the bowl and the engine starts? Are these switches voltage sensitive,ie, do they work on 6 Volt?

[WHSEWARD]

Just a final follow-up as promised earlier. Participated in AACA's 58th Texas Tour on April 14-16. Drove 200 miles Katy to Killeen, 2 days of touring, then 200 miles back on the 17th. Wrapped the fuel line but not the carb or fuel pump. Used 1 quart kerosene per 10 gallons fuel. No vapor locks but one incident where I flooded the carb that took about 2 hours before it would restart. During and after the tour I found that opening the hood to let the heat out solved most of my problems; just after stopping on a 40-50 mile drive the fuel line temperature (inside the wrap) was 130ºF; after 15-20 minutes the temperature had dropped to 100-105ºF. I found that this temperature was low enough to allow me to restart the car regardless of the jacket water temperature. Touring at 25-30 mph I never got above 180ºF in the jacket. Driving on the road at 50-55 mph I reached 185-190ºF but as I said, no vapor lock.

It's always tough to prove a negative. I wasn't attacked by elephants on the tour either, but wouldn't claim that that was due to wrapping the fuel lines or adding kerosene to the gas. Anyway, this information is presented for whatever you wish to make of it. Happy driving.

[Rusty_OToole]

I for one am grateful for the information. Too many times we get no feedback which makes it hard to know if we are getting things right or not.

The idea of leaving the hood open when parked is a good one. Did you open it all the way or just a couple of inches on the latch to let the the hot air out?

[DavidMc]

I also have found it necessary to open the hood, when the car is stopped and close to vapor locking. On my 1920's car with the different hood arrangement to the 39 Buick I have arranged a method of driving with the 2 hood sides lifted a few inches to allow plenty of extra air flow into the engine bay. This air comes in over the top of the radiator so it is cooler and it helps keep the engine bay area cooler.

[WHSEWARD]

Rusty,

39 Buicks have a prop that is supposed to hold the hood side up, but IMO is quite dangerous especially if the wind is blowing. It doesn't have a positive latching mechanism. On several ocasions during the tour the hood slammed down because the wind lifted it off the prop- if someone had been working on the engine they could have been injured. I found that I had to stay with the car for 10-15 minutes when the wind was strong and physically hold the hood up. That doesn't invalidate the idea - it just makes it more difficult to implement for my car.

I appreciate everyone's interest in and contributions to this thread - this is what makes these forums so effective.

[FLYER15015]

Bill,

Now that you have tested your car out on the road, and determined a "fix", you will need to invent a proper and safe "hood holder upper", and sell ithem here for lots of $$$.

Seriously, I don't know how much of a "purist" you are with your car, but I chose to reroute my gas line (that I made of copper tube) up from the pump to just under the cold air inlet tube, and back to the firewall, and up and over the valve cover (w/ 6" clearance) and to the carb's rear inlet. I did cover the line w/ plastic wire loom snap over covering, just to mask the copper colored tube. I don't use diesel and she cruises @ 60 from Buena Vista to Denver quite nicely on what ever kind of stuff that now passes for gasoline.

Best Regards,

Mike in Colorado

BCA#45728

AACA#994416

[Guest 39cent]

Buy a sack of grapefruit or oranges from a roadside stand or grocery. Cut one in half with your jack knife. Smush one half on the fuel pump. Eat the other half. Drive around until your car vapor locks again, should be several days or a week. When the orange or grapefruit dries out you will get another vapor lock. Just throw away the old one and put on a new one. Hope this is clear.

Now THATS an answer !!..love it

I was waiting for this fix! I first found out about this solution when my Dad did this to our 39 Pontiac on our trip to California in 1944. Only he didnt eat them he saved the other half for later use.

I had heating problems on my Century from time that I got it. I noticed when opening the hood how much heat was released and came to the conclusion there wasnt enough underhood ventilation, 39,s dont have much in the way of louvers etc. So then to get me home I put 2 little pieces of wood under each rear corner of the hood to prop it up. took off down the road and it did keep temps down. Also I could feel lots of heat coming from under the hood when traveling at speed. Also the heating would get worse at higher speeds. Finally looked under the front end and saw a gaping area under the radiator where the front crossmember acted kinda like a scoop. Thats when I thought it may be causing an air dam under the hood as air couldnt get out fast enough. well I covered that area and so far so good. And yes I,m going to install an electric fuel pump.

[Rusty_OToole]

A lot of old cars had tin shields around the motor, above the fuel pump, above the rad, below the rad or in front. They have a habit of jumping ship over the course of 50 years or so. Possibly some overheating problems could be cured or reduced, by having all the original tin work in place.