52 Hot starting

[flintbuick]

OK,

So my buick does not like to start up when shes hot. She cranks fine but will not fire. When cold it will fire in about 3 cranks. It will also start fine if shut down and then restart within a few minutes. However if i let it sit about 5 to 10 minutes i will have to wait an hour before i am motoring again.

Here is a list of new parts and motor condition,

brand new rings and rod bearings

new battery

new 00 cables

new starter

new pertronix flame thrower 2 coil

new points

new condenser

new plugs

new wires (solid coppers)

rebuilt carb

new valve job and guides

160 high flow stat

new radiator

factory exhaust and intake

heat riser valve is stuck in the full bypass postion

Stock mechanical fuel pump, tank and fuel lines.

thick 1 inch carb spacer

Timing is slightly more advanced than factory specs, car runs on the road great and doesn't ping under load. I set the choke at cold (75 ambient air temp) to just close the choke valve and it runs smooth until the choke is opened fully by the bi metal. Around 1 1/2 turns out from soft seat on the idle adjust screws. I am running ethanol gas and wonder if i am having fuel percolation problems. I also very slowly push the gas pedal to full open on hot start.

Any ideas???

[Pete Phillips]

Sounds like vapor lock, to me. Pete Phillips

[old-tank]

I am running ethanol gas and wonder if i am having fuel percolation problems.

That's probably the problem. Try starting like a flooded engine: slowly press accelerator to floor and start cranking. If your gas is anything like the stuff I had to use in Indiana, it will percolate at every shutdown.

Vapor lock will kill an already running engine and have a resultant hard restart: in this case choking the engine will help.

Willie

[Guest NikeAjax]

I agree: check the routing of your lines. Make sure you're not too close to a heat source. One of the things you can do to keep it from perc'ing is to either ad some diesel, or Marvel Mystery Oil to the fuel--it's a REALLY old trick that most folks don't even think about...

Jaybird

[trp3141592]

Hi,

This has been the story of my LaSalle's life, but there are lessons to be learned for all vintage cars. The Cadillac and LaSalle flat-head V-8's of the late thirties and 40's are notorious for vapor locking and hard starting when hot. I stood and watched the fuel boil in the settling bowl of the fuel pump on one occasion early this year when the car said, "No more" for a while. I was boiling also--with frustration. The underlying issue appears to be the lower boiling point of corn-gas compared with the real thing.

To me the situation was a choice: 1) do something that works with the vapor lock problem, or 2) scrap the LaSalle engine and install a Chevy 350 and automatic transmission in the car. My Niles neighbor, who also has a 40 LaSalle, chose option 2, and his car runs like a Swiss watch in all temperatures and conditions. I am jealous. But Option 1 seemed easier, especially since I don't have a lift available to me, so I have tried to "deal with it."

To deal with it, I did mechanical maintenance: new points, cap, wires, condensor, coil; had the vacuum advance rebuilt at Terrill Machine; static-timed the ignition to be "spot on" and verified it with the timing light. Then I insulated the exhaust manifold where it is located close (2-1/2") to the fuel pump, fabricated and installed an aluminum heat shield around the fuel pump, insulated the pump to carburetor fuel line, added a second gasket between the carburetor and the intake manifold, insulated the pump feed line, fabricated and installed aluminum heat shields between the exhaust manifolds and the carburetor, and installed an electric fuel pump in parallel to the mechanical pump (with a check valve, or else all it does is whirl the fuel around in a circle) to use as a booster and primer. I have not tried adding Diesel, Mystery Oil, or ATF to the tank. I am told that doing so helps the boiling point situation, and that the mix should be about 1/2 pint per tank full. I don't know anything about side effects of adding any of these fluids to the gasohol, so I haven't tried it yet.

It's difficult to find real gasoline any more. Some marinas sell it for boaters' use. You can check near you at pure-gas.org. You can also google "no-ethanol gasoline" for additional outlets.

I also found that my local (Niles, MI) Marathon station's regular gas is only 2% ethanol maximum. The first tank of the Marathon gasoline made a noticeable difference in the car's performance. I don't know if all Marathon stations have the same gasohol mix.

My LaSalle is a V-8, and our Buicks (mine's a 37 RM) are straight 8's. Some of the tricks I used on the LaSalle may not be applicable to the straight 8 layout, but you can pick and choose for your engine's situation.

And make sure that you're having fun while doing this work. If it's not fun, why are you in this hobby?

--Tom

[flintbuick]

Vapor lock has been on my mind. I often wonder about the routing of the fuel line. It runs straight up from the fuel pump up in front of the water goose neck and then turn towards the carb in a big sweep. I think i am going to play around with an electric pump at the tank to push to the stock fuel pump with a momentary push button used just for hot starting problems. Usually the only way i can get it to start is to place my hand over the intake while cranking, or let it cool down. I have taken temp readings on the base plate of the carb at around 108F. Thats what makes me think fuel boiling.

Here in Michigan state law does not require labeling of ethanol content in their pumps. I have asked a few pimple faces at the register but they had no idea what i was talking about.

[Guest btate]

I had an old 51 Olds that when it got hot, I would have to wait 2-3 hrs before it would start. Caused by worn rings. But, it ran great otherwise

[avgwarhawk]

Sounds like vapor lock as others suggested. The flame thrower 2. Is that compatible with your points?

[trimacar]

So often we ignore the obvious....and I'm not saying this is your problem, but I really think that we ignore the obvious....

Yes, you did the right thing with heavy battery cables....but what's between your battery terminal and the starter?

Grounded to frame, rusty connections, and so on...and if you use sandpaper to shine up connections, imbedded silica can actually insulate electrical flow...

I had slow starting on my Pierce, ran a big ground cable to stater mounting bolt, cleaned all connections to bare metal with a file, turns over great hot or cold.....and of course starter needs to be 100%....

Yes, the new fuel is awful, but you have to get engine spinning first!

[bhambulldog]

I've never had a vapor lock issue with mine.

I've been adding Marvel Mystery Oil to the gasoline, since we got the car forty years ago

[Guest NikeAjax]

Something you might want to try to see if it is a vapor-lock issue is put some wet rags on the fuel-lines to cool them down: this is a really quick and easy way to bring the temperature down on them, just like with people! I used to have a friend with a 1930 Pierce Arrow who taught me that trick: his Pierce would vapor lock until he put some diesel in the gas to stabilize it. I did that a few time until I installed an electric pump...

Jaybird

[packick]

FlintBuick:

For what it’s worth, I had the exact same problem with my ’55 Century. In my case the needles in the carburetor were installed upside down. One side of the needle is metal, the other side is “rubber” which should have gone against the seat.

Since there was not a good seal between the needle and seat, gas oozed into the carburetor after shutting down. The engine would crank and crank and eventually started once all of the excess fuel was drawn down. It started right up when cold.

You mentioned you had the carburetor rebuilt so I thought I’d mention this.

[Aaron65]

You, my friend, have two problems. #1 You live in Michigan... #2 You have a straight 8 Buick. After driving my '53 for 8 years, I have come to the conclusion that our gas is crap, and that big old manifold under the carburetor exacerbates that fact. You've done all the right things so far. If your carb has a sight plug on the float bowl, remove it and lower the float until it's just wetting the lower threads. The biggest help was some advice Jon the Carbking gave me...I created a fuel bypass. I run a threeway fuel filter with a bypass port near the carb, and I ran a hard return line back the the fuel filler. It would probably be better to run it back to the tank or sender. That helped a lot, but not 100%. How you start it makes a big difference. Every car is different. On the Buick, I touch the accelerator to crank the engine for about 2-3 seconds without squirting fuel into the carb through the accelerator pump. Then, especially on hot days, I hold it to the floor and it starts within a couple of seconds. I found that my V8 cars are much less sensitive to heat soak, probably because the carbs don't live on top of an exhaust manifold. My Corvair's terrible though, probably worse than the Buick.

[flintbuick]

I have confirmed the float level by pulling the plug while its running and it wets the threads.

I am pretty confident i have the needle in right but its worth looking into.

According to pertronix tech department and their application guide that is the best coil for a 8 cylinder with points.

I have heard of the 3 way fuel filter. Isnt that a chrysler OEM filter?

I will throw in some marvel mystery.

Thanks everyone for the brain scratching.

[packick]

The way I discovered my needles were installed wrong was to unscrew the plugs while the engine was running (no seepage there), and then turn off the engine which resulted in fuel seepage coming out of the plug. Good luck.

[Marty Roth]

I've been using, and suggesting, the "3-way fuel filter" for more than 20 years with good results. Some of my cars had vapor lock, even before we had to deal with corn-gas, so I had the need. I also have used 10% - 20% diesel fuel, especially in high-altitude, high-heat, and trailer-towing situations with my old 1978 Suburban's 454ci big block. All of these things help, and even more when used in concert.

Good luck...

Marty