Help- MY 54 235 engine runs good at low speed in town,but on the parkway at 50 -55 mph it starts to sputter and back fire after about 30 minutes, and if it stalls when I stop it will not turn over( i think the turn over part is seperate from the running) The engine temp is steady at 180,the points,rotor,and condenser and cap are only used about 3000 mile and look good,as are the plugs. thanks Jim

You may be running the battery down and your generator may not be chargeing enough to keep the car running. Of course you could have several problems,
1) generator not charging (sputtering backfireing won't turn over)
2) poor battery cables and/or terminals (won't turn over) if a 6 volot system you need heavy duty cables 00 gauge)
3) possible starter dragging or a bad solinoid(won't turn over)
4) Fuel line or carb stopped up, fuel starvation (sputtering backfireing)

I think 180* is not too hot. Are you loseing coolant?
One question... how do you really know the coil, points and condenser, cap and rotor are good? You can't tell by looks.

I wwould try another condenser, then possible coil...or loose connection??Point setting too close?

I had replaced the Battery and all cables, the generator is charging ok The car alway's starts 1st time when cold, this engine is in my 41 so there is no solinoid I never loose coolent, nor burn oil.The rotor cap & points are clean no pitting or burn marks,I checked all connections all are tight. I picked up a coil and wire's today I'll try them this week and check the carb, could it be vapor lock? I just can't figure out why only on long runs at 50 to 55 mph. Thanks Jim

The first thing that I would replace is the condenser....even though your present one is almost new..Some of todays replacement condensers are not woth a nickel.

Sounds like a lean out condition so I would check for vacum leaks, then back to the carb and check the float setting, fuel pump capacity, and finally recheck ignition timing is the mechanical advance working correctly, a drop of oil in the very top of the distributor shaft (small cotton like ball of material there) is what lubes the interior workins such as weights and springs. A new condensor would be worth the time.

i REPLACED THE COIL AND SPARK PLUG WIRES, TODAY i WILL REPACE THE CONDENSER, AND WORK ON CARB VACUME, ETC. I WILL LET YA KNOW AFTER I GET A CHANCE TO RUN DOWN TH PARKWAY. jim

i would be working on the turn over part before the run part . if it wont turn over you will not get it to run .with out knowing the history of the engine and starting system meaning are the batt. cables the right size the starter checked , has the internal parts of the engine been changed ? i have seen engines that have been overhauled and the pistons not fited correct would start cold and not warmed up if it is a piston problem it could be piston design

Exhaust manifold heat riser valve stuck open (cold setting). Works great when cold but will raise hell when hot.

The engine has never been apart,the new battery cables are 00 size, and with fenton headers dual exhaust there is no manafold heat riser, I don't have gap size for the points, they check out at .018 and timing setting ????. Can't find a shop in the area yet that knows. Thanks Jim

"A LEAN MIXTURE IS A HOT MIXTURE" do you think there is some crud in the tank cloging things up causing the engine to run lean and stall, allowing it to restart after it settles? I would look at the filter. I am thinking fuel all the way! I had a similar problem with an 78 AMC Jeep Wagoneer that I was restoring years ago
John

Try this site for timing and other important information. If you do not have a manual I would suggest a 25.00 investment as the computer stuff is usually not available on the road on a sunday afternoon.
http://chevy.tocmp.com/

The timing being "off" or the cooling system restricted should not cause the engine to stall...but will lead to other problems.
If its running at 180 it probably has a 180 thermostat.Set the timing so the pointer in the opening in the bell housing lines up with the steel ball on the fly wheel...with engine at slow idle speed,timing light hook to #1 plug wire.
The engine should be checked for fuel in carburetor or ignition spark when it stalls.Its loosing one or the other and the test is so simple.
Try a new condenser yet?????

Does the carb have an automatic choke (Rochester 2GC/4GC)? Your motor may just be choking itself to death, especially since it runs great when cold. Not necessarily flooding, just not getting any air when it needs it. With aftermarket headers and no heat riser your choke will stay closed if there's no increase in temp to expand the bimetal spring in the choke mechanism.

If heat riser was removed, reinstall or replace it (a couple feet of clean new metal fuel line of the right diameter with the lower end sealed off will probably work) and secure a few inches at the lower end of the tube that would have gone into the exhaust manifold to the outside of the exhaust header with a few wraps of wire or a metal band clamp. Sealing the end of the tube keeps dirty exhaust gases from entering the carburetor. It doesn't need to move air into the choke mechanism, it just needs to conduct heat.

A repair kit may be available with a special hose clamp that opens to clamp around the header pipe. A regular hose clamp won't open this way. Securing it first with a piece of wire will tell you if this will fix the problem. You can make it look pretty when you're done.

And of course, my standard disclaimer - my main area of technical expertise is not automotive. This free advice and five bucks may get you no more than a nice cup of joe at the place on the corner with the green sign.

And please don't hesitate to correct me on my nomenclature if I'm incorrectly presuming the heat riser to be that tube that runs from the exhaust manifold to the choke mechanism. I've always just referred to it as "that tube that runs from the exhaust manifold to the choke mechanism".

Wouldn't be the first time I was corrected either. The most recent in this forum was in regard to a banking matter.

I still hasve the manual choke ( this engine is in a 1941 chevy coupe ) Carter carb, oil bath cleaner, in case i didn't mention there is and electric fuel pump as a back up, I used it after 4 and 1/2 months in th winter tent, starts 1st try ever year. thanks Jim

So has replacing the condenser corrected the problem? Since it was suggested early on and its a cheap part, it's worth a try.

Also, does your electric fuel pump turn off after the vehicle is started, allowing the mechanical pump to provide the fuel? You could be getting an uneven pressure condition if you have two pumps working in unison cascading into one another.

PK- The heat riser on you 1958 is placed between the right exhaust manifold and exhaust pipe.(single or dual)...It looks like a spacer about 1 1/2" thick and has a weight (that should turn about 1/4 turn) attached ...weight is square.The heat riser forces exhaust thru the left cyl. head,thru the intake manifols under carb.,thru the right head and into the right manifold when cold.There is a thermostatic spring on the heat riser to determine temperature.This warms the base of the carb. when cold.Often the passage thru the intake manifold becomes plugged with carbon or the passage under the carb gets plugged.The exhaust contacts the iron base of the carb directly.This has nothing to do with the choke.The tube brings up hot air for the choke passes thru the center of the right exhaust manifold.The hot exhaust heats the air in the tube and a slight vacuum brings the heat up to the choke thermo. spring.The tube goes completely thru the exhaust man. ,the upper tube that you see slides into it.The manifold tube often rusts away allowing exhaust and water to be drawn into the automatic choke - causing it ti be inoperative.
If you don't see the heat riser some one may have removed it at one time.

Thanks Gene, that makes some sense, though I'll have to have a closer look when I get the engine back. I'm mixing the heat riser in my mind with the automatic choke, which is similar in operation but actually a separate system. My brief experience was mostly working on the carb itself and it's direct connections to the engine.

I had read that the tube in the manifold is sealed, and that they can foul up the works if they start blowing exhaust gases into the choke mechanism. 1439's setup with headers and manual choke is completely different though, and sounds like factory installations and accessories are long gone, being a '54 motor in a '41 coupe.

Come to think of it though, I have seen some of the effects of this heat riser of which you speak. I had some light pitting on the intake manifold around the heat riser holes under the carburetor gasket. I'll bet that was the result of the wrong gasket from the rebuild kit being used at some point in the past 40 years on a previous installation.

There were a couple of gaskets in the kit I used this spring that were the same shape, but one didn't have the holes to pass air through the base of the carb from the intake manifold. I don't know that I ever had the resultant problem from that, it may have been long ago, but I did see the marks it left. It was definitely holding back some warm moist air.

I hope the final fix, on the sputtering 54, I found the float stuck not letting in fuel, and the pump is week, I had the carb cleaned and reset, changed the filter in bowl and one under car in fuel line, I ordered pump, I will still have start problem after I run for awhile its probably the starter bushing expanding from heat.
I"ll try a heat wrap first.
Thanks for help Jim my 41