Ethanol free gas

[Davea Lux]

Another option we used on some of the hot rod engines was to block off the heat passage under the carb. I believe Edelbrock used to make a specialty gasket for this purpose. I was not real fond of this as it necessitates converting to a manual choke, but it was an option if one was running an 800 or 850cfm Holley carb as many of those performance oriented carbs already had the manual choke. Also required that the heat riser be propped open if stock manifolds were in use. As mentioned above, having everything in good working order is the best starting point.

Dave

 

[Turboomni]

Thanks for all of your input. I have an Edelbrock carb. I have a rebuilt points distributor and new points, condenser and ballast resistor and working vacuum advance that holds vacuum. Also new plugs and wires ,rotor and cap plus a 3/8th inch carb isolator. Vacuum is 20 at idle. Gasoline is ethanol free unleaded 91 octane. Engine is a 440 low compression engine, nothing special.
The Edelbrock carb with no vents problem intrigues me though.

 

[commando1]

FWIW, I'm in Florida with an Edelbrock on my '76 440 and I don't have a hot-start problem.
Your mileage may vary...

 

[saforwardlook]

FWIW, I'm in Florida with an Edelbrock on my '76 440 and I don't have a hot-start problem.
Your mileage may vary...

You must drive it like an old man..................................

 

[1978 NYB]

You must drive it like an old man..................................

With a hat!

 

[commando1]

Drove it a full six miles last week...

 

[CBODY67]

In the middle 1980s (or thereabouts), some Chrysler air cleaners had a second trap door in the snorkel. It was not hooked to the pre-heat pipe, but in the regular snorkel. When the engine stopped, it closed and kept all carb-related vapors in the air cleaner and carbon canister, rather than being dispersed into the atmosphere. During this same general time, GM had some air cleaners with a carbon screen inside of the filter element, made into the base of the air cleaner body. Hooked to the carbon canister, too. Obviously, there was a reason for them to be there or they wouldn't have spent the time and development money to put them there.

If the heat crossover passage is the culprit, it would be easy enough to block it with some steel shim material in warmer climates. Or remove the fiberglass "insulator" from the valley pan for additional heat dissipation/air circulation under the intake manifold?

When I was trying to "chase" this issue on our then-recently-new '66 Newport 383 2bbl, I looked at all of the "textbook" areas. The heat riser was usually stuck in the 1/2 open position (getting that fixed made little difference). Using 1/3 throttle gave less crank time, but I didn't like that initial fast engine speed or that it put more gas into the manifold with the related accel pump shot. End result, nothing really helped.

Some OEM Holley 4160s had "hot idle compensators". I put one of those on my '67 Newport and that didn't significantly help either, compared to the original AFB or 9801 TQuad (with matching Edelbrock Torker intake).

In short, no way I've found to make a carbureted motor start as quickly or easily as a modern FI motor. You can do what you can to ensure they do start quickly, perfecting the starting technique which works best for your car, and making sure the charging system if working well too. The factory owner's manual recommends 1/3 throttle for starting, hot or cold, so that might be a place to start. That "just touch the key" start was always elusive, for one reason or another, although "quicker" was more approachable.

I'm wondering if it might have more to do with an engine's "rod-to-stroke length ratio", as many engines that seem to "start easy" have lower rod ratios than B/RB Chrysler V-8s? The lower the rod ratio, the stronger the "yank" on the mixture column in the intake ports. Or perhaps a carb with internal fuel circuits that make the fuel easier to get from the float bowl to the venturi? Or combinations thereof? Maybe not a fuel percolation issue per se, but fuel evaporating out of the fuel circuits themselves and the extended crank time has to recharge them? As most of the "classic" causes have been addressed, typically, there might be something else other than decreased underhood temps?

CBODY67

 

[commando1]

People are simply spoiled by FI and have either no idea or no memory that carburetored vehicles dont instaneously start.
They all started perfectly when they were new.
Just fix it and enough with the voodoo, tiger piss and bandaids already.

 

[saylor]

 

[Turboomni]

In short, no way I've found to make a carbureted motor start as quickly or easily as a modern FI motor. You can do what you can to ensure they do start quickly, perfecting the starting technique which works best for your car, and making sure the charging system if working well too. The factory owner's manual recommends 1/3 throttle for starting, hot or cold, so that might be a place to start.[/QUOTE

May I ask if "Back in the day" with good old leaded gas was this a problem then?? I do not remember any problems as this with my 72 Fury 360 or my Chevelle or 68 and 69 Olds Cutlass. But this was way back when.
My Omni has a primitive batch fired injection but it has no problems starting when hot. If driving around and I stop on a rather cool day in the Fury I smell nothing. On a hot day sometimes I smell gas vapor as if the carb is a kettle on a stove boiling.

 

[Turboomni]

May I ask if "Back in the day" with good old leaded gas was this a problem then?? I do not remember any problems as this with my 72 Fury 360 or my Chevelle or 68 and 69 Olds Cutlass. But this was way back though.
My Omni has a primitive batch fired injection but it has no problems starting when hot. If driving around and I stop on a rather cool day in the Fury I smell nothing. On a hot day sometimes I smell gas vapor as if the carb is a kettle on a stove boiling. I am rather pissed the ethanol free gas din't do as much as I had hoped. I also hear it is more a problem with big blocks or is that not true?

 

[CBODY67]

The 360, being a LA motor, did not have the same issues as the B/RB motors usually did. The LA motors had the reputation of "running cool" compared to the B/RB motors, back then. On my '80 Newport, I had to make sure the pcv hose (runs behind the carb to the pcv valve) didn't sag as it would collect grunge and eventually clog the line, resulting in a flaky idle.

Those earlier (mid-late '60s) 318 B-body cars (which the local dealer sold to many older ladies) would also clog the heat riser passage in the intake manifold. Have to remove the manifold and clean it out. That lack of crossover heat meant the choke would not heat up enough to fully open, even on a warm engine. No issues with New Yorkers, though.

The '72 Fury, as our '72 Newport, should have a carbon canister to collect gas vapors from the float bowl. '71s had a different system.

What we started to see in the middle 1980s was "hot fuel handling" issues. Not fuel percolation per se, but more like vapor lock symptoms. On the Rochester QJet, the original float bowl is small anyway, then populate it with a "bowl stuffer" and a baffle for the incoming fuel and the total volume decreases a bunch. The factory TSBs recommended doing some things to get the fuel lines away from heat-producing areas (exhaust manifolds, engine brackets, etc.) but usually didn't help. When I happened to see a Camaro IROC, I realized that all of the a/c lines and other vacuum lines were all running side to side in front of the carb. Very little cooling air could even reach the carb.

By this time, too, the OEMs knew that FI was coming in a year or so, so rather than any real "fixes", more Band-Aids than anything else.

When our '66 Newport was still a "used car", it had an extended crank time issue in the middle of the summer. Not "extended" enough to run the battery down, but enough to notice. NO strong smell of gasoline under the hood, either. And we were running Gulf No-Nox gasoline (as that's what it liked). When the weather cooled, no issues. That was with the original Stromberg WWC-3 2bbl. When I upgraded to the Holley 2210 OEM carb, seems like it started a little quicker, but by then, I'd learned to better modulate the throttle setting and things tended to work nicer. One of those things that I just got used to and didn't "key" on it any more. One of the little Chrysler quirks that tend to be "part of the breed" (a VERY NICE breed, that is!). By the time the Holley arrived, I had the car tuned as good as it could be. Spark plugs filed and gapped just so, magnetic suppression plug wires, the carb adjusted just so, although I let the dealer do the points. So it stared quicker than many usually did, so less issues with hot restart in the summer.

CBODY67