Hot engine starting issues

[Roy Ale]

My car with a 307 starts well when cold , but has always had issues restarting when the engine is hot , and now we are into above average summer temperatures . The car will restart but runs rough and takes a while for the engine to sort it self out . So cannot restart and just start driving , i have to wait until it sounds normal or it will stall , and i will be into another restart . To make sure the engine has less issues restarting i lift the hood when i get somewhere to let the heat out . and when i get home i lift the hood to let the heat out . So any ideas what i can do to have less hot restarting issues ? or no hot engine restart issues ?

Part of problem may be ethanol in the fuel , i see on internet ethanol boils at 180 F
have turned the air cleaner up side down , this has helped a bit , maybe it lets boiling fuel vapour out . have disconnected and plugged off vacume hose from carb to charcoal canister the other hose goes to fuel tank this i think may reduce sucking in fuel vapours from tank .
next thing would be replace carb gasket with something that reduces heat transfer to carb.
Carb is a Rochester QuadraJet with the Hot air tubes to choke

 

[Olds 307 and 403]

A thick gasket may help. Yes, it fits your Quadrajet as well.

https://quadrajetparts.com/carter-thermo-quad-insulating-base-gasket-thick-p-917.html

 

[Roy Ale]

Melville thanks thats a good tip .
was told the R. Q. has a small float bowl so fuel boils off faster than other carbs
I have the cast iron # 17 intake .
would the A4 aluminum intake help at all to reduce heat soak to carb ?
Does the # 17 intake have exhaust gas passages under carb to heat carb ? if the # 17 does , should i plug them off ?
Does the A4 have exhaust gas passages under carb ?
I think the exhaust gas passages under carb help the carb from icing up in winter time , but do they over heat carb in summer ?

 

[Olds 307 and 403]

You need the crossover for the hot air choke to work. You could use an A4 which should run slightly cooler and block the intake opening with a piece of flat plate stainless steel. This will require conversion to an electric choke coil. The proper way to block the crossover is remove the heads and valves. Then pour molten zinc or aluminum to fill the crossover ports. A lot of work, more than you probably want. The thin stainless plate should keep some heat out, along with the thicker gasket under the carb. Good luck.

 

[Roy Ale]

i have the hot air tube choke , it works fine , if i put in the thicker gasket .325 ( 8.255 mm ) and a stainless heat shield plate . The hot air tubes will not be long enough. So options are ? could i bend what i have to fit ? make new longer tubes for the hot air tube choke . Or change to an electric choke or a divorced choke or a manual cable choke . The manual choke sounds simple , no wires , no tubes ! is there an ideal best choke ?

 

[Olds 307 and 403]

The hot air choke needs flow from the crossover or it will stay on. Go electric, either splice from the distributor connector or the ignition terminal in the fuse box. A manual choke sucks in my opinion.

 

[Roy Ale]

So that i do not have to lift the hood every time i stop , i removed the big long rubber seal that fits on a metal edge at top of fire wall . The rubber seals off the engine bay from the cabin air intake when the hood is closed . When removed it sure lets the heat out. But when i turn on the vent fan or AC its not good , as car then has engine bay smell . This idea only works if i put windows down and do not turn AC or vent fan on . But might work if i could put a rubber seal only around the cabin air intake.

other ideas to let heat out with out lifting the hood , Oldsmobile hood vents or ram air dual hood scoops from the 442 . Any ideas about hood vents for a 4 door delta 88 ? or would hood vents look to out of place on a 4 door car ! may look OK if i put the Oldsmobile ralley rims on .
Q ? does anyone know if a Delta 88 could have been ordered from the car dealer with 442 hood scoops or hood vents or fender vents ?

 

[Roy Ale]

early spring i put in a new 180 thermostate . way before the hot weather and hot starting issue . some say they run a 160 F thermostate . not sure if lowering to 160 will help ? as would the engine coolant run at a temperature depending on size of the Rad , Fans , hood vents etc

 

[Olds 307 and 403]

It all depends on your cooling system. Another thing try is carefully hit the condenser and rad with a pressure washer.

 

[Roy Ale]

I did pressure wash the Rad and AC condenser .
may need to ad an electric fan and may need to increase rad size and install a temp gauge so i know what temp my engine is running at .

Q ? cool air intake and dual snorkel air intakes keep air cooler when engine is running but would it help at all after turning engine off ? maybe a little as carb was a bit cooler before engine was turned off .
Q ? when turning off a hot engine , how much more does the temp gauge rise up ? 15 deg F ?

 

[Olds 307 and 403]

Yeah, it can rise 20 degrees, according to my temperature gauge.

 

[Roy Ale]

Thats interesting another 20 deg F after engine stops .

To get more air flow and venting in the engine compartment , i removed the front fender inner wheel well rubber dust shields. i would think this should allow for more air movement . Q Are there any issues with removing these two rubber dust shields ? this car will now only see paved roads !

 

[Olds 307 and 403]

It might help.

 

[Roy Ale]

Took the rad cap off for a look see at cooling tubes , tubes look plugged up . Should have been first thing to check !
So next thing to reduce engine heat is rad. Rad shop says rad now is 2 core but is an up grade 2 core do to having AC . Rad shop can recore with 2 core upgrade or 3 core and use my end tanks . So Q ? recore and use my tanks or buy a rad ? after market options plastic end tanks or all aluminum rad . and how many core for a 307 ? can a rad be to big ?

 

[Olds 307 and 403]

If you recore, go to the 3 core. The single core aluminum plastic cool quite well.

 

[Roy Ale]

So did Rad recore end tanks would not fit a 3 core but would fit a 2 core with 3/4 inch tubes. should have had bigger end tanks on stand by. engine cools very well now .

i am interested in looking at all items that might create heat.

The EGR valve reduces combustion temperatures. Question ? does that also mean the EGR reduces over all engine temperature ?

I have a TH250 C , Melville informs me the C is converter lock up . Question ? on road trips with long steep hills , if the C does not lock up would this be another source of heat build up ?

 

[Olds 307 and 403]

It will create a bit more heat going down the highway. It effects rpm, 300 higher without lock up.