Car lags on hot days

[Bri guy]

Today is around the 90s and clear skies and a baking sun. Noticed the car will stumble while idle or reverse. Would die if I didn't use 2 feet for these situations. Cruising in motion seems fine until i put the pedal down then it hesitates before kicking down. Car temp was around 220. On a day with 80s or less, the car temp is around 180 to 200F. What does this "stumble on hot days" mean? I need a better fan or radiator? Or is the gas getting to hot in the carb? Or I need a bigger mechanical fuel pump or Carb to make sure I'm getting all the gas I need?

 

[83StreetMachine]

Probably vapor lock. The fuel.is getting so hot in the engine compartment or in the carb that it's boiling.

Do you have a carb spacer?

 

[olds307 and 403]

You may need both a bigger rad and a larger fan. Is the hot temps at idle, then probably the fan. You want a 2 core rad with 1" or larger tubes. The stock 5 blade 307 clutch fan isn't large enough. Foxtrot on here used the GM 4 blade solid fan and spacer and dropped a noticeable amount. Either that or get a 7 blade clutch fan and make sure you have a shroud. Good dual electric fans that draw 40+ amps on startup also work, I have the Dodge Stratus fans on my 88 Cutlass.

 

[Bri guy]

Probably vapor lock. The fuel.is getting so hot in the engine compartment or in the carb that it's boiling.

Do you have a carb spacer?

No carb spacer....engine is a built 403. Carb is a 600 edelbrock..

 

[Bri guy]

You may need both a bigger rad and a larger fan. Is the hot temps at idle, then probably the fan. You want a 2 core rad with 1" or larger tubes. The stock 5 blade 307 clutch fan isn't large enough. Foxtrot on here used the GM 4 blade solid fan and spacer and dropped a noticeable amount. Either that or get a 7 blade clutch fan and make sure you have a shroud. Good dual electric fans that draw 40+ amps on startup also work, I have the Dodge Stratus fans on my 88 Cutlass.

Ya, on days like this (90s) it goes to 220 when idling and acts like it wants to die.

 

[Bri guy]

Allstar Performance ALL30101 Allstar Performance 4-Blade Steel Fans | Summit Racing

Free Shipping - Allstar Performance 4-Blade Steel Fans with qualifying orders of $99. Shop Fans, Mechanical at Summit Racing.

www.summitracing.com

Would this one work? Motor is 403 from a 76 delta 88 or regency.

 

[olds307 and 403]

Allstar Performance ALL30101 Allstar Performance 4-Blade Steel Fans | Summit Racing

Free Shipping - Allstar Performance 4-Blade Steel Fans with qualifying orders of $99. Shop Fans, Mechanical at Summit Racing.

www.summitracing.com

Would this one work? Motor is 403 from a 76 delta 88 or regency.

That looks the same as the one on my 70S, it moves a lot of air.

 

[Bri guy]

Here's the current fan. Measured 17inches. Plus has 2 broken blades....shouldve replaced that when I first bought the car. Think I will order the fan and hope it fits

 

[Bri guy]

That was easy to pull off. Noe just have to wait for the new one

 

[83StreetMachine]

I'm glad you got rid of the flex fan. They are garbage and as that one shows they break apart and send shrapnel everywhere.

A good stock clutch fan would work great or go electric. NO MORE FLEX FANS!!!

You need a fan shroud as well.

Put a carb spacer under that Edelbrock. Preferably wood but phenolic will work as well.