Underhood heat and throttle response

[yellow wagon]

Playing around with the 409 and attempting to solve something. My engine when cold is super snappy, runs great. When it heats up say after a 40min drive, it doesn't rev cleanly. Power otherwise is good. Drivability is good. Starts well hot etc.

I suspect it could be a number of things going on: hot underhood, fuel getting hot, coil could be getting too hot, msd box could be getting too hot etc. I drive the snot out of this car so anything is possible.

Is it asking too much to be able to rev it up a little to lay some rubber once it's hot? Mind you I have the stock hood and I'm sure driving around on a hot day is turning the underhood area into Hades.

I do have a suspicion that perhaps the air filter is causing some issues. But that's just a hunch really. Like maybe not enough cfm causing some airflow issues or trapping gas fumes or something. I could do a test and drive it around without the air cleaner and see how it likes that for a test?

What have you guys encountered or have any tips for things to try? The car runs great overall, pulls like a freight train otherwise etc so not worth changing a ton of stuff. But just wondering if I get keep that snappy throttle response cold and hot. Thanks guys for your tips!

 

[Don Jacks]

Try running w/o the air filter and see if that helps any.I really suspect underhood heat is your major culprit though.

 

[1961BelAir427]

A cowl induction or other scooped hood would help a lot with getting hot air from under the hood.....and a cool can would help too. I don't think I would do either one to your car though.

How about: Insulating the fuel lines. Ceramic coated and/or wrapped headers. A flat aluminum tray sandwiched between the carbs and intake.

 

[1961BelAir427]

How about spacing up your stock hood at the hinges a couple inches? That is something easily undone, won't hurt anything, and will let out a lot of heat. Used to be pretty common I think.

 

[yellow wagon]

I have the section of fuel line insulated that snakes past the headers on the passenger side. 1/2" phenolic spacers under the carbs and the headers are high temp powder coated black. Car runs 170-175 all day long. The exhaust dumps in front of the rear axle so perhaps they are heating the tank?

 

[yellow wagon]

I changed the title too so in the future people can find this easier if they have similar problems

 

[Jim Sullivan]

What type of air cleaner are you running Jason?
Would an open element air cleaner pull more hot air from the engine than a dual snorkel?
Or is under hood air the same temperature where ever it pulls it from?
I wonder this as I just started running a more open air cleaner (picture in my avatar) without snorkels. Haven't got enough driving in to tell if there is a difference.

 

[DonSSDD]

Remove your hood and see if anything changes? That would tell you if it is under hood heat? You could install a set of Hella H4's in your high low beams and remove the 2 high beams, replace with a cold air intake (and look cool), if the hood thing makes a difference.

Before you remove your hood, drill a small hole (small enough to be invisible) through yours hinges and the lower hood skin, to use as an alignment hole when reinstalling the hood. Lines it up perfectly and easily.

Don

 

[yellow wagon]

High beam delete lol!

 

[DonSSDD]

High beam delete lol!

That didn't take long, how long to get the hood off?

Don

 

[yellow wagon]

Haha deleted the high beams last year

 

[63 dream'n]

I like the tip on running with raised hood on hinges like Bob Walkers 63 loving chevrolet.Although I don't know what promotes cooling,removing hood or causing air to flow through(is that really taking place) sounds like a little trial and error.do you have one of those aim and point heat sensors????

 

[63 dream'n]

I also had a fella with a beautiful 60 Biscayne tell me a lower valance made a world of difference in his underhood temps.I believe he told me he pulled one from a 2000 Buick,said it was an easy install.

 

[MRHP]

Cowl ducted air cleaner. That made all the difference in my car when hot. I know exactly what you mean when hot. My car used to do that to a tee. Not no more.And it looks good too.

 

[yellow wagon]

Know anyone that can make one of those cowl ducted air cleaners?

 

[Phil Reed]

UsTE="yellow wagon, post: 282668, member: 1711"]Know anyone that can make one of those cowl ducted air cleaners?[/QUOTE]
offer to buy Brian's!!!!

 

[409newby]

If you run Ethanol fuel try with Non and see what happens, my car changes with corn juice

 

[MRHP]

Hell, you can make one in a couple hours, and some old pots and pans!

 

[oldskydog]

Happy when cold usually means rich. Can't get too much fuel when cold.

 

[1961BelAir427]

I saved the part number for those headlight screen covers from a post of Models' on here. Trans Dapt part #9128. They seem to be discontinued now. Spectre has some, but I don't think they are quite the same.