Carburetor Heat Spacer

diablopony · 03-02-2003, 08:33 PM

My car runs great until it gets hot, then it runs a bit rough at low RPMs. Could this be a fuel percolation problem? Also, any recommendations on heat spacers? What are the pros/cons of plastic, aluminum and wood?

Thanks for the help.

Rev · 03-02-2003, 09:07 PM

Personally, I've never seen the need for one. I do run an after market (Performer) Al. intake with some exhaust through the intake, but no "heat riser" valve that shunts more exhaust through under the carburetor when cold. The carb does have a vent that prevents pressurizing the float bowl. I'd bet it's something else causing the problem. Also, how hot do you mean? Shouldn't let it get over, say, 200 F, IMHO.

Rev

diablopony · 03-02-2003, 09:35 PM

Thank Rev,

It is not getting very hot. About 160 - 170, pretty much normal operating temp. Feels like a slight bog at low RPMs but goes away at about 2000 RPMs.

I'm running an Edelbrock Performer RPM intake with an Edelbrock 600 CFM carb. I have not changed the jets or metering rods yet. I'm wondering if the jets may be a bit small for this motor.

Rev · 03-02-2003, 09:57 PM

Probably just a little more shot in the accelerator pump might fix it. It's worth a shot (pun intended).

Rev

diablopony · 03-04-2003, 08:05 PM

I moved the accelerator pump up 1 notch and that helped. However, I think its running way lean from the look of the plugs. I think I'll go the next level up on jets and metering rods. I'll let you know how that goes.

Thanks for the help.

mustangII460 · 03-04-2003, 08:25 PM

Do you have a automactic?

Maybe you suffer from too low of vacum not drawing in enough fuel. A big cam will kill your vacum.

I recomend a larger spacer between your carb and intake, 1 1/2 or so. It will help out vacum. SO will a vacum canister. Especially if you have a auto drawing out most out of it.

Spray some WD around your inatake/carb/head areas to make sure you don't have a vacum leak anywhere.

All great ideas previously posted.

Good Luck.

03-02-2003, 08:33 PM	#1
diablopony Registered Member Join Date: Jan 2001 Location: Clayton, CA USA Posts: 116	Carburetor Heat Spacer My car runs great until it gets hot, then it runs a bit rough at low RPMs. Could this be a fuel percolation problem? Also, any recommendations on heat spacers? What are the pros/cons of plastic, aluminum and wood? Thanks for the help. __________________ '68 convert, 5.0 GT-40 Crate motor, C-4, Tri-Y headers, 3.25 rear gears

03-02-2003, 09:07 PM	#2
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	No need Personally, I've never seen the need for one. I do run an after market (Performer) Al. intake with some exhaust through the intake, but no "heat riser" valve that shunts more exhaust through under the carburetor when cold. The carb does have a vent that prevents pressurizing the float bowl. I'd bet it's something else causing the problem. Also, how hot do you mean? Shouldn't let it get over, say, 200 F, IMHO. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

03-02-2003, 09:35 PM	#3
diablopony Registered Member Join Date: Jan 2001 Location: Clayton, CA USA Posts: 116	Thank Rev, It is not getting very hot. About 160 - 170, pretty much normal operating temp. Feels like a slight bog at low RPMs but goes away at about 2000 RPMs. I'm running an Edelbrock Performer RPM intake with an Edelbrock 600 CFM carb. I have not changed the jets or metering rods yet. I'm wondering if the jets may be a bit small for this motor. __________________ '68 convert, 5.0 GT-40 Crate motor, C-4, Tri-Y headers, 3.25 rear gears

03-02-2003, 09:57 PM	#4
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Accelerator pump? Probably just a little more shot in the accelerator pump might fix it. It's worth a shot (pun intended). Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

03-04-2003, 08:05 PM	#5
diablopony Registered Member Join Date: Jan 2001 Location: Clayton, CA USA Posts: 116	I moved the accelerator pump up 1 notch and that helped. However, I think its running way lean from the look of the plugs. I think I'll go the next level up on jets and metering rods. I'll let you know how that goes. Thanks for the help. __________________ '68 convert, 5.0 GT-40 Crate motor, C-4, Tri-Y headers, 3.25 rear gears

03-04-2003, 08:25 PM	#6
mustangII460 Factoy Five Roadster Join Date: May 2000 Location: Sevier Co,Tennessee Posts: 1,681	Do you have a automactic? Maybe you suffer from too low of vacum not drawing in enough fuel. A big cam will kill your vacum. I recomend a larger spacer between your carb and intake, 1 1/2 or so. It will help out vacum. SO will a vacum canister. Especially if you have a auto drawing out most out of it. Spray some WD around your inatake/carb/head areas to make sure you don't have a vacum leak anywhere. All great ideas previously posted. Good Luck. __________________ Frank

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