hard to start when hot! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

powerdriver 1958 · 08-07-2009, 05:17 PM

Two of my trucks would vapor lock after header installs.One big block 76 and the truck I use for muding.The fuel line runs inside the right frame rail just Inches from the headers.I moved the fuel line to the outside of the frame.

68 TT · 08-08-2009, 10:01 AM

Chances are the headers are hotter than they should be because the engine is running lean.

If you haven't tuned the carb for the headers and intake swap so you have the proper air / fuel ratio then you will have higher than normal exhaust gas temperatures which will make the headers hotter than they should be.

This is causing the extra hot headers to heat soak the starter and heat up the air in the engine compartment more than it should. You may have a combination of a hot starter and a vapor lock issue because of it.

Get an air / fuel meter and jet the carburetor to match your combination before you go changing any parts.

jchav62 · 08-12-2009, 02:23 PM

Quote:

Originally Posted by powerdriver 1958

Two of my trucks would vapor lock after header installs.One big block 76 and the truck I use for muding.The fuel line runs inside the right frame rail just Inches from the headers.I moved the fuel line to the outside of the frame.

That's a great idea! Never thought of that.

Hey Volker! Have you tried anything? Still having issues?

08-07-2009, 05:17 PM	#1
powerdriver 1958 Kid's Mechanic Join Date: Nov 2006 Location: Kansas City Posts: 8,241	Re: hard to start when hot! Two of my trucks would vapor lock after header installs.One big block 76 and the truck I use for muding.The fuel line runs inside the right frame rail just Inches from the headers.I moved the fuel line to the outside of the frame.

08-08-2009, 10:01 AM	#2
68 TT Still plays with trucks Join Date: Jul 2009 Location: Spokane, WA Posts: 3,570	Re: hard to start when hot! Chances are the headers are hotter than they should be because the engine is running lean. If you haven't tuned the carb for the headers and intake swap so you have the proper air / fuel ratio then you will have higher than normal exhaust gas temperatures which will make the headers hotter than they should be. This is causing the extra hot headers to heat soak the starter and heat up the air in the engine compartment more than it should. You may have a combination of a hot starter and a vapor lock issue because of it. Get an air / fuel meter and jet the carburetor to match your combination before you go changing any parts.



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