2005 Other Chevrolet Models Vapor lock- street rod

JACKFED

MEMBER
2005 CHEVROLET
V8
2WD
AUTOMATIC
180 MILES

I have a 1940 ford deluxe with a chevy crate 502 engine with a holley carb model 4150, 850 cfm. When my engine temp gauge reads 195-200 (which is where these motors want to run) it will tend to stall. I've installed a 1" phenolic heat spacer and a heat shield under the carb, re-routed the fuel line away from the block and have installed a heat shield sleave for the fuel line (from chassis to the carb) yet the problem persists. I've seen fuel coolers which look like mini trans coolers but I'm not sure that will slove the problem. I want to avoid converting to a fuel injection system due to the cost but if I have to I will. What do you think?

7 Replies

RACEFAN966

MECHANIC
5,029 POSTS

Ok I need more info before I can try to help. What ignition system do you have, meaning what distributor is it points or electronic and what type of electronic? As for vapor lock I don't think so this is not as common as people think. In order to vapor lock the fuel must get hot enough to boil before the fuel pump. So if you feel that is the problem then you must look at that side of the fuel line. Also what type of fuel pump are you running? Where is that pump mounted? I have put a 502 ++ in a 67 firebird and had no problems. Get back to me with the needed answers and we will see what we can figure out.

SPONSORED LINKS

Was this

answer

helpful?

Yes

Thursday, March 18th, 2010 AT 9:44 AM

JACKFED

MEMBER
4 POSTS

Thanks for your reply, the ignition system is HEI (gm part number 9344086), the gas tank is after market stainless steel 15 gal cap with an electric fule pump located outside the tank between the tank and the rear axle. The fuel line runs down the passenger side chassis and looks to be clear from any heat source. So the fuel line runs: tank, elec pump then all the way to the carb. Hope that answers your question. Thanks, Jack

Was this

answer

helpful?

Yes

Friday, March 19th, 2010 AT 8:53 AM

RACEFAN966

MECHANIC
5,029 POSTS

Ok who's tank and pump? Is there a return line? Do you know if the tank has a pressure cap or vented cap?

Was this

answer

helpful?

Yes

Friday, March 19th, 2010 AT 9:53 AM

JACKFED

MEMBER
4 POSTS

See pic of tank, fuel pump & fuel filter & vent line. The fuel pump is a carter p/n 152-875, there are no markings that I can see on the fuel tank, the gas cap is a "vintique" with the ford V8 emblem on it and I don't know if it's vented or not (sorry) but you have to push down to get it on and locked in place. The tank vent line (in the back ground of the pic) comes out of the top of the tank using hose and is draped over the chassis and just hangs there after the shock absorber towards the front of the car and is not connected to anything ie: it's vented into the air.

Sorry I've tried three times to upload the pic but it won't take, do you have another e-mail address I can send it to?

Was this

answer

helpful?

Yes

Saturday, March 20th, 2010 AT 9:18 AM

RACEFAN966

MECHANIC
5,029 POSTS

So when it dies have you loosened the gas cap to see if it has pressure or vacuum? If there is a vacuum then you will need to find a vented gas cap for it. Let me know what you find.