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By Dobie Gillis - 12 Years Ago
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As the weather warmed up I began having vapor lock issues with the 292 which are getting progressively worse. It's to the point now that I can't drive farther than about 12 or 15 miles before it starts acting up and finally stalls. I have a 500 cfm Edelbrock carb that is practically new and is properly set up, new fuel pump and fuel filter. I suspect the exhaust passage in the intake is causing the gas to boil out of the float chamber. I have a 1" phenolic spacer coming, but I was wondering if it would be advantageous to block off the exhaust passage in the intake? Seems like eliminating the source of the heat would be the best option. Can I just loosen the manifold enough to slip a couple of pieces of thin stainless shim stock in between the heads and the manifold? If so, do they go between the manifold and gasket or between the heads and the gasket?
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By Talkwrench - 12 Years Ago
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Just maybe.. is you gas cap vented?
I think you would have a hard time just trying to lift the manifold to slip something in, you'll probably damage the gaskets anyway.
Its sounds like your carb is new but I think you have to take the top off and double check the float level.
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By paul2748 - 12 Years Ago
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Next time this happens, take the gas cap off. if you get a WOOOOSH) the vent in the cap is not working. Drill a 1/16 hole in the cap. This may be your trouble.
I agree with the prior response re the intake gasket - remove the intake and fix it properly.
Also check the heat riser valve on the right side header pipe. Make sure it is operating properly. If you aren't in a very cold temp region or do not use the car during the winter, replace the valve with spacer that is readily available from the parts suppliers.
I assume you have already checked this, but make sure all the fuel line is not too close to any heat source. There are covering available although they are not very pretty.
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By Dobie Gillis - 12 Years Ago
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Talkwrench (9/12/2013)
Just maybe.. is you gas cap vented?
I think you would have a hard time just trying to lift the manifold to slip something in, you'll probably damage the gaskets anyway.
Its sounds like your carb is new but I think you have to take the top off and double check the float level.
The gas tank itself is vented with a tube that vents to atmosphere at the filler neck. I blew compressed air through it the other day and it was clear. The gas cap is not vented that I can see, but it is a slightly loose fit on the filler.
I checked the float level before I installed the carb and it was OK.
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By Dobie Gillis - 12 Years Ago
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paul2748 (9/12/2013)
Next time this happens, take the gas cap off. if you get a WOOOOSH) the vent in the cap is not working. Drill a 1/16 hole in the cap. This may be your trouble.
I agree with the prior response re the intake gasket - remove the intake and fix it properly.
Also check the heat riser valve on the right side header pipe. Make sure it is operating properly. If you aren't in a very cold temp region or do not use the car during the winter, replace the valve with spacer that is readily available from the parts suppliers.
I assume you have already checked this, but make sure all the fuel line is not too close to any heat source. There are covering available although they are not very pretty.
The heat riser valve isn't there anymore and the hole is plugged with a bolt; it was that way when I got the car. Could that be the culprit?
None of the fuel lines are close to anything hot.
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By PF Arcand - 12 Years Ago
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If your tank vent is clear (?) a vented gas cap isn't needed. How hot is the weather when this happens? Have you checked to see if debris has gotten to the filter ? Maybe your tank is really dirty?. Try cranking the engine (carefully! with an extingisher on hand) with the fuel line pumping into a container to ensure a normal fuel supply. If all is normal there, maybe it's an electrical problem, like a bad condensor?
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By Ted - 12 Years Ago
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Two things come to mind. The first being an air leak on the suction side of the pump. That leak could go all the way back to the internal line in the fuel tank as my ’55 Customline had a crack in the line on the inside of the tank where it attached to the fitting for the outside line connection. My ’54 Victoria had a crack at the flared line that connected to the flex line going to the fuel pump. Both of these took awhile in which to diagnose. The crack in the line within the tank showed up more predominantly when the tank was low while the crack in the line on the ’54 Vicky would just show up randomly. It took another fuel tank to fix the problem with the '55 Customline. . The other item is simply low fuel pressure. This check can be performed with a pressure gauge. As Paul also brings up, a volume check where the pressure line is simply diverted to a container while the engine is running would also be recommended.
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By Dobie Gillis - 12 Years Ago
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PF Arcand (9/13/2013)
If your tank vent is clear (?) a vented gas cap isn't needed. How hot is the weather when this happens? Have you checked to see if debris has gotten to the filter ? Maybe your tank is really dirty?. Try cranking the engine (carefully! with an extingisher on hand) with the fuel line pumping into a container to ensure a normal fuel supply. If all is normal there, maybe it's an electrical problem, like a bad condensor?
Ambient temperatures in the 90s. Replaced both fuel filters soon after the incidents began, tank is lined. I am going to drain it and have a look inside with an inspection camera this weekend, but I'm not expecting to find anything. Ignition is Pertronics II, no condenser.
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By Dobie Gillis - 12 Years Ago
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Ted (9/13/2013)
Two things come to mind. The first being an air leak on the suction side of the pump. That leak could go all the way back to the internal line in the fuel tank as my ’55 Customline had a crack in the line on the inside of the tank where it attached to the fitting for the outside line connection. My ’54Victoria had a crack at the flared line that connected to the flex line going to the fuel pump. Both of these took awhile in which to diagnose. The crack in the line within the tank showed up more predominantly when the tank was low while the crack in the line on the ’54 Vicky would just show up randomly.
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The other item is simply low fuel pressure. This check can be performed with a pressure gauge. As Paul also brings up, a volume check where the pressure line is simply diverted to a container while the engine is running would also be recommended.
I'm going to replace every bit of rubber hose, carb to tank this w/e to eliminate those as possible culprits. The fuel pump is a new (reman) from Cardone; I put it on after the problem cropped up. The car runs fine until it warms up, then falls flat on its face. If I let it cool long enough it will run fine again until it warms up. I'm still leaning toward vapor lock...
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By DryLakesRacer - 12 Years Ago
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When I bought my car everything on the engine was new and had new paint. The paint soon blistered on the exhaust crossover under the carb. The first thing I did was wire open the exhaust heat riser and that helped a bunch. The gasoline was boiling in the carb. (Carter WCFB) yours is already done.
Next I added a 1/4" phenolic spacer and the problem dissappeared. (I checked the fuel flow by pumping it in a can all was good). I added a glass bowl filter in the fuel line and placed it about where the 57 bird is done above the intake at the #1 cylinder which is in the air path of the fan. I also used steel tubing to the filter and from the filter to the carb. Bought a flare tool and multisize bender from Harbor Freight; great for the garage guy.
Engine temp runs right at 170 at the thermostat housing. I have a lazer temp gun (Harbor Freight too) to read stuff at times on the intake, exhaust, and other places. The fuel line does read higher than I like sometimes in the 140 range as it passes over the exhaust crossover area. Going to put in the restricted intake gaskets soon.
The last thing I'll point out is the gasoline we have today is liquid junk. You may want to put in an additive with every tank. I use Sta-Bils product for help negating the ethanol..............Good Luck
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By Dobie Gillis - 12 Years Ago
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DryLakesRacer (9/13/2013)
When I bought my car everything on the engine was new and had new paint. The paint soon blistered on the exhaust crossover under the carb. The first thing I did was wire open the exhaust heat riser and that helped a bunch. The gasoline was boiling in the carb. (Carter WCFB) yours is already done.
Next I added a 1/4" phenolic spacer and the problem dissappeared. (I checked the fuel flow by pumping it in a can all was good). I added a glass bowl filter in the fuel line and placed it about where the 57 bird is done above the intake at the #1 cylinder which is in the air path of the fan. I also used steel tubing to the filter and from the filter to the carb. Bought a flare tool and multisize bender from Harbor Freight; great for the garage guy.
Engine temp runs right at 170 at the thermostat housing. I have a lazer temp gun (Harbor Freight too) to read stuff at times on the intake, exhaust, and other places. The fuel line does read higher than I like sometimes in the 140 range as it passes over the exhaust crossover area. Going to put in the restricted intake gaskets soon.
The last thing I'll point out is the gasoline we have today is liquid junk. You may want to put in an additive with every tank. I use Sta-Bils product for help negating the ethanol..............Good Luck
Where did you find restricted gaskets? The parts stores here only have the unrestricted ones.
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By oldcarmark - 12 Years Ago
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Dobie Gillis (9/14/2013)
DryLakesRacer (9/13/2013)
When I bought my car everything on the engine was new and had new paint. The paint soon blistered on the exhaust crossover under the carb. The first thing I did was wire open the exhaust heat riser and that helped a bunch. The gasoline was boiling in the carb. (Carter WCFB) yours is already done.
Next I added a 1/4" phenolic spacer and the problem dissappeared. (I checked the fuel flow by pumping it in a can all was good). I added a glass bowl filter in the fuel line and placed it about where the 57 bird is done above the intake at the #1 cylinder which is in the air path of the fan. I also used steel tubing to the filter and from the filter to the carb. Bought a flare tool and multisize bender from Harbor Freight; great for the garage guy.
Engine temp runs right at 170 at the thermostat housing. I have a lazer temp gun (Harbor Freight too) to read stuff at times on the intake, exhaust, and other places. The fuel line does read higher than I like sometimes in the 140 range as it passes over the exhaust crossover area. Going to put in the restricted intake gaskets soon.
The last thing I'll point out is the gasoline we have today is liquid junk. You may want to put in an additive with every tank. I use Sta-Bils product for help negating the ethanol..............Good Luck Where did you find restricted gaskets? The parts stores here only have the unrestricted ones.
You dont need special Gaskets.You can cut a small piece of Tin or Metal to cover the openings in the Heads before you put the Gasket in place.In other words cover the Crossover completely instead of using the restrictor Gaskets to partially restrict heat.There is also a blank spacer plate available to replace the Heatriser altogether.Most of the specialty Suppliers like Tee-Bird etc sell them.
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By charliemccraney - 12 Years Ago
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Dobie Gillis (9/14/2013)
Where did you find restricted gaskets? The parts stores here only have the unrestricted ones.
I think they are Best Gasket brand and Mummert probably has some. I have restricted gaskets, and absolutely no heat issues, even in stop and go traffic, here in Atlanta, in the summer.
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By PF Arcand - 12 Years Ago
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Restricted crossover intake gaskets, if not available in your local, are likely available by mail from Gasket City, Hamilton Ontario. www.gasketcity.com or 1-888-335-4686, toll free (eastern time) He advertises in Hemmings & has a huge inventory of seals & gaskets..
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By ejstith - 12 Years Ago
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You have posted the same post that I posted a few years ago. I chased everything there was to chase on the fuel system. I changed fuel pumps, checked vents, replaced the metal fuel lines to the motor with rubber ones, blocked off my heat risers with a strip of metal ( I just loosened the manifold & slid them in & tightened it back up). I installed an electric fuel pump to no avail. Normally mine would only do it at idle or poking along like in a cruise. Finally it did it going down the road at Turkey Run in Daytona & I was dead in the water along the side of the road. My son was with me & he touched the coil & it was hot as hell. I had never believed it was the coil (as some on here had suggested) because it was a brand new Mallory coil. I went to Advanced Auto Parts & got an MSD coil & have never had another minutes problem with it.
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By Dobie Gillis - 12 Years Ago
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Thx EJ...coil's brand new (I had the same thought). It does seem to be in a rather warm spot, but it's in the stock location behind the carb on the passenger side. I'm thinking of mounting it on the firewall or inner fender just on general principal, but the stock location seems to have worked for Henry...
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By paul2748 - 12 Years Ago
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I have a set of the restricted gaskets on my 56 Bird. Went from NJ to CA and back (6300 miles) and no sign of paint burnoff on the intake. I get mine from CASCO, TBird parts supplier. Some say they are truck gaskets.
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By Y block Billy - 12 Years Ago
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Never had a Y block vapor lock, however I did have a chrysler 300 with a 440 that did, when I bought the car it had all kinds of tinfoil wrapped under the carb, put a kit in the carb and that was the end of it, drove it for 10 years after that without a problem. If you block off the exhaust passages, run a line to them from a windshiled washer container and fill it with Ice and water, turn the pump on and you will have an intake cooler!
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