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By Mortimer452 - 6 Years Ago
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Been driving my 1956 Mercury Monterey (312ci) around quite a bit this summer. On hot days, I have vapor lock issues. Drives fine for about as long as I want it to, but after I turn it off, after it sits for 10 minutes or so, it won't start back up until it's cooled down. It never gets too hot while driving - my temp gauge is only "C" and "H" but it never goes past the halfway mark in normal driving, even in sweltering hot weather.
My remedy so far has been to pour a small amount of fuel down the throat of the carb - I can hear it hiss and boil when I do this. Pour a little, start it up, runs for a few seconds and dies . . . repeat 2-3 times and it'll finally start and keep running, then I'm good for the trip home.
I've troubleshooted and fixed vapor lock on other cars in the past, but still pretty new to the Y-block. Original Holly teakettle carb, do I need a spacer between the carb and intake maybe? Any common areas to check? Thanks!
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By Dobie - 6 Years Ago
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You need to insulate the carb from the intake manifold. A phenolic spacer will do the trick, 1/2" thick will probably suffice but 1" is better if you can close the hood on it.
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By paul2748 - 6 Years Ago
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might want to look into this
http://www.coolcarb.com/index.html
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By 62bigwindow - 6 Years Ago
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My car does the same thing but not as severe. Opening the hood a little when you park it helps. I put in a 1/2" phenolic spacer and that helped too. The next step is to block the heat crossover and I'm going to make a cover for the pump to carb line to insulate it from the engine heat. I plan on using either a 3/8" or 1/2" piece of fuel line for that. I am going to make it so it's easy to remove for shows.
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By 57RancheroJim - 6 Years Ago
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I'm sure these problems are caused by the damn Ethanol in the fuel. I have a 1960 F100 with a 223 six and a glass bowl Holley. I can shut the engine off and after about a minute I can watch the fuel start to boil in the carb. I now have a spacer and it helped. I have spacers on all my other engines too. The Holley 390 on my Y hasn't given any problem with a 1/2" spacer and it's been 100+ here for weeks..
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By geo56 - 6 Years Ago
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I have found that certain carburators are more prone to vapor lock than others. I ran two different sizes of Autolite/Motrorcraft carbs (0.14 and 0.08) on my 56 Victoria with 292. On a hot Tulsa day if I would shut it down and start it up again a minute or two later it would start again quick enough. However, let it set about 10 minutes and it would take an embarrassing number of rolls of the starter to restart. I tried stacking another black 1/2 composite spacer on top of the 1/2 inch 2 to 4 barrel adapter that was already on it and it didn't help much if at all . I ended up replacing the Autolite 2 barrel with a Holley 450 CFM 4 barrel and vapor lock was gone. I remember back in the mid 70's a friend of mine's father would drive him to work in an early 60's F100 and my friend told me then that the not so old truck would vapor lock bad in the summer. A lot of those late 50's early 60's Y blocks ran Autolite carbs and I am guessing that vapor lock was a common complaint and I wonder if there was a service dept. solution back then. Also, I have run 289's in the past with Autolite 2 barrels and don't remember the vapor lock problem on the small block like it was on the Y block with the same carb. Maybe the Y block intake manifold puts out more heat than the 289 does. Just a guess.
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By PF Arcand - 6 Years Ago
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One thing that can really cause a problem like that is if the exhaust manifold heat divertor flap is stuck in the closed position. Another thing that might help is to block the heat crossover or use partly restricted truck intake gaskets.. Good luck!
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By Mortimer452 - 6 Years Ago
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geo56 (8/3/2018)
I have found that certain carburators are more prone to vapor lock than others. I ran two different sizes of Autolite/Motrorcraft carbs (0.14 and 0.08) on my 56 Victoria with 292. On a hot Tulsa day if I would shut it down and start it up again a minute or two later it would start again quick enough. However, let it set about 10 minutes and it would take an embarrassing number of rolls of the starter to restart. I tried stacking another black 1/2 composite spacer on top of the 1/2 inch 2 to 4 barrel adapter that was already on it and it didn't help much if at all . I ended up replacing the Autolite 2 barrel with a Holley 450 CFM 4 barrel and vapor lock was gone. I remember back in the mid 70's a friend of mine's father would drive him to work in an early 60's F100 and my friend told me then that the not so old truck would vapor lock bad in the summer. A lot of those late 50's early 60's Y blocks ran Autolite carbs and I am guessing that vapor lock was a common complaint and I wonder if there was a service dept. solution back then. Also, I have run 289's in the past with Autolite 2 barrels and don't remember the vapor lock problem on the small block like it was on the Y block with the same carb. Maybe the Y block intake manifold puts out more heat than the 289 does. Just a guess.
Good to know. This is pretty much where I'm at now - I can turn it off long enough to pump a tank of gas maybe, but if it sits for more than 5-10 minutes I may as well pop the hood and wait another 30 for it to cool off before I even bother trying.
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By PF Arcand - 6 Years Ago
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Geo 56: re the carb/intake spacer. Just a thought, was it aluminum? Because aluminum transfers heat quickly..
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By 82warren - 6 Years Ago
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91 Octane gasoline without alcohol will help, this alcohol gas boils at a lower temp'.
warren
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By 82warren - 6 Years Ago
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Just worked on a nice '55, somebody had put a power valve in place of the vacuum control valve on the carb' ....... did not work too well. Lucky I had a used one to install.
Where can a guy get these ... if at all, several such items are not around for these Y-blocks, just not enough demand for odd parts.
warren
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By 82warren - 6 Years Ago
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The vacuum 'pancake' on your distributor has to be there and work, many now have puked diaphragms, they are getting old y'know. I put a new one on mine, bought one for a '53 flathead which is the same except for the 90 deg' bend in the arm where it hooks into the points' plate, I cut it off, turned it correct and welded it back together again. Make sure the length is the same as the old one you took out. Anyway this worked perfect, car runs great and top shelf power and speed.
warren
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By KULTULZ - 6 Years Ago
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http://www.carburetor-parts.com/Spark-Control-Valve_p_1166.html
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By KULTULZ - 6 Years Ago
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What you are experiencing is engine heat soak @ shutdown with resultant fuel percolation and fuel evaporation in the carb fuel bowl.
Minimum will be a phenolic carb spacer and as mentioned make sure the heat riser valve is fully operational or wired open during summer. Also be aware that the air cleaner housing also acts like a heat trap and makes air circulation difficult.
If you can find a source of non-methanol gasoline, it will alleviate most of the problem(s) (methanol having a much lower boiling point) (or go to an electric pump).
ALSO- The HOLLEY 4000 design has the fuel bowl elevated under the air cleaner and absorbs more heat than say a later HOLLEY 4150.
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By KULTULZ - 6 Years Ago
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... ??? ...
... methanol ...
That's ETHANOL...
... you would think that after fifty years of acute alcohol consumption I would know the differences ...
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By Tedster - 6 Years Ago
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Years ago (maybe they still do) T owners and others use to add a small amount of Kerosene, maybe a pint, to a tank of fuel. This was supposed to help with vapor lock. Modern gasoline is formulated for use with fuel injected un-vented closed systems and is undoubtedly more prone to this in collector or classic cars.
One strategy that might be worth exploring is using a manifold vacuum advance connection. This results in far more ignition advance at idle and stop and go driving and cooler running temperatures as a result.
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