Engine compartment heat

Is/has anyone suffering/ed from engine compartment heat causing fuel system vapor locking? How did you solve the problem

After driving on a hot day and shutting down, the engine compartment temp goes through the roof essentially boiling the fuel line dry. Makes

I'm running a chevy sbc engine with edelbrock 600cfm carb with 1/4 spacer between the manifold, a mild cam and a 4 core griffin radiator. Driving temps are normal range. I've taken to opening the hood after driving to give the engine heat a greater chance to escape and cool down faster.

I'm looking at adding a header blanket insulation, insulate the fuel line, and spark plugs.

Currently running the faux louvered hood, and would love to find someone to convert it to actual working louvers.

Charles

Make sure your fuel line isn't close to the exhaust.  The insulation will help, but much better not to get it too close to begin with. Unfortunately, there isn't much room to work with and moving the line may not be possible.

If the problem can't be solved with insulation, you may have to resort to a return type fuel supply.  GM used mechanical return fuel pumps to combat vapor lock.  That may help you, but you would have to install a return line all the way back to the tank.  Just about any car or truck from the 80's should have that type of pump.  The downside to the mech system is that when you shut the engine off the fuel can still boil because it's  not moving and cause hard starting problems.

You could also go to an electric pump.  It should be as close to the tank as you can get it and below the bottom of the tank.  This helps because the fuel in the line stays under pressure (instead of suction with a mech pump) and slightly raises the boiling point of the fuel.  Plus you have the advantage of the pump pressuring the lines when the key is turned on.  I use electric pumps on all my hot rods because I can prime the carb before I start the engine.  My cars usually sit  for long periods and the fuel can evaporate.  Running the electric pump a few seconds will fill the float bowl up and prevent unnecessary grinding on the starter.

The best system would be an electric pump in or near the tank  combined with a bypass regulator under the hood.  The pump will circulate fuel through the regulator and back to the tank as soon as it's turned on.  This will fill the lines back up quickly even if the fuel does boil off.  

With any return type system (mech or electric), the fuel will stay cooler because it is constantly being circulated back to the tank and never stays in one place long enough to pick up much heat.  Except for the line from the mech pump or regulator to the carb.

Thanks for the electric pump advice. I'm researching electric pump options; think I'll go with Edelbrock to match the carb.

Also having a local custom shop quote a vented hood.

One thing about the Edelbrock carbs is that they don't like fuel pressures above 5 PSI. I believe this is in the tuning manual that comes with the carb.

I usually run a regulator on them no matter what type of pump I'm using. They will suffer from flooding if the pressure is too high. I've had very good luck with the cheaper Holley brand regulators.

Has anyone tried/considered converting the hood louvers to actually work?

My MX (SBC motor) has had the same issues and Hotrods advice regarding electric fuel pumps would likely solve the issue. I intend to plumb one in this Spring although with a slightly different approach. I had a electric priming circuit in the aircraft I built. Essentially I used a 12v Facet electric fuel pump to pressurize the system. The engine had a mechanical pump as well, lots of redundancy designed into aircraft engines. The boost pump was only used to start the engine and on takeoff and landing approaches. The primer was an electric solenoid valve actuated by a push button in the cockpit. You would switch on the pump, push the primer button for a few seconds and start the engine. Once running you would switch off the Facet pump and run off the mechanical until taking the active runway. Facet pumps are cheep, 50-60 bucks, put out up to 5psi, are self priming, and capable of lifting fuel about 12" if necessary plus no return line. I would omit the whole priming valve thing and simply plumb the pump into the existing fuel line at the tank. To facilitate a hot start (where I experience my start problems) I would flip the switch on for a few seconds, start the engine and flip it off. I'll post my success/failure on this when the ice age comes to an end up here.
Regarding the hood I had ambitions of addressing the louvers as well. With a little internet searching I found companies that sell louver sections in various dimensions and metal gauges. I envisioned carefully cutting out a 12" section of the existing fake louver and creating a slightly sunken perimeter lip that the new metal section could drop into. Would rivet nut plates to the lip so that the metal louvers could be screwed in place and replaced if necessary. You could either retain the remaining fake section of cut them down flush to the hood as this whole process would likely require fiberglass refinishing and painting anyway.
As it turns out I will be starting a new car project this Spring so once I solve the hot start issue, I will probably be putting my Healey up for sale. I'll leave the louver issue to the next enthusiast.

Sad to hear you'll be leaving our little site DrJ
Your contributions were always much appreciated, and cool insight into the aeronautical world!

No worries David, I plan to continue to enjoy this site you created going forward. It is a fine environment you have assembled and it has attracted a great group of automotive hobbyists. I have, and hope to continue to learn from this group as fellowship should have no restrictions such as make and model. The vapor lock issue we have been discussing will very likely come up in the new project. Solutions for it and many other "complications" usually apply throughout the hobby.

That's great to hear! Always feel free to post any of your other endeavours in the "off-topic" section, that's why it's there. Pretty fun to see we have members from all walks of life who all contribute in their own way. You'll always be welcome here!

David

Well, after experiencing the same problem with engine compartment heat like so many others....and reading about the many attempts on this forum to remedy the issue. This is what I did that made my Sebring MX transform in about an hour. This fix not only lets the heat out when parked, it also adds a fresh air source which my car needed (and I didn't know) while running. On-line sourced metal chrome and stainless vent. Single BEST thing I have done for this car.

So did that stop your over heat problem? I have the same issue here in FL. sometimes to point of vapor lock..

Absolutely did, in addition I added vents in the wheel wells too. The change was immediate...no hard starting after a short ride (vaper lock?) I used to hear the gas boiling in my carb....no longer have to open the hood to cool off ...just non of that. Plus the engine ran better guessing it needed more air....I followed everyone else....fan, cooler plugs, timing, heater bypass valves, wrapped headers, thermostats, after all that, the vents on the hood worked. We have nasty hot summers here in New Jersey just like Florida.

Just finished. Hope it does the trick![You must be registered and logged in to see this image.]

looks great, try to bend the vents open a little more.

no problem they bend easily

What stops water from entering these vents when it's raining?

Put these in. Work much bet[You must be registered and logged in to see this image.]
ter.. Move a lot of air..

So, did it solve all your problems....Running better?

Seems to have. Seems to hold at 190 -200 mark. Also put new fan and shroud, tin work by hood, vented inner fenders, wrapped headers... Reset timing, new Holley 650.(was 750.to big), new wires.. new HEI coil and module and cap. Jury still out..

I had this problem also, I have a 383 stroker in my Healey, I also got the electric
fuel pump with regulator. I have the hood with a false scoop, so I cut it out and
made it functional. I then shrouded the radiator (Griffin). No more problems.