Hood Louvers

Hi there, new to the Forum but have always loved Healeys. Am getting more serious and searching for a 3000 now. I have one question on the models that have "fake" hood louvers. How is it possible to run one of these cars with a 350 or 383 engine without it over heating? I have a 38 Chevy Coupe running a 383 stroker engine that requires 3 electric fans to keep it from overheating.

Hey Beeker,
I'll give my 2 cents worth. I have a mild 351W with carb. Runs on regular, so not over built. Has a 4 core hi-efficacy brass radiator, properly timed and jetted with 1 electric fan. Have never overheated and we live in Phoenix. The 3 main things to make it that way is a good radiator (aluminum now days), making sure all the air entering the front goes through the rad, not around it and room for heated air to exit. For every cubic foot of cold air entering the radiator, 4 cubic feet comes out. Some listers here have put vents in the fenders like factory race cars had and they look really good. In the assembly manual, there are pictures of where to cut the inner fender wells to allow more air flow. This has worked well for 20 years and 26k miles.

Well, I don't know. I'm in south Texas with a humid heat...the Chevy has a dozen vents on each side of the hood. And it's a folding 2 piece hood so not a very tight fit. Large steel radiator with one pusher fan in front and 2 pullers at the rear. On hot days I have to watch the temp closely. I'm glad to hear you haven't had a problem.

Beeker, I live in east central Louisiana.  I know the heat/humidity conditions you describe well.  I can pass on my personal experience with my Sebring, which was poorly built and tuned by the original builder and I will try to pass along things that I have learned in 40+ years of hot rodding.

When  I bought my car, it was pretty miserable to drive any distance.  The 350 SBC had no power, drank fuel like there was a whirlpool in the tank and the under hood temps were terrible.  The high temps bled over into the passenger compartment which made the car very uncomfortable to drive.

The car had been built with a cross flow copper/brass radiator, which was an option from Classic Roadsters.  Most had a vertical flow.  As a general rule, cross flows tend to work a little better.  I think it's because most modern grill openings are horizontal rather than vertical, so the incoming air has a clearer path to more of the radiator core.  In contrast, my 46 Ford coupe has a wide horizontal grill and a vertical flow core.  That car has always been marginal on cooling at best.

I'll expound on the "timing and tuning" that Jerry spoke of.

The first thing I found wrong was the distributor.  It had no advance mechanism at all since it had been originally in a computer controlled truck.  I swapped that out for a conventional HEI distributor with vacuum advance.  Vacuum advance is one of the keys to helping an engine idle cooler, make more power and get better gas mileage.  I have seen a LOT of street rods with the vacuum advance disconnected.  GM put vacuum advance on some of the most powerful muscle car engines of the 60's, so there is no practical reason not to run it on anything but a super high performance race engine.  Many hot rods are equipped with heads that have "lazy" open chambers.  These heads like a lot of advance to get peak cylinder pressure at the proper time in the power stroke.  Mechanical advance does this at high RPM and vacuum advance helps at low RPM.

Vacuum advance should be connected to straight manifold vacuum, not so-called ported vacuum.  Ported vacuum is a relic of the early days of smog control.  Remember air injection pumps pumping air into the exhaust manifolds?  The factories used ported vacuum to retard timing at idle so that raw fuel was being dumped into the manifolds where it was burned by the additional air.  This cleaned the exhaust emissions up a little, but also killed fuel economy and drove underhood temps sky high.  I've looked at a lot of pre-smog factory engines from the 50's and 60's and just about every one ran straight manifold vacuum.  Changing the distributor and getting the advance sorted out felt like I doubled the engine power and almost doubled my fuel mileage.  Underhood temps dropped dramatically.  I also didn't feel like I  needed asbestos shoes to keep my feet from roasting!

Next on the list was air/fuel mixture AKA jetting.  The Rochester Quadrajet that was on my engine was a smog era carb from a car with EGR.  Most people don't realize that EGR carbs were jetted lean.  Running them on an engine without EGR caused the engine to go very lean.  Lean mixtures are hard to ignite and burn very hot compared to richer mixtures.  I jetted the Qjet up a little and it helped with power and reduced the engine temp a little.

My car came with a mechanical engine fan that was about 4" from the radiator with no shroud.  It was doing virtually nothing to move air through the radiator.  I replaced that with a cheapo 16" electric fan mounted directly to the radiator, also with no shroud.  This should have been a marginal setup, but it worked great.  The car never got much over the 180* rating of the thermostat unless I forgot to turn it on.

Also, after all this tuning, my gas mileage went from struggling to get 10 MPG to a solid 18-20.  I even hit 22 on a couple of tanks.  Temps were completely under control and the car became fun to drive.  This was in a typical Louisiana summer.

So yes, a Sebring can be made to cool well in Texas, but everything has to work right.

As to your 38, you didn't ask, but I will comment anyway.  Late 30's Chevy's tend have airflow problems and there isn't much room for a radiator.  When you cram a wide footprint V8 into the inline 6 engine bay, you obstruct air flow around the engine.  The pointy rounded grill looks great, but wants to deflect air around the car.  The grill bars offer a lot of resistance to air flow since every one of them creates turbulence as the air passes around it.  Turbulence effects air flow greatly and out of proportion to it's actual size.  In other words, a little turbulence makes for a lot of air flow restriction.  This turbulence happens whether you are pulling air though with fans at a red light or forcing it through on the interstate.  The fact that it takes 3 fans to move enough air tends to support this.  I will say that my experience says that while the pusher fan may help at low speed, it really hurts at high speed.  It acts as an obstruction to air flow.  The 37's were a little better due to the flatter grill shape, but everyone I've ever known that had a late 30's Chevy street rod had cooling issues.  I'm a street rodder and we create a lot of problems fitting 250+HP engines in cars that were designed for 100 at best and were never intended to exceed 50-60 MPH.

I live in SoCal where we get plenty of 100 degree days and my Sebring now always runs 160-180 degrees. My car has a mild Chevy 350/Auto and AC. When I bought the car it had a junkyard cross-flow radiator, assume out of a Mustang, a mechanical flex fan without a shroud and a cheap pusher electric fan and it would occasionally overheat in traffic.

I took care of my overheating issues by having a new aluminum radiator custom built to a pattern that I made to be the largest that would physically fit under the hood. I added sheet metal to the sides of the radiator support to block air from going around the radiator and I added a two-speed high-volume electric fan with an integral shroud that covers the radiator (the fan is a Cooling Components that I strongly recommend and put one on all of my hot-rods). Don't forget a large coolant recovery system and you should be good to go. I could easily cool a much more powerful motor with my set-up.

+1 on the Cooling Components fans.  Very powerful motors and they really move air.  Lots of air.  Just be sure to have a lot of alternator.  They will spike to 60 amps on startup and run at 40.  Need a good relay too (70 amp) if you are only using one or use a CC solid state fan controller.  I have ran them both ways.  Love the CC controler too.

I posted a thank you message that doesn't seem to have gone thru. Appreciate the feedback, I don't have any further concerns about possible Healey overheating problems. And I will reinvestigate the cooling system on my Chevy after I get it back from the shop.