So Perry, if your analysis is correct, then the use of an electric fan pushing
air through the radiator, combined with an air deflector underneath the
radiator directing air from below into the fan and the engine compartment
provides sufficient air flow over the engine to keep the carbs cool enough to
keep them from overheating? In addition, the fan should be kept operating
while stalled in traffic and say 5 minutes before shutting down the ignition?
The fan seems to be the most used application, while the deflector and the
bilge fan directing air directly to the carbs seems to be the next most
effective application.
I will let the list know when I get my BJ8 running as it will have the fan
operating with a control on the dash board and the deflector underneath the
radiator deflecting the air into the engine.
By the way, I have a friend who used an inline electric fuel pump near the
carbs controlled with an on/off switch on the dash to increase the pressure to
the carbs while in traffic, along with a radiator fan on his Triumph and never
had a problem. That application could be a 4th in a series of how to solve the
problem of overheating and vapor lock.
Bob Begani
67 BJ8
From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of Perry
Sent: Thursday, July 26, 2018 5:57 PM
To: healeys at autox.team.net
Subject: Re: [Healeys] Interesting (?) Photos
Folks
Before we get to excited about a cooler carb please consider what is happening
in a running carburetor controlled engine. The carb acts like a swamp cooler.
The vaporized fuel is mixing with air and the charge mixture is as cool as it
gets before ignition in the combustion chamber. Ever notice little droplets of
moisture on the exterior of the carb body when humidity and heat is just right?
The real overheated carbs usually occurs when the airflow (radiator fan wash)
over the engine is limited or restricted (read stuck in traffic or
participating in the 4th of July parade). Worst case is when you shut down the
engine and the engine begins the process of trying to make everything in the
engine bay the same temperature. Hot! The photos do show the hottest areas on
the engine, exhaust area and the head. Without airflow and vaporization in the
carbs they rapidly begin to heat up. So does the fuel in the fuel bowls. How
hot does it have to be to cause vapor lock?
Just a few thoughts for consideration and comment?
Perry
Sent: Thursday, July 26, 2018 5:03 PM
Subject: Re: [Healeys] Interesting (?) Photos
David
I noticed that too - I figured the carbs would show warmer. If I remember
I'm going to bring the unit home again this weekend and poke a bit more
under the bonnet.
Keep in mind that this is one car in one circumstance - the guys chasing the
overheating issue might see something different with thermal images of their
cars (it would be interesting to know).
I must admit I have not been following an overheating carb thread. What is
the issue? Maybe I should take some more thermal images around the carbs.
Thanks.
Bob
-----Original Message-----
From: David Nock BCS [mailto:healeydoc at sbcglobal.net]
Sent: July 26, 2018 9:57 AM
Subject: Re: [Healeys] Interesting (?) Photos
The interesting part that I see is that there is very little heat at the
carbs, So that tells me that the problem everyone is chasing of overheating
in the fuel in the carbs may not exist.
David Nock
British Car Specialists
209-948-8767
www.britishcarspecialists.com <http://www.britishcarspecialists.com>
-----Original Message-----
From: Bob England
Sent: Tuesday, July 24, 2018 4:29 PM
Subject: [Healeys] Interesting (?) Photos
I thought I'd share a few photos of the engine running in our BJ8.
Photo 28 is taken near the front right headlight looking down. 29 is taken
from above the right front wheel looking towards the radiator. 31 is from
the same position looking down at the valve cover and distributor.
I'd taken these when trying to find toe-frying hot spots in the foot-wells.
Not the greatest photos, but interesting nevertheless.
Bob
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