Bill's comments are very interesting. I have tried various temperature
lowering suggestions (checked radiator is OK, installed correct sleeved
thermostat, added multi-bladed fan, added electric fan in front of rad,
checked rad ducting) all without much success in preventing overheating
problems - specifically mis-firing when the water temperatures reach around
175 degrees F. Not that high!
The other day, after it got even hotter, I swear she was only running on two
cylinders for a while! It sure ruins the fun when this happens.
The possibility that radiated heat from the exhaust manifold is causing
vapour lock in the carbs is a new thought for me. I am tempted to rig up a
remote water spray for the carbs, that can be actuated by the driver whilst
still on the road, to test out this theory!
Has anyone tried upgrading the carb heat shielding to address the issue?
Neil
...........................................................
Neil McDonald
BN6
North Vancouver BC
Canada
----- Original Message -----
Bill Lawrence wrote:
(snip)
> The close engine compartment restricts air flow even more and
> concentrates heat from the engine particularly radiant heat from the
> exhaust manifold.
>
> The front carburetor's float bowl and jet feed passage is directly
> exposed to the radiant heat of the exhaust manifold and, under extreme
> conditions, is prone to vapor lock.
>
> These things being said I find that even though the engine temperature
> rises under these conditions the engine runs fine up to a point above
> 212 degrees when the carbs will start to load up (vapor lock). If you
> spray down the carbs with a little water it all goes back to normal. I
> don't think the engine cares much about the extra BTUs until it gets
> well beyond the range of the temperature gauge.
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