'65 FI flame arrestor

[Michael G.]

Just wondering how the "flame arrestor" on a '65 FI unit functions (without tearing things apart). I know its function is to stop a flame from propagating back into the injection, but what structure accomplishes this? Can anyone explain the internals?

Thanks,

[John D.]

Re: '65 FI flame arrestor

Michael, I can tell you one thing. They never seem to wear out. When I get a fuel injecion in and it has a filthy flame arrestor with it rather than replace I clean it to perfection. I think the screens criss- crossing one another help prevent a fire.
Now to see what the gurus say. John

[Michael G.]

[Duke W.]

Re: '65 FI flame arrestor

The purpose of a flame arrestor is to keep a backfire from propagating into the crankcase where it can cause an explosion because most the the crankcase vapor is combustible air-fuel mixture from ring blowby.

In PCV systems with valves the valve will not flow backwards, so that keeps a backfire from reaching the crankcase on the outlet side, and on the fresh air inlet side there is usually a screen, which acts as a heat sink to quench the flame.

Since your '65 PCV system has no valve and can flow either way depending on engine operating conditions. it probably has screens on both sides. Port or direct injection engines are less prone to backfire caused crankcase explosions because their manifolds are "dry" and a backfire can't propagate very far up the port, if at all.

Back in my nutty teenage years a couple of friends crazier than me learned the hard way not to try to light farts without wearing underwear, which acts as a flame arrestor.

Duke

[Michael G.]

Re: '65 FI flame arrestor

Thanks guys. Just looking to tap into the crankcase vent feed line as a source of cool clean air from the FI filter. All the air flow available in that line leading to the flame assessor isn't used for venting the crankcase (the exhaust of this air to the plenum is much smaller), so I hope to cool the spider with some of this air. Currently working on 3D printing an air manifold to enclose and cool each spider line...