Reply to "Weber air filters"

My Std Warning on Weber air cleaners: do NOT use foam air cleaner elements with them, no mater what the factory says. Webers generate massive air pulsations thru their throats and will meter gasoline into an airflow going in either direction. This generates a fuel cloud standing above the carb throat(s). Foam air cleaners will almost instantly saturate with that fuel.

Second thing about Webers is, they have no warm up chokes (they use a separate enrichment circuit) so they tend to backfire a bit thru the carbs until the engine is thoroughly warmed up. Even a small backfire can ignite a fuel-saturated foam air cleaner. When I was playing with Webers, I had two (2) engine fires from this in commuter traffic and only a passing 18-wheeler with a fire extinguisher saved the car the first time. It did cost me an engine.... The second time (6 months later) I had my own Halon extinguisher! I got rid of the factory Porsche air cleaners, too.

How to lose an engine from a Weber carb fire:
the air cleaner fire MELTED a few carb's long narrow aux. venturis (made of low melting cast zinc). Molten zinc ran down the short intake pipes into one cylinder where the intake valve happened to be open. The next time that piston cycled up, the zinc had cooled into a metal lump which cracked a top ring and forged piston. Result was an overhaul plus one piston & set of rings. IMHO, a Halon fire extinguisher should be sold with each set of Weber carbs! Note- this dual-direction fuel metering does not happen with 8-stack EFI.