Re: Diagnosis Needed

Posted by PackardV8 On 2010/3/27 19:20:14

Does the miss also occur at a SUSTAINED EVEN speed of about 40-50 mph??? On a 8 cylinder it mite be difficult to detect.

The problem u describe is something new i have been running into over the last 4 to 5 years on my own engines.

Recently, i found that the exhaust valves in a 2.0 F ohC engine were geting real sticky for about the last 1/16" of travel to the closed position. ( COMPLETE major overhaul done on this engine 25k miles ago)

The engine would start and run just fine. Accelerate and wind out thru the gears very strong. It wasn't until the speed evened out to a sustained 40-50 mph that the miss would set in.

I removed valve cover and damned up the valve guide and poured snake oil while spinning the valve and working it up and down to clear what ever varnish or carbon had built up.

Same problem with a small 3 hp Tecumseh engine and a motorcycle engine.