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So I have a 1978 f150 with the 6.6 ltr v8 400 and was wondering if it is an interference engine or a non interference engine. Also looking for a good vacuum diagram. And for the factory snorkel thing
I've heard "interference engine" used different ways. For my clarification, what are we calling an interference engine here? My understanding of it is, that an non-interference engine cannot have valve to piston contact, in the event of a cam timing failure.
Personally, I've had great luck with the 400M engines.
I ran one for over a year with a rod-knock. When purchased with supposed bad tranny, the pickup came with a rod-knock. hahaha _ _ go figure, right.
In the time I ran it, I purchased a used (supposed rebuilt) engine which was not, so I freshened it up with a "Greaser-refurb" and switched engines.
Was in a '76 F250 Crew Cab, and had a Fed-Ex driver follow me to a stop and asked if he could buy it. I sold it to him 2-months later.
I ran into him several years later and he loves the pickup, so the 400 was running strong.
I've heard "interference engine" used different ways. For my clarification, what are we calling an interference engine here? My understanding of it is, that an non-interference engine cannot have valve to piston contact, in the event of a cam timing failure.
Or in the event of mechanical over rev causing contact between the two because the valve spring cannot close the valve quick enough to miss the piston. Valve float
Interference means that if the chain or belt driving the cam breaks leaving a valve fully open it can hit the piston.You would have to have a very big cam and or compression ratio on a 400.
Right. By that definition, a 400 is an interference engine. I had a stock 351M bend valves after the nylon gear teeth sheared off the camshaft gear. Yes, the 400 has shorter compression height pistons, but that only makes a .047" difference in deck clearance. Not enough to prevent piston to valve contact.
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