The Ford Barn - View Single Post - What Defines Over-Revving The Model A's Engine

john charlton · 05-09-2020, 02:33 PM

The 3" bore AF engine fitted to most English cars produced 28 BHP at 2600 RPM . The rear end had 4.55 ratio gears so in practise they were revved far higher than a stock 3.78" bore engine . The engine is way smoother than the 24 HP I guess due to less rotating weight . The crank and flywheel were the same for both engines . The AF camshaft was "hotter" the trick of the day was to fit this cam and the 14.9 head to a 24 HP engine and super cheap extra horse power . The Achilles heel of the small bore engine is that they ate their "Celeron" timing gears frequently so that did act as a rev limiter !!!

John in cold weather on the way Suffolk County England .

05-09-2020, 02:33 PM	#13
john charlton Senior Member Join Date: May 2010 Posts: 1,304	Re: What Defines Over-Revving The Model A's Engine The 3" bore AF engine fitted to most English cars produced 28 BHP at 2600 RPM . The rear end had 4.55 ratio gears so in practise they were revved far higher than a stock 3.78" bore engine . The engine is way smoother than the 24 HP I guess due to less rotating weight . The crank and flywheel were the same for both engines . The AF camshaft was "hotter" the trick of the day was to fit this cam and the 14.9 head to a 24 HP engine and super cheap extra horse power . The Achilles heel of the small bore engine is that they ate their "Celeron" timing gears frequently so that did act as a rev limiter !!! John in cold weather on the way Suffolk County England .