Dave Lopes Fordor Model A

[BRENT in 10-uh-C]

Originally Posted by daren007

To what level would one have to bring back a "A" engine to replicate the original engine characteristics. After reading many posts on how original unmolested engines are much smoother then todays what needs to be done to reach this level.. Std. deck height, Std. crank and rods, Std. "Ford" pistons and rings. Std. cam and cam bearings, Std. lifters and lifter bores etc. Could you skip the cam bearings and other items? I find it hard to believe "Ford" shipped cars that you could not tell the difference between clutch chatter and engine vibration. I realize the I-4 has inherent vibrations but apparently todays engines could be much smoother. My "T" runs like a swiss watch in comparison.

Daren, several things factor in on this. The commonly-available pistons that most rebuilders use is heavier than original pistons, ...and even the wrist pins on today's pistons are almost 100 grams heavier than Ford's OE piston pin. That is huge when it comes to slinging a piston upward and then changing it's direction.


Next you must realize when the crankshaft is machined undersized, the offsetting material is babbitt which is not an equal weight transition. Next, most people opt for higher compression ratios which affects the feel of the engine. Each time the piston reaches TDC, the higher compression creates a 'snap' (think back to little Cox airplane engines and how hard they were to prop thru the rotational cycle) that causes a minute amount of crankshaft deflection on each cylinder pulse.


From my experience, most rebuilders of the typical '$2895.00 short-block' do not balance the internal parts of the engine. If they claim they do, are their tolerances & weights equal to what Ford had? If not, there your answer.