Boring a 125ci AF motor to a 200ci A motor

[johnbuckley]

Great Britain offered the smaller bore size because of the road tax system in place there at the time. (though the 3285cc engine in cars was also available as an option). The smaller diameter bore brought the fiscal horsepower rating of the car in at 14.9hp, the larger diameter gave a fiscal hp rating of 24hp and attracted a higher annual tax paayment. This tax system was meant to favour the UK vehicle home manufacturing industry ( think small engined Austins and Morris). But in fact it shot the Uk industry in the foot as their cars became less and less suitable to export. The larger bore Model A engine was used on commercial vehicles in the UK which had different tax regime.
The smaller diameter bore engines of the Model A were GB specific though a few obviously made it across to europe and the empire countries.

[Mike V. Florida]

Originally Posted by johnbuckley

Great Britain offered the smaller bore size because of the road tax system in place there at the time. (though the 3285cc engine in cars was also available as an option). The smaller diameter bore brought the fiscal horsepower rating of the car in at 14.9hp, the larger diameter gave a fiscal hp rating of 24hp and attracted a higher annual tax paayment. This tax system was meant to favour the UK vehicle home manufacturing industry ( think small engined Austins and Morris). But in fact it shot the Uk industry in the foot as their cars became less and less suitable to export. The larger bore Model A engine was used on commercial vehicles in the UK which had different tax regime.
The smaller diameter bore engines of the Model A were GB specific though a few obviously made it across to europe and the empire countries.

So the original AF stamped engine Rowdy states he has is most likely a commercial engine.

[Rowdy]

Mine came out of a Phaeton which was brought stateside from Australia. Vince's research turned up the fact it was part of a knockdown shipment and the car was likely assembled in South Africa. Rod

[johnbuckley]

Originally Posted by Rowdy

Mine came out of a Phaeton which was brought stateside from Australia. Vince's research turned up the fact it was part of a knockdown shipment and the car was likely assembled in South Africa. Rod

Gosh how intriguing! presumably the engine went to South Africa from England and the rest from Canada . What year would that be?

[Rowdy]

It never was in England as has been discussed before. Please take the time to read ALL of which Vince's research has revealed and not assume all AF engines were made in England.

http://www.fordgarage.com/pages/ABenginenumbers.htm

[johnbuckley]

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Originally Posted by Mike V. Florida

So the original AF stamped engine Rowdy states he has is most likely a commercial engine.

AF as used in UK was used only to designate small bore engine. If Rowdy has a UK 3.3 with AF stamped on it it has indeed been bored out ( see original question) or it's incorrectly numbered!!!

[Rowdy]

I can not post a link of the previous discussion of my block at this time due to the factI have not mastered cut and paste from my I-phone. Do an advanced search and likely you will easily find it minus Vince's comments. Yes there is a pic of the number stamp pad. If I remember my camera today I will get more pic's. I have no real explaination of why it is std bore, just know where I bought it and its history stateside. Rod

[Jim Huseby]

Was the c.i.d. of the AF really 125? What was its BHP? How high, compared to the 200.5, would it rev? Was it also de-stroked? What did the Limeys do to hop it up? What were its performance specs when hopped up? Did it use standard 1.5" valves? Were the ports the same (about 1 3/8") ?

[montanafordman]

Originally Posted by johnbuckley

Great Britain offered the smaller bore size because of the road tax system in place there at the time. (though the 3285cc engine in cars was also available as an option). The smaller diameter bore brought the fiscal horsepower rating of the car in at 14.9hp, the larger diameter gave a fiscal hp rating of 24hp and attracted a higher annual tax paayment. This tax system was meant to favour the UK vehicle home manufacturing industry ( think small engined Austins and Morris). But in fact it shot the Uk industry in the foot as their cars became less and less suitable to export. The larger bore Model A engine was used on commercial vehicles in the UK which had different tax regime.
The smaller diameter bore engines of the Model A were GB specific though a few obviously made it across to europe and the empire countries.

Ok, That makes sense. Thanks! Now I understand why we drew a line in the sand with taxes on stamped paper and tea... I kid... I kid...

Does anyone know how the engine weight was affected by the smaller displacement? Practically speaking how much of a performance detriment was this really in top speed and hill climbing ability?