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Updating an A-65?

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cluttonfred

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I have seen a few A-65 engines for sale recently at pretty reasonable prices as today's sometimes hefty pilots choose to upgrade their Cubs, Champs, Taylorcrafts, etc. to more powerful engines. Some of those engines are with accessories, some without, some have logs, some don't. If refurbishing (I didn't say overhauling) an A-65 for use in a homebuilt, are there any upgrades to any part of the engine or accessories that would be worth doing? Ignition, carb, oil pump, rings, anything? Or just get it up to speed like it came off the line in 1945?
 

TFF

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Add a mixture control carb would be nice. Increasing the compression essentially turns it into a 75 or 80. In this world, rings are rings and oil pumps are oil pumps not much different. Ignition is doable but not really cost effective unless that’s what you want to spend your money on.
 

Victor Bravo

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Slight OT, sorry.

The A-65 was considered the hot rod upgrade on the T-crafts, Cubs, Champs, etc. back in the day. Keeping the airframe light yielded surprising performance. The Taylorcraft would get me and another fat guy off the ground and climb safely when flown right.

There is more to be gained in the FWF installation than by adjusting anything on the outside of the engine. Oil cooling wound up being a de facto operating limit in some cases. Baffling issues and such make a significant difference.

That being said, a good, well-adjusted carburetor is worth having. The old Bendix carburetors are frequently never overhauled, adjusted, or cleaned... for decades at a time.

When you overhaul it, or top overhaul it... then you can get in there and play with a few things that could make a difference.
 

TFF

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That’s why you rarely see a Lycoming O-145 today. 65 hp but smaller prop. Rubber to the road is different from a A-65. Hangar one down from where I’m standing has a couple of Lycomings on the ground and none on airplanes. Mainly form of legacy snobbery of a 90 years old. You see almost all Continentals because the Lycoming versions of planes were worth less money. Scrapped or dismantled first. Spoils to the victor.
 

TFF

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I’m sure they have. The crankshafts are better in the later series where the A-65 is as basic as a crank gets.
Technically you can machine the case and put C-85 cylinders on, crank and rods drop in but it starts getting crazy when a C-85 would be cheaper. It starts going overboard.
 

Pops

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The Cont overhaul manual says pistons within 10 grams is OK. I balanced the rods and pistons on the C-85 in the JMR to with-in 1 gram. I did polish the inside of the intake spider, don't know if it helped. The engine is running strong.

When building a A-65, a new set of mags will make you faint. Will not say anything about the mag gears.
 

Victor Bravo

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"porting" the small Continentals would mean adding material into certain parts of the port to make it smaller, not hogging it out with an abrasive tool like most people would think. Balancing works, but the RPM's are low enough that the benefit in terms of making additional power are non-existent. Balancing it would make it safer to run it at a higher RPM, which does make a little more power.
 

Pops

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You are right, at the low rpm's you don't want to slow the intake flow down with enlarging the intakes. I just smoothed surface of the walls of the intake spider.
 

t46craft@yahoo.com

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Buy a C-75-8 or C-75-12 (remove starter and generator) all parts (excluding carb venturi) are exactly the same as C-85 except RPM certified for use. Many times C-75 engine (because of engine tag) sells for much less than comparable C-85 when in fact they are the same engine and many C-75 venturi has been changed and are in fact a C-85. Carburetors or A-65. A-75, C-75 or C-85 are simple l930 area carburetors.
Using stromberg with its back suction mixture is sufficient for most of our flying. If you are flying the sierras yes I would invest in a marvel--schebler carb and C-85, C-90 or 0-200 for that type of high daily flying. However, A-65 or A-75 (same engine, drilled rods and minor changes) only turned higher RPM) will provide many trouble free hours for most local fliers.
 

Doran Jaffas

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I have seen a few A-65 engines for sale recently at pretty reasonable prices as today's sometimes hefty pilots choose to upgrade their Cubs, Champs, Taylorcrafts, etc. to more powerful engines. Some of those engines are with accessories, some without, some have logs, some don't. If refurbishing (I didn't say overhauling) an A-65 for use in a homebuilt, are there any upgrades to any part of the engine or accessories that would be worth doing? Ignition, carb, oil pump, rings, anything? Or just get it up to speed like it came off the line in 1945?
My My
I have seen a few A-65 engines for sale recently at pretty reasonable prices as today's sometimes hefty pilots choose to upgrade their Cubs, Champs, Taylorcrafts, etc. to more powerful engines. Some of those engines are with accessories, some without, some have logs, some don't. If refurbishing (I didn't say overhauling) an A-65 for use in a homebuilt, are there any upgrades to any part of the engine or accessories that would be worth doing? Ignition, carb, oil pump, rings, anything? Or just get it up to speed like it came off the line in 1945?
My .02 worth? There is always some "upgrade" . No AD's that I'm aware of. They are pretty bullet proof as a stock uncomplicated engine.
I have seen a few A-65 engines for sale recently at pretty reasonable prices as today's sometimes hefty pilots choose to upgrade their Cubs, Champs, Taylorcrafts, etc. to more powerful engines. Some of those engines are with accessories, some without, some have logs, some don't. If refurbishing (I didn't say overhauling) an A-65 for use in a homebuilt, are there any upgrades to any part of the engine or accessories that would be worth doing? Ignition, carb, oil pump, rings, anything? Or just get it up to speed like it came off the line in 1945?
 

TFF

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I know of a couple Champs that occasionally loose the prime. Picking the tail up level for a bit usually solves it.
 

DanH

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Prime problem is a hogged out accessory case oil pump cavity, usually combined with a worn shaft on the cantilevered oil pump gear and a hogged shaft bore. I recall someone developing a procedure to install inserts and re-machine.

Anyone need one of these? Make an offer.
 
Last edited:

Armilite

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I have seen a few A-65 engines for sale recently at pretty reasonable prices as today's sometimes hefty pilots choose to upgrade their Cubs, Champs, Taylorcrafts, etc. to more powerful engines. Some of those engines are with accessories, some without, some have logs, some don't. If refurbishing (I didn't say overhauling) an A-65 for use in a homebuilt, are there any upgrades to any part of the engine or accessories that would be worth doing? Ignition, carb, oil pump, rings, anything? Or just get it up to speed like it came off the line in 1945?
=========================

If, you can buy it Cheap, and rebuild it yourself and maybe do some Upgrades! You can make more hp.

1. Raise CR.
2. Better Cam.
3. Porting & Polishing.
4. Bigger Valves.
5. Use Higher rpm.
6. Use the different Engine Coatings.
7. Use EFI.
8. Add a Turbo.

Type: Reciprocating, Horizontally-opposed, 4 cylinders, air-cooled
Power rating: 48.5 kW (65 hp) at 2,300 rpm
Displacement: 1.8 L (171 cu in.)
Bore and Stroke: 98.4 mm (3.875 in.) x 92.1 (3.625 in.)
Weight: 77.6 kg (171 lb)
Low 6.3cr

The 171 cu in., at 2300rpm = 65hp! Dialed in as 86% VE

The 171 cu in., just turned at 2750rpm = 78hp! Same rpm as O-200!

The 171 cu in just turned at 3000rpm = 85hp!

Manual
 

Tiger Tim

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Is there a sneaky way to hot rod an A65? Maybe drop in a longer throw crank out of something? I ask because there’s a homebuilt Champ at my home field that just walks away from all the other A65 powered planes, including other Champs. It even out-revs an 85hp Cub on the same prop. We know where the engine came from (another Champ crushed in a hangar collapse) but apart from giving strong oil pressure and not making metal we haven’t dug too deep into the engine itself.
 
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