A-65 numbers

[MikeB]

I'm trying to sort out some numbers on A-65 parts I finally got around to looking at. I have a block with the name plate number 0-170, appears to be 1942 vintage by it's date stamping and came out of a L-4. Is there any difference between this block and a 'standard' A65-8? Everything appears to be the same and the block (including the cam bore) is in very good shape. Also, the piston number (casting??) is 4557 which is the same number as my 'spare' A65, but I can't find that number in any publications. Both are standard 3 rings. The intake valves are stamped 639661 which comes up as 100 octane, however there are no part numbers that I can see on the exhaust valve. The only difference I see between the valves (80 vs. 100) is the exhaust valves (100 ??)seem to have a 'dish' in the valve head.

After measuring the cam bores on the two blocks I can certainly see how you can lose oil pressure through the cam journal to bore fit. They do offer a .020 + cam, but I'll bet it's a bear to fit and maintain proper gear lash, etc.

One other thing: the crank from the 0-170 has external oil tubes (old technology) feeding the journals rather than drilled internal passages. The shaft measures up within new standard specs. Any reason not to use it? (assuming it checks out for cracks, etc).

Mostly I'm just trying to see what I've got for parts between the two engines. Thanks for any help you can give .
Mike

[Ron Babos]

Mike: The 0-170 is military for 65 . 170 cubes. The journal will almost never wear out at the gear end but the front journal will eat itself up. It has little bearing area that actually is used, as things aren't centered well in this area, plus all the dirt in the oil sees this area and grinds it to death. The cam itself will wear out of spec in this journal sometimes on a taper. You should not have any problem with maintaining gear lash of .009-.013 unless that gear bore is really worn.
There is a speciall reamer from CMC for this job, and some people may still have one. Case machining is the rage at the moment to salvage the bores instead of the reamer method, but if the rest of the case is good for decks and mains, ream it and get an oem .020 cam from Fresno. In 60 years the cam bores could be built up with weld and rebored. On that note, don't even think of boring it. You will drive yourself crazey trying to get a tool and bar that won't chatter at that small of a dia. Been there, done that, won't do it again.
Check the lifter bores before you go to far. Too sloppy, the cam followers will not rotate, and you know what happens there The 100 oct valves are Stellite faced like on the A-75-A80. I have four downstairs , but don't remember the number. I don't think the intakes matter a rat's.

Ron

[MikeB]

Ron,
Understand about the cam and lifter bores. Regarding the 100 octane exhaust valves: are they 'dished' across the valve head (rather than being flat)? When I first looked at them I thought they had been overheated and stretched or "tuliped" as we used to find on big truck gas and diesel engines in the 60's. But it appears the whole set is the same so they must be made that way and the intake part number comes up as 100 octane for whatever that's worth. All these parts, including the bearings, look like brand new or very few hours. There's no log on the old engine so I have nothing to go on.

Any thoughts on the crank as I described it? I can take all the parts up to Bolduc, but just trying to sort things out now (until a better project comes along).

Thanks,

Mike

[Ron Babos]

Mike: the valves I have are convexed slightly, like a lifter. Not sure what you mean with the crank, as mine has tubes that are visible through the lightening holes from main to rod journals.
Ron

[MikeB]

These would be 'concaved' (dished in). Not to worry.....I can check with Bolduc as I'll probably take all the parts up for inspection anyway. Your crank is the same as mine and has tubes going through the lightening holes. My other crank is more conventional with internal drilled passages. Guess I'm just not used to looking at 1930's technology. I won't worry about it for now. Supposed to be nice today (30 degrees) with light winds....think I'll go flying instead .

Mike

[Nathan K. Hammond]

Mike, I seem to remember the new Exhaust valves on my engine were dished in like you talk about.

Sunny side up.

nkh

[MikeB]

Thanks for the info, guys..........I did go flying instead. Finally a beautiful day in western Wisconsin. Put about two hours on the Champ burning up natural resources. Even got a crosswind landing on blacktop in and kept her right side up. Wonder what the max crosswind is on a Champ......I keep saying "nose straight, nose straight....you idiot... .........nose straight" !!

[LOWELL]

If you have an old A-65, WWII ventage, check out the FAA web site
on the T/C. Some OLD A-65 engines are NOT approved! You will also
see just how many different setups there are on the old engine. The note
about using a C-75 crankcase is true, they just don't tell you about the size of hole where the cyl barrel goes. Good reading.

[Jody Wittmeyer]

I believe the "dished" valves are standard. The 100 oct. stellite valves are flat across the top and have the letters EX across the top.

[nowlen]

what the note in the t/c( according to a continental rep)really means is that continental made a special crankacse(-12) that would adapt to a c-75 accessory case with the gears required for turning a starter/generator and allowing the use of the a-65 cylinders.. the mooney mite used this engine and they a very rare. if you find one i'd buy it.bernie

[Ron Babos]

The standard 100 oct exhaust valve is #654066 for A65 and the Stellite faced exhaust valve is #21479. These are used in the A-75 and A80
Ron