# 0200 pistons

Discussion in 'Firewall Forward / Props / Fuel system' started by hohocc, Apr 5, 2008.

1. Apr 5, 2008

### hohocc

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Hi folks. Have been told chevrolet 327 pistons can be used in an 0200 continental, can anybody confirm this? If so is it a straightforward swap or is there more to it...
Thanks

2. Apr 5, 2008

### PTAirco

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And on the same subject; has anyone had personal experience with using Chevrolet pistons in a Ranger engine?

3. Apr 6, 2008

### jumpinjan

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I have never heard that before, but I would love to check that out, but only later in the year until I can get to my Rangers. I have two engines (not Rangers) right now that I need to assemble and test.
(Now that the weather is nicer, in Ohio)
Jan

4. Apr 7, 2008

### wally

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Well to start, the O-200 engine has a bore of 3.875.

The only Chevy engines with the same bore are the 283 built from '57 to'67 and the 307 (known as the smog motor) built from '68 to '73.
The 327 was the first small block engine with a 4.000 bore so it won't work.

As far as wrist pin diameter and wrist pin to piston top height, or piston skirt clearance on the downstroke or the way the piston rings work, especially the oil rings, I just don't know. I do know the wrist pin is full floating in the O-200 with buttons in the ends to center it in the bore. The Chevy rods for the most part have the wrist pin heat shrunk to the rod end and float in just the piston. Most car engine pistons have an undercut on the sides to lighten them and there may not be enough depth to support the buttons that center the wrist pin.

And just thinking about this, I don't know of a way to retain the piston/rod combination and have the cylinder so you can assemble it the way it needs to be assembled. THe cylinder with piston stuck in it as deep as the wrist pin is held up to the case and the pin and button is pushed through the rod end. Then the cylinder is pushed on down to mate with the case. The head is mated permanently to the barrel. There isn't a way to put it together like a car engine with caps on the crank end - can't get to it because the engine is horizontally opposed and the cylinders are in the way. The rods have to go on the crank before the cylinders are in place because the only access is either before the crank is put in the case or from the opposite side cylinder hole.

Well maybe internal circlips would work in the wrist pin holes but that isn't how Chevy does theirs so that would mean a mod to the piston.
All sorts of other helpful info is probably lurking somewhere on the interweb if you do a search for it.

Best wishes,
Wally

Last edited: Apr 7, 2008
5. Jun 2, 2011

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Wally, you got some serious wrong claims here. O 200 engine bore is 4.06. Same bore than .060 oversize 302, 327 and 350 Chevy engine. There is plenty of different piston and compression ratio for those engine/piston family. There is several full floating pistons available in those piston family too.

I really dont know how good match you can find on those pistons, but i think it is probably possible, at least with some minor modification like rods bearing/piston pin and maybe some fine tuning for compression ratio.

These piston are probably even better than Continental own pistons. They are build for bigger loads, piston speed and hp rating.

6. Jun 2, 2011

### pie_row

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You said it. stroke is listed as 3.8 something" bore at 4.060"

7. Jun 3, 2011

### TFF

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I bet the air racing 0-200 used Chevy racing piston forgings. You can buy them as a lump of an aluminum then you have to machine it into a working Continental piston. Done all the time in auto racing engines. Drop in no.

8. Jun 3, 2011

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I got O 200 core and i want to try if i can use those Chevy pistons. I start to work that engine at next winter, so ill let you know if you can convert Chevy (forget, high compression) pistons and how you can do it. I make new topic for that too, where i put all possible modifications that might reguest.

9. Jun 3, 2011

### Dan Thomas

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Be careful with this auto-parts substitution thing. Lots of parts will fit but that doesn't mean they're safe. I used International Harvester truck piston rings in my A-65 because someone said they'd fit. They did fit, too, but they trashed the cylinders in about 20 hours. You see, the International's (and any other automaker's) rings are designed to run on a cast iron cylinder bore. Cast iron is hard stuff and once the rings break in, the cylinders are polished and lots of ring tension makes good compression. Put those rings in the much softer 4130 steel cylinder of an aircraft engine, and they tear it up. Continental's rings are just a bit narrower (as seen from the top) and exert much less pressure on the cylinder wall. Such mistakes cost money; I lost four very good, very rare cylinders. They were already .010" oversize, as far as they can go. Brand-new Continental rings would have been far cheaper to start with.

Making pistons so they'll fit is beyond most homebuilders. The wrist pin fit is extremely critical and its clearance is measured in ten-thousandths of an inch. Even a bit loose gets a knock going, since the aluminum piston expands more than the steel pin when it's hot, and any extra clearance means accelerated wear and poor heat drainage from the piston into the rod. The piston itself is not round; it's "cam-ground," which means it is larger in diameter 90° to the pin axis than in line with the pin axis. It's that way because the areas farthest from the pin get the hottest and expand the most, meaning that the piston gets larger, faster, at the pin axis than across it and when it's hot it becomes round. Machining such things can be way more expensive than just buying them.

Dan

10. Jun 3, 2011

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I need to check those piston rings, so good point here. You can buy chrome moly rings for Chevy pistons. I plan to use Chevy pin and make new bearing to rod end. Easy and fast. Every good machine shop can make it and ream it to fit perfectly for those Continental tolerances.

Making pistons to fit is more like fine tuning that compressing ratio and possible make some valve "pocket" in a piston head if needed.

11. Jun 3, 2011

### PTAirco

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True - but my Fairchild Ranger manual tells you ream bearings such as connecting rod ends to size by hand, so it can't be all that hard to get it right. And the original A-65 engines and many, many others ran with round, lathe turned pistons before they came up with a cam-ground one. Cylinders also distort when running, but apparently it causes no great problems. (Pictures a radial engine where the front of the cylinder gets most of the cooling.)

If a dimensionally identical automotive piston is out there, I'd have no hesitation in using one in an aircraft engine, but you might want to do some homework on the expansion coefficient of the material used and the appropriate clearances; an aircooled engine will run hotter than the car piston might have been designed for and the modern material might not expand quite as much - using the same bore/piston clearances might mean you'll always have loose pistons.

12. Jun 3, 2011

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I got 135 hp Harley, so air cooled and hot rodded engines is familiar for me. You have add little extra tolerance of a piston that was mend to be in water cooled engine. I am really sure that Chevy pistons are superior compared Continental own. There is so good manufactures like Keith Black. Those KB pistons are like jewelery, almost too fine to put inside of a greasy engine. Modern materials are far more than decades ago too. Those aluminum alloys are so good too. Just use good oil and run hard.

I was on a KB site and there is at least dozen of different 4.00 bore pistons (and you can order .060 oversize/stock O 200) with different top/pin height that start 1.1 to1.8 inch, so i am quite sure that you find one that fit there. O 200 people use C 85 piston in O 200 engine to get more compression. Those pistons are 3/8 longer than O 200, so there is plenty of room for minor top height variation. I must pick up stock O 200 piston next week and measure that thing, too interesting subject to ignore!!!

Last edited: Jun 4, 2011
13. Jun 5, 2011

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I check today that piston pin size. All those 4.00 bore Chevy piston got slightly bigger piston pin, only couple of thousands, so you can use Continental own connecting rod ends. You may can even ream those old ones that need overhaul fit to the Chevy pin.

14. Jun 6, 2011

### Elmog

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I'd rather have the assurance of using aircraft approved parts even at the outrageous prices they charge. There is something to be said about peace of mind when flying over mountains or large bodies of waters knowing that you put the highest quality, approved parts in your engine. Will Chevy pistons work? Sure, but for how long? Were they run thousands of hours to prove that they are up to the job like aircraft pistons have? Some may have had limited success doing this swap, but are you willing to bet your life on it? Modifying an auto piston to work in a car is a little different than modifying one to work in an aircraft. You are paying for peace of mind vs. saving a little money at the front end.

15. Jun 6, 2011

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I got that peace of mind for Chevy piston rather than Continental cast one. I am Hot Rodding that engine anyway, and if i run 3000-3200 rpm constantly i really trust piston that guaranteed to 8000 rpm. Keith Black make pistons for nitro burn 5000 hp 1/4 mile people, so i really trust that kind of piston maker. These engines cost more than new Cessna.

Friend of mine put apart Chevy BB marine engine that had 2000 hours. Pistons was fine. Those marine engines run 4000-4500 rpm constantly, so those pistons travel more than Continental ones on same hour. Marine engines keep in good shape because they use good quality oil and there is no dust in air.

I am not try to save money here, just try to find better alternative. Money saving is bonus.

Last edited: Jun 6, 2011
16. Jun 6, 2011

### Dan Thomas

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Marine engines also get the best cooling possible, while aircraft engines run far hotter. Marine engines, especially those in recreational boats, might run anywhere from 5 hours per year to maybe 100 at most. Sure, they'll last a long time with good cooling and infrequent use. They probably rust out before they wear out.

The Chevy piston would be of higher quality and of better material than the old Continental's, but there are many more factors beyond machining quality and composition. A Chevy piston has struts in it that might limit the expansion too much and cause loss of compression and oil consumption. Or the piton might get much hotter than it was designed to and the struts come loose. Many, many things to consider.

Dan

17. Jun 6, 2011

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I do some measurements today for Continental piston, O 200 and that 7:1 compression. I find lot of fine pistons in a Keith Black catalog: http://www.kb-silvolite.com/assets/automotive_catalog.pdf

On of the best ones was Chevy and Pontiac. They piston pin is little bigger, only few thousands. Chevy 327 flat top give little extra compression, height was .80 more than original. As you know, you can use 3/8 taller C-85 pistons on that engine.
Other GM was Pontiac 151 and 389

There was some Ford too, but those Ford pistons need to build rod end bushing. Ford piston pin is smaller than Continental. Match Ford was: 302, 351 C and 351 W. First one is match for compression, others give more than 7 but less than 8.

There was Chrysler too. They got something like .060 bigger piston pin. Match was 360 340 and 392 hemi. First one got little extra compression (like Chevy 327) and last one is close call like C-85 Continental, it might need work for valve pocket.

There was one Holden too,that can use for this purpose.

You need piston with 4.06 size with 1.600-1.900 compression height. Comp height measure middle of piston pin to top of piston. You may need cut some piston skirt shorter, to clearance properly. That you need to measure too.

Everybody who want to try this kind of a conversion must understand what they are doing and must understand measure every cylinder, valve clearance and compression ratio after conversion. They might have slightly off compared to each other because of company manufacturing process. Dont believe just one cylinder/head combo!! If you do not know exactly what you are doing, forget that one or hire some professional for this kind of job.

You are your own risk here. I believe that it is fine conversion and i am doing that on my own engine next winter. I give your guys new topic for that when i do it.

Last edited: Jun 6, 2011
18. Jun 7, 2011

### millerperf

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ive seen ford 302 60 over pistons used you have to hone the pins!

19. May 5, 2015

### rotor1976

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Good day! You managed to install the piston from a car engine in the G-200? The engine works? Thanks for the answer.

20. May 5, 2015

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