0200 question

[swoeric]

I have read that 85 pistons in the o200 require a slight chamfer on the piston to clear the head. has anybody tried to machine just past the cylinder into the combustion chamber to make room for the piston. the idea here is that typical hemi heads have horrible swirl. by cutting into the combustion chamber to make room for the piston there will be a ledge or shelf 90 degrees to cylinder wall and create more turbulence.




if not here would anybody know of a forum that explores motor subjects

[Acroeric]

Re: 0200 question

Don at Don's Dream Machines knows this mod well. I had him mod a set of C85 pistons for me a while back. Don is a great guy and can tell you how to get the most out of the little continentals. Most all this stuff makes your motor experimental so keep that in mind.
My O-200 with C85 pistons, 530788 cam, flowed cylinders, and A65 ported spider was a real strong engine. I'd bet somewhere around 110 HP at 2750.
Eric

[astjp2]

Re: 0200 question

I knew of a 172 with an O-300, put in the 85 pistons and burned up all 6 jugs in about 400 hours. Tim

[Jim Herpst]

Re: 0200 question

I have heard similiar horrer stories with mods like those. Remember race engines aint built to run more than the race.......

[jim cooper]

Re: 0200 question

A few years back I had a 140 Cessna with the Don Swords mod. It flew well and there were no problems. Most reports I've read speak very highly of this mod. if done to his specs. JC

[Jim Herpst]

Re: 0200 question

Lets not get confused here. There are STCd 85s still certified and then their are the others.Yes having heard good stuff I want to jump on the band wagon too. However just about a month ago a friend of mine Ken Harrill down at Owens Field in Columbia SC told me of his friend who had his quit ...twice no less. I would like to do this mod to my Cessna 140 one day. Done to the letter I dont think the Certified engines being an issue. It s like the examples sited above and when one gets into the "experimental" aspects of the engines that I begin to question the wisdom... afterall not sure I like taking a certified engine and making it Experimental it is then... well.... experimental !

[jim cooper]

Re: 0200 question

The 140 Cessna I had was restored by an AI who had worked in production at Fairchild aircraft for many years. It was, as is my current BC12D, a trophy winner. He took an 85hp engine and did the dons dream machine conversion EXACTLY as Don told him to. There was nothing "Experimental" about it. It was properly documented and was flown as a Certified aircraft. It flew very well BUT I think I should have changed the prop (an old polished McCauley) to more of a climb prop. The 140 is a ground lover but once in the air it boogied nicely. Bill Pancake is VERY familiar with this conversion and speaks highly of it. You might want to check with him. (The correct prop is SO important!) JC

[NY86]

Re: 0200 question

The engine you are talking about most likely was a C85 with O200 crank, rods and pistons. This modification is approved by STC. There is no approved modification that involves both an O200 crank and C85 pistons.