C-85 Pistons/ High Compression mods

[Acroeric]

I know we have discussed performance mods for experimental 0-200's and C90's here for a while. I just got a set of C-85 pistons (for my C90)from Ed Athey and they look awesome. Ed found a place here in NC to moly coat the skirts and ceramic coat the dome. The race car guys have been doing it for years with good results- I will post the contact information as soon as I get it from Ed. I think he said they charge 25-30$ per piston for the service.

[Forrest Barber]

Re: C-85 Pistons/ High Compression mods

Interesting thread , we built the race ship "Estralita" an Art Williams design here in Alliance at the Barber Airport in 1946-47.... WOW did that engine cook, the secret of course was high RPM. Would you believe 3800 to 4100 rpm and the master of props was Steve Wittman. Then we had the fellow in here with a "65" Cont. sure trimmed my butt in an 85 hp Taylorcraft.... These are all experimental stuff but lets see what can be done with 175 to 200 lbs of engine...l

[Swick-T N7010S]

Re: C-85 Pistons/ High Compression mods

I have decided to sell my 180 Lycoming and install a small Continental. What do you guys think would be the ideal engine for a experimental Swick conversion. I would like to have a fuel pump for fuel injection for an inverted system. A stock C-90 has more torque than an O-200 I was told but if I install high compression piston in an O-200 I can get ~115 HP. What is better HP or torque. Or can i hop up a C-85 to get a good engine without sacreficing the reliabitity to much.

Mike

[Acroeric]

Re: C-85 Pistons/ High Compression mods

Mike- The easiest set-up for inverted fuel delivery is a little ellison EFS-3A TBI and a Facet low pressure fuel pump (3-5 psi). The pressure from gravity is plenty for normal flight- just turn on the little boost pump when doing any aerobatics. A small 5 or 6 amp 12v battery will power it for hours. If you are set on the engine driven fuel pump then stick with the C90, it is rare to see an 0-200 machined for it. There is only 1 place that does it and they charge $300 (Divco)

As for the best engine- Any of the 90's, or 0-200 can be made to produce torque. The cam we spoke of in the other post along with the high compression pistons seems to be good for 110-115 hp. The 0-200 in it's stock form is not a torque producer. With the 530788 Cam it will come alive. For me it came down to weight- the C90 is a little lighter. (C-90-8 would be the lightest, I have a C-90-12 which is 10 pounds lighter than the 0-200)

IMHO torque is best for acro and is achieved at somewhat lower RPM, if I were wanting to go really fast then I would spin it at high RPM.

On the downlines I did occasionally turn the 0-200 around 3200 RPM (140 MPH)- this allowed me more energy for the vertical stuff. It also always worried me that the metal prop would eat itself.

[3Dreaming]

Re: C-85 Pistons/ High Compression mods

On this clipwing we just put together we used a AeroCarb. It's a very simple set up with no fuel pump. So far it is working very well. Giles Henderson has one of these on his clipped Cub, and his imput was the reason we went this route. Tom

[Swick-T N7010S]

Re: C-85 Pistons/ High Compression mods

Does the Aero Carb work when you are upside down?

Mike

[3Dreaming]

Re: C-85 Pistons/ High Compression mods

Does the Aero Carb work when you are upside down?

Mike

It will work in any attitude. Very simple, only 2 moving parts the throttle slide, and the mixture valve. It does require some tuning changes from summer to winter. This takes less than 5 minutes to adjust, and a EGT is recomended. Tom

[Ragwing nut]

Re: C-85 Pistons/ High Compression mods

I have been ratholing a PS-3 carb for years for a clipwing project. I think it should work fine.

Why could you not use the vaccum pump drive on the O-200 for a fuel pump drive as long as you check drive speeds? It is a standard SAE pad.

Eric, how is the C-90-12 10lbs lighter than the O-200 when all the parts are identical in physical size? I know the -8 is roughly 10lbs lighter.

Mike

[Acroeric]

Re: C-85 Pistons/ High Compression mods

Mike- I know the C90 case is a little lighter and the mounting ears are different- I was just going by what I remembered in the manual. Could be wrong- happens all the time.

Also I plan to leave out the vac. pump drive mechanism- you gain a little power via the friction reduction and loose a little weight as well.

As for the Aerocarb- Giles had removed his about a year ago in favor of the EFS-3A I thought. I spoke with him a few times about it- If they work well that is the most economical option by far!

[jgerard]

Re: C-85 Pistons/ High Compression mods

IF you plan on using the 0-200 case on the short mount it would be wise to tie the left upper and lower engine to mount mounting points (I know thats hard to follow) together like the long mount for the 0-200 is. Look at the Captain Johns slide show of the factory and there are a few shots of the motor mounts and you can see what I'm talking about.

Jason
N43643