C-85 Stroker vs C-90 in a Champ

[Michael Hahn]

Anyone with experience with a Stroker 85 vs a C-90? Trying to determine during an engine rebuild in a Champ 7DC that will be sold, whether to invest in a upgrade to either a Stroker 85 or converting to the C-90 to make it a more desirable sale. Any opinions on either engine? Performance experience? Converting a 7DC to an E for the C-90, difficult with the FAA? Do you have to change the prop? What prop is best to run with either engine? Thank you in advance. Mike

 

[cubdriver2]

Anyone with experience with a Stroker 85 vs a C-90? Trying to determine during an engine rebuild in a Champ 7DC that will be sold, whether to invest in a upgrade to either a Stroker 85 or converting to the C-90 to make it a more desirable sale. Any opinions on either engine? Performance experience? Converting a 7DC to an E for the C-90, difficult with the FAA? Do you have to change the prop? What prop is best to run with either engine? Thank you in advance. Mike

Welcome. Both engines would work great and about the same power. If you have not bought a Champ yet why not buy a 7AC or DC with one already installed? Would be cheaper and a lot easier. Good prop on both is a 1B90 7343

Glenn

 

[BC12D-4-85]

Might be hard to recover the cost of the HP upgrade from a C-85. Nobody wants to pay $0.10 extra but everyone wants the performance. I've had all three..C-85, C-85 Stroker, and C-90. I like the + power but only if I planned to keep the plane. That's unless you need a new crankshaft and one for an O-200 was the only option.

However you could negotiate prior to sale with a prospective buyer over the cost for the upgrade.

GAP

 

[bob turner]

I agree. It is maybe a push between the two engines, and I believe even the 7AC can legally handle an O-200, because I just brought one back from Denver, and it looked legal to me.

But I really agree - whether you just overhaul what you have or change engines, you will never recover your investment. The Champ with a 65 is $25 K in average condition, and with a brand new O-200 not much more than $30K. You won't even recover your labor cost.

 

[RaisedByWolves]

I prefer the 90 over an 85 stroker. Flown both in Cubs and champs, and like the 90 better.


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[scout88305]

C90, I flew them all in Aeroncas including 0235,,,, 90 seemed to pull heavy loads better. I used these Champs

 

[BC12D-4-85]

I believe the major performance difference between a C-85 Stroker and C-90 is due to the cam and lifter bodies. Different for each engine. See page 13 Table XI for cam lift and timing specs: http://www.culvercadet.com/manuals/C85_overhaul_manual.pdf

The C-90 has slightly more valve lift that can contribute to better volumetric efficiency/air flow through the cylinders, and slightly more power providing the intake and exhaust systems are optimized.

The cylinder compression and engine displacement are the same for both along with crankshaft and cylinders. Carburetor specs may vary depending upon model.

Continental Service Bulletin M47-16 (Rev 7-952) discusses a potential conversion that I hear works well: http://www.mooneymite.com/pdfs/ContSB.M47-16.12-30-47rev7-9-52.plus.1960supp.pdf

GAP

 

[bob turner]

So,Michael - have we helped? Are you going to build up an engine and sell the Champ that way? What will be your asking price for the completed project?

 

[cubdriver2]

I had 2 C90 planes, one stock and 1 with a 0200 cam. I have flown behind 5 C85 strokers, 1 stock STC, 1 with a 0200 cam, 2 with C85 pistons and 1 with 85 pistons and C90 076 cam. They all run great, some make a tiny bit more power but hard to tell

Glenn

 

[bob turner]

That is what I would have guessed. Don tells me that a stroker is $19,000 now. The O-200 Champ I just ferried was 28K. Very low time.

 

[BC12D-4-85]

And that explains why it's not economically rational to do + power in a fixed-value aircraft with the intention of recovering expense at sale. However.....some of us riding the wave to shore in flying felt it was worth it while we could enjoy the performance. I have over $18K in my engine.

Beats sitting on a park bench eating a bacon sandwich, feeding pigeons, and yelling at kids.

GAP

 

[mvivion]

Beats sitting on a park bench eating a bacon sandwich, feeding pigeons, and yelling at kids.

GAP

Yeah, Gary, your previous lifestyle was pretty mundane. :lol:

MTV

 

[CamTom12]

It's probably a lot easier to see the kids trying to get on your lawn from the air as well.

Not as easy to yell at them to get off your lawn from up there, though.


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