PA-18 with c90 convert to O200
- Thread starter TJim
- Start date
cubdriver2
FRIEND
upstate NY
NoStripNeeded
Registered User
Visalia, CA
I converted my 56' PA-18 w/ C90 to an O200 30+ years ago w/ a Field Approval. Not sure you could do a Field Approval in today's world. Depending on where you are looking to gain performance you might want to stick with the C90. The C90 would take-off shorter & out climb the 0200 with a Cessna 150 sea plane prop. It is a certified cub but highly modified for short field ops with flaps, flaps extended inboard, drooping ailerons, no electrical, single gas tank, old school Air Streaks. When light it was a lot of fun to fly. Fun fact: It was Cub Crafters Serial #1 for their Drooping Aileron STC.
cubdriver2
FRIEND
upstate NY
The 0200 moves the engine ( weight ) about 3/4" forward
Glenn
Glenn
Increasing HP by no more than 10% can be done by field approval. You need to come with an approved prop combination, and as Glenn stated, the O-200 will be somewhere between 3/8” and 3/4” farther forward so there may be some cowl clearance issues. If your local FSDO won’t do a Field Approval, I could do an 8110-3 engineering approval.
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Ron Graham
Registered User
You would have to spin the C90 to 2750rpm to achieve the 100hp the O-200 is rated for. Changing the cam will basically give you the same make-up as the O-200 with the exception of through bolts on the center main crankshaft bearing. The O-200 has them and most C90s don't. You risk breaking out the bearing saddle in the C90 when you start using it like the O-200. I've even seen just a standard C90 do this. Not a catastrophic failure when it happens. Oil pressure and other issues then you discover the problem upon investigation. The saddle can be repaired (welded back into the crankcase) but a lot of hassle for little (if any) gain.
RG
RG
FAA Form 8110-3 is the form used by DERs to approve data here in the US. Certain DERs can approve data for major repairs and major alterations. I’m authorized to approve anything that the FAA could do as a Field Approval. That said, the documentation requirements for a DER are more stringent than what an FAA inspector is required to have for the same approval.
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cubdriver2
FRIEND
upstate NY
My 11 had a C90 with 0200 cam when I bought it back in 94. Normal climb out was over 2700 and it had thru bolts. Had 2200hrs on it when I wrecked it and still had over 40 psi oil pressure when hot. My other C90 was in my Champ on floats and it was stock but also had thru bolts and would turn a 1b90 4341 at over 2600 climbing, great engines.
Glenn
Glenn
Steve Pierce
BENEFACTOR
Graham, TX
Look at the torque curves on the C90 and then on the O-200. I would keep the C90 on a Super Cub, O-200 on a formula one racer.
