C-85 to O-200

[Grant S. Bailey]

I am now at the point in the restoration of my 1951 Model 19 where I am starting to think about the engine. The previous owner had completely dismantled the C-85-12F 14 years ago after a thrust bearing failure. I finally gathered up all the parts and pieces (it was all there) and took them to a very reputable shop in Canada for an assessment. They have advised me that the case is no good and the crankshaft is no good!! I had counted on the crankshaft being no good and had been thinking of overhauling the engine with the O-200 crankshaft, rods, and pistons STC, but I wasn't counting on the case being no good. If I continue that route, I now have to find a good C-85 case. The other option is to buy a run-out O-200 and have it overhauled as there seems to be a few more of those around.

So this is my question. Is there a lot of mods required in an original model 19 that had a C-85 to install an O-200? I believe the motor mount was slightly different. Are there any differences in the cowling or can I use my existing cowling without mods? How about exhaust? Big changes to use a Cessna 150 exhaust system in a Model 19? Paper work isn't the issue here as the aircraft is in the owner maintenance category in Canada.

[Dan Mahalak]

c85

hello. I do not know the answer to your question, but I do know where I can get a case for an 85.

If you are going to go the 0200 route, then i woudl be interested in purchasing your bucket of c85 parts.

cheers.

[David Price]

Had someone today say they had an C- 85 case to sell.
Will check further tomarrow!

[paulp]

conv to 0200

Grant,

I'm just now completing the conversion of my bc12d to a model 19. If you already have the model 19, I would recommend that you find another 85-12 case(check with Divco in Tulsa, OK) Have them do the machine work that will allow the case to accept the o200 crank and buy a new or reman. crank from Superior Air parts and their STC for for the conversion. You will wind up with 0200 pistons, rods ect and with 100hp!!! If you can find a good machinist, have him turn about .025 off of the bottom of the barrels, port and polish the spyder and you will have somewhere around 115-118 hp and most importantly, you will have a big increase in the torque. Remember that HP sells engines and torque flys airplanes.

[NY86]

I would be surprised if your case is not repairable. Unless there's a big chunk missing, someone like Divco should be able to fix it up good as new. There's likely someone in Canada that could do the same thing.

Mounting an O200 on a mount designed or a C85 will result in the whole engine being about 1/2" forward of where it was. This may or may not be a problem...

Be wary of HP claims for the O200 crank conversion. While the potential may be there, the end result is never as good as the claims. That said, being in the owner maintenance category gives you a little more leeway to get more out of the setup. If you use the same prop as before you will find cruise at a given RPM unchanged. Full throttle RPM will be higher (red line, anyone?) and climb performance improved. If you repitch the prop higher you can go faster and retain the same cruise as the C85. Or go finer, ignore the red line, and climb like crazy...

YMMV
John

[Grant S. Bailey]

Thanks for the comments fellows.

I think I will give Divco a call and enquire about sending my case down there or possibly purchasing a replacement case. Also, if anyone has a case out there, I would be interested in talking more. I just don't want to end up with another case that is no better than what I have.

[David Price]

Looked at the case today, seemed to be in good condition. There are no logs with it. There is an engine data plate attached. The owner says to make an offer. I have no clue as to what they are going for. Anyone have a figure to work from?

[Grant S. Bailey]

I called Divco in Tulsa today. They have yellow tagged crankcases for the C-85-12F in stock. $1,200 big ones outright, $600 with a repairable exchange.

[captjon]

Crankcase Services, Inc.

Bailey:

I have sent out two cases, a C85-12 and an A65 to Crankcase Services, Inc. of Sand Springs, Oklahoma in the last year. They seem to do a nice job and they were about $550 plus freight for the yellow tagging. That price includes everything necessary to get that yellow tag. You might try them.

The C85-12 is still awaiting assembly for Tami T-Craft's model 19 conversion, with O-200 crankshaft STC as you mentioned. I remember asking them what was necessary for it and I think they said there was nothing special that they had to do.

The A65 just flew this afternoon for the first time since rebuild. So far, so good with 1.3 hours on it.

Good luck with the project.

Regards,