The Cessna 120-140 Association Forum

Hello All,
I'm in search of some guidance. I'm putting together a 140. I just finished the fuselage and paint and moving to the firewall forward. I have a C90 that came with this project and was told was the engine that was one it. Last known flight was in early 80's. Any how, in doing research for hardware, engine mounts, and etc. I realized that my C90 is a -16F model with a vacuum pump drive. The TCDS only allows for a -12F or -14F. I've searched the forums here but haven't been able to produce any results for this matter. I'm thinking a field approval should be relatively easy considering the minor differences between the engines. Has anybody run across this? Any all all advice is greatly appreciated.

The -12 and -16 use the conical rubbers. The -14 uses the Lord mounts. The F is a flanged crankshaft, and all the C-90's used that. If you were to want the vacuum pump you would have to put a bubble on the front of you cowling, or better put a cover over the pump drive.

Thanks for the additional information. What I'm really in need of is the approved data for installing my -16F. I have the mount from the original -12F so the physical install of the -16F will be straight forward. I'm thinking I'll attempt to acquire a field approval. However, if this has been done by someone in the association; a copy of that 337 would be greatly appreciated!

A basic question that should be answered when seeking info such as yours - what records do you have, do you have the OKC disc for the aircraft and all the log books? Are you your own IA (with the authority delegated by the FAA). Yes, one would think a field approval should be no problem but then again your dealing with the FAA - generations past our aircraft. If you haven't, check the TCDS for the engine - exactly the same as the approved except the vacuum pump ( and as Randy pointed out, the reason why one can justify not using the pump) and noting that pump would not be used in a field approval, if you have to go that route. If a field approval is sort, be very detailed citing the info from both TCDSs. If you find any kind of reference to the past installation, you could create a 337 with the phrase, "recording the alteration previously done by persons or persons unknow", etc.

Random thoughts, FWIW.

Yeah, first make sure you have reviewed all the existing documentation. Was the installation logged? If so, you could fall back on the idea that whoever installed it deemed it a minor modification. If there is no documentation, or it is incorrectly documented as a -12, then I would be sorely tempted ot write it up as a minor modification, especially if the vacuum pump is not installed, and leave it at that.

Nice shot and good project, nice to see another 140 revived. For the vac. pump I simply trimmed out a hole in my cowl and let the pump stick out slightly, its hardly noticeable and provides for cooling. On the engine you might consider an O-200 at this stage if you can find one, I sold my as removed C85 and bought a runout 0200 for about the same price 3 years ago, the cost for overhaul of C85 vs O200 is about the same ( I don't know what shape your c90 is in). As far as the legality of the C90 engines I would think this a minor problem with a competent IA able to figure it out easily with the FAA records.