O 300C value?

[Bruce Fenstermacher]

BTW I know of several people who have had an A model engine with a 6 bolt crank. As paperwork shuffles go, it is one of the easier things to fix.You may already have the answers in your log book. You or the new buyer could comply with the Continental SBs and convert it to a C model. What needs to be done paperwork wise really depends on where this engine might be installed. The cleanest is to comply with Continental Service Bulletin (SB) M75-6 and convert it to a C model. Then if the buyer has a 170 or a 172 that requires an A model, they buy the Association STC to install this C model and the appropriate prop. If it is going in a 172A through H then it is legal to install per the TCDS and they would use a prop also approved by the TCDS.

[Lhorn]

This is all great information, and I think all is correct, it's just that I am working from afar, and not bodily there with the logbooks in my hand. Just contacted my mechanic (who has the logs) and he said that last 337 I just sent IS the notation that the engine was converted to a C model.

[Lhorn]

As for the prop, that's a different story, and a whole other topic. In fear of having my friend pull his hair out, I am going to not broach that subject until I have the logs in hand and can go digging myself.

Question still stands though, what is "top dollar" for a +half time O300A?

[GAHorn]

As for the prop, that's a different story, and a whole other topic. In fear of having my friend pull his hair out, I am going to not broach that subject until I have the logs in hand and can go digging myself.

Question still stands though, what is "top dollar" for a +half time O300A?

Well…the “question still stands” … are you selling it as an A or a C engine? Because unless it is properly documented…. it is not worth very much except for an air-boat or yard-art.

That Form 337 Still needs to have Block 3 explained: Is Block 3 Approved by FAA..?? or was the form 337 simply filled-out by an A&P and placed in the logbooks..?

(The darndest things sometimes occur. I once owned a C-206 that the instrument panel was significantly altered and “updated” from the goofy original instrument placement Cessna did to it in 1964 to a modern “Basic T” format. The A&P who did the work filled out a Form 337 describing the work, and stating “I consider this a minor alteration”. …which is a bit idiotic because a 337 is only for Major Alterations. All a minor alteration requires is a logbook entry.
Furthermore, he never sent a copy to OKC…. apparently he thought he’d get away with this by making it “appear” to be properly documented.
Even crazier: Years later one of our own Assocn’ Members contacted me to ask if I had anyone I knew in the FTW FSDO that could help get approval for a ferry permit…because the FAA-Inspector he was dealing with refused to approve a ferry permit for a retractible-gear airplane to fly with the gear locked in the Down-Position.
I asked him the name of the FAA-FSDO Inspector and….Guess WHO ? Yep…the same guy as who inappropriately and dishonestly did the instrument panel work on my airplane…. and who himself actually Became FAA !

Point is: Paperwork alone doesn’t make things correct or airworthy….Nor does improper paperwork necessarily make something unairworthy.

Your engine may be an O-300-A with a C crankshaft properly OR improperly documented… OR it may be an A converted to a C without proper documentation. WHICHever it is… the paperwork needs to be investigated and corrected to properly-reflect the current condition of the engine if you wish to receive maximum value in a sale.

AFTER that paperwork correction…. the engine will need proper/complete inspection for conditon before any trustworthy “value” can be estimated, IMO. Until then, it is worth significantly less than a properly documented engine in good running condition freshly-removed from service.

A freshly overhauled O-300 complete and ready for install with accessories (mags/carb) is probably worth about $45K in todays market. A fresh “major field repair” (often incorrectly termed “overhaul”) engine is probably worth about $35K. Both examples would require in addition, a repairable “core” trade-in.

A “mid-time” engine would be a 900 hr engine, with a deductible per-hour value of $12 to $15/hr.
900 times $15 equals $13,500 to deduct from the above values (disregarding the core-exchange, which for a WAG I suggest $7500)

This would mean the Maximum your engine might be worth (inc accessories) being about $14K.
Again, IMO.

Hope that helps.

[Lhorn]

That is super helpful GAHorn, and I appreciate the time to type out that story. Must have been frustrating to say the least to see that inspectors name pop up on your radar like that again.

I'm not trying to put one over on anyone, and you are correct, the paperwork needs to be thoroughly inspected before I list it for sale. Here is the signed and stamped other side of that form. Looks like it was indeed sent to OKC. They just did not modify the data plate indicating the change from A to C.

[Lhorn]

And just saw at last overhaul the prop was changed to the one it has now, which is a McCauley model 1 C 172 7643

[GAHorn]

And just saw at last overhaul the prop was changed to the one it has now, which is a McCauley model 1 C 172 7643

Well,…That is an incomplete prop description….. what are the two or three letters immediately in front of the 7643..?? MTM ? MDM ? EM ?

Hopefully it’s something like 1C172 EM 7643 ??

(PS a 7643 would be a climb prop…or perhaps used on a seaplane..?)

[Lhorn]

It's an EM. Glad you knew enough to give me a few prompts, I couldn't quite cypher the squiggles from the photograph of the log (posted earlier in the thread). I knew it was pitched to climb, the plane could always jump off the deck, even at altitude.

[Lhorn]

Here is the other prop I have, brand new in the box. It's a seaplane prop: McCauley 1A175/SFC8042

[Bruce Fenstermacher]

That 337 IS NOT the 337 that converted the 0-300-A to a 0-300-C. It IS the 337 that approved the installation of a 0-300-C and a 1C172 prop, with an incomplete description, there are several 1C172 props, on your 170. What you need now is a 337 that spells out how the engine was converted to a C model or a work order or at least a log entry. This would be hopefully in your engine logs or with your engine logs.

It appears this engine had the C model crank installed prior to it being put in your 170, will it was installed in N7681X. Looking at N7681X historical records I find no such 337 for a engine model change so hopefully you have a copy with your engine logs or it didn't happen. I don't really mean it didn't happen, just that we have no way to track done the historical record to prove it happened if there is one.

You see there is no historical engine data kept under an engine serial number, in fact this is the same for any accessory installed on an airframe such as a propeller. The accessory records are filed with the airframe the accessory it was installed on. So if the engine was converted while it was not installed on an airframe a form 337 can't get completed because it requires airframe information for filing. The actual work on the engine could have been completed on a work order, which even if we knew who did that, would not likely have a copy. When the engine is installed a 337 should be filed with the new airframe info referencing the work order other wise the actual work will never reach the FAAs historical records.

You should be looking in your engine log for any entry that describes how the engine was converted from an A to a C model.

I wouldn't bother your mechanic with this even if he is a good friend. Friendships only go so far when dealing with this minutiae.

If you find nothing, that doesn't mean an IA couldn't follow an SB 75-6R1 then fill a 337 now using your 170 aircraft information. Even if it was properly done before. It maybe the path of least resistance.

[cessnut]

Actually, that 337 field approval is worthless, since it is checked as an airframe alteration only. It does nothing to alter the engine. Anyway, it wasn't accurate because they installed an O-300A, not an O-300C, and it was specific to that serial number engine.

[wingnut]

George, Bruce and others have already mentioned this Continental SB, but may help to read. From my reading in this thread, I would bet the entity that did the overhaul forgot to stamp the data plate after the conversion to a "C". Your engine should have a "CC" stamped after the "A" (hint-hint )

1. Continental Engine Model Change M75-6R1.pdf

[cessnut]

George, Bruce and others have already mentioned this Continental SB, but may help to read. From my reading in this thread, I would bet the entity that did the overhaul forgot to stamp the data plate after the conversion to a "C". Your engine should have a "CC" stamped after the "A" (hint-hint )

1. Continental Engine Model Change M75-6R1.pdf

I wouldn't encourage anybody to just go stamp the plate. If the work wasn't documented by an authorized individual, you don't know how it got installed, or whether it was even an airworthy part. I recently ran across an O-300C with a D accessory case- no mention in the logs.
Also, the 337 above was not signed in block 7, so it was never returned to service legally.

[wingnut]

George, Bruce and others have already mentioned this Continental SB, but may help to read. From my reading in this thread, I would bet the entity that did the overhaul forgot to stamp the data plate after the conversion to a "C". Your engine should have a "CC" stamped after the "A" (hint-hint )
1. Continental Engine Model Change M75-6R1.pdf

I wouldn't encourage anybody to just go stamp the plate. If the work wasn't documented by an authorized individual, you don't know how it got installed, or whether it was even an airworthy part. I recently ran across an O-300C with a D accessory case- no mention in the logs.
Also, the 337 above was not signed in block 7, so it was never returned to service legally.

Where did you see words of encouragement?

IF the only difference in an "A" and a "C" is the crankshaft, an IA can do a conformity inspection and sign it off as "conversion from "A" to "C" completed by unknown persons at unknown time. Inspected and determined this engine conforms to blablabla.....stamped data plate in accordance with Cessna M75-6R1. This engine is approved for service". Additional research may be necessary, but this is not an unusual scenario.

That Form 337 above is an airframe 337 for the installation and has nothing to do with the engine.

[Lhorn]

Standby, he's going to go through the logs tonight to look for the entry. Hopefully it's there, but if not, sounds like an easy fix. IF the logbook entry is there, then it would indicate there was never a change to the data tag to indicate the engine mod.