C-145-2 Crankshaft conversion

[Brad Brady]

There is an AD requireing the replacement of an air melt crank in the Cont. IO-520 engine when the case is split. I've been led to understand these cranks, though no longer useable in an IO-520, may be used in the O-470 series since the AD does not apply to that engine.
Since there is also an AD requireing the same action in the Cont. IO-360 series, I see no reason an air melt crank from that engine wouldn't be useable in the O-300. If I was in need of a crank, I would certainly look into it. After all, Cotinental uses the IO-360 crank as a replacement in the O-300, and an IO-360 air melt crank is only a boat anchor otherwise. I would think one would be cheap.

I wondered about that......but if I can find a C-145 I'll go that way......Thanks, BL

[lschleinat]

If you have a C-145 then you have an 8 bolt flange, the new cranks and the crank in the O-300C and D are 6 bolt. If you went with this crank you would need a field approval and anew prop. I've got a crank that is turned 2 under that I didn't use in my recent C-145 rebuild. When I did my rebuild, I got varying information as to whether the 2 under was legal (I believe you have to use O-200 bearings). I looked for a C-145 crank (no luck) as well as purchasing something new, I finally found a nice core from Dodson for $3500. This turned out to be a good decision as I got a nice serviceable crank. It also allowed us to follow a pick-of-liter approach as we had two sets of everything to pick from. I ended up using the case, accessory cases, oil sump/etc. from the core as they were much better parts. The left over parts are nice to have as well as the Dodson core had 6 ECI cylinders with about 150 hours on them.

[Bruce Fenstermacher]

If you have a C-145 then you have an 8 bolt flange, the new cranks and the crank in the O-300C and D are 6 bolt. If you went with this crank you would need a field approval and anew prop.

Actually he would need the Associations STC that allows a C or D engine as well as the appropriate prop to be used on a 170.

[lschleinat]

I was refering to the use of the C/D crank in the original C-145 case, not the replacement of the C-145 with an O-300C/D and the use of the STC. I don't think the aforementioned is covered by the associations STC's, though it is possible that I am mistaken (there are certainly more knowledgable folks out there). In my case, I could not find a used crank of any type and the cost of a new crank was about the same as the C-145 Dodson core. All things considered, cost, paperwork, and the availability of additional parts, made the core, at least for me, the better alternative.

My original intent was to underscore some of the difficulty with rebuilding the C-145. In my case, after rounding up everything required for the rebuild (it took a while), I spent in the neighboorhood of $15K on new/used parts and parts remanufacturing (case, steel - crank, rods, etc.). This did include things like all new Airforms baffling (early dog house style) and new ECI cylinders as well as upgrades such as a SkyTec starter and an F&M oil filter adapter. So, depending on your needs and objectives, there are certainly opportunities for cost savings.

You will also run into some unexpected expenses as well; for example, even with two engines, I didn't get a good complete set of accessory case gears (we only had 1 good gear out of 6). After searching high and low for the other gears (don't remember which two), I ending up finding a new pair which cost in the neighborhood of $2000!

As one final point, when I found out my original crank was bad, I also considered purchasing a compete O-300A (8 bolt flange so I could use my existing prop) that had about 100 hours on a professional rebuild. The engine had been removed from a totaled 172 airframe. The owner wanted a firm $16K for the engine. After some careful consideration, I decided to proceed with the purchase of the core and rebuild the engine to my own personal standards. All rebuilds are not created equal.

With everything said and done, I might have been better off chunking the C-145 and finding and rebuilding a good O-300C/D core even with the need to replace the prop. Of course hindsight is always 20/20 and once you get far enough down a particual path it is difficult to alter course.

At the end of the day, I wound up with about as "new" a C-145 as you can build today.

[GAHorn]

That's a nice message, Larry. Thanks. Do you have contact info still for AirForms?

As for installing a 6-bolt crank into a C-145 or O-300-A... the best/simplest method would be to convert the engine to an O-300-C via TCM M75-6R1, found in the MX Library. It's mostly a paperwork issue and very easy to do as far as approval is concerned. (No field approval, necessary. Just purchase the Assn. STC., which also covers the prop (McCauley EM 76XX) and spinner.)

[lschleinat]

The Airforms website is www.enginebaffles.com. To the best of my knowledge they are the only source of the older Dog House style baffles for the non-pressure cowling. They will also powder coat the baffling if requested. I had mine done in White with Black seals. I believe it only took a couple of weeks for them to deliver what turned some really nice stuff which fit perfectly.

[Brad Brady]

That's a nice message, Larry. Thanks. Do you have contact info still for AirForms?

As for installing a 6-bolt crank into a C-145 or O-300-A... the best/simplest method would be to convert the engine to an O-300-C via TCM M75-6R1, found in the MX Library. It's mostly a paperwork issue and very easy to do as far as approval is concerned. (No field approval, necessary. Just purchase the Assn. STC., which also covers the prop (McCauley EM 76XX) and spinner.)

That's just where I'm at, thanks,George...Ron just told Dad he had two 0-300C cranks that would go in Dad's C145-2 engine.....But we would have to change props.......eight to six.....I don't know if that is worth the effort...we have a good prop and the rest of the engine looks......good from my perspective.....and that's just that.....my perspective...I still don't need an other prop if the one I have is good....as long as I can build an engine that matches the prop....But , of course I'm still thinking from the perspective,that I don't NEED a six bolt prop......And I can rebuild this engine.....Brad

[GAHorn]

Don't forget you might sell that 8-bolt prop to alleviate the costs of a 6-bolt prop. The 6-bolt EM-series of prop is slightly more efficient and also saves weight, over a DM-series. The end-result is that you'll have an engine that is brought into "modernity" from the standpoint of future support.

[Brad Brady]

Don't forget you might sell that 8-bolt prop to alleviate the costs of a 6-bolt prop. The 6-bolt EM-series of prop is slightly more efficient and also saves weight, over a DM-series. The end-result is that you'll have an engine that is brought into "modernity" from the standpoint of future support.

George,
Good point, I never thought about that...It's just going to be a real issue trying to do all the work, and the paper work....when I work for Dad for nothing ......I certainly owe Dad something, for getting me into aviation....Maybe a swift kick in the a** .....But if I weren't here, I have no idea where I would be......Brad