C145 or 0 300D?

[Mark Harwood]

I am a new member (and a novice) needing some advice. I purchased a 1949 170A last winter and burned a hole in a piston after 4 hr flying. Decided to tear engine down. I currently have a C145 non dampened crank that is yellow tagable at Aircraft specialties and I have an 0300D case at Divco that is yellow tagged. They were married in 1971, I now understand illegally. The prop I have is for the 8 bolt flange. Is the undampened crank going to lead to any problems that a dampened crank would avoid? Is there an STC avail to put an 0300D in a 170A? How much would the STC cost? If I were to sell in the future, would a C145 vs. an 0300D effect the value? I am going to be spending a good chunk of $ either way. It would be cheaper for me to build a C145 with my nondampened crank ad 8 bolt prop. I don't want to wish in a few years that I had spent a little more and gotten a considerably better product. Any input?

[lowNslow]

The STC for installing the 300D in a 170 is available from the 170 Assoc. I believe it is $200.

[Bruce Fenstermacher]

Actually the STC for the 0-300D might be cheaper for members. It is VERY reasonalbe in any case.

There are only 2 advantages I can think of to having a 0-300D over a C-145 undampened crank.

1. The undampened crank version of the C-145 is restricted to a 25 amp or less generator.

2. The 0-300D could/should have an angled starter. That in itself is not the advantage and many mioght argue a disadvantage. What the angled starter does give you that might be an advantage is a vacuum pump pad.

Two years ago I was about at the point your are at. I had a good undampened crank and needed to rebuild. I considered replacing the crank with a newer dampened crank from a 0-300D essentially (but not legaly) changing the engine to a 0-300C.

I decided to keep the engine a stock undampened C-145 because I didn't think either of the advantages I outlined was worth the hassle and expense.

In my opinion given two otherswise identical 170s to purchase, an aircraft with 0300D verses an undampened crank C-145 only offers a slightly better value. And I'm not sure I'd pay more for it.

[Mark Harwood]

Thanks for your input! How would I go about finding info and obtaining STC to convert to 0 300D if I decide to go that way? Thanks! Mark

[Bruce Fenstermacher]

I'm not sure there is an STC to convert the engine. There is one to put a 0300D into the 170 airframe.

The first place to start is with the parts manual to see what parts are usable on what models and what is interchangable. It's been a while since I looked at this.

I won't have one in front of me till tonight if no one else chimes in with the answer.

BTW like most every subject we've discussed this here before but it's been some time. Perhaps a search of the forums will turn up info.

[GAHorn]

The MX Library contains reference to a TCM Service Bulletin which addresses changing one engine model to another. You might wish to review it, and contact TCM directly with this question.
http://cessna170.org/phpBB2/viewtopic.php?t=2303

[Mark Harwood]

I spoke to TCM and I am likely going to build up a c145 to avoid the cost of a new prop and crank. I can put the c145 crank in c 145 0r 0300A case as I understood TCM, they are identical. I am currently dealing with a builder in OK close to Divco and AC Specialties which is where my parts are. Thanks for the input!