0-300B STC available?

[gparker]

I've seen that there is an STC to install the 0-300-B in my 1956 airframe, but when I looked at the members' list of materials, all I saw was a list of previous 337s. Is there such an STC? Who owns it and how much is it? Anyone with experience here? Any reason not to use the -B engine?

[Bruce Fenstermacher]

Yes, the Association owns the STC and it is available from HQ for $75 for members and $150 for non-members. It is not listed in our documents library. (Because I haven't thought about listing it)

There is no reason not to use the -B engine. It is the same as a -A but it has the control on the side for an adjustable prop. This control is just wired closed.

Where did the -B engine come from? Was it in your 56 when you got it or is it a spare engine. You see Continental changed from the naming convention of using horse power, as in C-145, to cubic inches, as in 0-300, some time between 55 and 56. It is entirely possible you 56 cam from the factory with a -B engine. Even though it was never listed on the TCDS.

We've ever been able to positively show that a 56 came with a -B because there are just to few 56s made. And of course there is a big possibility none of the 56s did come with a -B and all where delivered with 0-300-A engines We will never know unless we could gather the build records for every 56 and check the engine serial number.

If you could show that this -B was the original engine as delivered from the factory in your 170, then I wouldn't be to worried however for $75 the associations STC will satisfy any legality issues anyone could bring up.

[cessna170bdriver]

... You see Continental changed from the naming convention of using horse power, as in C-145, to cubic inches, as in 0-300, some time between 55 and 56....

If you're talking year models, could be. If you're talking calendar year, my '55 B-model rolled off the line in October1954 with an O-300A, the same one that's on it now.

[Bruce Fenstermacher]

And my point is that any time after that point which the engines installed at the factory had the cubic inch designation, that if the factory had a call to install an engine with the prop control, they would have installed a 0-300-B. We have no documentation this happened but it could have. Of course we know the -B never made it on the TCDS but I would say that is not a definitive indication the factory didn't install any.

[gparker]

The engine is one I've seen for sale. Just got word that I need three new cylinders on my -A engine, plus at least one loose connecting rod. May be time for overhaul of my engine. I can get this -B engine for a pretty good price, not too much more than parts for mine. And the B engine has less time than mine.
Thanks for your replies... I'll let you know what I do.

[gar450]

Ok, not to stir sleeping dogs just wondering since the stc is available what would be the significance if there ever was a 170 with the 0300b installed. Just curious.

[c170b53]

Accompanied with the STC paperwork, it would be a legal installation. Without the paperwork it would be a "stealth" installation.
Welcome, hope you enjoy the company!

[GAHorn]

I'm not where my copy of the STC is....so I'm relying on my poor memory.... Bruce, are you certain the B engine is included in our STC?
I seem to recall it includes the C and D engines....but I don't remember it mentioning the B. (Nor the E, for that matter.)

[blueldr]

Put the B model engine in. I guarantee you wont lose any sleep over it, even without the STC. Stealth adds a little spice to aviation. Makes it more fun.

[marathonrunner]

Continental has a bulletin that allows you to change from one model to another and you just re stamp the data plate with a "C" then the Letter of the new model number. I can research it and find the exact bulletin but it is a legal way to do this and just a log entry.

[marathonrunner]

The bulletin number is M75-6R1 Release date was 06/04/1975 titled "Conversion of Engines from One Model to Another"

Hope this helps

[mike roe]

C170 Assoc STC 01837SE-0300-B allows installation of 0300B in 170.

[Bruce Fenstermacher]

Ok, not to stir sleeping dogs just wondering since the stc is available what would be the significance if there ever was a 170 with the 0300b installed. Just curious.

I don't have the STC paperwork available here at work but will look at it again tonight.

To understand the answer to this question you have to understand the circumstances that surround it. At one time Continental named their engines by their horse power. A C-145 was rated at 145 hp at 2700 rpm. They changed the naming convention to match their competitors and started using cubic inches. So the C-145 became the 0-300. To be more specific the C-145-2 became the 0-300A and the C-145-2H became the 0-300B.

The Type Certificate Data Sheet (TCDS) for our Cessna 170s allows the use of a C-145-2 on the 170, the C-145-2 and 2H on the 170A and 170B. When the name of the engine was changed an optional engine was added in item 112 to allow a 0-300A on all the models.

Notice the C-145-2H was never approved for the 170 and it's equivalent the 0-300B was never added to the TCDS for the 170A and 170B. Many knowledgeable folks don't realize this and just assume all the engines are OK on all models of 170.

It does not make sense really and we can only speculate that at the time not many people cared as they knew the engines were the same and common sense was applied. Of course today everything must be in black and white and unfortunately it is not.

Ron Massicot who developed the Associations STC was not trying to right all the loop holes. He was actually just trying to get a propeller approved to install on a 0-300D he already considered to be OK to install. So his STC was written with the goal to document approved propellers and of course to close the circle engines and spinners one might use.

Since then we have come to realize some of the missing engine airframe combinations and have received either additons to the original STC or in the case of the 170 a different STC. (The Association actually has 2 engine STCs)

There are still a few questions about certain engine/prop/spinner combinations that are not addressed specifically by our STCs because common sense, if it prevailed, has been followed.

I can not remember if the combination of 0-300B on our 170s was addressed by our STCs but I believe it was. I will check and report back.

So to answer the OPs question. If we could prove that Cessna delivered a 170B in 56 with a 0-300B after Continental changed the name of the approved C-145-2H, it would go a long way, in my mind, to showing they considered the C-145 and the 0-300 engines to be the same.

BTW I know of only one 56 (could be a 55) that might have a 0-300B (could be a C-145-2H) installed. This aircraft is member Dave Bengtson of TX who is also running the only known McCauley two position prop which requires one of these engines. I've not been in a position to review this aircrafts records because like most of us, Dave doesn't carry those records with him.

[gar450]

Thanks guys. Bruce, great explanation. So if i understand it is one more loophole closed against the Feds. as well as peace of mind.

[Bruce Fenstermacher]

Thanks guys. Bruce, great explanation. So if i understand it is one more loophole closed against the Feds. as well as peace of mind.

You can think of it that way I guess as long as our STC does in fact cover the 0-300B in the 170 which I'll confirm tonight.