crankshaft gear

[Robert Harik]

When installing a starter adapter on an 0300 C engine do you have to change the crank gear?
Thanks, Rob

[Robert Harik]

The engine an O300C had a belt driven vacuum pump and the owner was told he could intall a starter adapter and mount the vacuum pump to it. The engine was built up and when he went to install the starter adapter it would not fit , because the gear on the crank was to large to allow the end of the adapter shaft to fit into the bushing or for the two gears to mesh.
Thanks , Rob

[Bruce Fenstermacher]

The D engine uses gear # 627846 while all the other models use #35016. The C model also uses # 632227 Pivot, starter pinion, which is not the same as any of the other models. The D model doesn't use a starter pinion but # 628919 Bushing, removable starter.

We know that the starter pinion on all the models including the C is pinned into the case halves and can not be removed without splitting the case. So removal of the pinion to use the required bushing for the angle starter can be done but not easily. And while with the changes to the right gear and bushing the starter should work fine I'd have to wonder what approval would be required to use the D model angle starter, gear and bushing on a C model engine.

[Robert Harik]

I have to wonder too!
I was not in on the engine rebuild, but I think not enough research was done before the work was started ,and too many "experts" were listend to.
The guy rebuilding the engine is a new A and P doing it under the direction of our instructor at A and P school. The instructor made sure all the proper manuals were used and that all the neccessary parts were yellow tagged or new ,including accesories, but I think he trusted the students research a little too much. The pinoin was remove during the rebuild and a bushing was installed, but the wrong gear was used on the crank and now it looks like it wont even be legal !
The owner is going to cry. Is there any STC for this or does it have to be redone?
Thanks, Rob

[Bruce Fenstermacher]

Rob all I did was look in the same parts manual they should have been using to get the information I gave you.

I didn't say it wouldn't be legal I said I'd have to wonder. It is clear before the engine is used for any purpose either the correct gear will have to be installed for the D model angle starter or the correct pinion installed for the C model starter.

As for legality I now it is possible to convert nearly any model engine in a series to another model ie 0-300A to 0-300D or in this case 0-300C to D. This is accomplished using a Continental service bulletin.

What I haven't researched is what parts are actually needed to convert an A or C model to a D model engine. It may be nothing more than the gear, bushing and angle starter or there might be other parts.

Then once the engine is converted to a D model there is the legality of using the new model engine on the airframe. If this engine is going on a 170 of any model it will not be legal (nor was the C model) without some bases of approval. In the case of the C or D model engine the association has an STC that will cover this installation in any 170 model as well as a few of the earliest 172 years.

A big problem with being an "expert" is sometimes you get caught saying things off the cuff or not giving complete answers assuming the listener knows there is a bit more to the story. If I'd been asked in passing if you could put an angle starter on a C model engine I'd probably say yes with out much thought though I've learned to verbally question the legal bases for doing such modifications.

Sometimes it is hell being an "expert" and much easier to mind your own business and keep your mouth shut. Fortunately for me "experts" have helped more than they've hurt and I'm so glad many, specially here at the forum, aren't afraid to put on their "expert" caps and share information.

[ron74887]

Rob---Bruce says "As for legality I now (know)it is possible to convert nearly any model engine in a series to another model ie 0-300A to 0-300D or in this case 0-300C to D. This is accomplished using a Continental service bulletin"

I think that is very correct and the legality would be that you have all the required "D" parts in the "C" case which can be found in the parts manual. On the type certificate of the O-300 series the difference betweenthe "C" and "D" is the angle drive stater adapter which would have to include the gear and the bushing. The data plate would have to be stamped XXXX O-300-CCD as per service bulletin to convert it to a "D" engine. Then get the STC from the Assoc. to be legal on your plane. Both cranks use the 6-bolt EM series prop.

Miles was going to put the starter adapter on his "A" engine but had to break the case halves and that ended that. So that can be done.

If the bushing for the angle drive starter adapter was put in the engine during rebuild then change the gear to fit the "D" engine per parts manual and change the data plate and it is now a "D" engine. I see no big problem. Ron

[GAHorn]

"Expert" is such a tough definition to meet.

Note "C" in the Introduction of the Overhaul Manual states: "All O-300-C engines subsequent to serial No. 21001 are so equipped that a right angle starter drive can be used if desired."

Now, as everyone has surmised so-far in this discussion..... that's a wildly-optimistic statement. For example, with WHICH GEAR? or pinion? or bushing?

Generalizations aside, if the C-engine is to be converted to a D-engine, the accy case will have to come off and the pinion removed (perhaps by cutting, otherwise the case-halves must be split) and the proper gear and accy case will have to be installed.

If this is the same engine as another member has called me about, (story sounds very similar), the front-mount belt-driven vacuum pump was removed and an engine-driven vacuum pump was intended to be installed....when it was discovered that an angle-starter would have to be mounted...and the caller wanted to know "what STC applies....and what adaptor is required.....) etc etc.

The simplest solution is: LEAVE the front-mount vacuum pump REMOVED, and convert the airplane's vacuum system back to the original venturiis... and install the original pull-type starter on the O-300-C engine, get the STC for installing that C-engine on a 170, and get on down the airways, and enjoy!

[Robert Harik]

Bruce , Ron ,Gahorn, thanks for your replys .

Bruce I meant "Expert" in the bad way, thats why the quotation marks. By those, I mean people who give advice in an "Expert" way , but dont really know what they are talking about.

I come here because there ARE experts here and I really do value the help I get.
I will find the service bulletin that applies.
Does any one know of a D gear(#627846) for sale or where to find one?

Gahorn ,it is not the same engine. The airplane has no venturi's.
The airplane will get alot of IFR time, and I know he wont want to install a venturi. Should he at least go for a wet pump instead of a dry one?


Thanks, Rob

[GAHorn]

Bruce , Ron ,Gahorn, thanks for your replys .

Bruce I meant "Expert" in the bad way, thats why the quotation marks. By those, I mean people who give advice in an "Expert" way , but dont really know what they are talking about.

I come here because there ARE experts here and I really do value the help I get.
I will find the service bulletin that applies.
Does any one know of a D gear(#627846) for sale or where to find one?

Gahorn ,it is not the same engine. The airplane has no venturi's.
The airplane will get alot of IFR time, and I know he wont want to install a venturi. Should he at least go for a wet pump instead of a dry one?


Thanks, Rob

My suggestion is still: Install venturiis. SUPER venturiis if you like. Venturis are perfectly GOOD for IFR work. The only shortcoming a venturi has is that the gyro's will not work until you're 300-500 airborne, so zero-zero takeoffs are not such a good idea. (But since when IS a zero-zero takeoff in a single-engined airplane a good idea?)

Vacuum pumps are failure prone. Especially dry vacuum pumps. (Yes, If I were foolish enough to remove my venturiis and install a vacuum pump, I'd at the very least install a WET pump.) Vacuum pumps require the engine to drive them. They fail. So do engines. Venturiis ALWAYS work if you are flying.

"What about ICE?", somone always asks. Answer: What the *&^$&^%*&%# are you doing trying to fly an airplane NOT approved for ice in icing conditions? In any case, the airplane will 1) quit flying before the venturiis ice-up sufficiently to become your biggest problem and 2) that's what the electric back-up gyro and partial-panel flight-training is for!

PS: Do not take wrong, my forceful attempt to persuade you to the joys of venturis. (Despite the way I worded my argument against pumps, I do not mean it as criticism of those who disagree with me.) I feel strongly about this subject and am really unsympathetic to the woes of vacuum-pump convertees. This is one subject to which my "originality (mostly) nut" slogan applies. But if you are danged-and-determined to install a vacuum pump, I have a new-in-the-box Sigma-Tec Model 1U128-006 for sale, cheap. $150 less than list: ($350 plus shipping)

Or pay $500 PLUS for one elsewhere. Here's where you can buy one at that price:
http://www.aircraftspruce.com/catalog/i ... gmatek.php

Here's a pic of the one I have for sale. (credit card OK, I'll invoice via PayPal the first victim who contacts me with an email address. )

MVC-019S.JPG

[Bruce Fenstermacher]

Rob it would seem that George has the easy answer in that the overhaul manual allows the angle starter on C model engines if I am reading his post correctly. And again reading into his post the overhaul manual doesn't get into detail as to exactly how that is to be done. Sooo in my "expert" opinion you would use only the parts necessary and in this case that is at least bushing and different gear. Perhaps the C model accessory case can be used. I don't know if there is any actual difference in the accessory cases between models. I'd be looking closely at them were the starter bolts on. I don't have my parts manual on hand to varify if the part numbers are different.

Preferred Airparts, 800-433-0814, http://www.preferredairparts.com lists having 30 serviceable gears with part number 627846 in stock. You will have to call them for a price. I've found them to be good to deal with.

[ron74887]

Rob, not have the parts manual in front of me, if I am not mistaken ( which I am often enough) the starter adapter uses the same 3 bolts that were used to hold the old pull starter on and the new starter is at 90 degrees from that and the vacuum pump bolts on the rear of the starter adapter. ?? I think the rear cases are all adaptable to the angle drive starter adapter. Again if Miles was going to put it on his "A" I don't see the acc. cases being different. Miles???? Ron

[c170b53]

I could be classified as one of those experts (as in a bad one) and I certainly don't have the time in as these other folks have (cause they been at it just a bit longer than me) but are we talking about the gear on the crankshaft? What is also amazing is the amount of info that's not documented here but may be available if you dare ask.

[Bruce Fenstermacher]

Yes we are talking about the gear that is mounted on the crankshaft which is different for the angle starter.

[c170b53]

Thanks Bruce, I'm thinking that gear has got to cost a few bucks.

[n2582d]

Thanks Bruce, I'm thinking that gear has got to cost a few bucks.

There's the understatement of the year. From Fresno Airparts 559-237-4863 for $875. This used one is available in England for "only" $743.

e824.jpg

The lightweight, no moving parts, totally reliable, venturi setup is looking even better! The drawback to the venturi system is that one's heirs won't be able to collect millions when a vacuum pump supposedly fails during IFR. http://www.engr.sjsu.edu/epeterson/Avia ... awsuit.doc