0-300A Overhaul Recomendation

[Bruce Fenstermacher]

Rich

Lucky you. The answers are yes and yes in that order.

The same engine mount and exhaust is used for the C-145-2, 0300-A, B, C, and D.

You will need an appropriate propellor and spinner for the D and you will need to acquire an angle starter if the engine doesn't come with one and address the way the starter is wired and activated which is different that the cable pull starters found on the earlier models.

[cessna170bdriver]

Thanks, Bruce, that's kind of what I figured.

Also, two other questions about the A to D conversion:

1) Do both the A and the D use the same engine mount?

2) Can I use the same exhaust on the A and the D?

Thanks, once again for all your help.

Rich

YES on both questions.

Miles

[Iceman07]

Thanks, guys. Great info.

I've made the decision to go with the 300D conversion.

I have found a 0 SMHO that has a vacuum pump. I have searched the forums, but I can't find the answer to this question: Is there an STC to convert from a venturi to an engine driven system?

Another Question the STC specifies a McCauley IC-172EM or Sensenich M74C prop. Are there any advantages of the McCauley over the Sensenich (or vice-versa). And where is the best source for a prop/spinner?

Thanks again

[GAHorn]

The venturi system was an optional item on the type certificate. Removing it is a change to the equipt list and wt/bal. and log entry, in my view, but some will see it as a Form 337 item, no further approval needed. (FAA gets a copy but no approval needed in Block 3 because the aircraft is approved without a venturi system.)

The addition of the vacuum pump is also a Form 337 item, but not requiring Block 3 (Field Approval) either. Be certain to include ICA (Instructions for Continued Airworthiness) per the pump mfr and per Cessna Service Manual for the airplane.

The conversion to the O-300-D is covered by the TIC170A (our assoc.) STC formerly owned by past prez Ron Massicot....obtainable from headquarters.

The McCauley is preferable, in my opinion, because it has marginally better performance (if both props are new -- but a new Sensenich might meet/outperform a used McCauley depending upon condition) ... and the McCauley is much more common in the used marketplace.

[Bruce Fenstermacher]

I've not read the Association's Engine STC yet so I don't know exactly all that it approves. If it does not cover the vacuum pump I would think this would be an easy additional approval under a separate 337. After all you are just using the same system approved for thousands of 172s.

As for the Mcauley over the Sensenich I would probably go with the McCauley. This may not be the case with these two model props but for the original McCauley and Sensenich props specified for the 170 the McCauley performed slightly better according to the numbers in the owners hand book.

If I where you I'd try to get a copy of a later 172 owners hand book or AFM which might have performance numbers for these newer props and see if this still holds true.

[ron74887]

Rich, The STC covers the engines 0-300-C,D,and E, props Mcauley and sensenich,as well as seaplane, spinners both shapes and vacuum pumps wet and dry. You can use your current mag switch with a push button or you can switch to the new mag with the start position. BE SURE TO KEEP YOUR OLD DIP STICK, mufflers, baffling and carb heat box!!! If you need any help call me or email me, I'm in the directory or someone will give you all the info you need. thanks Ron

[GAHorn]

Ron is correct, of course, as to the STC covering the installation of a vacuum pump on the engine. But the STC only references other IPC sources for actual installation details (converting a venturi to a pump on the airframe) and that's why I feel it's imperative to include a separate Form 337 covering the airframe, if converting from venturi-to-pump at the same time as the engine/prop STC. (dotting i's and crossing t's)