O-300-D Install and STC

[Sask170b]

I'm contemplating the install of a O-300-D engine into my 55 170B. I have read quite a few of the forum threads and see that the STC SA7441SW is avaialble through the Association and that is great. What I can't find the answers to are the questions of whether I can run the engine after removing the vacuum pump assembly ie: is there a cover plate etc. another question is whether the exhaust requires modification of the lower cowl skins , as it looks to me that the O-300-D pipes I've seen look set wider apart? I was hoping to purchase a set of the Bartone pipe extensions for the O-300-A presently on the plane, and would hope they would transition over to the O-300-D? I do realize the prop flange is different for the 300-D. Any information from anyone having done the install, or experienced members I would appreciate. Thanks Mike

[Bruce Fenstermacher]

The same exhaust is used on the 0-300D with STC as is used on the 0-300A so it would exit at the same place. When you look at a 172 exhaust your are indeed seeing a slightly wider exit as the 172 exhaust is wider than the 170. As for the Bartone exhaust, they are only the exit tubes, you still use the 170 Hanlon Wilson mufflers.

You do not have to install a vacuum pump with the STC. If you do not I suppose it would be wise to install Continental #640380 cover, made for the purpose of covering the vacuum pad. It is not directly addressed in the STC.
See item 34 below

Form X30014 figure 20

This cover could easily be an owner produced part in my opinion.

This change has been done hundreds of times with and without the STC to make it a legal install. It is nearly a bolt in replacement/swap of the C-145/0-300A except one has to add the electronic components necessary to operate the different starter and one needs a different prop and spinner if they are not using the skull cap type spinner.

[Sask170b]

Afternoon Bruce,
Thank You very much for the information. Just to clarify without sounded stunned, I would use my O-300-A muffler / Exhaust system on the O-300-D in order to exit through existing openings? My thoughts on removing the vacuum pump is that the venturi works well right now, and removing is less weight, and one less thing to go wrong? Who do I contact for buying the STC? Mike

[Bruce Fenstermacher]

Why would you be stunned to find you use the same muffler for the same engine, the differences being prop flange and options that can be put on the accessory case.

Yes the C/145 and all the 0-300 models use the same Hanlon-Wilson muffler system setup on a 170. (I suppose if one was still running pancake mufflers and wanted to continue doing so, they'd be OK as well). And as the STC is also good on a 172, one would then use the muffler system from those years of 172 the STC applies.

No need to explain, I wouldn't want a vacuum pump either. Fact is I could take or leave the angle starter as it is more complex. In reality the 0-300 C would work just fine for me if I had a 6 bolt prop. You could install your accessory case and starter from your 0-300 A on to the D and convert it to a C and install that with the STC if you choose to.

Contact Jan and Headquarters to buy the STC.

The International Cessna 170 Association, Inc.
22 Vista View Lane
Cody, WY 82414-9606

(307)587-6397 (Phone)
Email headquarters@cessna170.org

[GAHorn]

I am also a proponent of the O-300-C and venturiis. The angle starter adaptor has it's own set of failure modes which I do not care for.

[Sask170b]

Thanks George

[c170b53]

Sweet Avatar Mike, nice plane

[Sask170b]

Thanks Jim

[Sask170b]

I came in second on the salvage bids on a low time O-300D within province, so my search continues, or end up rebuilding the O-300A. I still have hours left on this engine, just couldn't pass the D model up for the right price.