What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

O-320 options for finishing kit

YellowJacket RV9

YellowJacket RV9

Well Known Member
Patron
I am at the point where I need to think about ordering my 9A finishing kit. Unfortunately, I do not yet have an engine, and plan on buying used in the next year or so when I spot a good deal. Plan is for a low-compression O-320, but 160HP not out of the question.

I need to specify engine mount type and induction type (vert or horiz) to order the finishing kit, but obviously I don't know yet, so my question is if there is one setup that is most common among the o-320's I am likely to find, so that I can plan on that, and if need be make changes later. I believe that most are Dynafocal type I, but am unsure as to induction style.

Any suggestions from the experts? Thanks!

Chris
 
Last edited:
Here is my understanding.

Dynafocal 1 is vastly more common. I would plan for it. Buy an engine for it.

Dynafocal 2 was designed for engines with LONG prop extensions such as some twins that used (I)O-320s and long hub constant speed props.

In each case, the focal point of the engine mount is designed to be as close to the CG of the engine/prop system as possible.

While it does work, as shown by the RVs that have them, Dynafocal 1 without the long prop hub (not used on RVs) seems to me like an intentional design error.
 
Got it, must have had it backwards about the engine mounts. Thanks! Any thoughts on the induction style? Does it affect anything other than the lower cowling?

Chris
 
Engine mount

Vans doesn't sell a 9 mount built for Dyna II engines. I acquired a Dyna II engine (Twin Commanche) and had the case converted to Dyna I by Divco. The stock O-320 engine mount should work with the common 320's you are likely to find. There are exceptions like the the H series engines and the R22 non Dyna version. Maybe the engine should be the next acquisition for your project since it will drive other decisions.

Don Broussard

RV 9. Rebuild in Progress
 
Dynafocal 1 carbureted (vertical induction) 0-320s are the most common by far. As previously stated there are always several conical mount wide deck O-320 engines on the market that were removed from R-22s for decent prices.
 
You must log in or register to reply here.
Back
Top