R

rsr3

Well Known Member
Let’s say I have a choice of two engine cases to build up. An O-360 case that has been fretting and would need work by Divco or a HIO-360 case that has Dyna 2 mountings vs Dyna 1.

If you had a choice of building an engine up with dynafocal 2 mountings vs getting the case machined to dynafocal 1, would you do it? If not, why not?

With the geometry of the Dyna 2 mount designed for engines with a cg that is further forward (I.e. using a prop extension) is there anything to suggest that it would not work just fine with an engine that didn’t use a prop extension and therefore have the cg in the normal position?

Would the Dyna 2 with “normal” engine cg make it any less structurally sound, or affect vibration damping or mount longevity?

The obvious benefits to the HIO case is the beefier bearings and piston oil squirters.

The obvious downside to going for a Dyna 2 mount now that I already have a Dyna 1 mount bolted to my airframe is that the new mount might not match up with my holes and would also require buying a second mount. I also have Dyna 1 Barry mounts ready to go - I guess I will need to buy some different ones for the HIO-360.

Thanks for your input!
 
Have you checked into finding a motor mount for the Dyna 2?

I would seriously consider using the HIO and having it reworked. Oil squirters may need a bigger oil cooler.
 
I am using an IO-320-B1A for my RV-9A just got my bill for the overhaul of the case and converting from Dyna 2 to Dyna 1 and it was $2075 for the work at Crankcase Services in Sand Springs Oklahoma.
 
Thanks for the pointers, both. I was only aware of Divco to do the machine work. I’m in contact with Vans who are apparently reconsidering offering a type 2 mount. So far Divco have been unresponsive and so Crankcase Services will be my next port of call.

Thanks again.
 
Interesting that Divco is non-responsive. I used them this spring for case fretting repair on my Aero Sport O-360 A1A w/9:1 CR, Superior case. They were very responsive and helpful - talked with Jane on the phone to set up my drop off. I drove the case down and Monty Barret (rev B) gave me a Divco shop tour. He also suggested a Lycoming SI mod that puts additional dowels in the case to help with fretting. If you want the case ASAP, you can pay an expediting fee (As I recall, $300).
 
I am using an IO-320-B1A in my RV8, I got a Dyna 2 mount from Vans. When I ordered it in 2020, they said it was a special order and I wouldn't be able to return it. With that being said it fit perfectly and I am happy with it.
 
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