SonexBuilders.net

After admiring my replacement crankshaft for a couple of months ( you might remember, the first one had rusty journals ), I decided to actually assemble the engine. (Oh yeah, I finally got the back-ordered parts a week ago. Only took 6 months).

Page 9 of the assembly manuals (both turbo and non-turbo) would have you drill the oil hole located on the #1 main bearing to an oversize of .127in. (#30 drill).

Having, over the last 2 years, drilled something like 8,000 #30 holes, it wasn't hard to tell the bearing had not been opened up to that dimension. The hole that the bearing comes with is .087in. Not even a #40.

None of this would be of interest had it not been for the fact that we bought the engine kit at Airventure 2017, and as a BONUS ?? we got the pre-assembled crankshaft.

The shaft is currently at the machine shop having the prop hub removed, as drilling the hole while it's installed is not an option.

So boys and girls, if you haven't put your engines together yet, check the hole dimension before assembly as it looks to be moderately important that the #1 bearing gets enough oil.

Going through the rolodex to get Hummel's phone number here @Area 51%

Hello Folks,

Do NOT have that that prop hub removed! Wish you would have contacted us first before having the pre-assembled crank sent to your machine shop. We have not been enlarging that hole for many years as we've found it to not make any real difference. Our oversight for not updating the manual, and our apologies for that, but this should be a lesson to all to please consult Sonex first before jumping to any drastic course of action such as dis-assembling your Sonex factory pre-assembled crank.

--
Mark Schaible
General Manager
Sonex Aircraft, LLC
phone: 920-231-8297
fax: 920-426-8333
http://www.SonexAircraft.com
http://www.AeroConversions.com

Sales Info: sales@sonexaircraft.com
Orders: orders@sonexaircraft.com
Accounting: accounting@sonexaircraft.com
Tech Support: tech@sonexaircraft.com

Gee Mark...............

Update the manual, don't update the manual, don't really care.

Where I went when I discovered the discrepancy was directly to the service bulletins. You know, THE SERVICE BULLETINS!! When a change is made or rescinded. You know, the place I'm supposed to visit frequently to insure all technical data is up to date. You know, the fine print that puts the responsibility back on me.

Didn't see anything about reinstalling the restrictor plug to the #1 bearing either, so it didn't make much sense to restrict the oil flow at the bearing.

I was told that the assembly manual takes precedent over all other forms of information...........written or anecdotal. I suppose the fact the slinger rattled around loosely on both of the cranks I've had the pleasure of knowing, (you know, the slinger that the hub allegedly pinches tightly against the crank so it can do it's job) was also just a typo or something that was overlooked?

You'll have to excuse me now..........I have some fixing to do here @Area 51%