SonexBuilders.net

Posted: **Tue Jun 18, 2024 6:11 pm**

That prop spacer is what I was thinking would have to be done. 1" seems really heavy and overkill. A picture would be worth 500 words (inflation you know).

Posted: **Tue Jun 18, 2024 6:14 pm**

Kai wrote:Check that the crankshaft has the smaller ø20mm prop flange bolt, and not the bigger one.
Get the prop dynamically balanced.
Find a proper place for the 4 cht sensors like shown on these pages previously.
Be very suspicious if you ever see the cht at anything much above 300F.
Check the ignition system for proper timing. When done, check it again.
Get hold of very high quality valves. If you´re not very comfortable with cutting seats and grinding in valves and seats yourself, take them to someone who is.
If the carburettor has a leaning device, always keep the A/F ratio below 12.5-12.8
Make sure that your cooling air plenum and baffeling is super tight. ALL the air must go where it cools- especially on the underside of the heads..
The exit lips on the air outlets in the cowling like suggested by Sonex must be in place. At least make them so wide that the the lower edge is flush with the bottom of the fuselage floor. Even better extend the cowling outlet channles back to the firewall. As an alternative you could also put side outlets in the cowling- mine made a real difference.
And finally- run the engine exclusively on good quality high octane fuel. Detonation will kill it faster than anything else.

That’s quite the comprehensive list. Thanks! Many (all) of those tasks are beyond my current limited (nonexistent) mechanical skillset. Lots to learn…

Posted: **Tue Jun 18, 2024 6:15 pm**

Kai wrote:Get the prop dynamically balanced.

I'd argue this is a nice to have, not a must have.

Posted: **Tue Jun 18, 2024 9:21 pm**

Kai wrote:Get hold of very high quality valves. If you´re not very comfortable with cutting seats and grinding in valves and seats yourself, take them to someone who is.

So, would you replace the valves that ship with a new head from Sonex?

Posted: **Tue Jun 18, 2024 9:33 pm**

Hambone wrote:So, would you replace the valves that ship with a new head from Sonex?

I'm curious if the valves from Sonex are the same as when I bought my engine. Aerovee S/N 795. Pretty close to Darick's S/N I'm guessing. I noticed the valve stems had deformed under the valve keepers a bit. I think the stainless quality of the 2014 era valves were not the best.

Posted: **Tue Jun 18, 2024 11:36 pm**

Here's a good page from the massive amount of information Mark Langford has on his site. In the beginning he was flying a KR2 with a VW engine and chronicled his work with maintaining the 2180 conversion it had.

He gets into various types of VW heads and some of the issues with each and includes some of the errors discovered when he selected the wrong heads to use.

Lots to learn here: http://www.n56ml.com/n891jf/vw/

Posted: **Wed Jun 19, 2024 1:23 am**

BRS wrote:That prop spacer is what I was thinking would have to be done. 1" seems really heavy and overkill. A picture would be worth 500 words (inflation you know).

No- not really! 1 inch is what allows for space between prop and cowling for those 1 inch dia balancing weight washers. Besides, the spacers from Sabre are made from aluminium and are super light- really a work of art. I´ll venture out to the field as soon as the rain stops- you´ll get your pic: promise!

Posted: **Wed Jun 19, 2024 9:31 am**

Using my Dyna-Vibe balancer with a wood Sensenich prop on my CAMit 3300, was able to bring it nicely in balance by just adding some large washers under the nuts of the prop bolts. That was about 3 or 4 years ago, time to do it again.

David A.

Posted: **Wed Jun 19, 2024 10:57 am**

DCASonex wrote:Using my Dyna-Vibe balancer with a wood Sensenich prop on my CAMit 3300, was able to bring it nicely in balance by just adding some large washers under the nuts of the prop bolts. That was about 3 or 4 years ago, time to do it again.

David A.

I've the same balancer. I should at least give it a try and see how far out of balance I am (the plane not me). Really though, in flight it feels smooth, it's just that if there is something to be tweaked (in a good way) why spend my time flying when I can find a reason to be wrenching. Ha.

Posted: **Wed Jun 19, 2024 11:02 am**

BRS wrote:Really though, in flight it feels smooth, it's just that if there is something to be tweaked (in a good way) why spend my time flying when I can find a reason to be wrenching. Ha.

If it's not broke, fix it some more!

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