Tuning the Bing CAMit 3300

[DCASonex]

Ken,

As you have noted, many small things can affect CHTs and EGTs.

The inserts I made to top of my plenums were made to fit with existing cooling vents to mags and fuel pump (photo of that in files section Jab-CAMit forum). Not at all surprising that something a bit different works better on yours.

Likewise, minor cowling and baffle sealing differences may account for the differences we see in jet sizes by changing the air pressure the carb sees. Ian mentioned working up some test rig for this to make installations between various air frames more consistent, but sounded like that was a work in progress. If fuel flows are up near same as mine, it is likely you are close to correct, but surprised your cruise EGTs are not higher. Needle shape will make a big difference, but at WOT it is is essentially removed from the jet for all but its small tip, which is about same on all needles, where mine was just too lean with anything smaller than a 2.80 needle jet (and 2.55 main).

Simple test just to provide a ref. point, put in a larger main (bottom) jet. That should not affect anything other than WOT operation. If nothing changes, it is your needle jet that is restricting flow at WOT. If slightly larger needle jet is then installed can reset main jet. If larger needle jet makes EGTs at cruise go up, you were running lean of peak. If EGTs go down, you will need a needle with fatter swelled area to restrict flow at cruise while passing enough fuel at WOT. Worth making this check just to confirm all is good to protect that new engine and provide confidence in your tuning.

No flying here today. Snowing like heck, not even IFR, just IRS, as in stay in and finish taxes.

David A.

[racaldwell]

Hello Ken,

Are you still on here? I am about to hang my CAMit 3300. I would like to know where you got the CAMit instructions for the EGT locations. I only have their Operation & Maintenance Manual. Did they make an Installation Manual? If so, can to send me a copy?

Also, did you install the engine mount spacer on the bottom mounts only like the Sonex instructions say?

Thanks, Rick Caldwell
Xenos 0057

[DCASonex]

Rick, I have a two page CAMit engine installation Specifications sheet that came with my 3300. It does not mention EGT location but can send it to you if want. I have my EGTs in the exhaust pipes about 4" below the cylinders simply because that is where they were in my jab 3300 installation, and i am using the exhaust pipes from that.

David A.

[kmwoody]

Hi Rick,

I had sent an e-mail off to CAMit asking their EGT locations. I don't recall why I questioned Jabirus EGT locations, but CAMit sent me a two page PDF illustrating their measurements, hence the 42mm measurement.
I sold my Sonex last year and deleted everything I had from Sonex and CAMit so, sorry, I cannot produce the PDF.
As far as the spacers, I put them where I needed to get the engine as close as possible to mounting specs.
Everything I received from CAMit was on the disk that came with the engine.

Sending you a PM.

Ken W

[racaldwell]

Thanks, David & Ken for the reply. Yes, David if you could send me what you have for installation from CAMit. That should be helpful. Send me a PM if you can't reach my email from this site data.

Ken, I'll use the EGT locations that you stated from CAMit.

Now my issue is the alternator interference. I'll address that under a new heading.

Rick Caldwell
Xenos 0057

[racaldwell]

David,

No need to send that. Ken jogged my memory that there was a CD and I see the inhibitor and EGT install instructions there.

Thanks Ken. I totally forgot about the CD,

Rick Caldwell
Xenos 0057