Jabiru CHT temps high one one side - EGT's OK.

Jabiru CHT temps high, on 2,4,6, but 1,3,5 OK.


I flew my new Zodiac for the first time today, It was great, except for the high CHT.

I had someone else fly it first, did my GA conversion and flew it today.  I was told cyl 4 was too hot (170 C), so I installed a baffle in the ram air duct above cyl 4. (Jabiru 3300), The test are much cooler.

When I flew it cyl 6 was hottest.= the baffle cut air to 6.

I tried cutting off the lip on the cowl, and moving it back, made it slightly better, but still too hot.

It is running a bit rich, but I will leave that until run in,

I am thinking of cutting the exhaust pipe which extends about 8" past the cowl to a close fit, I am told that may help.

My next steps are to experiment with the cowl shape.

Any constructive ideas welcomed.  Can;t wait to sort this so I get to the real flying.


Bob Emery

Newcastle NSW Australia


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Comment by Robert Emery on June 26, 2011 at 1:53am

Thanks for the replies.  I installed an aitr intake divider today.  Amazed at the results.

I now have much improved CHT;s when I flew today.

I also am experimenting with the lower cowling lip - position, size and angle.

Great stuff.

Bob Emery

Comment by Michael Herder on June 25, 2011 at 9:33am
As you've may have heard before, an intake divider helps tremendously.  my EGT's and CHT's are all tolerable with about 10 or so hours of tinkering.
Comment by Michael Herder on June 25, 2011 at 9:32am

Try tilting your bing carb. It makes gets more fuel to your lean bank of cylinders and helps them run cooler.  It really makes a difference.  When you tilt, double check to make sure you have full control of the throttle through all ranges.  Ask me how I know:).


Are you monitoring your EGT's?  The advice I just gave assumes that some of your cylinders are running lean, and therefore hot.

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