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Permalink Reply by John L Warren on August 7, 2022 at 4:45pm

I have the gen4 on my Cruzer and I love it, Temps are great, I installed the Hacman value to control the mixture a little better and it's working good. John W. N10477

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Permalink Reply by John Austin on August 8, 2022 at 9:25am

I have zero personal experience with the Gen 4 3300 (my 745 hr engine was built in the transition from Gen 2 to Gen 3 and has some, but not all of the Gen 3 upgrades), but I follow the Jabiru/Camit Engine Forum on groups.io and here is a typical comment (C to F temp conversions added by me):

I replaced a Gen 3 hydraulic lifter engine with a Gen 4 no 2862 in October 2019. It has done 230 hours.

It is almost a different engine. No SB’s or SL’s. Servicing is more about look and check rather than unbolt. Excellent compressions and easy start. No problem with hot starts. Oil consumption is low, but should still be changed every 25 hours. Cooling is stable and within limits. Hottest temp seen on a hot day (for the UK) is 175 deg C (347 F) on climb out. EGT’s are on the low side at 620 deg C (1148 F) with a fuel burn of about 20 – 24 litres per hour (5.3 - 6.3 gal) at 2800 – 2850 revs and 110 – 115 indicated airspeed in clear air and level flight. Oil temp is usually at or just below 80 deg C (176 F).

Dull but that is how I like aircraft engines.

Peter Knight G-PHYZ J430

This is in a Jabiru J430 airframe, so it's an apples-oranges comparison to a CH650, but I posted it primarily because it seems to echo most of the random comments I've picked-up about the Gen 4 experience so far. 

For those who don't know, the Gen 4 is constructed mainly from cast and machined aluminum parts rather than virtually all CNC'd billet aluminum the previous generations had.  Probably the most significant difference is that the cylinders and heads are screwed together similar to conventional Lycoming and Continental construction rather than using head bolts.  This eliminates the torque checks of the head bolts, simplifying maintenance checks.  Also significant is that the cylinders are now all-aluminum with a Nikasil coating rather than steel liners.  As I understand it, this allows tighter tolerances as the piston and cylinder expansion rates are closer, resulting in less oil consumption.  I also understand the exhaust valves are rated for higher temps. A new development I just heard about on the groups.io forum is that Jabiru just switched to a Mikuni 38mm CV carb as the Bing 94 is no longer in production. 

John

N750A

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Permalink Reply by John Burns on August 8, 2022 at 2:39pm

I chose the Jabiru because it was less expensive and easier to install as an air cooled carbureted engine.  No water cooling system, high pressure fuel, or fuel return required.  I have almost 80 hours on the engine in the very slow high drag CH750 STOL and it has performed very well with no cooling issues.  The original Gen 1, 2 and 3 engines had a different cylinder that seemed to have more challenges with keeping the cylinder head temperatures down, but my generation 4 has never come close to high CHT issues even when flown in 90°F weather.  Time will tell, but I have no regrets with this engine choice so far.  The Firewall forward kit from Arion Aircraft was complete and of good quality and the available installation instructions (photo guides and video) are excellent.

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Permalink Reply by John Austin on August 8, 2022 at 2:46pm

Glad to hear your experience so far, John B!  If the reports keep coming-in like this and if I am still healthy and flying when I hit 1000 hrs on my 3300, I will likely seriously consider just swapping out for a Gen 4 rather than  doing the top-end overhaul on my Gen 2/3!

John

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Permalink Reply by Joel L Thompson on August 9, 2022 at 9:26am

All,

Thanks for the inputs!!  Great info!!

Joe T.

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Permalink Reply by John Burns on September 19, 2022 at 8:05pm

Just finished a trip to the Zenith Factory for the homecoming.  Round Trip 8.5 hours 626 nautical miles.  Used about 12 ounces of oil most of which seems to be in the breather catch can.  Still running good with 95 hours total time.

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Permalink Reply by Jerry Griego on November 26, 2023 at 10:07pm

Hello John , can you explain to me why the jabiru spit so much oil back into the catch can, and is this normal. I fly a 701 with a Rotax 912 uls and there is no oil consumption. I have a 3300 that will go on my almost completed 650 , which has an early generation engine.

Thanks Jerry G. 

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Permalink Reply by John Austin on November 27, 2023 at 9:13am

Jerry, although your query was directed to John Burns, I can give you my take on the oil in the breather.  Supposedly, Jabiru's do fine with relatively low oil levels - many recommend keeping the oil only about 1/3 of the normal range on the dipstick.  The theory is that at higher levels, more oil is aerated and foamed and thus gets into the breather outflow.  I also run a Motion Aero oil separator installed in-line with the breather hose and it returns oil to the crankcase.  I don't even bother to use a catch can as it is a very rare drop of oil that ever exits the breather tube downstream of the separator!

I'm not sure if the Motion Aero separator is still available, but plans can be found to make one.  A good discussion is located here.

John A.

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Permalink Reply by John Burns on November 27, 2023 at 7:51pm

It may be because I am always keeping the oil fairly full when flying over an hour at a time, or it may be because of way the engine is designed.  I think an air oil separator like the one John Ausitn uses is in my future.  I plan to make one, but they are still for sale.  Link below

Motion Aero

I use about a quart every 25 hours and remove about half a quart from the catch bottle so net the engine is burning about half a quart between oil changes.  Our Club Cessna drips more than that.

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Permalink Reply by Mark Ertz on November 28, 2023 at 5:24pm

The gen 4 3300 is my engine of choice. Had the Gen 3. Gen 4 is cooler, stronger & easy to maintain. Did have some growing pains with the new stator. Front seal replaced early.  Had leak oring on value tube. Minor stuff... Never high cht s or egt s. Run cruise prop 2700 rpm @ 130 mph @ 5 mpg.

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