Tests of new Gen 4 2200

[skypics 89]

It's been just 21 hours so far after installing my new Jabiru Gen 4 2200.

I have flown behind 2200s for over 3,000 hours and in that time I have had a sucked exhaust valve, a displaced valve seat and relined my valve guides 3 times. Of course, this also happens to "real" aircraft engines. That said, I have always thought that while the bottom section of this engine was very robust, the top section had many design flaws caused by inadequate rocker box lubrication. 

This causes early valve guide wear which causes sloppy valve positioning which can result in valve head separation.

In contrast to the earlier generations, the Gen 4 appears to have addressed these flaws with;

A) Larger fins

B) Head and jugs are now cast aluminum instead of CNC. This allows tighter tolerances since the piston and cylinder are of the same material.

C) The rocker boxes are lubricated up through the pushrods where the oil moves into the rockers and to the rocker bushings. 

D) The engine starts every morning in two blades without using the choke. When warm the engine starts instantly. I believe it may be hand propped. I will try this soon.

E) The engine can idle smoothly at a mere 600 RPM.

F) After tweaking the air duct to fit under my Avid MK 4 cowl, all CHTs and EGTs are well within specs as recently tested on a long climb out from 533 MSL to 9,000 MSL at full power.

G) After 21 hours the oil still looks clean and still is at the dip stick full mark.

H) There is only a tiny bit of water/oil collection in the breather bottle.

I am swinging a Whirlwind 66"two-blade prop.

So far I am well pleased with this engine.

I did have to buy a new engine mount since the new engine moved the top two engine mounts 15 mm to clear the larger fins.

The new mount cost $895. I sold my old MK 4 mount for $300.

Sold my old 2200 for $2K.

The new engine was $15K plus shipping.

John M

 

[Allen Sutphin 705]

Glad to hear you are pleased with it. Remind me again of the flying weight?