Jabiru – Oil leak ..sorted

The ongoing issue of the oil seepage has kept me grounded for a long time now …. The plugging of the rocker breather holes in each head (now I’ve conveyed to solid lifter from hydraulic) has certainly helped see the wood for the trees with only small but positive amounts of oil showing at the base on the rocker guide tubes on ground runs

Each ground run, where I let it get up to 50 degrees then push to as much throttle as the small heel brakes will hold .. usually around 2,300 rpm …at those revs the brakes are starting to squeak and object … but you can get short bursts of higher and accept the move forward if clear.

The option I did in the summmer … tying the tail to the hangar metal upright girder .. I’m not so happy about now .. his was after reading an Australian post on a Jabiru site about having Jab 2200 in taildraggers and excessive ground running NOT being good .

The reason sighted for this was possible oil starvation of the front cylinders, rockers due to the significant slant of the body

So I don’t do prolonged hot ground runs .. if I can avoid it.

Anyway .. to the fix

Having spoken with the engineer I decided an ‘in situ’ fix in a cold dusty hangar wasn’t ideal and to whip the engine out, pop it in a boot and strive up to Yorkshire was probably the far better, sensible, solution !

Engine out Friday, marking all ancillaries and safely supporting the exhaust … carb body status in situ so you don’t d disturb choke and throttle … and it’s craned out and in the boot in just over an hour

Drive to Yorkshire Sunday, work on it Monday, Back Monday night, reinstall Tuesday, Ground run Wednesday !


The engine was mounted on a sturdy bench … nose down … bolting 3 bolts through the prop driver plate through the table … this made a really easy working environment and the engine was easy to rotate

Given the photos I’d sent ..we looked to remove the rocker push riot tubes from one side first and investigate … rocker cap off, rockers undone .. pin removed … head slackened in turn …and tubes slid out of position

The alloy tubes sit in small alloy cups that then mate into the sump body. The place they insert has a rubber ring in the sump body, the allow tube has a rubber ring … the cups should be quite stiff to remove … but weren’t

This was repeated for all 4 tubes on one side and all cups were relatively slack

These were thoroughly cleaned and de greased and then new rubbers, Vaselined up and a dab of heat proof silicone for surety … and popped back in place .. this was related both sides of the block

Kevin had pre drilled the rear of the backplate – Spider to allow easy (regular) torque checking of the new flywheel bolts vs the big in situ strip.down I had to do when replacing the bolts and nordloc washers last time 👍

Blog at WordPress.com.

Up ↑