jabiruken

Just a thought, u do have a hole in that vent hose to allow air in carb. It’s difficult to see in video, I used to make it a big v with side cutters to ensure it did not clog.

Removed tappet cover and checked valve clearances today and yep exhaust on suspect cylinders 2-3 thou above my set 10. Oil change and a hard run for .4 in the air ( Italian tune up ) and she has settled back down, I suspect nev was right about rust in valves which is something I never considered. My pull through now is even as it was before and I’m one very happy camper. If this reoccurs I will be removing heads and have them serviced at a machine shop such as camels. Ken

My engine still has the original starter motor and has always gave a clunk and strain upon starting, borrowed leak down tester and found exhaust valves on 1,2,3 are leaking.

Yes engine had warmed up and let cool after 1:2 hour flight. All temps good in flight, cold start with no choke as usual for this time of year, hot start good but tight as usual upon crank, ( gives a heavy clunk as starter engages) however pull through finds not the familiar even resistance.. not having access to leak down test gauge will slow my research, but I know something is wrong with my girl.

4-6 weeks she sits in hangar waiting for air work, and it’s not for very long as I don’t have time for long stints these days. Grummo advised leak down test as nev has said suspecting valve stems. Mark at jabiru says through bolts are done in full overhaul and not top end for my engine being 730 + serial number. Perhaps a good flogging may sort my issues out, or at least bring them to head..

ive not flowin my sp for a while and have noticed 3 cylinders during prop pull through are not as high as the other, nearly half the resistance in fact. Guessing rings are issue as valves haven’t needed adjustment for a few years, (about 96 hours) tappets still around 10thou gap. I Have noticed a bit of oil in intake but oil consumption doesn’t appear un usually high at this stage. She is the original engine 2001 with 780 hours, jabiru informed me there is no heads available and that they would be able to do top end over haul late may. My thoughts were to strip the cylinders and heads off an send to jab for service but after talking to them got the impression they want the whole engine. Any thoughts or opinions?

Bruce, I found the legs had delaminated at the lower half. Once cut all you see is brownish discolouration in between the layer of glass here and their, they appeared to be totally sound other than for strange colouring in glass which I assumed was moisture related.

Seb can’t locate video after my move, it’ll show up in some stupid place I’m sure, took photos whilst doing oil change this morning the lower cowl has deflectors which hug around tail pipes, the video showed engine on stand with cowls fitted and blanked off at fire walll end, he used a smoke/fog machine and a large fan, u could clearly see the air flow through the cowl and swirling effects, personally I think it’s all a bit over the top as I found just little bits of tweaking on previous jabs had fair result with many hours flown on engine relatively trouble free.

The drifter wing is not constructed strong enough to withstand the fabrics shrinking process, Wayne fisher said too much distortion would occur When I asked why only tails and ailerons were seconite and not wing.

No, No deflector, there is actually eight components involved in his modifications. I should have taken lower cowl off so you can get better view. The cylinders are nearly fully Encased with Kevlar like duct and air is forced out bottom of cylinders nearer to engine block. Have moved recently so may take a little time locating the stuff you require

Hi, Seb My intakes appear standard with an insert (grey coloured) in pics. You need to remove these inserts prior to removing cowl as they are screwed in. The hole intake moulds are not jabiru and are hand made of thick fibreglass and there is no deflector on drivers side, completely open unlike photo of passengers. Yes oil cooler is from bottom inlet and cooler mounted on lower cowl then air forced into lower cowl that exits with exhaust. I have a video somewhere that shows the engine on bench with smoke and fan showing air flow. Will try to locate if you wish.. I think the scat hose is used as a balance for air pressure balance during different angles of attack, not sure but all seems to work ok.

I bought this jab because of the builders detail to duct work etc. photo taken at 32 deg day @ 1000 feet last year. Oil cooler attached to lower cowl, large opening lower cowl and hand made air ducts that Inclose spark plugs and has scat hose at rear of ducts used to balance air between the 2. On hard climb no 3 can reach 156 on a stinking hot day but lowering nose will quickly lower temps. Oil is a bit cool, but I don’t want to play around with it and up set something else

We used to clean the spots where bugs hit wires with turps and 2 stroke oil mixed, worked a treat.