jetboy

Reply to J430 posting: I'm getting worried about the valves / guides issue, having come across an example on Matronics which I'll copy here. The factory must know something about material changes that us field testers are not privvy to. I can smell another CAA AD if this trend continues without some proper explanation. Is it possible that valve leakage is occurring regardless of lean mixtures, but due to abnormal guide wear? Ralph Posted: Fri May 11, 2007 3:22 pm Post subject: New rocker arm bushings in Well, the old bushings were a teflon-coated bronze over a steel shell (TPFE, I believe they are known as) and for whatever reason, they failed at...or at least I discovered them failed at...273 hours. I decided not to replace them with the original style bushings, because I don't know the history of how these bushings hold up under the splash-lubricated, high-pressure (the valve spring), environment they operate in. Now to be perfectly honest, maybe nobody else has had a problem with these bushings, but I did, so I elected to try my own "shade-tree engineering" and put in oilite bronze bushings. In doing so, I decided to supplement the oil that ordinarily makes its way into the side of the standard bushings. The standard bushings are allowed (according to my owners manual) .004"-.010" side clearance. I did not change this, but I did drill a .093" hole vertically into the rocker arm, at exactly the 12 o'clock position of the rocker arm. This will allow the oil a chance to run into the hole and help lube the bushing. If anybody cares, I'll continue to report how I installed the bushings. They came 16mm wide and the rocker arm is 15mm, so I shortened them on my lathe. I had pressed the old bushings out, and after drilling the rocker arms for the oiling holes, I drilled the bushing oil holes a little larger, then pressed them into place, keeping the alignment of the holes in mind. They all came out aligned as hoped, and then I had to ream the bushings to the size suggested in the owners manual... .474"-.475". This provides for 2-3 thousandths oil clearance for the .472" shaft. I then swapped the rocker shafts side-for-side, to enable the new bushings to ride on the un-used part of the shaft. I also chamfered the sides of the new bushings to further allow oil to make its way into the oil space provided between the shaft and arm. I've got to further say that I don't know squat about teflon in engine bearings...my only use of teflon (that I know of) is frying eggs in a pan....low (relative) heat, no pressure, and the eggs taste fine. I wouldn't have eaten eggs cooked on the teflon that was visible inside the removed bushings...they looked like the frypan had been attacked with a steel spatula, if you'll permit me the kitchen analogy. : ) Again, I'm not saying that Jabiru made a mistake, maybe I just got a lemon, and if my "fix" doesn't work out, I will have no apologies to make. My engine is in a Kitfox Model IV *experimental* airplane, and that's JUST what I'm doing...experimenting. Lynn Matteson Grass Lake, Michigan Kitfox IV Speedster w/Jabiru 2200 flying w/275+ hrs do not archive

Thanks Brent, My notes from the last 50 hr for the plugs reads: "No.2 darkish, others light brown." The exhaust usually is a light gey/tan similar to the Cessna 150 that also ran 100 Avgas. Cruise EGT is 695 and full pwr 680 which is OK for the original carb tuning but on the high end for the currently published 2nd revision. For peace of mind I'd still like to know if the current spate of valve troubles is occurring to Welltite seats or a different seat material. If valves are tuliping into the heads I suppose that is a case of overlean. At last 50hr all my exh. valves were found at .008 and were reset. Inlets were good. Ralph

minor valve recession Thanks guys, I only mentioned the occasional readjustment to to highlight the problem with the new manual showing head bolts, valvegear checks @ 100 hrs. Yes I do check the head bolts @ 50 hrs and they have rarely moved. As the engine is at 195 hrs there has only been 3 50 hr checks and 2 of those are post carby tuning kit install. So forgive me for not knowing what the trend is. I have recorded which things needed adjustment, to compare at next check. I will be doing leakdowns and borescope checks @ 200 hrs and depending on that outcome may rejet the carb in line with the most recent documentation. EGT / CHT are in limits and it runs OK in colder weather. If I tested with a Lambda probe I might be OK to leave alone, but in the light of the recent data I will probably err on the conservative side. Ralph

While reading the current edition manual for my 2200 / solid lifters it seems theres an error in the inspection interval charts. sect 6.3 says the head bolts and valve adjustment is each 50 hour Sect 7.11 inspection chart calls for this every 100 hrs Am I reading this wrong? that would be nice, but I dont think so.... I usually have to lossen the exh valves on a couple of cyls by 2 thou, every 50 hrs. Ralph

Looks good although I would have thought it more appropriate to call it a 142 as it resembles the 140 and they often made the trigear versions the -2. seeing they already had the name Skylark, that would have sounded nicer too. The figures are not much off those of the 150C, last of the fastbacks, : Max SL 127 mph Max @ 75% 125 mph Climb 760 fpm Ceiling 15600 ft TO ground run 680 ft, 50' 1205 ft Land 360 ft, over 50' 1055 ft range std. 610 mi, longrange tanks 945 mi I miss my 150a already....... Ralph

Nev, Thanks, I presume if seats of that composition alloy erode there must be something else very wrong to cause that. The real question is when did Jabiru change to it? Has a head failed with these seats, or were they all a previous material? Ralph

Geoff, Just reading your lines previous... "Could it be light cruise loads or perhaps operation between 2000 & 2400? But you would expect school aircraft to cop a pounding in those areas too. In all of my bike and car motorsport I have always associated abnormal valve & seat wear with mixture issues which should directly relate to, and be seen in, CHT &/or EGT readings." In my days of pumping avgas for the car ralllies that used to come thru town, The aeroclub instructors were allways bemused about these guys thinking their cars might go better whereas they were more likely to wreck their engines. Because avgas has a slower burn rate than most other gasolines the ignition timing needs to be more advanced, otherwise the stuff is still burning as it exits the exhaust valve, so I'm told. Theres also something about 100LL that came in the late 70s, the 0-200 engine was AD'd requiring the mag. timing to be set back 4 deg. to 24, to "prevent cylinder assy detaching from crankcase". The AD still applies, except to new design cyls. So in expanding on our interest in what's going on, I think the fuel could also affect valvegear - I suppose most are using "green" avgas 100/130 - and we need to know exactly what metal composition was used on the seats and valves, for serial no. of engines. My engine is #1680, and has "Welltite" or similar engraved on each head, I presume that relates to the seat alloy. Did earlier engines use iron seats? when did it change? what is it now? the ones that have failed, were they old type or new? Are all valves the same? Appreciate if anyone has this detail, it helps for deciding if a particular installation is at risk. I've done 145 hrs on the leanest of the carb tuning, and will be altering that shortly. Ralph

oil pressure Rick, a factual thread is a good idea. I would prefer to see serial nos, tis information included as they made many changes which affect the outcomes. I will put my item in the list in case it helps others. I know that at the time I solved my problem, an OEM using this engine was having low oil pressures in about 30% if new installations. 2200a - ser. 1680 (2003) hours = 1 tractor installation, optional oil cooler not fitted, fuel pump not fitted. SB 004-2 oil pump mod carried out. oil = aeroshell 15W50 stable oil system readings: startup 50 psi, cruise @ 2400 rpm 20psi,220 deg F, cruise @ 2700 rpm, 20psi,230 deg F. Added oil cooler adaptor and one length 6' of AE601 aeroquip hose with AN6 fittings. stable oil system readings: startup 50psi @ 900rpm, cruise @ 2800 rpm, 50 psi @ 180 deg F, 47 psi @ 200 deg F, 40 psi @ 220 deg F, 35 psi @ 230 deg F. I later did fit an oil cooler ( a proper one ) but that was for a different reason, and this had no effect on the oil pressures established with the fitting of the hose. These are the facts. As requested, I make no assumptions to the cause and effects. There are plenty of A grade mechanics and lanmower repair experts around here that have opinion. Please also bear in mind that this work was undertaken at a time when coolers were an option and the procedures in the manual, at that time, were followed. Ralph

no more than 50 rpm at runup (2000 rpm) I think the discussion re inducing formation of ice is more related to flying with partial heat applied, in my years of GA flying all manuals and teaching advises against this: it should be on or off, and if clearing ice the engine stumbles a bit then full heat should be held. Certified A/C need to produce a rise in intake temp something like 40 deg C which is probably why the rpm drop is more severe. Discussion on the fulltime electric carb body heaters sold in UK is interesting, but for peace of mind I'd like both. Ralph

Daryl and Brent, any updates? I am running a 2200 #1680 this is a late solid lifter build, 195 hrs. It had the first economy tunining kit version - the thouroghly tested one- yeah right - fitted @ 50 hrs and fuel use went from 18 L/hr to 15L/hr A couple of side- effects were the oil temp increased 5 degF meaning I had to fit a cooler and the muffler colour changed to a darker shade it doesnt look like stainless anymore The full power EGT has gone up by 50 deg F and low cruise 2700 by 100 deg f. Currently running a tailpipe EGT of 680 deg C full power and 695 deg C @ 2800 (the probe only fits the 2" single tailpipe I use so I dont know the exhaust port EGTs) I'm planning on rejetting to the later spec. depending on what I see with leakdowns and borescope at 200 hrs check. The EGTs are still rich of peak but it might be better to move them a bit further from the "edge of destruction" Did Jabiru change the valve / valveseat alloy used in some engines , my heads are engraved "Welltite" if I remember correctly? Ralph in ZL (ZL1TBG)

My 2200 #1680 has engraving on each head "welltite" or "wellite" which i assume relates to the valveseat material and / or valves alloy used. So at some stage they must have changed the materials, for better or worse? I need to recheck the carb jetting as I have the first iteration of the economy tuning and its been revised twice since Ralph

I had one that I put togeteher as a parade display, with the 'A' wings shortened to 2/3 for street use. It was in corroded condition when i got the unbuilt kit, 35 sold in NZ by AESL as agents. about 3,500 kits sold worldwide for about 300 that flew and 60 fatals. The last bit is also a good reason to just admire the neat design, IMHO. I have all the newsletters with the kit explaining why parts were not available etc. and most people never got the engine, undercarriage and spars. They were not billed for those items, though, but completion to the plans with the 70 hp zenoah? 3 cyl 2 stroke was near impossible. There is one here thats fitted with a Honda civic 1300 engine turboed to 105 hp, fuselage has to be stretched 2" and 50 lbs ballast added in the nose for this install. One of the turboprop conversions a few yrs back was a fatal. The one here that has a 2 stroke has flown twice, crashed twice, 20 yrs apart, at Ardmore. There was another around here with a Honda city turbo motor proposed as powerplant, would be quite good 110hp and lightweight. I expect the Rotax 914 would go OK or a 13B rotary? If you really need to go out in style, the BD10 may be the ultimate Ralph

I'd have to second that, the A200 is practically identical to the Bendix king Ky97a including the mount trays, I've worked on many installations and the A200 is allways good. For people with limited panel the Xcom has the better intercom and weather channel receive (handy in some NZ areas - not sure if you have marine wx in au), but there have been some serious issues with many of them over here, in a few cases it was setup problems but there have been intermittent receive failures and transmit noise issues that need software correction. Probably OK if you buy a new one, as those things will be taken care of. Perhaps the other issue is ergonomics, its no fun trying to fiddle small knobs through menus while dealing to turbulence, the A200 is much better there. Ralph, \ full time radiotech, part time flyer + driver of the Honda Z JetCar

At high angles, oil pressure is normal but temp will climb steadily. Well lets say i've seen 245 on a bad day. The 2200 in 701 is not ideal and i avoid 30 Kt climbouts unless necessary. Flap down 50 Kts can do full throttle climb satisfactorily. This gives better cooling than the "cruise-climb" GA technique. The engine power is not that high, 2900 rpm = maybe 65 hp? I think the prop 60 x 38 too coarse for 701 climbing. WOT level flight on a good day = 3050. So I never get to see 80 HP. Even after 180 hrs "development' I'm still fine tuninig the little things. Plan to add inter-cylinder baffles next service to get a little more cooling to the rear. 701s go nowhere fast and I have a friend up North doing one with a 3300. I hope he can get enough cooling. I have the larger ram air ducts, and CHTs are well in limits, mostly below 300 F, except steep climb work. Next on the list would be a larger, but finer pitch prop, around 62 x 32 or 64 x 30. I'm not keen to go experimenting right now till the Flywheel issues are more settled. Ralph

I run a 2200 and had the following conditions (aeroshell 15/50) rpm psi temp F 2400 20 220 2700 20 230 2900 22 240 Then I did the oil pump SB which made absolutely no difference. Then, in preparation for an oil cooler, I fitted the adaptor with AN hardware ans 6' of AE601 hose, in the form of a large loop. startup 50 psi warmup 65 psi idle @ 120 deg F 50 psi 2800 rpm cruise, 50 psi 180 deg 47 200 40 220 35 230 I went on later to fit the cooler, which did not change the pressures, just the temps. The point is that adding 6' of braided hose just might help smooth out those pesky high pressure fluctuations that Jabiru allude to on their SBs, which may prevent the relief valve being forced open and dumping oil pressure. i dont care which theory is correct the results are what matters. At the time I reluctantly fitted the cooler more 2200s were being trashed because of the cooler than without. I used a proper automotive engine pressure type cooler which I think is what they switched to later anyway. You are right to leave it out if you dont need it. Now done 180 hrs runs OK Ralph in NZ, serial 1680 or therabouts

diamond / midwest / norton Guys I've just registered and reading this group rekindled my interest. I'd wanted to use a rotary in my 701 however no response to enquiries and no availability meant using a Jabiru 2200 (which has worked OK) The best fit would have been the Diamond (formerly Midwest formerly Norton) http://www.diamond-air.at/diamondengines+M52087573ab0.html There was even a dealer in aussie but they dont seem alive to email Another prospect is Wade engineering in NZ they are rumored to be producing a 2 rotor w/ gearbox similar to the 13b There is supposed to be a 95 hp single rotor version too which would be easier on the cooling ? but what i've just read suggests there is advantages in 'flying home' if one chamber goes out Ralph in NZ - CH701 with Jabiru 2200 oh and my other engine is a JFS100a just a little noisy for the locals