jetboy

The weekend yielded another mechanical problem, not my engine but a similar 2200a solid lifter with the last of the thick fin heads, done about 150 hrs since crank replacement and 25 hrs since valvegrind due to low compressions. Rough running on startup all valve clearances checked OK except last exhaust one where the rocker was observed not moving - pushrod jammed on side of tube. The adjuster nut appeared set correctly and still locked. Owner is currently researching conversion to Rotary. I dont blame him. But the point is, how did this happen and is it common? Ralph

Lyle I noticed you had been planning to shift the bolt holes and backfill them with epoxy: this would not be correct because the Jabiru prop is located soley by the aluminium bushings supplied that fit through the holes in the engine flange and engage with the recess bores in the prop driven face. Ralph

Hi Daryl, yeah it would be nice to have an answer too but in this real world it comes down to when and how often you are prepared to pay for these features, like you can go for an unproven copy of the Jabiru with EFI and all the works for a lot more $ (or check out their new carb. version - why have they gone back?). The truth is all the engines have car parts (tractor, actually, for the Continental/Lycomings - where did you think Slick mags came from?) or better still snowmobile motorcycle and lawntractor stuff used. I'm happy with pistons from Repco (but not Holden, please) in my 2200 as long as the alloys used are up to it I dont consider it a bad thing that the same alloys might be used in engines for other roles. VW, Subies if modified well seem to cut it OK in aircraft; yes I am concerned about my engine but less so than some others I used to fly even the O-200 can have a few bad days it just has more warning and more $ to fix Cheers, Ralph

You only need the 620 Loctite if you did the SB (3 years ago) and had a problem Ive not heard of a single instance of repeat problems since this was made a repetitive 50 hour AD in NZ (and if there was one, show me the evidence..... this is a mandatory report item....) when the torques were revised. Its a fine article, but posting it here and on Matronics without changing the title to reflect its old news is misleading because this only applies to old engines (like mine) Ralph

My Jabiru prop didnt take long to warp out of crushable tolerance with regard to track and pitch symmetry. Mine was 1.5 degress different pitch between the 2 blades at 75% chord. Neatest way to measure this is with a laser pointer held across the rear of the blade tracing onto the floor, then positition the next blade at same place and compare. the correction according to Jabiru manual is to install a non-epoxy resin f/glass packer under the prop which has been wedge shaped and can take the heat, FWIW. Ralph

Back on topic This discussion seems to be drifting so heres some fresh data The oil pressure indication I reported earlier has been corrected by placing a new VDO sender on the lower of the two oil gallery ports on front of engine. The indication is lower but real rather than false and I dont expect the sender to wear out like the original. 4 exhaust valves were pulled due to minor leakage of 2 of them at 100 hrly (300 hrs) Leakdowns were 80 /62 and above. Valves and seats had minor pitting there was some stem / guide play and a couple of seats were not totally round. A legacy of following the advice of the factory lean running kit me thinks. As engine has allways been tight after running the procedure in AVDALSR050 was carried out. This involved grinding a clearance off the 16 cylinder base nuts where they contact the radius of the flange. Irregular non shiny areas in the lower portion of the cylinders were observed, in line with many photos seen on other NG. I was not tooled up to deal further with this at the time so all was closed back up. Engine has now picked up 200 rpm both at idle and full throttle. In disbelief I had to fit a digital tach to verify as my analog is only scaled to 3300. Level flight now runs 3540 rpm which means the engine has finally caught up to the prop. Ralph

On the GPS3pilot it is a CR2032 lithium 3.6v button cell with wires that needs replacing inside, it is attached with foam tape to the battery housing. On the GPS3 model it is a smaller lithium button cell my guess is CR1220 that is tag soldered to the main board. I just had one each of these open today and replacing the batteries would not be hard Ralph

"Hard starting jab As reported in a earlier Forum My New members jab was very hard to start Well now starting on the second or third swing on a cold Morning Found that in the enrichment disk in the carby needed to be drilled out to 1/16 and turn the disk around to the 8 oclock position (Dot on the Shaft) and this engine is only 10 hrs old from Factory also will futher test and may need to increase jet size in bowl for choke side off fuel supply now 80 85 available as standard James" The above was posted last month (linked at the bottom of this thread) I dont know if thats what is been kept secret however its not really applicable unless the status of the drilling (or not) of the idle air hole and the idle jet size are known for a particular engine. These items changed a lot with the various issues and revisions of the carb tuning kit. As I've not had cold starting problems but keep a can of SYB handy as a threat - just reading the label cheers me up. Ralph Ralph

As above read the threads 12 or so back for track record of either of the local brands, you'll have to read between the lines or pm people direct for some of the reasons. Of course you cant buy a local Xcom any more and if you check the current ACS pricing you'd have to conclude the previously unknown Flightline 760 is worth considering. I think you have an ACS dealer there and they could also be available in the shop. The problem facing all of us in choosing a radio (or engine, for that matter) is the low number of units operating in the field from which to form an opinion. The only other guidance you have is the specifications and what level of certification it purports to meet. The only 2" round hole radio you can buy with a good record is the Becker, but then you have the price to consider. Ralph

Yes fitted one checks OK so far but plane is not flying yet. The rev-Q is little different to the rev-P in fact if you want less to go wrong and lower current consumption the P is better. You should read the threads about 12 back on same subject; getting hard data on problems and the truth behind them is difficult. I see this every day in my job - typically a radio comes in with misleading or no fault description attached then it tests perfect on the lab bench for half an hour and there you go - another NFF (no fault found) these types of faults properly take upwards of a month to sort out, I can see why a seller having an interest in keeping warranty costs low and having no certainty over how the equipment was installed might simply return the item as repaired. A company's reputation is not only won or lost by quality of product, but how problems are dealt with if they arise. I would not fit any rev. of either brand in my own plane, if that helps answer your question. Ralph

a probe placement error will not be transferred throughout the range. A cold junction error will. If you are asking about a standard Jabiru installation you have both errors built in. The tab under a sparkplug reads the plug temperature minus the cooling temperature around the lug. Typically reads under by 20 deg c but if the plug washer is leaking can over read. the proper way to fit the probe is clamped inside a hole in the head or clamped on the surface of the head with insulation under the clamp. If the cold junction is at 50 deg c as specified in the installation manual you get another 50 deg (less ambient) under reading. Some gauges have cold junction compensation, some dont. Proper handling of a cold junction is that the end of the thermocouple wires terminates to the gauge wires or terminals at the same ambient temperature as the gauge, and gauge is a compensated one. Then again, if you are dealing with a Jabiru the factory limits are set with the above errors in mind, so you have to decide what reference you are to use. I understand new engines have a hole in the head (dont they all?) for a probe. To check a gauge, an accurate electrical digital voltmeter can be used, find the readings and corresponding temp. for the corresponding K or J thermocouple from the web. Voltages are only a few millivolts, and you add the ambient temp. to the reading because most DVM dont do thermocouple corrections. Dont sweat over the detail, your setup will be close enough unless exhaust gas or cooling air is getting across the probe. Ralph

In NZ everyone flying microlights has one, many are the OZ made GME 410 which I chose partly on price and local support but also the type of batteries they use; remember most need replacement every five years in some cases it will be easier to buy a new PLB. The GME uses a commonly available battery, most others dont. Also there is not any easy way to tell what the reliability of any model is; you only get to find out when its too late. Ralph

yes "flocking the rotors" is topic of the day on Yahoo Jabiru engines right now Mine went wobbly @ 200 hrs and I epoxy araldited new ones on. Oddly they had allways been tight when checked previously and had no glue from factory new. Other issue @ 150 hrs oil pressure sender went erratic I opened it up and the wiper had worn thru the wires at the 40 psi mark Replaced with VDO sender into the lower port where the sender reads the engine oil pressure not the pump pressure Just off 300 hrs check there are 2 valves starting to leakdown to exhaust faintly but mostly to sump and still above spec readings of 62/80 plus. I wont speculate further but probably do a followup leakdown while I wait for the parts costing / availability to come back or 50 hrs whichever comes first Ralph

I wouldnt want to push anyones barrow but if I was in the market for a round hole radio I'd be taking a punt on a couple of these: FLIGHTLINE FL-760 TRANSCIEVER from Aircraft Spruce I say a couple because that way you can afford for one to go belly up and still be ahead. Which has happened to us repeatedly with (previous) local contenders. Also worthy of consideration is the MGL series, but I dont like membrane button keypads for controls where a knob does best. When it comes to rectangular panel radios, My choice is Icom then Bendix or Garmin. The other consideration often made on cost and style is headsets is very variable. There has been a myriad of difficulty with Alltronics here so the standard cure is now DRE. I'm not sure if they are specially better than others. Personally I dont use DC but they are very reliable and well liked by those that do. I just buy in PCA (pacific coast avionics) branded clones for parts (gel earpads and electret mics mainly) to keep my older generic Mil-style Heli-style ones going. I have fitted Headsets Inc. ANR kits and these are a good value conversion. Look for firm cables and good mic attachment system that can take the standard mic connector some of these stalk type mics fall off on notime Ralph

Just get a finer pitch prop. It will keep the cruise revs out of the forbidden zone, and the carb will keep the mixture and fuel flow corrected for the higher rpm. There is no change to fuel consumption, you get a better climb and keep off vne. It will make more noise and wear out faster, and you have to watch for over rev, but thats not an often observed problem on any Jabiru i've seen. I did the prop change on my CH701, but with all my drag vne is never an issue, staying aloft using only 75% is! Ralph

The radio was brand new a week ago. What you describe seems exactly whats happening. It didnt appear to be transmitting and the PTT switch still seems to click in the headsets when pressed while the red light is lit or flashing. This morning it was behaving properly. Was going to replace the switch but will hold on that for now. Thanks for the info. Ralph

Microair PTT I probably should have started a new thread but this problem may fix itself anyway... After running Xcoms until they ran out we've changed to a Microair in an Avid Flyer last week. Just a minor pin reassignment on the connector and new radio all go. All functions tested fine. Preflight today and the TX red light comes on then flashes. Fiddled with PTT switch (only one in this A/C so should be simple) but that didnt do much, TX still operating. Powered off the radio and back on, problem gone. During flight TX stuck on after a transmission twice. Back on ground, all OK. Now we didnt have a 4KG milk bottle handy but has anyone found a difference with the Microair that makes it susceptible to leakage on the PTT line (or if not, inside the radio?) I may well find a fault in the switch but we didnt have that issue with the other radio(s) Ralph

The diagram you have is for the A200 - the A210 may be different, but if it is the same the followng will apply: The intercom on that wiring scheme will only work from copilot mic to the headsets. The pilot mic will be dead to the intercom. the A200 manual shows their correct method. For the intercom to operate, both mics must connect to K input. It matters not if the pilot mic is left connected to the J input, except that all the noise from the copliot mic also gets transmitted over the radio. If you want both mics to work the radio, put the intercom on/off switch at terminal K. Unplug the non-used mic when operating solo. If you dont want the noise of the Pax throwing up during your transmittings, use a double pole switch with 1 pole for each mic lead on its way to the K terminal. Ralph

While it may be choke/throttle settings the rough startup can also occur due to faulty slipper clutch, dog clutch preload, or starter sprag. There is a service bulltein specific to the starter sprag for the 912s. we found it applies to the 80hp too. ( low starter current = slippage in sprags. The dog slippage is checked by locking the gearbox with pin and scales on prop. Both problems on an engine with less than 200 hrs. Ralph

No warning here, 503 just dropped a few hundred rpm during climbout and by the time I'd cycled the throttle setting the prop had stopped. Engine had been running very well prior to this incident which was caused by needle rollers exiting the cylinder and breaking rings on the way. Facthunter has it right dont bother refurbishing its actually more economical to replace and pass it further down the food chain when its met its design life (300hrs) Ralph

Probably normal, both 503s I ran did it, more so with the dual carb, believe it or not the fuel oil mix is not a continuous flow through the carb, it spits back out and some oil stays on the filter. If its a foam filter, its self oiling. Ralph

I used a high temp RTV (silicon) on mine, not too much, with the rotors firmly on all the way, at the first 100 hrs. New from factory the engine had no glues of any kind. a 100 hrs on, and both rotors were wobbling about, with the sealant no longer attached to the shaft but it was still present on the clip and some of the rotor. Think silicons are too flexible. My replacement rotors went on with Araldite epoxy. I'm rechecking them soon. I think it needs to be a firm glue that can take some heat. The appearance of the rotors is consistent with heat deformation where it contacts the shaft but it could be wear. the rotors are the same as original, Bosch from Supercheap, black thermoplastic, and fit firmly when new, just like the originals did. Somehow they go from tight to loose and wobbly. If these ones get loose, I will have to find another glue, perhaps 36hr Araldite. If they stay tight, I wont need to get them off. If they go loose, I wont have any trouble getting them off. Ralph

Depends what is meant by rebuilt. For rotax 2 strokes a rebuild includes new crank assembly and that would alleviate a lot of failure prone areas. Anything less is not really a rebuild and dont forget the gearbox. I've been thru this once before and chose to renew the engine. There is still a viable market for tireder patched up engines if reliability is less valued. Our Rotax service center here took the club thru a 200 hr check on a 582 which inluded a careful visual of the crank for cracks which do occur its only a matter of time even the 912 is not immune. My personal feeling is if its reguarly run and checked like yours and not operated with harsh loads like high prop pitch its better to keep going and replace when beyond refurbishment. Ralph

Yes Macgyver HT leads = spark plug leads. Sometimes they work out of the distributor and start arcing there too, if they had been put on with air trapped under the rubber. You can measure each one with an ohm meter, should be around 5,000 - if there is no reading at all there might be a missed end connection arcing. At 90 hrs the plugs should not have changed enough to make new noise. A loose distributor rotor is still a possibility. There is a lot of other stuff that could be the source, some GPS make lots of noise on various frequencies, carb should have a factory grounding wire to the engine block, scat tubes where the wire rubs on things, alternator wires burning up at their connector. If it still traces to ignition noise, I have some fairly technical test results on the Yahoo group here: http://groups.yahoo.com/group/jabiruengines/files/Radio%20noise/ The P leads to the coils (from the ignition switch) seldom are a problem, they are normally shielded leads but you could check that the braid is still grounded at the coil ends. Ralph

people have reported gradual worsening of noise caused by the distributor rotors getting wobbly on their shafts. The original carbon powder HT leads dont help also, factory new engines now have something better. As plugs wear (around 200 hrs) the gap widens which may contribute to increased HT noise. If your not running certified category, you can swap to DR9EA or the ND iridium plugs for better results (sit down while you price these) of course, your noise may be from something else. Ralph