Jump to content

John M

Members
  • Posts

    19
  • Joined

  • Last visited

About John M

  • Birthday 08/08/1937

Information

  • Aircraft
    Avid Flyer MK4
  • Location
    KAJO
  • Country
    USA

John M's Achievements

Member

Member (1/3)

  1. Jenny I have over 5,000 hours behind Jabiru 2200 engines. This most recent Jab is the Generation 4. On this version Jab improved the top end which allows closer tolerances so that I don't have to add any oil between oil changes at 30 hours. The engine is much simpler design that fits easily into my Avid MK4. The earlier engines had issues with valves, valve guides and separated valve heads. As mentioned the top end has been completely redesigned including better lubrication of the rocker box. That said, the Rotax engines do have some advantages which can also be a disadvantage. The gear box allows longer props, but the gear box is one of the problem parts. The engine sound is different since it typically is running at twice the room of the Jabs. The engine is about 20 pounds heavier which eats up some of that extra hp. Yes, parts are much more expensive. Two carbs have to be synced properly. I mix gas types with no issues and run my 2200 on ARCO premium 91 AKI. The higher compression of the Rotax may not allow this octane level. Although I have noticed that some do run mogas. The Rotax engine is well built and runs a long time between overhauls. It's the gear box and Sprauge clutch that need more frequent servicing. I fly a lot and already have 160 hours on my new Jab gen 4 engine. The only issues I have had is Starter Bendix unit. Jabiru changed from the reliable Honda Bendix to a brand the only lasts for 50 hours in my experience. I am in contact with Jab in encouraging a change back to the Honda brand. My engine burns 2.8 gph at above 7500 MSL when I lean it out. I am counting on this engine to take me to the day when due to age I'll have to hang up my headset for good. I'm 83 so I still have a few years to enjoy flight.
  2. Forgot to mention in that last post... The starter Bendix cover developed a crack at 50 hours. It was cast, as much of the Gen 4 is now. Jabiru replaced it with a CNC cut cover. Then the Bendix itself failed to engage properly and they replaced that on warranty. John M
  3. Mystery Marvel Oil...is oil and is added to avgas all the time. John M
  4. I am flying my 3rd Jab 2200. I have over 3,000 hours with the engine. The TBO for the top is 1,000 hours. On my 1st Jab I tried to see how far over I could go. At 1195 hours the valve seat on number 4 dislodged causing the piston to hit the valve with same damage. I sent the engine in to Jab in Tennessee and Ben rebuilt the damaged area. The newer Jabs now have a recess in the top of the piston to prevent the stuck valve from being hit by the piston. On #2 engine it started running rough at about 900 hours. I found that the hyd lifter on #1 was sticking. The bottom of the lifter was mushroomed which made it hard to remove. The cam lobe was worn by this event, but I replaced the lifter and the engine ran well. I sold it to someone in Canada with the caveat that the cam lobe was worn. I bought a new Jab 2200 Gen 4 to take me to the end of my flying days. I'm 82, so time is short. This engine has a completely redesigned top end which was the weak point on earlier engines. Head and jug are one unit and all cast aluminum so tolerances can be held tighter since we don't have to contend with different expansion from Aluminum head to steel cylinder. The lubrication of the rocker box parts is much better with oil up through the push rods instead of from an outside pipe. Roller lifters make it possible for extremely low idle...500 RPM when warm. The idle is very smooth. Leak down test at 95 hours was 72/80 lowest and 75/80 highest. This was done on the cold engine so a hot leak down would be much better. My aircraft is an Avid Flyer MK4 with fiberglass tanks that can't take ethanol laced motor fuel. This has always bothered me because I know that running avgas just loads the piston tops and other parts with lead accumulation. Do I had a brain fart. I bought a marine plastic 6 gallon tank which sits on my right seat. I know...fuel in the cockpit? I flew a Piper Cub for many hours with the tank suspended above my legs and my header tank is behind my seat. Jabiru requires octane of 95 RON. I use 91 AKI ARCO gas. AKI is RON-MON/2 so to get 92 octane AKI RON has to be 95. I have taken a before borescope shot of the #1 cylinder showing the lead accumulation on the top of the piston and the head. After flying off several tanks of mogas I will take an after shot to see the difference. In summary: I like the simplicity and low weight of the Jab 2200. My friends all have Rotax 912s and while the engine is robust, the ancillary parts...gearbox, sprague clutch, water pipes, etc are not so robust. The Jab is turning a 66" Whirlwind 2 blade prop which allows me to climb 1000-1200 FPM and cruise at 100+ MPH on 2.8 GPH. The fuel tank I mentioned allows me to fly about 80 miles round trip on $1.00 less per gallon than avgas. For more info on the Jab engine there is the JabCamit forum.' Fly safe. John M
  5. I am new to the site. Personals: over 8,000 hours, Commercial, flying Avid Flyer MK 4 powered by the Jabiru Gen 4 2200. live here in the colonies in Southern California. Fly to Idaho back country every July to enjoy the pristine beauty and the many back country strips. John M
  6. New Zealand has been on my bucket list for many years. Been to Fiji, Cook Islands, Tahiti, etc, but regret we never made it to Kiwiland. I fly an Avid Flyer MK4 with a Jabiru 2200 Gen 4 engine. Good for the Idaho back country strips.
  7. John M

    Oil leak around head

    Skypics234 here: I had a problem with #1 head on my 2200. It was leaking around the head/jug seal. Looks like the head was not properly sequenced at my 1195 hour overhaul. It had burned the aluminum at the seal so I had to fork out almost $700 for a new head. The new head that was sent was for an older early hyd lifter engine when there were issues with the pressure in the crankcase not allowing the oil to exit the rocker boxes down through the push rod tubes. This caused the oil in the rocker box to coke up and eventually affect the valve guides and valve stems. However, my engine (3239) has the deeper oil pan and so this problem was eliminated. So I had oil leaking from the new #1 head and had removed that head 5 times. Each time I checked the rocker rod and push rod tube O rings and all were good. Finally we noticed that besides the oil holes in the rocker box that lubricate the valve guides and stems, there was a hole up in the middle between those oil holes and we found this to be an air vent hole leading to the outside of the engine between the fins. This hole was Jabiru's fix for the coking oil issue. My friend and I just drilled tiny holes in the top of our rocker box covers and had no problems. I had to place some high temp RTV in between the fines where the hole exited. My oil problem is fixed. Since then a friend found a way to place the head on his lathe and he resurfaced the small 3 thousands divot in the head seal so I have a usable head that will fit on #1 or #4 if anyone should need on and don't want to pay close to $700 for a head. This one does NOT have the air vent hole. John M
  8. My engine s/n 3237 has just past 1100 hours. Relied exhaust guides at 960 hours and replaced exhaust valves. #4 cylinder is a bit soft but it's running great. John M
  9. Fraser: I fly Avid Flyer Aircraft and flew my model B for 2400 hours with a grey head 582 and then changed to Jabirus for another 1980 hours. First a summary then the pros and cons. I bought my Avid in 1990 and have had 5 different engines in it since that time. It came with a Rotax 532 with single ignition and rope start. I got rid of that one quickly and installed a used Rotax 582. Flew it for several hours and had it overhauled a couple times. It had a C box and no starter. I hand proped it. Then I pulled that one and installed a new 582 with an Ebox with built in starter. I ran 100% synthetic oil which I mixed by hand in the fuel. I ran it 100:1 ratio and got 500-600 hours between overhauls. I believe this is due to the fact that I fly a lot of hours and because of the synthetic oil. The 2 strokes only had minor issues. The pros in the 582: They are one of the cheapest power plants. You can swing a longer prop due to the gear box. The cons of the 582: All Rotax parts are very expensive. They start out light and simple in concept, but after you install the heavy muffler, two carbs which have to be syncronized, short TBO times (recommended at 300 hours) and oil container for the injection oil. water with anti freeze, rotary valve oil supply, water hoses and radiators you now have a much heavier and more complex engine. Oh...and the chain saw sound. How about the Jabiru 2200s: These are very simple engines with one constant depression carb (somewhat altitude compensating) and light weight. Almost the same as the fully equiped 582 at about 130-135 pounds. The 1st one I had was one of the early hyd lifter conversions. At 200 hours all the valve guides were worn and replaced on warranty. At that time the valves should have also been replaced, but weren't so at 585 hours it sucked an exhaust valve and I dead sticked back to the airport with no damage. The #3 piston was busted, the rod was bent so I took to my dealer in Fresno (no longer in business) and he rebuilt the engine . After I got it back it ran for about a minute and threw a rod. He was embarrased to say the least and I was pissed. He placated me by selling me a much newer engine (at half price) with all the rocker box and valve issues addressed. It also had different hyd lifters, cam and heads. I have put 1030 hours on this last engine. At 980 hours I saw some evidence of valve guide leakage on the rear exhaust valves. I was getting ready for a back country trip so I relined the exhaust valve guides and replaced the exhaust valves. On the trip to the Nevada back country I made a bad landing and totaled my plane. One week later I bought a newer Avid with a Rotax 582 grey head with 280 hours on the last overhaul. I flew it for a short wihile listening to the engine turning 6000 RPM with the 3 blade prop only turning 2000 RPM and burning 7 GPH. I sold the engine, prop, spinner and motor mount and have installed my Jabiru 2200 from the wreck. The leak down performed on a cold engine after not being run for over a month came in at 75/80 for the lowest. Took the new Avid on a maiden flight today and glad to have the quiet simplicity of a direct drive 4 stroke. Jabiru Pros: Simple, light weight, parts are cheaper..many off-the-shelf, much quieter, under 3 GPH fuel burn with mixture control, easier installation, longer TBOs (1000 hours top...2000hours bottom) Jabiru Cons: Some engines are not being installed properly and are over heating and failing sooner than needed. Some range of serial numbers of the early hydraulic lifter engines had early failures. Only one reputable dealer in the US. Currently a airworthy notice pending in Austrailia which was poorly drafted and is being contested. Hope this helps with the decision. John M
  10. Mark: Why do you advance the throttle rapidly? I have been taught ever since I got my private in 1963 that slowly advancing the throttle was much easier on the engine stress due to the gyroscopic and inertia affects of the prop. What was the oil temp when you did the mag checks? Excessive mag drops can be caused by: 1. Fowled plugs 2. Incorrect spark gap 3. Incorrect air/fuel mixture 4. Incorrect or bad fuel What do the EGTs show during mag checks? JohnM
  11. Phil: My first Jab 2200 was an early Hyd Lifter type that was more a boat anchor than a reliable aircraft engine. At 200 hours the valve guides were all worn and replaced on warranty. This was caused by the fact that the crankcase pressure would not allow the oil in the rocker box to flow back down into the crancase and so it just cooked into carbon. My west coast distributor replaced the valve guides but he should have replaced the valves also since badly worn guides allow the valves to hit the seat slightly off center causing stress on the valve just beneath the head. So at 585 hours the number 2 exhaust valve head broke free and distroyed the piston and bent the rod. I dead sticked back to my home field. The engine was rebuilt by the same dealer and after 60 seconds of run up it threw a rod up through the case and into the starter motor. Of course, I was pissed, but the dealer made me an offer I couldn't reuse on a brand new on with all the needed upgrades ( different cam, crank case, lifters, fly wheel pins, etc) so I was placated. My current Jab 2200 (s/n 3237 has 890 hours on it with absolutely no minor or major issues except for hard starting in cold weather which was corrected when I moved the battery from behind my seat to up front on the fire wall. However, I did notice some carbon blackening near the exhaust valve springs on the rear two pistons. I took the head off and found the guides to be just out of the widest spec. My friend has the equipment to bore out the existing guides 30 thousands and insert guide sleeves. I ordered 4 new exhaust valves at $50 each. I used Aeroshell greese with molydnum disulfide at 20% on the stems and rocker bushings. The engine has 5 hours on it since this was done and is running strong. This should easily get me to the recommended 1000 hour top and beyond. The compression is good. JohnM
  12. Rick: In regards to needing and engine oil cooler as related to oil pressure. Having a cooler and associated hosing will increase oil pressure due to the the resistance of the afore mentioned. Having low blood pressure is a good thing...right. But, having vessels occluded with plaque raises the blood pressure. The resistance of the cooler and hoses will increase back pressure that can be seen by the oil pressure sensor. This begs the question: Is it better to have more oil flow at less pressure or less flow at more pressure. I think you will find that and oil cooler system WILL indeed RAISE the oil pressure. By the way... I have my oil pressure sensor moved from the normal mounted position to the gallery hole just below that placement. This both eliminates much of the pulsation from the oil pump and let me know the oil pressure in the engine galleries. Here in Southern California where temps get into the tripple Farenheit levels an oil cooler is manditory. John M
×
×
  • Create New...