Vev

G'day Ross, Yes I did fit the K liners and it all seems to work as advertised ... I have done 42 hrs on them so far and all is very good, in fact my oil consumption is almost nil now. However I did also replace the rings and gave the bores a light hone too. I also changed the out the push rods and rockers for the new hollow type, which also allowed me to blank off the oil feed gallery and turned to old rocker chest oil feed "T" piece into a breather .. I think this also helps keep things cooler in the rocker chest owing to better drain back of oil to the sump. Cheers Vev

Jaba-who, I think the best I can suggest is the parts manuals ... I think the 2200 parts book is possibly the best diagram, albeit not that clear. Cheers Vev

Hi DC10, Sorry to hear about your latest engine experience but glad your dog was not with you to extend your misery. Thanks for the feedback on the engine condition... The service info, re checking the torque, came from Aug Jabachat and may take a while to find its way into a service bulletin. I thought it was interesting the info made mention of the economy tuning kit being fitted for part of its life may cause a bolt failure .... it's basically an admission that the previous factory jetting may cause a future failure even if the recommended jets are fitted. I presume Jab are recognising that through bolt fatigue from detonation caused by lean jetting is a problem .. it makes me wonder if there should have been a recall on all engines to address this issue rather than provide a procedure to check bolt tension as a precursor to a failure? Although having said that I wonder how many failure there has been, albeit cold comfort if it's your engine. Cheers Vev

It really is unacceptable that the through bolts should fail ... I have heard (unconfirmed by Jab) they are working on an improved system, which I'm sure will be well received by many. Attached is a maintenance quote from Jab to manage through bolts. "Occasionally a high-hour engine will suffer a failure of a crankcase through-bolt or crack a cylinder base. The cause of these issues can be detonation (such as if the engine operated with early versions of the economy tuning kit for part of its life) or uneven positioning of cylinder base nut to thread/shank. In some cases crankcase fretting will occur as a secondary effect of these same factors. While fretting is rare there is a simple check which allows the problem to be detected early: By checking the tension of the nuts on the bottom crankcase through bolts (the ones easier to access) at a setting of 28lb.ft. These bolts are tensioned at 30lb.ft during engine assem- bly, so if there is any movement in these nuts at 28lb.ft some form of bolt or case damage is likely. Jabiru should be consulted if this is found. Note that increasing the bolt torque beyond 30lb.ft will damage the through bolt, so torque wrenches must be accurately cali- brated before carrying out this test. We recommend that this test be carried out as a precaution during the last 200 hours before the engine is due for a top- end overhaul. In addition, if the engine is extremely hard to turn after a through-bolt has been replaced, this is a likely in- dicator of crankcase fretting and Jabiru should be consulted". In addition to this procedure when checking or torquing new bolts, one should check both ends of the bolt as just doing one end isn't sufficient. Cheers Vev

Hi Dieselten, Glad no one was hurt. The engine hardly sounds like it was under any stress when it failed ... as you suggest, not a time you would expect to see detonation. Couple of questions on the failure if you don't mind? Were the barrels every off this engine or the studs removed? Was the torque ever checked on the through bolts and was there any movement? What was wrong with the heads when they were reco'd? Does this engine have a EGT, if so, does it ever run >1250 deg F? Cheers Vev

Hi Bob, I got exactly the same response from Rod Birrell yesterday ... he said CASA had informed the RAA that 600kg would be through by Christmas, just didn't say which one! Cheers Vev

Hi Ian, Yes this is excellent stuff in terms of RF and good to see you have made this commitment. However, I think we need a fundamental philosophical change in the way weather is reported and taught to meet CAR 120 requirements. The code system is outdated, cumbersome and exposes infrequent users to risk thought misinterpretation of the data. As I have said before, this is one of those left over processes that belongs to the flat earth society and not 21st century airmanship.... we have better communication systems available why not use it officially! Cheers Vev

I spoke with Rod Birrell (RAA Board Member - Victoria) today and he says Plain Language Avmet has now been raised at the board level and adopted as a policy to implement. However as usual, it is about priorities and needs to be elevated to get some resource allocated towards getting it through the hoops. Birrell said whilst it is in the Ops Managers basket of things to do, he suggested if this is something the members want a few letters of support would be useful to get things moving along a little faster. So guys, if you want to take a few minutes to send Rod Birrell an email ( [email protected] ) and let him know in the interest of safety you support the adoption of a plain language weather report, I'm sure this will lift the profile and speed of implementation. Cheers Vev

Cheers Doug .... very nice. Vev

Hi Pud, Yes you can strip ethanol out out of fuels ... however you will deplete the octane of the fuel which will cause significant performance problems (detonation etc), not to mention you will end up with a waste disposal issue and an economic loss of 10% of your purchase price. Apart from all of that, it's also dangerous to mess around with such volatile products, which is never a good idea. I think one is better off avoiding using ethanol blend fuels whenever possible ... if you have a choice, use unblended fresh fuels every time. Cheers Vev

G'day Jack T, Strewth cobber, to learn the lingo will be a mongrel for a septic ... you will sound like a galah for a while but you'll be apples in the end. To give you the drum, head past the black stump and do some jackaroo yakka .. no raw prawns out there mate and you'll pick up dinkum stuff. Hooroo Vev

In my view, ethanol fuels is really all about meeting political agendas ... I think there are very few positive characteristics about ethanol and wont use it in any of my toys. I say ... Alcohol is best mixed with drinks and not mixed with flying. Cheers Vev

Hi Jack, You are spot on in terms of fuel consumption increase using E10, although it should be more like a 5% change ... the energy value of ethanol is close to half of mogas and therefore you need to burn almost twice as much to get the same energy value. The actual octane rating on the pumps in Australia is measured differently to the US. Aust report the RON number and the US uses what is called the AKI (Anti-knock index) which is the average of the RON & MON (R+M)/2.... in reality AKI 93 in Florida is the same as RON 98 in Australia. You will find that 98 is available from just about all the major oil companies. Cheers Vev

Hi Jetjr, Spot on ... the plenum has to come out, split plenum and replace the divider. However, it's not that big of a job. Cheers Vev

Hi Powerin, Whilst the Arion chap may have improved things, I would be quite concerned about the EGT temps over 1250 deg F ... I think this fellow will see a number of heat related problems very soon. I think the easier improvement on the 6 cylinder EGT spreads is to simply remove the manifold divider and replace it with a 12mm round rod drilled thru the centre to bolt back into the manifold ... job done! However, don't take my work for it, call Don at Jab and ask him. Cheers Vev

Hi Nev, Re Flywheel bolt problem. Thanks for the quality input as usual. Would you expect the 4 cylinder to be more of a problem than the 6 owing the more aggressive firing pattern? Cheers Jack

I wonder if Jabiru are considering a 6 cylinder engine? Cheers Jack

Onya Darky ... well done indeed. Cheers Vev

Hi Bob, Sorry to hear about your engine letting go. Jab claim the thru bolt failures are mostly caused by detonation .. to that end they have been slowly reducing the compression ratio over the past couple of years. The very latest engines now have either a 0.5mm spacer under the cylinder or a 0.5mm longer cylinder to pull back the compression ratio. The lower comp and better cooling with the more fins and a richer jetting in the Bing should all help reduce the detonation, so long as you are all using the right octane fuel too. By the way ... what fuel was that broken engine running? Cheers Jack

I called into Rotec yesterday and took a look at their Liquid Cooled heads … very impressive According to the guys at Rotec they said if they can get this to work as well as they hope it will fix any potential over heating or detonation problems in the Jab engine for good. The guys started up their 6 cylinder test engine for me and ran it to demonstrate the effectiveness of the cooling. What struck me instantly was how much quieter it ran, I presume the water jackets around the head must dampen some of the over head engine noise. After a short warm up the engine was loaded up to cruise power and then a full power over about a 30 min period… the CHT, oil and water temp remained well within in the green the whole time. In fact the oil temp may have been a little low in my view and might require some consideration around reducing the oil cooling. Despite the current test radiator being probably bigger than required for operational in-flight use, there was very little air flow over the radiator, owing to its position of being mounted at the back of the engine on the test stand. It seemed reasonably logical to me that a smaller radiator mounted inside the cowl will be quite adequate. They had an electric water pump fitted, which the Rotec guys said will have a thermo switch fitted, this will be good for start up on a cold engine to preserve battery power for turn over. I think I would also prefer a manual over ride on/off switch as a back up and to control power consumption at start up even on a hot engine. The guys said they would look at a 4 cylinder version soon, as the exhausts ports on the 4 cylinder are 180 deg different to the 6 cylinder on 2 pots and needs a new head shape. The rocker chest is based on the earlier narrow thick fined head, which should take all of the rocker configuration be it sold tappets or hydraulic lifters type. The new hollow push rods over head gear should fit too, but I think only just… personally, I would have preferred they had used the latest wider rocker chest configuration as I think this was an improvement and it takes all of the rocker configurations easily. The aluminium material used is much more substantial and head crush from head bolt over torque shouldn’t be an issue … nearly all the Jab heads I have seen have some crush around the head/barrel interface, which I have presumed a combination of soft material and too much head bolt torque. The guys at Rotec said they will be working with a few selected people to test the heads and see how they perform under operational conditions. I guess time will tell but it does look quite promising. Cheers Jack

Hi Modest Pilot, Yes I heard the same reports about lifter flushing, although I can't say I have experienced this improvement but it could be quite true. However despite the fact that the 50% blend of semi-synthetics in the 15w/50 Shell lube, I would think it unlikely that the synthetic base oil will flush any better ... in fact the solvency of synthetics is mostly poorer than mineral oils. If the multigrade lube is flushing the lifters better it is more likely to be a combination the better flow characteristics by nature of it being a multigrade and a very effective dispersant additive in the oil. Cheers Jack

Spot on JR .... Jab recommend a run-in lube for the first 25hrs. Shell make 4 grades in Aust. Shell Aviation - Australia Cheers Jack

Andrew, If you are running in a new top end you need to use a lubricant with minimum additive treatment such as AeroShell 100 (Not AeroShell W100 Plus) for the first 25hrs. If you don’t use a run in lube your engine may glaze the bores. After the engine is run in I prefer a multigrade such as AeroShell 15w-50 ... the 15w is the equivalent viscosity at 40deg c, the "W" stands for Winter and tell you that is will operate well below zero. The 50 is the equivalent SAE viscosity at 100 deg C and tells you it will maintain good lubrication qualities at higher temps. The multigrades are achieved by blending in Viscosity Index Improvers (polymers), where the oil is relatively thin and less restricted compared to a SAE 50 mono grade oil at low temps, thereby allowing the oil to travel around engine more quickly and reduce start up wear. This low temp performance is important in the Jab engine as not only does it assist in reduceding start up wear but it also helps with drain back from the rocker chest to the sump… the rocker chest is a source of thermal shock owing to the high heat of the cylinder head in the first few minutes at start up, which is more critical in the 4 cylinder engine but still an issue in the 6. In summary … I would use the Shell W100 to run in and then the Aeroshell 15w-50 after that. Hope this helps Cheers Jack

hi Andrew, Nev is correct ... engine lubricants need to operate in a range high enough to dry them as well as activate the additive systems, particularly in respect of anti-wear.... Too hot will cause oxidation of the base oil where it will break down. I am assuming you are using Shell 15w-50? At 80-90 deg c you are in the sweet spot and all is good. Cheers Jack

Hi Andrew, Look fwd to hearing hows things go. Re your jetting .. the 190 needle jet and the (i presume) 265 main is on the upper end of the recommended jetting so you will be getting a heap of fuel through. Just wondering if you have changed the needle to the new one as well? Cheers Jack