JabSP6

John Come to think of it i must have used at least a 25 pin plug. There are 12 sensors with a negative and positive for each sensor and i'm sure ther was at least 1 spare pin. Anyway the blokes from MGL will soon clarify this for you. Hope this helps mate. Wags

John What i did was go to a computer store and bought an extension cable of the right size plug. I think from memory it was a 23 pin plug. cost around $15. This saved having to join all the wires at the back of the gauge behind the dash. The pin plugged straight into the gauge and i cut the other end off the extension lead and ran it thru a grommet in the firewall. I then soldered all the wires from all 12 sensors to the computer cable out in the engine bay and had heat shrink around every wire. This is quite a lenghtly process to make sure all the positive and negative wires are hooked up correctly. I then just looped the excess sensor cable in the engine bay to keep things tidy. I was told that as long as you don't cut the sensor wires the sensors will still read acurately. You can extend the wires but you can't shorten them. To test this i then checked the reading against the original CHT sensor under NO6 plug and the reading was identical. Wags

Thanks Yenn I have been to Gladstone a few times. This could be an option. Maj The strip at Emu park sounds great. Do you know who owns this strip? I would like to give them a call to see if it would be Ok to drop in for a look. Might even be good for a day trip up there with the wife. Andrew

John Thanks for the photo. This looks very similar to my cowl. Do you have the dimensions for the upgraded Oil cooler? I would like to check that i have the latest one available. As for the deflectors i know they used to have metal ones that used to sit directly on the top of the cylinders which were recommended to be removed but i haven't tried the deflectors below the cylinders. This is something that Jabiru have not suggested but another fellow aviator has suggested it to improve the consistancy in the temps over the whole barrel. Will keep you informed of my progress. i will be trying these things one at a time while monitoring temps so i know if they work or not. Wags

Even Cooling over the Heads Garry & John I have done a few things in relation to the cooling of the cylinder heads. I was after a bit of advice in the deflectors you are talking about. i have looked into the Ram air ducts that sit on the barrels and heads. From factory there is a deflector right over the centre of Cylinder 5 & 6. As i now have my rear cylinders running around 5 - 10 degrees cooler then the front cylinders and the middle cylinders running around 15 - 20 degrees hotter than the front cylinders i was thinking of fitting a smaller version of the deflectors above the centre of the middle cylinders and just modify the length until the rear temps even out to the fronts and hopefully this will also reduce the centre cylinders to eventually have all around the same temp. I have also heard that you can fit a deflector under the barrels above the pushrod tubes to deflect the air coming between the cylinders around the bottom of the cylinders. i guess this would help even out the temps from the top of the engine to the bottom. just wondering which way you have done your mods? I was also wondering if anyone has got any photos of their lower cowls so i could look at how i can modify mine to give a better negative pressure in the engine bay. the previous owner has done some drastic changes to mine from standard which to me looks like it would creat a lot more drag and turbulance than improving the airflow direction to achieve the negative pressure required. Wags

John They are used in Hydraulic shops to block off fittings and hoses etc and can be bought i a range of sizes. Andrew

NEED HELP : Looking for Airstrips near Mackay and Yeppoon NEED HELP Hi group I am looking at the possibilities of heading up to Mackay and also heading to Yeppoon. I was wondering if anyone could help me out with the locations of any airfields that i would be able to use around these areas. I will be in my SP6 jab with an RAA licence leaving from Rolleston with 85ltrs on board so i will have plenty of fuel to get to Mackay but will require some fuel to be able to make it back to Bundaberg with plenty of reserve from either location. Any names and phone numbers of people that i could call would also be much appreciated. Andrew

Biggles I have fitted a MGL 12 channel 3 1/2" Gauge to my SP6 and the results will blow you away. I am in the process of redirecting airflow to even out the CHT's and have changed Jets in the carby to get better EGT's. For more info go to the Jabiru forum and look at a few of the post on "How to improve the reliability of the 6 cyl Jab Bought them from Bernard (0419423286) at Asia Pacific Light Flying in the A.C.T. Gauge was $395 6 x CHT sensors were $290 6 x EGT sensors were $423 Wags

Nev / Jack I am using Shell 100W PLUS aero engine oil which was recommended by jabiru. Should i be using 15w-50? Winter up here does't usually get below 10degrees

Jack I am running things a bit richer than the standard specs for now to see how things go with the other mods that i have done, ie. ceramic coating etc. 190 needle is 1 size bigger and 265 main is 2 sizes bigger. The WOT EGT's vary about 80 degrees from richest to leanest but the highest reading is around 650. The cruise EGT also vary about 80 degrees but the highest is 685. So according to these temps the mixtures should be, depending who you talk to, fairly close but just on the rich side but i am going to fit an air fuel ratio sensor short term to the exhaust to find out exactly what it is doing. The needle is the Jabiru spec one with the one circlip groove and the 3 rings as a marking which i believe is the correct needle. Once i can even out the temps for both CHT and EGT i will look at possibly rejetting if needed. I would rather burn a bit more fuel than risk engine damage. The Oil temp on the way out sat around the 85 degrees. Some people say it must be around the 90 mark ad others say the lower the better. What are your thoughts on the temp of the oil?

Guys Just to let you all know I have the motor back together and after some testing of around 6 hours over the weekend I have made my first flight today back out to work. The hour meter was right on 2.0 hours for the trip this morning including run ups and taxi times. I have fitted the EGT and CHT sensors with the MGL Gauge and I noted some reading during the flight. I took off from Bundy and climbed to 4500" at a steady 300"/min. this took around 20nm to achieve cruise height. I then levelled off and cruised out to Rolleston (205nm). Sitting on just over 2800RPM on the tacho my airspeed was 120knots. I have a 3 blade Patroney Prop fitted set at 14 degrees pitch. I then had a slow decent to rolleston starting 20nm out of around 300"/min. The temps were as follows on cruise EGT 1/ 602 2/ 673 3/ 621 4/ 682 5/ 639 6/ 681 CHT 1/ 103 2/ 95 3/ 127 4/ 108 5/ 101 6/ 92 I have increased the needle jet to 190 and the main jet to 165 to make sure there is plenty of fuel for the first few runs while i try to get on top of the difference in the CHT's. I have not yet done the mod of the Plenum chamber but when i do i will hopefully see more consistant figures across the EGT's. I am also trying to redirect some airflow over the middle cylinders (4 & 3) by fitting deflectors in the ram air ducts like they have done from factory over the rear cylinders. i will be doing this when i get home on the weekend. this should even out the CHT's. The SP6 tank was right on the 80ltrs (avgas) in the hanger before i took off and when i checked it again at the hanger at work it was right on the 40ltrs. I think this is a pretty good result. Average 20ltrs/hour including run ups and taxiing times. As the motor gets a few more hours on it I am sure the temp will improve and i may need to look at the jetting again after I perform the Plenum Mods. I will keep you all informed. Andrew

Jack.I will talk to the guys at Jabiru when i get home on the weekend about the carby mods and i will keep you all informed. I hope that by performing these mods the carby might work ok with the standard jetting recommended. I was running the latest Jabiru needle with the recommended 285 Needle jet & 255 Main jet & 35 idle jet. This gave me a cruise temp of 750 degrees C and a maximum power temp of 780 degrees C. I have increased the needle jet to a 290 and the cruise temps are now around 700degrees and I increased the main jet to 265 to achieve a maximum power temp of 680 degrees. these are still a bit higher that what you have recommended so i will see what happens after the carby mods are done and the plenum chamber mod is done. I am still working on cooling the head temps and it has been suggested i fit baffles under the barrels to even the air flow around the cylinders and fit a lower cowl boomerang to improve the pressure differential. I will keep you updated on this mod also.

JACK. This is very good info mate and i appreciate you taking the time to tell us about these changes. I do recall hearing about the change to the deflector in the plenum but had forgoten all about it. I will make sure I do this. Also the Carby mod is a new one that I will be asking about. Do you have any more info on this as I would like to know a bit more about what they do before I go asking the question. I am curious about the valve inserts. Can you give me a part number or suggest where I can purchase these items. Are they made from a different type of material and do they run tighter tollerances. It has been suggested the standard guides are an aluminium/bronze guide are are not as good as a Phosphorus/bronze guide. Thanks again Jack

Guys. I don't want to be a stickler for the rules but this is a Jab forum. I am really not interested in hearing about the rotax motor or how cheap the parts are. I am looking for options other than the standard replacements and factory rebuilds for the Jabiru motor. If anyone can give some advice on the actual topic of this forum this would be much appreciated. Andrew

Deadstick. I would like to have a chat with the bloke about the mods that have been done in NZ. This is exactly the sort of thing i am looking at doing here myself. I too had to have some porting done to the new Fine finned heads for the same reason. Very inconsistant machining from 1 head to another. It is good to see that other people are experiening the same issues i am confronting. I am hoping for good results once i get the motor back together if i can talk to some people and gain some good feedback of their experiences. I had an Engine builder look at the heads and another comment he made was looking at the flow of the ports, the size of the piston and stroke, he has concluded that the size of the exhaust valve is too small compaired to the size of the Inlet valve to achieve the correct air flow. He had some formular that worked all this out which is abit out of my league but has suggest and Exhaust valve 3mm bigger in diameter would improve the effectiveness of these heads. He said that by machining out the seats slightly this would easily allow the fitting of a bigger valve that could be made to suit. It's just a thought that i am throwing out there. Any comments or ideas about this?

Jetjr.that is a good point about the flashlube. When i bought the plane the previous owner suggested i use upper cylinder lubricant in the fuel which i have done. i use around 50mls in every tank.Gnarly.There is a company in brisbane that can make 1 piece valves from stainless. titanium etc. They also use a nitriting process to harden them. I don't know exactly what takes place here but they use these in all types of Drag motors which are subjected to much higher RPM's than 3300.Jetboy.Thanks for sharing with us your experiences. These types of stories are all too common which is exactly why i posted this forum. I just want to make it clear that i am not here to run down Jabiru. I live in Bundy and have a good mate that works there and has been extremely help ever since i bought the plane. He has helped ensure the Maintenance is done by the book but still the problems occur. When this motor goes back together it will have all the latest mods done to it including a full set of new nuts, bolts, seals, oil pump mods, dowled crankshaft, latest fine finned heads, barrels, pistons, rings and the list goes on. As i said earlier i will be fitting a set of CHT & EGT sensor to try to see what is happening also. What i am trying to achieve hear is to put together a motor that i won't have to think every time i go to work, is it going to make it. Unfortunately at the end of the day the feedback I have recieved, and i won't mention any names, is that even with all these changes i still probably won't make the TBO. This is why i am asking if anyone has tried thinking outside the square like some of the things i have suggested and had any success with these ideas.

Jetjr.My motor is the early Solid lifter engine and i agree Jabiru have done some R&D to try to improve a few things in this area. I have purchased 6 EGT and CHT sensors and gauge that will be fitted when the engine goes back in as i believe my motor has suffered from inconsistant mixtures between cylinders as you mentioned. To combat the overheating of the heads i have purchased a set of the latest fine finned heads. Thanks for the tip on the EFI site. I will look into this as i believe, like you, this is a real problem. The performance and efficiency gains are quite remarkable and will solve this issue. The water cooled heads for a Jab are now available from around $3500. Not sure if i would have room for the radiator in my SP6 engine bay although i was seriously thinking about them before i settled on the fine finned heads. This is why i was thinking about what else we can do to these engines to make them go the distance so we don't have to constantly be told how bad our motors are every time you go to a fly in etc. Eg a friend of mine had fitted a Subaru 2lt EFI automotive engine to his gyro and has achieved 7000 hours and is still on the same set of pistons, rings and valves for that matter. I'm not suggesting we can achieve this from our motor but surely we should be aiming higher than 400hrs. I don't believe this is too much to expect.

Quentas.This is my point exactly. It is stated that they should be able to go 1000hrs so why should you settle for replacing valves every 400hrs. By replacing the valve with a stronger better wearing one piece Stainless Steel valve and reducing the temps of the components with Ceramic coating wouldn't this help to achieve the reliabilty we are all after. I have looked into the cost of these valves and the ceramis coating and you would be surprised at who little the cost actually is to help achieve the result s i am after.Any thoughts out there on this?

Thanks Blackrod and Walter.As you are all quite aware the Manufacturer believes that there is nothing wrong with their motor design and when operated within their strict operating guidelines the motor is extremely reliable and will make the 1000hrs TBO.I, on the other hand believe in the concept a motor should be 100% reliable, especially in a plane and should be able to withstand a variables that often are thrown at us from time to time. My plane is not a factory build so the concern about entering new ground is exactly what i think we need to do and won't change anything with reference to the manufacturer pointing the finger. They do it now with a completely standard configuration. I am a firm believer of sticking with what you've got and if necessary use the wealth of knowledge and experience that is available to improve things. The engine design is quite simplistic and with a few improvements should easily be able to out perform the trusty 912. I was just curious to see if anyone else had tried some of the suggestions. I have seen photo's of a gentleman's motor in NSW that has fited multi point (& single point as a back up) fuel injection with great results. These are the sort of ideas i am looking for.Thanks again for your input. Andrew

Hi all. I am currently in the process of rebuilding my Jabiru SP6 motor after experiencing No2 exhaust value deciding it would rather travel thru the top of the piston several times instead of closing on the exhaust seat. It separated from the exhaust value stem at the base of the head and at 2800 RPM as you can imagine caused a fair bit of damage. luckily i was 10mile out of the airfield and at 4000feet AGL so manged to perform a glide approach and land safely. luckily the motor continued to spin over although obviously running extremely rough so i reduced to just above idle and it somehow continued to run untill i shut it off after taxiing from the runway.Total time on the Motor and plane is 750hrs and it was fully overhauled by a LAME at 320hrs after finding metal in the oil filter. At 550hrs the leakdowns were quite bad and oil usage was extremely bad so a top end was again performed which revieled bad piston carbon deposits and rings siezed in the grooves.I would welcome the chance to talk to you all about anything you might have done to try to improve the reliability of these motors as i use the plane for transport to work and have flown 240 hours in the past 9 months. Has anyone looked into the option of running one piece stainless values to eliminate the chance of the 2 piece std version separating again? Also has anyone looked into running a nickasil coating on the bore and running a better quality ring to reduce the chance of the std 4140 barrell devloping rust deposits if left sit for lengths of time and then the initial start up prematurely wearing the cast rings resulting in poor leakdown results in relitively short hours. Also what about applying a ceramic coating to the combustion chamber and top of the cylinder to stop as much combustion heat transfering into the air cooled engine components? Just some ideas that are comonly used in other forms of transport which don't require anywhere near the amount of maintenance repairs. Don't get me wrong - I love my Jab. i just want to try to make the 1000hr claimed TBOLooking forward to utilising your knowledge and experience.Andrew

HelloI am currently in the process of rebuilding my Jabiru SP6 motor after experiencing No2 exhaust value deciding it would rather travel thru the top of the piston several times instead of closing on the exhaust seat. It separated from the exhaust value stem at the base of the head and at 2800 RPM as you can imagine caused a fair bit of damage. luckily i was 10mile out of the airfield and at 4000feet AGL so manged to perform a glide approach and land safely. luckily the motor continued to spin over although obviously running extremely rough so i reduced to just above idle and it somehow continued to run untill i shut it off after clearing the runway.Total time on the Motor and plane is 750hrs and it was fully overhauled by a LAME at 320hrs after finding metal in the oil filter. At 550hrs the leakdowns were quite bad and oil usage was extremely bed so a top end was again performed which revieled bad piston carbon deposits and rings siezed in the grooves.I would welcome the chance to talk to you all about anything you might have done to try to improve the reliability of these motors as i use the plane for transport to work and have flown 240 hours in the past 9 months.Looking forward to utilising your knowledge and experience.Andrew