Hi all I recently noticed a low CHT reading on No 1 Cyl in cruise. Engine is a Gen 3 2200 in my Jabiru J170D. The temps usually sit around 140deg on all Cyl but the last few flights No 1 Cyl is bouncing around between 95 and 105deg. I have checked the wire connection to the cylinder which looks intact, but haven’t gone any further at present. I have also been advised to put the probe into boiling water and check the gauge reading but haven’t had the chance yet. At this stage I am assuming maybe a broken or chafed wire between the gauge and the Cyl probe. The instrument is the MGL grey Bar type EGT/CHT display. Just asking if anybody else had this issue and the resolution.

Issue resolved. The coil was the only fault & the new one fixed it. The runup miss was due to about 30-40 engine starts to find the fault & no normal temp or RPM engine running. As mentioned the shutdown mag check was good after the first flight. Next flight was good. Runup no miss on either mag & smooth operation throughout the rpm range plus seemingly more power now.

I tried the cold cylinder procedure as advised by an old LAME by starting the engine on Mag 2 & found cylinder 6 cold. I thought I'd found the problem but after replacing the plug that cylinder wasn't a problem but the miss was still there. This was when it began to get confusing. I think there is/was more than 1 problem. The new coil has solved one of the issues, now I have to find whether the other is the distributor or HT lead/s.

At work to isolate a cylinder ignition problems on Lycons a spray of paint on the exhaust headers 5 cm from the head, run engine in defect mode, left or right mag etc . Have someone watch the paint start to burn off. Stop engine,the defective cylinder should be obvious as less burned, colder.

My Gen3 3300A started running rough between about 2800 & 2950RPM & then after returning from a day at Tenterfield Mag 2 (RH MAG as seen from pilot seat had at least 1 cylinder misfiring. First I swapped out all 6 plugs one at a time with spares I had (used but going perfectly when replaced. I've got 36 of them). No change. Then I borrowed a lead tester & checked all leads. All checked out as good. Next I removed the distributor & it looked perfect but gave it a good clean & used some contact cleaner. Next started the engine, shut down Mag 1 & removed each plug lead 1 at a time. There was a RPM drop on each cylinder. Next got a new (genuine Honda) Coil from Jabiru & replaced the original (Honda knockoff) coil but still the problem existed. Mag 2 on runup 2000rpm had at least 1 cyliner misfiring. I took off & full power all good & the rough running was less noticeable but still there & full power S&L was 130 knots indicated at about 3200 running smoothly. On shutdown the idle mag check was good on both 1 & 2. The next thing I can do is swap distributor caps to eliminate that. My current thoughts are that I have a faulty HT lead or maybe 2 even though they all checked out using an HT lead tester. Anyone had anything similar of have any other ideas?

Checking your CHT readings with a couple of different instruments is always a good idea. A temp probe under near the ex port might shock you.

Problem solved. My 12 channel MGL temperature monitor had been fitted incorrectly and was connected to the aircraft earth. The instructions clearly state the instrument should be earthed on the engine block. After correcting this my CHT temperatures all remain below 150°C and agree with the Jabiru original sensor fitted under #6 sparkplug. Finding this earlier could have saved me a lot of stuffing about with ducts and engine cowl flaps, to say nothing of an early complete engine re-build by Jabiru taking it to the latest Gen 3 spec ( After fitting the CHT monitoring I thought I had been over-heating my engine continuously - hence my caution). If you want something doing correctly - do it yourself comes to mind. Alan

I have 12 channel temperature monitoring on my Jab 230C with the sensors fitted between the spark plugs on the heads. I was wondering whether there is any known calibration differences between these and the original Jabiru sensor ring fitted under a spark plug. On a hot day during climb out my between head CHT indication can rise up to 180°C, (although in reality I slow the climb to keep the temps down, max last flight was ambient 35°C, CHT =178°C). However, the original Jabiru spark plug senor is always well in the green? Alan

I hope it lasts as well as mine has. Never thought about the 2 way terminals but depending on location that is a handy feature.

Tried one of these in my J200 recently(after reading your post) as the odyssey battery couldn't cope with the winter cold starts... So far so good, with temps below 0 deg The Mottobatt starts it first go no problems.. Cost me $175 delivered. The two way terminals is a good feature too.

It will need to have enough power to throw the pinion out to fully engage the ring gear. You could also install a car style starter with a pre-engage mechanism. The problem with this is presumably a weight disadvantage.

you could do it actually, in a crude but effective sort of way with an extra starter solenoid in series with the starter cable, and a time delay relay. The 2nd starter contactor has a small loop of wire across the contacts. Initially the starter is engaged with the 2nd contactor 'open' so the starter is connected via that length of wire, which acts like a resistor taking a couple of volts off your battery. After one second the time delay relay times-out and the 2nd contactor pulls in, shorting the loop wire, giving your battery full voltage. You could substitute a resistor and capacitor for the time delay relay also, just becomes a little more sensitive to battery voltage.

I have made a soft start for the Jabiru. It works by simulating a flat battery . It gets the starter engaged at low voltage- as once it is engaged it does stay engaged down to a few volts.... then winds up the voltage... Going to install on mine next week, have been messing with a starter motor (same as Jab ) on the bench. Will make up some kits..... Goes in series with your starter pos cable from the solenoid...

Bruce has mentioned Lithiums, which because of their much lower weight, are attractive for aircraft. I tried small AGMs for several years and found them only just up to the job, especially in winter. When I fitted a LiFePO4 (which claimed a 400 CCA rating) I also fitted a PowerMate regulator which seems to have mated up well with this battery. As Bruce says, a lithium may not be a drop-in replacement for a LA battery; the charge regime is different and their much lighter weight may cause you CoG issues. Besides its very light weight and ability to keep its charge for months even in the cold, Lithiums are attractive because of how they deliver their power; on cold winter mornings my Li battery cranks incredibly slowly, like its flat. After a few seconds the cranking rate picks up as it warms. That gentle start is kind to Jabiru flywheel bolts, but re-starting when it’s hot is not.

I have a Motobatt MBTX20U AGM battery which is 21Ah with 310 CCA that has been going well for 5 years so far. Never had a problem on freezing cold mornings. It cost about $110.00 but they are about $150.00 now I think. Heaps cheaper than Odyssey which are overpriced IMO. It weighs 6.5kgs so no lightweight.

My Jabiru kit came with a motorbike lead-acid battery which was not good enough to start the engine, well after I left it on a small solar charger for months. It was replaced with an Odyssey, which performed well for more than ten years. It is still going, that battery, these days on a farm buggy. I am sure Onetrack is correct, but I didn't know that stuff at the time. The reason for replacing it in the plane was because of weight. A LiFePO4 was 5kg lighter! and much cheaper too, from a chinese hobby online shop. ( without the charging electronics and the case which looks like a regular car battery) These lithium batteries are not as robust as the odyssey, and I am on my second lithium after about 5 years, on account of buggering up the lithium battery by leaving the master on. ( I had done this with the Odyssey, and it came good again... one tough battery, huh.) My advice is not to change to lithiums unless you are quite expert. There are types which are dangerously flammable, their voltage is not compatible with simple charging systems and they cannot stand terminal voltages outside a narrow range. In particular, don't be sucked in by a " lead acid equivalent" figure.

The only two ways you can increase starter torque is by increasing the cable and connector sizes - or by increasing the battery voltage. Battery voltage drops to about 10V at the starter when cranking, normally. If you utilise a larger battery you may see a slight increase in battery voltage at the starter when cranking, but I personally don't think you would see any substantial increase in starter torque. A slight gain, perhaps. CCA is really quite a poor measurement for our climate. It's an industry standard set in, and for, North America, to determine a batterys cranking ability on their bitterly cold Winter mornings. The Nth American Winters get down to -10° and -20°C, and at those temperatures, battery performance really suffers. For us, unless you're in an Australian Alpine location, we don't often get any lower than about -2° to -5°, and that is usually only for a short period, unlike America, where it can be -10° or -20C°, all day. There is a battery measurement for our climate, and it's termed HCA - Hot Cranking Amperes. But you will find it difficult to get that figure from manufacturers, as CCA is the "recognised figure". If the battery you're looking at is Chinese, take the CCA rating with a degree of scepticism. Chinese electrical ratings are always over-rated. I'd be more concerned about increasing battery weight in an aircraft, by going to a bigger battery. The Odyssey battery is a deep cycle Absorbed Glass Mat battery, and deep cycle batteries are not recommended for use as starting batteries - even though people do often use them for that purpose. A dedicated starter battery can produce the high amperage needed in short bursts, such as starter motor power demand. An AGM battery is designed to produce a smaller amperage current supply, over a longer period of time - and to be able to be cycled a lot more often, between a fully charged state, and a discharged state. Accordingly, I'd suggest a dedicated starter battery be fitted, rather than another AGM battery. But at the end of the day, it's your choice.

Just like sports car manufacturers brag about how much horsepower their engines have, battery brands tend to do the same thing with their performance attributes. Enough brands and companies have told people over the years that "more is better" when it comes to cold cranking amps, that a lot of folks now believe it always the case. While more may be better, it may not be necessary and it may be more expensive. One of the performance attributes is how many cold cranking amps (CCA) a battery can generate. So how is this determined? Since "Cold" is in the name, they put a battery in a cold environment (0°F/-18°C) and measure the discharge load in amperes that a new, fully-charged battery can deliver for 30 seconds, while still maintaining terminal voltage equal to or higher than 1.20 volts per cell. Why did they pick a cold environment? Ask anyone who lives in a cold climate with a high-mileage diesel truck- it takes a long time to start some vehicles, whether that is due to high compression engines, extremely cold temperatures or both. Does a J230 in Australia operate in these conditions? A good starter will draw amps under load (while cranking the engine). So if the battery can deliver can deliver 200 amp when it is is chilled to -18C, it will produce more than that at our usual air temperatures. Buying a 300CCA battery would be overkill, unless you want to run a full glass panel, air conditioning and cabin entertainment system at the same time. Getting to the point of your question, the 300CCA battery will not generate extra torque. It will just provide power for longer. And keeping a starter motor cranking for extended period of time will overheat it and burn it out.

Up until now I have always used Odyssey Batteries in my J230. However, I have just found my local battery shop is quoting a 2 months supply delay, so I went looking at alternative lead/acid batteries. Now the Odyssey battery is quoted as 200CCA, some of the batteries I have come across advertise 300CCA. Given the starter ring is at the back of the motor and the flywheel (prop) is at the front, should I be concerned for the starter ring attachment, crank shaft, etc as a result of the extra torque? Alan

Has anyone got a drawing of the Camit Oil separator that screws into the top of the engine Cheers Tony

I have just asked the spare parts guys at Jabiru about a fuel pump kit. The manual says " the fuel pump is replaced as a complete unit" so it may be that this is going to be expensive. Has anybody done this job? What should be a fuel pump life anyway?