Keenaviator Posted June 7, 2015 Share Posted June 7, 2015 I replaced one of my coils with the Cold Start Kit. Does anyone know if that coil is well-matched with Iridiums? I'm running iridiums in an old very low hour 2200a. I fitted the cold start kit mainly because my engine has an early smaller starter motor and they struggled especially in cool weather. The cold start kits works very well with the iridiums. As someone said above, don't adjust the plug gap of iridiums - they come at .028". Initially I closed mine to Jab spec and it wasn't successful. All good now. 2 Link to comment Share on other sites More sharing options...
Keenaviator Posted June 7, 2015 Share Posted June 7, 2015 I'm doing a trip soon where I'll have to use avgas for an extended period. Does anyone have any knowledge about iridium plugs an avgas? Link to comment Share on other sites More sharing options...
Russ Posted June 7, 2015 Share Posted June 7, 2015 Well then....why are some folks installing these iridium plugs ( I'm one ) Why I did i,......folks were saying how good they were. So........what's good about these plugs, or should we keep using the orig plugs. I've been running these iridiums for the last 60+ hrs! all's good. Somewhere way back here, someone said the ol jab factory guru, recommended the iridiums....I think ?? Christ.......now I'm worrying. Link to comment Share on other sites More sharing options...
AVOCET Posted June 7, 2015 Share Posted June 7, 2015 The jab coils dont like getting hot , cool air should be ducted onto them . The only trouble ive had is with long hot taxi , at Avalon one year , changed the coil out and have not had any issues since , irridium or D9EA plugs . Link to comment Share on other sites More sharing options...
Keenaviator Posted June 7, 2015 Share Posted June 7, 2015 The jab coils dont like getting hot , cool air should be ducted onto them .The only trouble ive had is with long hot taxi , at Avalon one year , changed the coil out and have not had any issues since , irridium or D9EA plugs . Done Mike re the cool air directed to coils. So far so good. Laurie 1 Link to comment Share on other sites More sharing options...
Jabiru Phil Posted June 7, 2015 Share Posted June 7, 2015 I'm doing a trip soon where I'll have to use avgas for an extended period. Does anyone have any knowledge about iridium plugs an avgas? Over 300 hours on Irridium plugs with Avgas, all good. Phil. 1 Link to comment Share on other sites More sharing options...
Keenaviator Posted June 7, 2015 Share Posted June 7, 2015 Over 300 hours on Irridium plugs with Avgas, all good.Phil. Thanks Phil, great information. Laurie Link to comment Share on other sites More sharing options...
dazza 38 Posted June 7, 2015 Share Posted June 7, 2015 Well then....why are some folks installing these iridium plugs ( I'm one )Why I did i,......folks were saying how good they were. So........what's good about these plugs, or should we keep using the orig plugs. I've been running these iridiums for the last 60+ hrs! all's good. Somewhere way back here, someone said the ol jab factory guru, recommended the iridiums....I think ?? Christ.......now I'm worrying. Iridium plugs don't foul easily. I had a Yamaha WR426, and due to their carby design, they would foul normal plugs occasionally. Changed it out with an Iridium plug and never had a problem after that. Link to comment Share on other sites More sharing options...
facthunter Posted June 8, 2015 Share Posted June 8, 2015 The heat range of your plugs are the main cause of fouling. A "cold" plug has a shorter and thicker insulator (the bit that projects into the cylinder.) Two strokes suffer from it more than four strokes because there is more oil around. Iridium is used with the points of the electrodes. The centre one is very thin and due to their design and material used, the points don't erode as quickly as normal plugs. You can often leave them in for 100,000 kms. Helpful when they aren't very accessible. I've said this before that I'd rather change ordinary plugs a bit more often as they are about 1/3rd of the price than leave any plug in for a long time. Additives (anti Scuffing) to modern oils foul the insulator by burning into it. The cars they were designed for don't burn oil to any extent so the additives aren't often a problem.in that application. Nev Link to comment Share on other sites More sharing options...
jetjr Posted June 8, 2015 Share Posted June 8, 2015 Agree with Phil, 500 hrs plus on iridiums, all Avgas, never had an issue of fouling or problems They are still removed and inspected at service. Starts and runs bit better i think and they last much longer 1 Link to comment Share on other sites More sharing options...
hyundai Posted June 9, 2015 Share Posted June 9, 2015 Ok guys thanks for that info I have one of the early 2200 engine first hydraulic lifter but I have converted it back to solid. I have the Honda coils. Cheers Hyundai. Link to comment Share on other sites More sharing options...
hyundai Posted June 9, 2015 Share Posted June 9, 2015 One thing I would do when fitting long life plugs remove them every 100 hrs or so. Years ago I fitted, any one remember Golden Lodge plugs ?? To a Holden after a long time I went to remove one it broke off In the head it seized. Just a thought. Hyundai 1 Link to comment Share on other sites More sharing options...
Russ Posted June 11, 2015 Share Posted June 11, 2015 Off topic.....but, Jabs carby's......at higher alts, 8.....9000, does your fuel burn maintain, or do you use more fuel...??? Just curious.. Link to comment Share on other sites More sharing options...
facthunter Posted June 11, 2015 Share Posted June 11, 2015 You need anti seize on the plug threads especially with alloy heads. If you don't the metal may pick up and ruin the threads in the head. Nev Link to comment Share on other sites More sharing options...
facthunter Posted June 11, 2015 Share Posted June 11, 2015 Russ, At altitude your indicated speed, drag, power ALL drop off. Your carburetter relies on pressure drop to raise the dashpot and it opens less, even though you may have the throttle wide open at the butterfly, the needle meters less fuel as a result and the carburetter keeps a relatively appropriate mixture ratio depending on the needle taper. Nev Link to comment Share on other sites More sharing options...
Old Koreelah Posted June 11, 2015 Share Posted June 11, 2015 Off topic.....but,Jabs carby's......at higher alts, 8.....9000, does your fuel burn maintain, or do you use more fuel...??? Just curious.. More. Mobs more. Link to comment Share on other sites More sharing options...
facthunter Posted June 11, 2015 Share Posted June 11, 2015 Most carburettors need to be leaned out by 5,000 ft. the Bing CD is supposed to be "compensating" to some extent, for height. If you examine planning tables for most GA light aircraft you will get information about power available from the engine at heights and fuel flows to be expected when appropriately leaned out. Piston engined aircraft don't normally need to fly at height to gain efficiency as much as jets do. Nev 1 Link to comment Share on other sites More sharing options...
Russ Posted June 11, 2015 Share Posted June 11, 2015 Now.....I am confused, Old KOR, Says mobs more fuel, Nev, mentions " leaning out" for higher alts.....that infers less fuel burn, yes/no ?? ( I need another rum to ponder all this ) Link to comment Share on other sites More sharing options...
facthunter Posted June 11, 2015 Share Posted June 11, 2015 You reduce the fuel flow because the mass airflow is less due to lower air density and pressure. You keep the mixture ratio optimum. at all heights and a bit richer at full chat T/O power..(only available at sea level on a normally aspirated engine) Nev 1 Link to comment Share on other sites More sharing options...
Keenaviator Posted June 11, 2015 Share Posted June 11, 2015 There is a way to trick the carby into 'thinking' it's at a higher altitude. Check this out. http://www.greenskyadventures.com/bing/HACmanFAQ.htm Basically you apply some lower than ambient pressure to the balance tube. The net result is lower fuel flow and leaner mixture. 1 Link to comment Share on other sites More sharing options...
jetjr Posted June 11, 2015 Share Posted June 11, 2015 And needs to be used with extreme care Unless you hve full EMS you could be running a cylinder to damage point Mixture spread can be really bad Link to comment Share on other sites More sharing options...
Jabiru7252 Posted June 11, 2015 Share Posted June 11, 2015 There is a way to trick the carby into 'thinking' it's at a higher altitude. Check this out.http://www.greenskyadventures.com/bing/HACmanFAQ.htm Basically you apply some lower than ambient pressure to the balance tube. The net result is lower fuel flow and leaner mixture. Err, isn't dicking around why RAA pilots have such a bad reputation? You're not playing with a hot rod or motor bike in the shed, it's an aeroplane. Service and maintain the thing as per the pilots operating manual and we'll see fewer accidents and incidents. I'm sure the greater proportion of Jabiru engine problems are from people fiddling and tinkering. 1 5 1 1 Link to comment Share on other sites More sharing options...
facthunter Posted June 11, 2015 Share Posted June 11, 2015 I have alluded to that before. 7252. Your point is relevent. Nev Link to comment Share on other sites More sharing options...
Keenaviator Posted June 11, 2015 Share Posted June 11, 2015 [ I'm sure the greater proportion of Jabiru engine problems are from people fiddling and tinkering. I wish it were that simple. 3 Link to comment Share on other sites More sharing options...
Old Koreelah Posted June 11, 2015 Share Posted June 11, 2015 Now.....I am confused,Old KOR, Says mobs more fuel, Nev, mentions " leaning out" for higher alts.....that infers less fuel burn, yes/no ?? ( I need another rum to ponder all this ) Sorry to cause confusion, Russ. I based my comment on a couple of experiences trying to climb over turbulence. The mobs of fuel I used may be due more to the climb rate than extra burn at higher altitude. Go with what Nev says. Link to comment Share on other sites More sharing options...
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