techie49 Posted September 19, 2013 Share Posted September 19, 2013 Hi Everyone, You may remember earlier in the year I was looking for an EJ22 engine or similar. I looked at the EA81 in the Zodiac and thought how difficult it would be to change to an EJ22, so I've managed to get another EA81 which has come back now from the local engine reconditioner. It's got a nice new set of pistons, reground crank and new bearings all round, including the piston pin end of the con rods, gudgeon pins or piston pins depending on where you come from. The heads have been skimmed and rebuilt too. So all in all it will be almost like starting from new. What I really need now is some practical help on choosing a carb. John, Bushcaddy 105, I think told me he runs an SU carb on his EA81 but I don't know from what vehicle. It needs to be as large as possible to get the maximum fuel / air mix into the cylinders. I've looked at Weber carbs but they are quite pricey at around $500. If I have to spend that kind of money well fair enough but has anyone out there any practical suggestions based on experience? Paul. . 1 Link to comment Share on other sites More sharing options...
Old Koreelah Posted September 19, 2013 Share Posted September 19, 2013 Have you considered the Rotec unit? 1 Link to comment Share on other sites More sharing options...
bushcaddy105 Posted September 19, 2013 Share Posted September 19, 2013 Gooday Paul I use an SU HIF6 which comes off a Volvo B series engine. Try to get one from a single carby engine - the twin carb version doesn't have a "choke". (It's actually an extra fuel valve). Going rate about $50 from a wreckers. Has performed faultlessly for 600 hours and doesn't have a diaphragm like Bing and Stromberg equivalents. 1 1 1 Link to comment Share on other sites More sharing options...
cherk Posted September 19, 2013 Share Posted September 19, 2013 Hi Everyone,You may remember earlier in the year............ What I really need now is some practical help on choosing a carb............. Paul. . Paul......G'day, I have a modified manifold with a (If I remember correctly) a Stromberg or Zenith 175 for the Ea81. I have some pics I can send ; if your'e interested ,when I get back home next week . In Bendigo at the moment. Link to comment Share on other sites More sharing options...
JimG Posted September 19, 2013 Share Posted September 19, 2013 Hi John, good to hear your suby is as reliable as ever. Yours is a great example of just how good these engines can be when set up properly. Good choice in the carby and does apply the 'kiss' rule very well, can you tell us what is the average fuel burn with your set up. Also with the Volvo B series engine , do you know the Volvo car Model and years of production, just to help when ringing the Volvo wreckers. Cheers JimG Link to comment Share on other sites More sharing options...
facthunter Posted September 20, 2013 Share Posted September 20, 2013 If you can install an updraft carb I would go for a Marvel/Schebler reconditioned from an 0-200 continental. Full mixture control. Nev 1 Link to comment Share on other sites More sharing options...
bushcaddy105 Posted September 20, 2013 Share Posted September 20, 2013 Gooday Jim The old book I have says any 144 from 1971 onwards. I have taken one out of a 244 at a wreckers, so I suspect that any 244 which isn't fuel injected may also have one. They were also used on Wolseleys, Range Rovers, Austin/Morris Marina, MG V8's according to my OLD book. There may be more as they were the last version of SU carbies made. What makes them ideal for aircraft is the small float chamber which surrounds the metering jet a full 360 degrees. Fuel level is pretty well constant at any angle. They also work at low supply pressure, gravity only on a high wing is fine. I only use an electric pump for initial climb and then turn it off. (I can still pull 4,000 rpm and 500fpm without the pump - a good safety feature). The choice of needle is dependent on the rest of your engine setup. The Volvo carby needle is NOT suitable, as that engine is either 2.0 or 2.2 litres. The jet is OK as is. I plan on 15 litres/hour and usually get 14 point something average on a trip. That's at the sweet spot of 4200 cruise rpm. 1 Link to comment Share on other sites More sharing options...
facthunter Posted September 20, 2013 Share Posted September 20, 2013 Some SU's use a weighted dashpot and others use a spring. IF you pull"G" they will richen up especially the one using the weight. The diaphragm type CV's don't have such a problem. The Bing's used on Rotax and Jabiru are not particular classy but they are common and available fairly cheaply. Nev Link to comment Share on other sites More sharing options...
planedriver Posted September 20, 2013 Share Posted September 20, 2013 Don't forget when the motors at fast idle, if you lift the pin under the dashpot more than about an eighth of an inch and the motor falters and quits, it's running too lean. I still have a Gunsens Colorplug which I bought decades ago in the UK. For those that have never heard of such a thing, it's basically a sparkplug with a glass top and you can see the colour of the combustion flame within the engine while it's running. If the mixture is right, it burns with a blue flame like a bunsen burner. Too rich and it runs with a yellow flame, too weak and it's light blue with whitish flashes from the sparks. I used to tune my Mini Coopers that way before racing or rallies, in conjunction with a Gunsens Carb-Balancer to make sure both carbies were properly balanced. Don't care if it's ancient technology, believe me it works a treat. Used it with racing go-carts as well. 1 2 Link to comment Share on other sites More sharing options...
Bubbleboy Posted September 20, 2013 Share Posted September 20, 2013 If you can install an updraft carb I would go for a Marvel/Schebler reconditioned from an 0-200 continental. Full mixture control. Nev They are a nice carb Nev, I am running one on my Corvair but you wont get a rebuilt one for less than a $1000. Scotty 1 1 1 1 Link to comment Share on other sites More sharing options...
techie49 Posted September 20, 2013 Author Share Posted September 20, 2013 Hi OK, I looked at the Rotec unit today on their website. Coincidentally they seem to setting up at Tyabb where the Zodiac lives. I waiting on a price but I've been told around $700 which seems a little pricey . Sell it to me with some more info....... Paul Link to comment Share on other sites More sharing options...
techie49 Posted September 20, 2013 Author Share Posted September 20, 2013 Hi Ian and John, I was hoping one or both of you might pop up and give me some good info. John, I remember you previously telling me you were running an SU but they come in varying sizes and models so at least now I can go to the wreckers and see what they have. Ian, I'd be very happy to see some pics as the next question I need to ask is about the I/L manifold. I have the original with the water passing through it but again, ask ten people and you'll get ten different answers about keeping the original or building an unheated one. What have you done? PD, I remember the Gunsons Colorplug and yes it did work ! The problem I've had on the zodiac's EA81 is the twin Bings. Even after changing to a two-blade Bolly, the idle is still not what I'd like and I get significant vibration below about 1500rpm. I think I may have to visit one of the maintainers and see if they can adjust it. This is one reason I want to go to a decent single on the 'spare' engine. I am trying to keep the costs down as I still need to get a PSRU. Having made enquiries, I'm looking towards a Rotax C box. The Air Trikes unit from Canada looked good but Vassili has moved on to doing boxes for the more modern Soobs. The local agent in Brisbane had one left but wanted me to send him the complete engine and $2900. Probably not bad but the Rotax even with an adapter to bolt to the flywheel shouldn't take me that high I hope. I was quoted $1400 for the box ,plus GST I suppose. Thanks so much to everyone for all your suggestions. Whilst we're here and having mentioned it, what about PSRU's ................ Paul 1 Link to comment Share on other sites More sharing options...
Old Koreelah Posted September 20, 2013 Share Posted September 20, 2013 Hi OK,I looked at the Rotec unit today on their website. Coincidentally they seem to setting up at Tyabb where the Zodiac lives. I waiting on a price but I've been told around $700 which seems a little pricey . Sell it to me with some more info....... Paul Sorry, I don't have any, beyond common knowledge. Link to comment Share on other sites More sharing options...
cherk Posted September 20, 2013 Share Posted September 20, 2013 Hi Ian and John,Ian, I'd be very happy to see some pics as the next question I need to ask is about the I/L manifold. I have the original with the water passing through it but again, ask ten people and you'll get ten different answers about keeping the original or building an unheated one. What have you done? Paul G'day Paul, I'll send some pics when I get home. The manifold I have is water heated as i'm of the school that thinks ((believes) that wet intakes should be heated to maintain vaporisation. But that's me. ( I personally think carbies SUCK!...I'm a firm believer in EFI) As to redrives , I'm running an Autoflight..c.a $3200 from Niel Hinz in NZ. I do have a Hirth box 2.25:1 (unused)on an ea81 c/w adapters etc ....you may be interested in! 1 Link to comment Share on other sites More sharing options...
Robert Posted September 21, 2013 Share Posted September 21, 2013 "I do have a Hirth box 2.25:1 (unused)on an ea81 c/w adapters etc ....you may be interested in!" What sort of money you looking at for the unit? Is it engine and gearbox or just gearbox and adapter to EA81 Link to comment Share on other sites More sharing options...
techie49 Posted September 21, 2013 Author Share Posted September 21, 2013 Hi Ian, Yes I'd like to see some details of the PSRU . As I said, the only one on the horizon is the Rotax C box as it's the same as I have. Paul Link to comment Share on other sites More sharing options...
cherk Posted October 1, 2013 Share Posted October 1, 2013 "I do have a Hirth box 2.25:1 (unused)on an ea81 c/w adapters etc ....you may be interested in!" What sort of money you looking at for the unit? Is it engine and gearbox or just gearbox and adapter to EA81 G'day Robert, no engine....Hirth G40 gearbox and conversion adapters /plates /flywheel_ring-gear /starter etc,all bolts up to ea81 bell-housing, around ~$1800 Link to comment Share on other sites More sharing options...
Aero28 Posted August 3, 2015 Share Posted August 3, 2015 Hiya Cherk, did you ever sell that Hirth Gearbox? Link to comment Share on other sites More sharing options...
Russ Posted August 3, 2015 Share Posted August 3, 2015 "C" boxes, widely used on ej22 soobs, and EA81's.......looong history, all good. ( gyros ) Link to comment Share on other sites More sharing options...
JimG Posted August 3, 2015 Share Posted August 3, 2015 I'm after a Rotax 'C' box with a 3:1 or 3.47:1 ratio if anyone knows of any for sale s/hand. cheers JimG Link to comment Share on other sites More sharing options...
Aero28 Posted August 3, 2015 Share Posted August 3, 2015 Thanks Russ, I thought the only robust option for the EA81 was A hirth..... no failures with the rotax? Link to comment Share on other sites More sharing options...
Methusala Posted August 3, 2015 Share Posted August 3, 2015 2.58:1 is the common ratio used on Sub EA81's. Regards Don Link to comment Share on other sites More sharing options...
terryc Posted August 3, 2015 Share Posted August 3, 2015 I have a amax redrive for a e81 if any of you guys are interested Link to comment Share on other sites More sharing options...
cherk Posted August 3, 2015 Share Posted August 3, 2015 Hiya Cherk, did you ever sell that Hirth Gearbox? yeah paul took it........! Link to comment Share on other sites More sharing options...
rotax618 Posted August 3, 2015 Share Posted August 3, 2015 G'day Jimbo I have an SPG2 gearbox 2.5:1 which was sold by Airtrikes Canada for Suzuki, Subaru and BMW engines, unfortunately th bellhousing I have is for the Suzuki G series engines but it would not be difficult to build an adaptor plate to suit. The gearbox was good for 160hp much stronger than rotax C. Want $500 for gearbox and bellhousing. Link to comment Share on other sites More sharing options...
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