Subaru EA81 annual tune up - how to do it.

[pilotike]

I recently bought a Zenith 601XLB with a Subaru EA81 engine. The prior owner ran me through the annual of the engine but he went quickly and I missed steps. Could someone point me to a resource for tuning up the EA81 or tell me how you do it?

 

Thank You

 

Carl

 

 

[Paul davenport]

I have an Avid with a Subaru engine in it an this is what I do for an annual to the motor. Change oil and filter (cut open filter to inspect for metal fragments if you wish) ,.Check and adjust as required tappet clearance ( the clearance will depend on cam used ) flush and change coolant ,check cooling system hoses check carburettor security and if you have bing carbs and the diaphragm has not been changed replace the diaphragms , syc carburettors (if you have 2) ,check engine mounts and mount frame for cracks ,check exhaust system,check /replace spark plugs as required ,inspect air filter . What I find works for me is after I have done all this and before I put cowls on I sit down have a cup of tea a deep breath and look again at all I have done just in case I for got something.

 

 

[Bruce Tuncks]

You got my attention there Paul, about replacing the Bing diaphragm.

 

Mine has never been done and I didn't know about the need. Have I been remiss?

 

The fuel pump diaphragm worries me too. I tried to get a replacement one but failed, so the existing one has been on there for 15 years.. Should I replace this too? They are flimsy bits of rubber for sure.

 

 

[Paul davenport]

You got my attention there Paul, about replacing the Bing diaphragm.Mine has never been done and I didn't know about the need. Have I been remiss?

The fuel pump diaphragm worries me too. I tried to get a replacement one but failed, so the existing one has been on there for 15 years.. Should I replace this too? They are flimsy bits of rubber for sure.

Cannot answer the issue on fuel pumps,it is only a auto. pump and they dont seem to give too much trouble in cars .the rubber is some what different in them compared to the carby in that it is reinforced with fabric ,the back up of and electric pump helps out here BUT if it makes you feel at ease replace it

 

 

[Jože]

I have a Subaru EA81 engine, 1800 cc, 80 Hp, a 1982 year. The engine is built on an ultra-light aircraft.

 

Now the engine has a standard camshaft.

 

I want to increase the power of the engine with a modified cam shaft.

 

Can anyone advise me where can I get such a shaft?

 

 

[Paul davenport]

I have a Subaru EA81 engine, 1800 cc, 80 Hp, a 1982 year. The engine is built on an ultra-light aircraft.Now the engine has a standard camshaft.

I want to increase the power of the engine with a modified cam shaft.

 

Can anyone advise me where can I get such a shaft?

In Australia I used a firm called Crow Cams . Just google it and a few firms will show up. Just a tip as adjusting the cam timing is difficult get a few degrees advance ground into it, I suspect if you use a firm like RAM engines they will supply this as standard. Good luck and keep us informed of your success

 

 

[Yenn]

Be careful with cam changes. The automotive way of increasing hp is usually to increase breathing at higher rpm. You may not want to increase revs, but rather improve breathing at lower revs.

 

 

[facthunter]

If you don't get to the revs where the "hotter" grind works it won't be an improvement and sometimes the exhaust system has to be more exotic to get advantage of the cam. A small amount of "boost" helps and works well at altitude. Nev

 

 

[Paul davenport]

If you don't get to the revs where the "hotter" grind works it won't be an improvement and sometimes the exhaust system has to be more exotic to get advantage of the cam. A small amount of "boost" helps and works well at altitude. Nev

On my Subaru it was a very mild cam grind, it still idles smoothly , along with twin Bing carburettors and a larger exhaust I am very happy with its performance. The EA 81 prefers to pull rather than rev, max revs is around 4900 but I cruise at 4/4200 if I am in a hurry 4400 but more revs does not equate to more speed just higher fuel consumption. I have a 72 inch warp drive prop and an AMAX redrive at full noise my prop is doing less than 2500rpm. Apart from the extra weight I am very happy with the combination,good fuel consumption, economical parts and very easy to service

 

 

[Jože]

Na mojem Subaruju je bilo zelo blago odmazenje kamer, še vedno miruje, skupaj z dvema bencinskima karburatorjema in večjim izpušnim sistemom sem zelo zadovoljna s svojo zmogljivostjo. EA 81 raje vleče, ne pa vrti, maksimalna obremenitev je okrog 4900, vendar sem križarjena pri 4/4200, če se mudi 4400, vendar več vrtljajev ne pomeni enake večje hitrosti, le višjo porabo goriva. Imam 72-palčni trdi pogon pogon in AMAX redrive v polnem hrupu moj prop je delal manj kot 2500rpm. Poleg dodatne teže sem zelo zadovoljen s kombinacijo, dobro porabo goriva, ekonomičnimi deli in zelo enostavnim servisom [/ QUOTE]

 

 

[Jože]

Paul Thanks

 

If I understand you, the Camshaft from RAM is the right solution for the aircraft engin?

 

Jože

 

 

[Paul davenport]

Paul ThanksIf I understand you, the Camshaft from RAM is the right solution for the aircraft engin?

Jože

I think given that you are from the North American area they would be your best choice. If you would like to know what other things I did let me know

 

 

[facthunter]

They are nothing special. The Bing.. Nev

 

 

[facthunter]

I would think you would have to derive the needle taper yourself if someone can't provide one to the tune of your engine. The size has to match reasonable close to your engine's breathing to get the dashpot up to full open at sea level. This is not absolutely essential as you probably know you can get away with an oversize carby throat on a CV carburetter , but reasonable matching is better. They are cheap and available.. That's about it. Some floats were sinking. Get the little tit on the diaphragm in the right place. Nev

 

 

[Blueadventures]

Hi Nev, realise they are just another variation on the theme.. of the CV style carb.., but having read on occasions how jetting had to be altered in the Jabiru, I was hoping someone may have had a Single Bing EA81 setup in use, to give me a starting point for the jetting they use. Thanks

Maybe have a chat with Shane at the aircraft maintenance at Longreach. He has the Jabiru out there so should be a help. Pass on a hi from me if you speak to him. Regards Mike