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Posted

I noticed that I was unable to run LOP yesterday because the #2 cylinder peaked earlier than the rest and then became way to lean to run smooth...  

 

After I got home I took the cowling off and found what is seen in the attached photo....

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Posted

There are no O-rings there. The tube nut threads on the injector like an AN fitting. Some staining there can be considered normal I think, ours does that sometimes. The ram air flow in that local area can have something to do with it.

Posted

Tighten all your intake bolts and silicone the seals where the intake tubes enter the area below the oil sump. I found that i had intake leaks after i was unable to run LOP as i normally had done. Your injector should ideally be turned 180 to have the letter in the deeper recess of your cylinder. How it is positioned now the fuel can drain out side the injector after priming and shutdown.

Posted

Those tubes where they go into the plenum are silicone o-rings riding in a machined boss. They actualy press fit rather tightly and if you go too far it cuts the o-ring. I have a hard time thinking they need sealer.

Posted

Things to fix are any intake leaks, and Lycomings suffer these more than we like to admit.

 

Possibly a partial blockage of the nozzle. Clean only if need be and maybe now is a good time, your A&P can do this.

 

While you are at it, check plugs and borescope while the tools are out.

 

Your living proof that the LOP pilot actually needs the EMS less than the ROP pilot  ;)

Posted

The IO-360 engine is unique among 4-banger lycomings in the fact it has equal-length tuned induction runners and the previously mentions silicone o-ring seals. That thing was designed to run LOP. . The O-360 engines have a rubber hose with hose clamps which looks like it can leak pretty often.

I'm not saying the IO can't leak, but the proper fix is a new O-ring.

  • Like 2
Posted

Just to be sure.. Is all of this input regarding the IO360 A3B6(D) ?  All IO360s are not the same.  (Having flown behind a few of the variations...)

Posted

It's funny how many mechanics frown on LOP when they should really embrace it. If I was a mechanic I would love all the business of fine tuning the ignitions, fuel and induction systems so the plane will run LOP correctly.

Those silicone o-ring are a very tight fit but unfortunately with my brand new ones they can leak. I discovered it after I couldn't get my engine to stop stumbling at idle and I could run LOP some flights and not on others. My cylinders would also vary on which one would peak first each flight. After consulting with a few locals that where familiar with the IO-360 it was suggested using the silicone. After putting some silicone around the o-ring I went out the next day fired up the engine and ran prefect but then started to stumble again. After shutting it down went back out and looked and some of the silicone apparently didn't set up all the way and was pulled into the seal. I removed it and reapplied it and made sure it really set up and ran it again. Worked great! All supervised by my Mx.

Posted

Good info. So you are putting silicone on the O-ring then reinstalling, or putting it in the groove outside the O-ring where the tube goes into the plenum?

Posted

I wouldn't silicone them. First they don't leak and I think they are supposed to move a bit when the engine heats up and the cylinders expand.

Even if they did leak, it's no big deal. It is a fuel injected engine the fuel comes from the injectors. I hate to say it but my engine was running a little funky once and when I pulled the cowl one of the risers had both bolts missing and was sitting about 1/2 inch below the flange. It still ran pretty good.

Posted

I wouldn't silicone them. First they don't leak and I think they are supposed to move a bit when the engine heats up and the cylinders expand.

Even if they did leak, it's no big deal. It is a fuel injected engine the fuel comes from the injectors. I hate to say it but my engine was running a little funky once and when I pulled the cowl one of the risers had both bolts missing and was sitting about 1/2 inch below the flange. It still ran pretty good.

Posted

The IO-360 engine is unique among 4-banger lycomings in the fact it has equal-length tuned induction runners and the previously mentions silicone o-ring seals. That thing was designed to run LOP. . The O-360 engines have a rubber hose with hose clamps which looks like it can leak pretty often.

I'm not saying the IO can't leak, but the proper fix is a new O-ring.

Excellent point Byron.

A little off topic but IMHO the IO360 A3B6(D) doesn't need GAMI injectors either. The stock injectors are so well balanced to begin with.

Posted

I wouldn't silicone them. First they don't leak and I think they are supposed to move a bit when the engine heats up and the cylinders expand.

Even if they did leak, it's no big deal. It is a fuel injected engine the fuel comes from the injectors. I hate to say it but my engine was running a little funky once and when I pulled the cowl one of the risers had both bolts missing and was sitting about 1/2 inch below the flange. It still ran pretty good.

Wouldnt your induction system leak to the outside with a turbo or is there still negative pressure?

 

The silicone doesn't bond it into place it is still very flexible and gives. It was an amazing difference in my particular plane. My EGT difference went from 110df at idle to 30df and I can go way deeper LOP in flight and runs much smoother.

 

PTK, I agree you don't need GAMI's if you spreed is good and all other variables are taken care of IMHO as well.

  • Like 1
Posted

The IO-360 engine is unique among 4-banger lycomings in the fact it has equal-length tuned induction runners and the previously mentions silicone o-ring seals. That thing was designed to run LOP. . The O-360 engines have a rubber hose with hose clamps which looks like it can leak pretty often.

I'm not saying the IO can't leak, but the proper fix is a new O-ring.

IIRC, the IO360 A1A only has O-rings on the intake end of the tube; the other end mounts to the cylinder with a 2 bolt collar and a flat gasket.
Posted

After consultation with savvy and GAMI. We have come to the conclusion that the injector is fine. My ap removed and cleaned it just to be sure. We have the problem of roughness lop narrowed down to the ignition harness.

Posted

Fuel nozzle dripping or leaking is usually caused by improper installation. See Lycoming S/I 1275C for correct cleaning and re installation procedures.

Clarence

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