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-   -   O360 problem (https://vansairforce.net/community/showthread.php?t=122965)

Ralph Inkster 02-22-2015 05:48 PM

I assume this is a new Ellison installation. Have you gone thru the full Ellison mixture & idle adjustment process for the throttle body? They state the factory settings are enough to get the engine running but then describe an extensive list of adjustments to get it running well.

If the engine had test cell run time after the rebuild, the rebuild shop probably used their own test induction (off the shelf shop carb or injection system), but later removed and shipped your engine with a new in the box Ellison TB un-adjusted. You may be lucky to get a unit straight out of the box that runs well at your particular altitude & humidity, or more likely a unit needing a lot of adjusting that initially runs like a total dog.

Jimzim 02-23-2015 05:10 PM

The engine was not run on a test stand after overhaul. I wish it had been, as I'd feel better about it. Also, I failed to mention that the Ellison is used. When I get it back from the factory, I intend to go through the full set up procedure. I tried to do that earlier, but didn't have any luck. We'll see what happens this time around. Thanks for the suggestion.
Jim (2015 paid)

Danny King 02-23-2015 06:43 PM

Rough 0360
 
Check for air leaks, and idle mixture.

If the engine is an angle valve, check the O-rings on each intake tube at the sump. They can roll or get cut during tube installation and suck air causing a rough idle. Check the intake tube flange gaskets at each cylinder and that the flange is evenly tightened.

If parellel valve, check hose and clamps between intake tubes and sump, and also at the cylinder flanges.

Check idle mixture on throttle body. Lean mixtures due to air leaks or lean idle mixture will cause a rough and weak idle.

sblack 02-23-2015 07:21 PM

If you had a huge variation in mixture your egts would not be equal.

Prop balance is very important. You say it feels like there are inches missing off a blade, but in reality an inch off a blade would make the engine part company from the airplane, it might not be your issue but at least do a static balance of the prop. Easy and cheap to do. I would not run a prop with at least checking static balance.

tim2542 02-23-2015 07:48 PM

Leak down test
 
Time for a leak down test. Or at least give it a pull thru and see if you get a squeeze on each cylinder. It's possible the valve lash was not set correctly and you have a valve being held open.
Also, good advice to look at the intake system for leaks. If it runs good at WOT then thats a good sign you have an intake leak.
Good luck
Tim

glenn654 02-23-2015 08:01 PM

Jim,

I flew an Ellison for 10 years on my O-320 powered -4 and am a big fan of these TBIs.
From what you describe, I think it is set too lean, the adjustment is critical to get the best operation.
I recommend you go back through the adjustment procedure and follow it to the letter.
I believe after doing so your engine will run smoothly and develop full power.
I had a similar problem with mine in the beginning and once adjusted properly I never had to touch it again.

Good Luck,
Glenn

Jimzim 02-24-2015 05:40 PM

I did look for induction leaks, and everything appears new and tight. As for the prop, I'll look at a static balance check. By the way, it's a parallel 0-360. I have high hopes for getting the TBI back rebuilt and then dialing it in. I know others who have had great success with Ellisons and that's how I ended up with it. Once they get going, I'm told they are really great! Any other tips appreciated and I'll report on results as I move forward...
Thanks, Jim

Jimzim 03-10-2015 04:54 AM

So the throttle body came back from Ellison totally rebuilt. Installed it and ran the engine again, absolutely no change. Engine still rough and shakes the engine mount at lower RPM. We began looking at the valve train and may be seeing an issue. There are gaps between some of the rocker arms and valve stems that look to exceed spec for an engine that has been ran; i.e. the lifters have been pumped up with oil. It is as if the pushrods are too short. We are looking deeper into this scenario, as that would mean the valves are not opening fully... We'll see where this leads.
Jim


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