ECi cylinder ADs

I am looking at an aircraft that has ECi ?group A? cylinders. The AD require a compression test each 50 hrs. The Group ?B? cylinder AD requires replacement.
My question is what defines ?group A? and ?group B? cylinders. Yes, I already know a set of serial numbers determine them, but I am not talking about that. I am asking what data caused these groups to be defined in the first place.
What was the failure data for group A? I see certain number of head separations quoted, something like 30 or so. But I never see how this is divided between the 2 groups. Anyone know any primary references ?

Thanks,
John

As I was told by ECI group "B" is where the problem is and they admit to having a problem. Group "A" is only a buffer. ECI explained it was just the FAA over reacting to the problem with group "B" . With that said, the person on the phone @ ECI a while later wasn't surprised to hear we had a group "A" cylinder fail at 90 ft above the water on take off. Basically said they would sell us another cylinder, yea right.
Good luck if you make the purchase.

You're only talking $5-6K for four new power assemblies (depends on the engine). Negotiate a price that leaves you the cash to replace them, then actually replace them so you have the peace of mind.

That?s basically my plan, to reserve $6000 for a new set of heads, and hopefully negotiating part of it into the purchase price.

Does anyone have a recommendation for the most reliable heads? Lycoming, Superior, etc.?
I know there are option like steel, chrome, nitride, along with rings that mate with them. Any recommendations there ? (Hoping not too much topic drift.)

John

Aviaman said:

That?s basically my plan, to reserve $6000 for a new set of heads, and hopefully negotiating part of it into the purchase price.

Does anyone have a recommendation for the most reliable heads? Lycoming, Superior, etc.?
I know there are option like steel, chrome, nitride, along with rings that mate with them. Any recommendations there ? (Hoping not too much topic drift.)

John

Click to expand...

I think you mean ?Jugs? (Cylinders) - you don?t replace just the head, like on a car engine. I have had good luck with simple nitride Lycomning cylinders. The break in nicely, and if you fly regularly, corrosion isn?t an issue.

Also running an all-Superior engine on our bush plane, and have had no trouble with jugs in 200 hours - but that?s not a lot of time to form an opinion.

Replacement Cylinders

The NiC3 electro plated cylinders by Continental Motors are an excellent option. They have a 5 year warranty on the barrel against wear and corrosion. Break in quickly too.

I have over 800 hours on the 'A' cylinders with no problems.
I had heard that there weren't any reported failures with that batch, though Ron's experience indicates otherwise.

I believe the issue was with stresses due to the tolerance of the head to cylinder fit. I never see CHTs above 400 as I always hit oil T warnings before.
I don't know if high CHTs are a factor in early failure, but there are differential expansion issues between cylinder liner and head.