My ZDZ80 siezed in flight on Friday. Dead sticked it with minimal damage to the airframe.

The crankshaft would turn some, but with much friction. Took it home and after removing the cylinder head found the culprit - the C ring (retainer for wrist pin) on one side had come loose and was free in the cyinder!

Never had this happen before with any engine I have had.

Engine had about 20 gallons thru it, and about 18mo since purchase. Was running with 91octane and 50:1 Belray H1R.

Anybody lost a C ring on this engine before ??

Pic of piston attached

Lost one in an old Webra black head .61, same result...

Beachhangar:
They don't like you taking apart engines under warranty.
If you sent it in assembled, they'd fix it for free.
Warranty is 30 months.

Ouch, I will keep a good eye on mine when I get it running...

Shortman,

Just curious. What are you going to look for? If you notice anything concerning this problem, it's too late and the engine won't run right anyway if at all.

Diablo is completely correct, if it breaks under warranty, don't touch it except to carefully box it up for shipment back to where you bought it.

Ken

No matter who takes it apart, the failure of a clip remains the cause...Not honoring a warranty if the owner takes it apart is just a way out for the company....There are no seals anywhere on an engine, no way to tell if it was taken apart or not......

If it were mine, I'd carefully button the engine up, delete the original post and photo, and send it in for repair. Otherewise, the service man might recognize the score marks on the piston and think "Where did I see that before"?

I would definitely close the motor back up and send it in they are rather new on the seen and I am sure they will want to make good on it.
Also I can not say for sure but a few years back I raced MX and found a lot of Carbon build up and parts failures with Belray products I am sure they are a good oil and have improved like everyone else however I have been running Klotz racing oil and am very impressed with the performance and condition of the motor after several flights. I really don't want to step on any toes just my 2 cents

An update -

I emailed Amelung Sunday night and received a response today.
Based on the description of the failure and photos attached - he is willing to repair the engine under warranty. That is excellent news! I am impressed when a company stands by its products!

In the email, I disclosed that the cylinder was removed. There was no commentary on that point from them.

The C clip was not loose in the cylinder, but rather, embedded in the cylinder wall. Upon closer examination, it appears that the material forming the outer wall of the retaining groove failed - allowing the clip to depart the piston.

I just had a ZDZ80 piston fail this weekend! Not due to a wrist pin clip though. The piston just lost a piece from the ring to the top including a chunk of the ring. The engine kept running long enough to get lined up with the runway then quit.

Although there is no warranty on mine, only the piston, ring, and cylinder casting were ruined. The pieces just exited the exhaust without getting into the case. I'm gonna repair it and fly it again, but the parts won't be available for several weeks!

I don't have any reservations about ZDZ engines though. Engine parts do break sometimes (you get used to it when you drive Chevy's)

Ben

Geo Manning ?
I am currently fly one of the old Buckers with a ZDZ60 -(one that Rojecki flew in 1990 -)
I know this means nothing to others - but I thot Geo was gone a racin--
Ralph - warranties are the "hard line" most companies have to hold .
How many times have YOU seen an engine /carb /ignition which had a problem - and the owner swore that he never opened it???
Even with his thumbprint on the coil/piston?
Why the clip failed on Mike's 80 is pure speculation -till it is thoroughly examined.
Mike is an engineer and I suspect he did not do the damage -BUT f you want a warranty honored - try to contain yourself . comply with the warranty terms -Even if you do "peek" in many cases there is good faith repair work provided.
I have been on the other side of this issue and the "I did not touch it - and I never did nuthin - just driving 30 mph " stuff offered is sometimes so outlandish - you are stunned that people would even try .
I always gave the benifit of the doubt.

You are right..But some of us are curious, can't keep the fingers out