Okay, with the rod out of the way would make it easy with pliers and these tips.

Ross4289 wrote:Here’s a picture of a counterweight being removed with the cylinder and connecting rod removed.

OK. Not so awful. Thanks for sharing that image Ross.

The SB is out

http://www.tcmlink.com/pdf2/MSB23-01.pdf

Thanks for posting that. Pretty interesting and I would never have thought much about the position of the snap ring but it definitely makes sense.

Thank you for posting that, my IO 550f was remanufactured at the end of 2021, I looked up the serial number, and luckily it is not affected. … since it was definitely in the date range they must have been able to isolate the issue to one lot or workstation?

So is this only on factory new/remans? The letter doesn’t really say one way or the other, but that would be my assumption… anyone know the answer for sure?

The only way an overhaul would be affected is if your crankshaft was replaced with a factory crankshaft assembly.

The affected crankshaft serial numbers are on the SB.

In addition to the serial numbers of crankshafts purchased separately, the SB has the serial numbers of any new or rebuilt engines which are affected. My engine, although factory remanufactured used a new crank, but it was not affected. … Perhaps the crank was old stock.

Ross4289 wrote:The SB is out

http://www.tcmlink.com/pdf2/MSB23-01.pdf

"COMPLIANCE: For Engines with less than 200 operating hours:
Accomplish immediately; an additional five flight hours acceptable to move to
a maintenance facility with minimum essential crew, if necessary. Compliance
time begins upon Service Bulletin receipt
For Engines with more than 200 operating hours:
No further action required"

I guess they figure that if it hasn't come apart in 200 hours,
it's not going to.
Hmmm....

That's the assumption. Not very confidence inspiring if you ask me.

MW

Today I thought I'd compare my 470A crank, that is probably still good, to the instructions on this current counterweight deal. Pacific Continental major overhauled my engine in 1972 and it had close to a 1000 hrs when I topped it in the early 90's. I took it apart in 1995 hoping I could make a 470R but this crank has smaller bolts holding the gear on the crank so I scrapped that Idea and built a 470K instead. I assume Pacific Continental rebushed the counterweights and whoever installed them put the snap rings in exactly opposite from the way today's are supposed to be. I found that kinda interesting. Also, the A could spin up to 2600 rpm. I coated the crank with oil so it wouldn't rust sitting around.

Getting the inspection done Monday. Hopefully it’s a non event. I’ll update when I get the results.

MW

Getting the inspection done Monday. Hopefully it’s a non event.

If it was mine, I'd make sure as they remove a cylinder that they retorque the through bolts with the official hold down plates or at least big flat washers so nothing shifts.

Sawing the bottom off an old cylinder is a good solution for this also

Fortunately I passed the inspection with not problems. Rumor is this will become an Emergency AD soon vice an SB.

MW

Kinda takes some of the value off of getting a factory reman engine, they at least could have sent a “oops we’re sorry card”

Hopefully most of the engines pass the inspection

Damn

Are the engines built in the States or in China?

Still built in Mobile, AL

It seems to me that due to the way this AD is written, ANY engine on this list;

Continental Aerospace Technologies, Inc. (Continental) GTSIO-520-C, -D, -H, -K, -L, -M, -N, and -S; IO-360-A, -AB, -AF, -C, -CB, -D, -DB, -E, -ES, -G, -GB, -H, -HB, -J, -JB, -K, and -KB; IO-470-D, -E, -G, -H, -J, -K, -L, -M, -N, -P, -R, -S, -T, -U, -V, and -VO; IO-520-A, -B, -BA, -BB, -C, -CB, -D, -E, -F, -J, -K, -L, -M, and -MB; IO-550-A, -B, -C, -D, -E, -F, -G, -L, -N, -P, and -R; LTSIO-360-E, -EB, -KB, and -RB; LTSIO-520-AE; O-470-A, -B, -E, -G, -H, -J, -K, -L, -M, -N, -R, -S, -T, and -U; TSIO-360-A, -AB, -B, -BB, -C, -CB, -D, -DB, -E, -EB, -G, -GB, -H, -HB, -JB, -KB, -LB, -MB, -RB, and -SB; TSIO-520-A, -AE, -AF, -B, -BB, -BE, -C, -CE, -D, -DB, -E, -EB, -G, -H, -J, -JB, -K, -KB, -L, -LB, -M, -NB, -P, -R, -T, -UB, -VB, and -WB; TSIO-550-A, -B, -C, -E, -G, -K, and -N; TSIOF-550-K; and TSIOL-550-A, -B, and -C model reciprocating engines.

will need a logbook entry showing method of compliance. Obviously the large majority will be signed off as Does Not Apply by S/N but the entry is still required, am I wrong?

Ross4289 wrote:Still built in Mobile, AL

Thanks Ross.

Are there any early impressions on how many discrepant installations are being discovered?

This is one of those things where one improperly seated retaining ring raised a red flag that’s practically impossible to isolate, while the ramifications of failure are so significant that fleet compliance commands a tremendous effort.