Rejected crank

[MooneyTunes]

So the engine in question is a 1983 io360A3B6D. It is in being overhauled by a reputable shop. I was just informed that the crank shaft was rejected during inspection. The reason given “Improper repair” most likely by the factory, Lycoming. Has anyone seen this before? Reason for the holes? Any recommendations for were I might be able to find a replacement crank? Thanks in advance. 

[takair]

If the factory was last to work on it, I would suggest contacting them. Do you have a work order for the previous overhaul?  It is very possible they had internal engineering approval and reasons for it. Would not junk it without exploring that first.  Certainly is odd, but maybe it was approved. 

[MooneyTunes]

This is a first run engine. Never been overhauled before. 

[takair]

16 minutes ago, MooneyTunes said:

This is a first run engine. Never been overhauled before. 

All the more reason to check with the factory. It seems the holes had to be made there. Maybe balance holes. Maybe manufacturing engineer (ME) approved. 

[N201MKTurbo]

It looks like they were doing a hardness check to find the depth of the case hardening. Probably the safest place to do it. I also suggest contacting the factory.

[KSMooniac]

1 hour ago, N201MKTurbo said:

It looks like they were doing a hardness check to find the depth of the case hardening. Probably the safest place to do it. I also suggest contacting the factory.

That is my first thought as well.  Hopefully Lycoming still has records and can support you.

I may have one available next month if you get in a bind.

[N201MKTurbo]

It kind of looks like there is some kind of thread insert put in the hole. That isn’t normal.

[Slick Nick]

Those are just punch marks they’re not holes. 

[takair]

51 minutes ago, Slick Nick said:

Those are just punch marks they’re not holes. 

Agree.  I was looking at it on my cell without cheaters.  It does look like the area is ground out though and then punches.  I agree that likely hardness testing….question is why.  If they had an approved deviation, likely documented at the factory and that might be usable as approved data to keep using it.  Fingers crossed for the OP.

[AndreiC]

Just an idea (I am completely a novice to these kinds of things). The SB 475C came out in 2003, long after this engine was assembled. Could it be that Lycoming came up with new measurements that acceptable cranks must satisfy, which were not in place in 1983?

[MikeOH]

FWIW, here is a link to SB475C:

 https://www.lycoming.com/sites/default/files/attachments/Crankshaft%20Gear%20Modification%20and%20Assembly%20Procedures.pdf

And, page 7 shows the dimension that is out of spec. per the "Final Inspection Reject" paperwork:

 

[MooneyTunes]

I have reached out to Lycoming. I will post their response once received. Thanks for all the inputs. All good recs. 

[Bolter]

3 hours ago, MikeOH said:

FWIW, here is a link to SB475C:

 https://www.lycoming.com/sites/default/files/attachments/Crankshaft%20Gear%20Modification%20and%20Assembly%20Procedures.pdf

And, page 7 shows the dimension that is out of spec. per the "Final Inspection Reject" paperwork:

 

 

That should mean the surface, not the extreme that is bottom of the dimple.  If you put the mating part there, is is setoff the correct distance from the other feature on the crankshaft?

[MikeOH]

17 minutes ago, Bolter said:

That should mean the surface, not the extreme that is bottom of the dimple.  If you put the mating part there, is is setoff the correct distance from the other feature on the crankshaft?

I think that is one question, but by the look of the photo the area with the dimples has been ground down.  If so, the surface is no longer properly flat since there is a 0.001" runout spec for that mating surface (you could also argue the dimples themselves violate that spec), Fig. 1 on page 2:

 

[MikeOH]

To ramble on a bit more....if this engine was truly first run, what the heck did they grind and dimple that surface for???  Note that the SB mentions the surface is NOT to be plated, so I'm not sure why anyone would be testing hardness?  Even more so, what was the reason to grind down the surface, presumably to then dimple when measuring the hardness below any plating (which shouldn't be there) or surface hardening?

It also looks like the SB allows machining the surface by as much as 0.090" to restore the 0.001" flatness as long as it doesn't reduce the thrust face to pilot minimum dimension.  I almost wonder if the grinding down in the are where the dimples are is too deep, and 'leveling' that surface would be below the minimum?  That is, I wonder if the crank was ruined by someone messing around with measuring that pilot surface for some reason??

[1980Mooney]

13 hours ago, MooneyTunes said:

So the engine in question is a 1983 io360A3B6D. It is in being overhauled by a reputable shop. I was just informed that the crank shaft was rejected during inspection. The reason given “Improper repair” most likely by the factory, Lycoming. Has anyone seen this before? Reason for the holes? Any recommendations for were I might be able to find a replacement crank? Thanks in advance. 

 

13 hours ago, MooneyTunes said:

This is a first run engine. Never been overhauled before. 

So this is a 42 year old Lycoming IO360 that you believe has never been overhauled since NEW.  That is a really unusually long period of time.  If true it sounds like a record.   

I happened to notice the 2016 Aircraft.com ad for the plane which said that it is a 1983 M20J and both the airframe and engine only had accumulated 680 hours since NEW by mid 2016.  That is only 20.6 hours per year on average since new as of mid-2016 (during the first 33 years of life)..   Or perhaps it was a combination of sitting for extended periods of time (months, years?) followed by more regular flying.

The Aircraft.com ad in mid 2016 also noted that it was being sold by an owner that had owned it for 29 years.  It appears that you have owned it for the last 9 years.  That accounts for 38 years of its 42 year life.  That means there was at least another owner or more in the first 4 years.

The mid-2016 Aircraft.com ad also shows a 3-blade prop which did not come with the plane new in 1983,  Are any of your Logs missing?  Is it possible in 42 years, that there could have been some undocumented major work done on the engine or crankshaft by one of the 2+ prior owners?...prop strike?  It is just hard to believe that the crank has not been touched in 42 years, but anything is possible.

[MooneyTunes]

3 hours ago, 1980Mooney said:

 

So this is a 42 year old Lycoming IO360 that you believe has never been overhauled since NEW.  That is a really unusually long period of time.  If true it sounds like a record.   

I happened to notice the 2016 Aircraft.com ad for the plane which said that it is a 1983 M20J and both the airframe and engine only had accumulated 680 hours since NEW by mid 2016.  That is only 20.6 hours per year on average since new as of mid-2016 (during the first 33 years of life)..   Or perhaps it was a combination of sitting for extended periods of time (months, years?) followed by more regular flying.

The Aircraft.com ad in mid 2016 also noted that it was being sold by an owner that had owned it for 29 years.  It appears that you have owned it for the last 9 years.  That accounts for 38 years of its 42 year life.  That means there was at least another owner or more in the first 4 years.

The mid-2016 Aircraft.com ad also shows a 3-blade prop which did not come with the plane new in 1983,  Are any of your Logs missing?  Is it possible in 42 years, that there could have been some undocumented major work done on the engine or crankshaft by one of the 2+ prior owners?...prop strike?  It is just hard to believe that the crank has not been touched in 42 years, but anything is possible.

 

3 hours ago, 1980Mooney said:

 

So this is a 42 year old Lycoming IO360 that you believe has never been overhauled since NEW.  That is a really unusually long period of time.  If true it sounds like a record.   

I happened to notice the 2016 Aircraft.com ad for the plane which said that it is a 1983 M20J and both the airframe and engine only had accumulated 680 hours since NEW by mid 2016.  That is only 20.6 hours per year on average since new as of mid-2016 (during the first 33 years of life)..   Or perhaps it was a combination of sitting for extended periods of time (months, years?) followed by more regular flying.

The Aircraft.com ad in mid 2016 also noted that it was being sold by an owner that had owned it for 29 years.  It appears that you have owned it for the last 9 years.  That accounts for 38 years of its 42 year life.  That means there was at least another owner or more in the first 4 years.

The mid-2016 Aircraft.com ad also shows a 3-blade prop which did not come with the plane new in 1983,  Are any of your Logs missing?  Is it possible in 42 years, that there could have been some undocumented major work done on the engine or crankshaft by one of the 2+ prior owners?...prop strike?  It is just hard to believe that the crank has not been touched in 42 years, but anything is possible.

Original engine logs have NO evidence of an engine damage repair ever done.  Low time airframe and engine is factual. This Mooney sat and sat. So “anything is possible”. I have contacted Lycoming and informed them of the findings. Waiting for response. I have  been told by others that the holes on the crank are consistent with a metal hardness test, usually performed at the factory. 

[varlajo]

5 hours ago, 1980Mooney said:

So this is a 42 year old Lycoming IO360 that you believe has never been overhauled since NEW.  That is a really unusually long period of time.  If true it sounds like a record.   

You think? 
Mine is 55 years old, >2700 SNEW. Never overhauled.

[Slick Nick]

4 hours ago, varlajo said:

You think? 
Mine is 55 years old, >2700 SNEW. Never overhauled.

My buddy’s C is still on the original bottom end from 1961. It’s not hard to believe at all.