SB 505 O-320

N282RV · #1 02-15-2007, 11:05 AM

Ok I have found a crank on ebay and it is now at Aircraft specialties getting overhauled and they said it did not "pass" the SB505. Now I have read this service Bulletin and from what I read the only way to "fail" would be to have pits or corrosion deeper than the 1.91 inner diameter allowed. My ID measured 1.919 and therefor is certifyable however they will not certify it to more than 150hp.....anyone been there done that? I surely do not want to do something unsafe but, first off is there any mechanical reasoning to this? or is it just the lawers telling them to tag it that way so if/when I put the high compression pistons in they have no liability with it.
Does anyone know what the ID was to start with?
All in all I think I got a good deal on the crank but I am curious if I am going to have a problem or should be concerned if I get this engine to make 170+hp.

c177tx · #2 02-15-2007, 08:51 PM

If you believe that it will measure out to pass sb505, and that the service center is just giving a blank rejection, then send it to another service center. I sent mine to ECI in San Antonio, who certified my 0320e2d crank with no problems. My crank was first run 2400 hours in service since 1967. When we pulled the plug to check the inside's on the crank, it was full of sludge, when we cleaned it out it was as shiny as the day it was made. No rust, no pits. If yours had pits, then it will need to be polished to get rid of the pits and then measured. Did yours have any pits?

N282RV · #3 02-15-2007, 09:57 PM

Not sure what they found except that they had to remove metal to clean it up, that being said I have .009 more material than required left in the inner diameter. So............its not rejected but they will only certify to 150 hp...? I dont understand why only 150 when the SB covers up to 180 HP engines and the cranks are the same ID if its 150 hp or 180 hp.....unless its all the lawers like I said.

az_gila · #4 02-15-2007, 10:47 PM

Quote:

Originally Posted by N282RV

Not sure what they found except that they had to remove metal to clean it up, that being said I have .009 more material than required left in the inner diameter. So............its not rejected but they will only certify to 150 hp...? I dont understand why only 150 when the SB covers up to 180 HP engines and the cranks are the same ID if its 150 hp or 180 hp.....unless its all the lawers like I said.

Jeremy... the ID (Inside Diameter) is the part where the material isn't....

So if yours measures 1.919 and the limit is 1.910, then you actually have 0.0045 LESS material in the "meat" of the crankshaft....

But I'm a bit confused too on this SB.... it used to be that the SB was only for the 160 HP version of the O-320, but reading revision B on the Lycoming web site, I see no reference any more to HP limits.

Does any one know if this is a Rev B vs. Rev. A issue??

This might explain the earlier post of a O-320-E2A crank passing easily, since that is a 150 HP version when used certified...

UPDATE... apparently the FAA issued AD has a different applicability than the SB...

From AD 98-2-08

Applicability: Textron Lycoming 320 series limited to 160 horsepower, and 360 series, four cylinder reciprocating engines with fixed pitch propellers; except for the following installed in helicopters or with solid crankshafts: HO-360 series, HIO-360 series, LHIO-360 series, VO-360 series, and IVO-360 series, and Models O-320-B2C, O-360-J2A, AEIO-360-B4A, O-360-A4A, -A4G, -A4J, -A4K, -A4M, and -C4F.

gil in Tucson

N282RV · #5 02-16-2007, 10:51 AM

Ah yes my math skills are a little rusty(should put out a AD on that) And now i do not like the number I was given from the shop. So....I read that AD you posted and I think the loop hole may be the fact that if it is a 150 hp crank that the AD is not applicable..? But the SB says it is applicable....I have a call in to the shop and Lycoming, will update later.

TBC..................................

ddurakovich · #6 02-16-2007, 12:04 PM

Quote:

Originally Posted by N282RV

But the SB says it is applicable....I have a call in to the shop and Lycoming, will update later.

TBC..................................

SB's are NOT mandatory for non-commercial operations. AD's are!

If it is safe or not is a whole 'nuther question

N282RV · #7 02-17-2007, 01:34 PM

Yes true enough, ADs are manditory and SB are not manditory even if the SB is "manditory" from the manufacture. what I would like to really know is how thick the crank starts out as. If 4 and a half thousands is something to really worry about on a piece of tractor techknology?

Sam Buchanan · #8 02-17-2007, 02:08 PM

Quote:

Yes true enough, ADs are manditory and SB are not manditory even if the SB is "manditory" from the manufacture. what I would like to really know is how thick the crank starts out as. If 4 and a half thousands is something to really worry about on a piece of tractor techknology?

I certainly don't advocate shaving safety margins, but.....if you take the Lycoming data plate off the engine you can run any crankshaft you want in your experimental engine. There are no regs that say our engines have to have yellow-tagged parts in them. That is why you will still see some experimental aircraft with "airboat" engines. Then there are the non-aviation engines out there....

Having said that, I made sure my engine rebuild was all new or yellow-tagged. But it was because that is what I wanted, not because I was forced into it by AD's.

LifeofReiley · #9 02-21-2007, 10:08 PM

This SB is BS... Ask the FAA how many planes have fallen out of the sky to to small pits in the crankshaft. It makes for $$$ for Lycoming when times ($$$) were slow.

az_gila · #10 02-21-2007, 10:59 PM

Quote:

Originally Posted by LifeofReiley

This SB is BS... Ask the FAA how many planes have fallen out of the sky to to small pits in the crankshaft. It makes for $$$ for Lycoming when times ($$$) were slow.

Actually, one or two, but they were in the more humid climate of the UK.
IIRC, a Piper had a lost prop, or at least a severely cracked flange, with the cracks emanating from the corrosion pits...

gil in Tucson