engine condition inspection--- maybe a 15-20 year ago overhaul--- maybe----

[tim bandy]

I have this O-320. 1957 model. it came with an airframe. No logbook with either. No verbal history.

It appears to have had maybe at least a top overhaul. Cyls look new or overhauled. new never run pistons.

It had NEVER had oil in the engine before i got it. Don't know for how long----

I filled it up with 12 qts od phillips 66 antirust oil 20-50. filled as far up as I could.

Now i have ordered a borescope. I would like to look at the cam- and anywhere else inside for any rust or
problems in general. Try to get an idea of what was done. (that may be difficult or impossible--- but if there is lots of rust---i need to know that too)

My plan is to drain the oil out and save it in a clean new bucket. im thinking that the oil residue might block my scope from seeing the surfaces clearly. i am considering washing it down inside with diesel mixed
with a little bit of some kind of oil-- maybe mystery oil. not sure what proportion.
see what I can see with the scope in the case. then look into the cylinders. Then when done -- try to
coat the cam with paralketone liberaly----- then refill the antirust oil back in.

To do this I guess I will have to pull a jug. Am planning to leave the piston on the rod. Is there any preference on which jug to pull ? I think this is an early no suffix 320. Lycoming says by serial it is a 57--- no banana plates. Is there any risk that the short studs in the case might move ? (instead of the exterior nut ?) I of coarse will not be able to see the bearings --- but I would like to check for a rusty crank-- because I have no idea how long it sat with no oil and what its envoronment was.

any suggestion on the wash down mixture ? and which cylinder best to pull ?

Tim

[Steve Pierce]

I have pulled both cylinders on one side to inspect for corrosion on the cam during a pre-purchase inspection on an engine that has been sitting for a long time.

[Frank Green]

What Steve said, 2 same side. Not just the cam but the lifter faces as well.

[dgapilot]

It’s a 50/50 issue. Both engines on my PA-30 sat 24 years. Aside from the fuel system I just fired it up and ran it. 50 hours in and still running great. Second oil change this weekend and fingers crossed that there is no metal. It is highly unlikely that surface corrosion would cause a catastrophic failure. I’m happy rolling the dice on my engines. I’ve seen far more engines with no issue that engines with bad cams and lifters. Your mileage may vary.

[tim bandy]

I was told once by a mechanic-- that it is dangerous to take 2 cylinders off one side on a 4 cyl engine-- the operative idea being that there might be a loss tension between the case halves and they might migrate apart. Any thought to confirm that idea ? i don't see right off how it would hurt to take two opposing cylinders off ----
And would it be good to slide the through bolts back in and hand tighten the nuts while the jugs are off ?
I would rather not make a mistake that might force a teardown--- at least not till later. (if it needs it) (like breaking the silk thread)
Tim

[JPerkins]

Pull the two cylinders off one side. Once a cylinder is removed use a stack of washers and the base nuts to retorque any through studs. That’ll keep the tension on everything and prevent a main bearing from spinning. Only two through studs per cylinder; easy enough to identify once the jug is off.

The main concern I’d have if it’s been sitting with no oil is the condition of the bearing journals on the crank. Personally I’d do an IRAN. Especially with no logs because now you have to comply with each and every AD that exists for that motor because you have no proof that they were ever done. A lot of which is simple once the motor is open.

[tim bandy]

yes-- is believe that it may have to be split later on-- when the airframe is further along. I just wanted to take a look --now-- to see if I see anything that would obviously disqualify it. If I don't like it now--- i may need the time to hunt for an IO-360 or an IO-470. (or even an o-540) either of those could take a while. (have to print out the AD list for it before I decide to split -- so I can see where each one is internally-- i know some are in the accessory section. )

[Steve Pierce]

So what airframe can take an O-320, IO-360, IO-470 or even an O-540?

[tim bandy]

i am building a 4 place bearhawk. I am about to finish the wing ribs. They are the same as the 2 place bearhawk.
The 320 is a bit small for the 4 place. (they suggest o-360 min) but maybe nicer for the tandem 2 place. If the o-320 looks good--- I will switch the 2 place plans-- and go forward. build the airframe to fit the engine --

If I continue on the pa-20 project--- I will have to split the engine for sure since it came with no logs.
(if for no other reason than AD compliance and condition inspection)

If it goes on a bearhawk---- at least some of that may be optional----- depending on a lot of things of coarse.

Tim

[Don D]

I have unused patrol plans. $200