IO550 hard to start following oil changes

[gsengle]

I can't figure out why this would be, but the last 3 oil changes, it seems the first start after the oil change is very difficult.  Anyone else have this happen?  Any theories?

Greg

[David Mazer]

Do you change your own oil?  Mine takes a couple extra turns but nothing noticeable and the pressure comes up pretty quickly even though I don't put oil in the filter before I install it but I have a TSIO 540 not an IO 550.

[Bolter]

Just brainstorming without any research on what links oil to starting.  Perhaps a little bored tonight.

Could the governor be taking too much time to fill, leaving too much air drag on the starter?  Maybe a similar idea with the oil pump pumping dry for a few revolutions that takes power out of the starter?  Either would be noted as slower turning of the prop.  

Could you get extra compression from draining from a warm engine and refilling with cool oil that takes a little longer to equalize the internals when you start?  

Is the engine still warm from bringing it in and you are doing your cold start procedure?

If you did not do the oil change yourself, is the A&P also checking something else that could be introducing air in the fuel lines so that you are are not as primed as you think you are?  

No promises that these make sense...

-dan

[Piloto]

I had a similar experience with the Exxon Elite oil. After I switch back to Aeroshell the problem was fix. The rough starting is due to the prolonged lack of lubrication of the push rod lifters because the new oil filter is initially empty. It appears that Aeroshell oil has a better retention quality on the lifters than Exxon Elite.

Jose    

[takair]

Quote: Piloto

I had a similar experience with the Exxon Elite oil. After I switch back to Aeroshell the problem was fix. The rough starting is due to the prolonged lack of lubrication of the push rod lifters because the new oil filter is initially empty. It appears that Aeroshell oil has a better retention quality on the lifters than Exxon Elite.

Jose    

[Piloto]

I don't think it causes any added wear on the lifters. But it tells me that the Exxon oil is not there when you need it most during the crancking process. If there is no oil residue on the lifters neither will be on the bearings, rings, valves guides and other engine parts. Because oil is not circulated inmediately you need the residue to lubricate and reduce wear during the first crancking revolutions. I have confirmed with two other engines that the problem is unique to Exxon oil of the same grade as the Aero Shell 20W-50. The problem is most noticeable during summer and after more than a week between starts.

Jose

[gsengle]

Quote: Piloto

I don't think it causes any added wear on the lifters. But it tells me that the Exxon oil is not there when you need it most during the crancking process. If there is no oil residue on the lifters neither will be on the bearings, rings, valves guides and other engine parts. Because oil is not circulated inmediately you need the residue to lubricate and reduce wear during the first crancking revolutions. I have confirmed with two other engines that the problem is unique to Exxon oil of the same grade as the Aero Shell 20W-50. The problem is most noticeable during summer and after more than a week between starts.

Jose

[Piloto]

Quote: gsengle

 

Problem is I'm using Aeroshell 100w plus.  Also, I preheat when below 50 or so...  Other data - engine is at about 1750 hours...  Runs great, but at higher power can go through a quart every 2-4 hours.  At lower power more like 4-5 hours.  I've also noticed on 3-4 occasions I've had a brief what felt like a miss or engine shudder about 5 mins into climbout, but no strange indications and it only happens once on a flight for a half a second.  I'd say this is about 1 out of 5 flights.  No idea if related.