flyingdaemon

My Feedback: (1)

I have an older 120 Surpass I with Pump that came with a used plane I bought. It was running great until the other day when it starting making a knocking noise. Luckily I didn't take off because while fiddling and trying to find something loose it quit and we realized there was something really wrong with the motor. Diassembly proved that the rear bearing was shot.

Here is the question. The front bearing has seals on both sides while the rear bearing had only one seal (towards the rear). I bought a pair of bearings front the local bearing supply house (6000-2Z and 6002-2Z) and they are sealed on both sides - should I remove one or more seals on the rear bearing and do I need to remove one side from the front bearing? One more thing - I can't seem to get the front bearing out. The rear one was troublesome until I gave it some heat, sprayed WD40 on it and waited 30 minutes. It came out easily then but the front one seems like it is glued in. Is there another trick to this?

Also, I cannot find any type of head gasket on this motor. Should there be one? It ran fine before without out one and it didn't fall out anywhere.

Thanks for any suggestions.
Glen

Bax

My Feedback: (11)

Glen,

The bearings aren't "sealed" those are shields to help keep dirt out of the bearings.

The stock rear bearing has no shield on the face towards the back of the engine, the stock front bearing would have a shield towards the front of the engine, only.

To remove the bearings, heat the crankcase, and they'll literally fall right out. Heat the case to reinstall them.

The cylinder head gasket is aluminum. When you look at the head, you see it, but it's such a close fit in its groove that many people think it's not there. A very close look will reveal it.

flyingdaemon

My Feedback: (1)

Bax;

Thanks for the reply, and yes they are shields not seals - bad terminology on my part.

Just to be sure, I am clear; the rear bearing should NOT have a shield on the connecting rod side but would on the front side facing towards the front bearing (front of motor). I found it installed the other way so I replaced it that way - perhaps that is why it went. I may replace the piston ring next since I seem to have lost about 300rpm since tearing the motor down, so I will have a chance to turn that bearing around.

Is the piston ring the same on this motor as it is on the Surpass II?

Bax

My Feedback: (11)

Over the years, O.S. has used bearings with and without shields. The newest engines have bearings with shields on both sides and pre-packed with some kind of grease/lubricant.

You can leave the bearing as-is, or reverse it, it shouldn't make much difference either way.

The FS-120 Surpass I, II, and E all use the same piston rings. The Surpass III is different.