how to get rid of baked oil in chamber?

[Slavomir Musilek (R.I.P.)]

Greetings all!

 

 

the head gasket got blown some time ago but oil was running rather into the chamber than out.

 

 

 

any tips how to get rid of it? Have tried agressive bike cleaner from Castrol (highly recommend to all!), technical petrol.. did not work.

 

 

also, after taking the head off, it is normal that horizontal free play of piston in chamber is 0.5mm.

 

thanks a lot for any help and also, happy new year to you!

[raz]

I would think you can just ignore it and it will go away with time, I can't see how it could do any harm.

 

I also saw you're looking for a new piston, surely if it's just carbon deposits and no other problem with it, it must be possible to clean it!!

[Slavomir Musilek (R.I.P.)]

I would think you can just ignore it and it will go away with time, I can't see how it could do any harm.

 

I also saw you're looking for a new piston, surely if it's just carbon deposits and no other problem with it, it must be possible to clean it!!

 

 

thats why I!m asking for advice the piston is covered by 0.3-0.4mm thick layer of burned oil so there must be some impact on power and etc. Same with the head.

 

Any tips how to get rid of it?

[Dan M]

thats why I!m asking for advice the piston is covered by 0.3-0.4mm thick layer of burned oil so there must be some impact on power and etc. Same with the head.

 

Any tips how to get rid of it?

 

I don't know if it is available in your part of the world but Seafoam will soften it up nicely.

 

http://www.seafoamsales.com/

[The Monkey]

Its winter anyway....Remove pistons and cylinders, lightly hone bores to get rid of the oil deposit on cylinder wall (stone hone), sandblast crown of piston, sandblast combustion chamber in head (valves in) then pop valves out, inspect the seats for deposits or build up, lapping compound will take out any minor build up. You will probably have to sand blast the exhaust port if enough oil was in the chamber, avoid hitting the seat and guide (internal) with the sandblaster by blasting in from exhaust port downstream. Check guide tolerance while your in there, reassemble with a new set of rings.

 

Cheap and cheerful....Piston to BDC, guaze around the top outer edge of piston remove deposit on cylinder wall with emery paper, out with guaze (a vacuum cleaner works great here) theoretically picking up the debris that fell down into the nether region, piston to TDC stuff guaze around edge, tap away at deposit, it will come off in chips until eventually your piston crown looks like Keith Richards face, tell yourself that will aid in the tumbling of gasses, pull up guaze about edge of piston. Do the same to the combustion chamber, valve springs off, inspect seats, lap to clean if necessary and reassemble holding tongue carefully in left side of mouth. Put on the bell bottom pants, congratulate yourself for avoiding the capitalist ream and run her hard with good fuel.

 

Happy New Year!

[GuzziMoto]

You could try oven cleaner, it is made for removing baked on grease which is much like oil. But unless you have a problem that the baked on oil is causing (ie, pinging or knock) then I would not worry about it. The coating of oil will raise the compression ratio slightly (which can be a good thing as long as the motor does not knock or ping) but other then that unless you have valve deposits from it or something else that will actually hurt performance or an issue with knock or pinging I would not worry about it. I would be reluctant to sand or doing anything that will create particulate debris that may end up creating issues in an otherwise running motor. And if it is not running right then take it the rest of the way apart and clean off the piston and cylinder with emery cloth, scotchbrite pads and/or sandblasting as required.

And if by horizontal free play with the piston you mean that it can rock slightly on the wrist pin then yes, .5mm is fine. Your cylinder still shows good crosshatching in the photo, that is a good thing.

[Skeeve]

You could try oven cleaner, it is made for removing baked on grease which is much like oil.

 

Uh, bad idea: keep strong alkalis away from your aluminum components unless you want to see them dissolve before your eyes.

 

Try this little experiment:

 

Take a sheet of aluminum foil.

Spray it w/ Easy Off.

Stand back & count to 10.

Any holes in it yet? No? You cheated & used the heavy duty stuff, you rascal! Fine: give it another count of 10.

 

Now imagine that on your engine internals. Not a happy thought, is it?

[Dan M]

Its winter anyway....Remove pistons and cylinders, lightly hone bores to get rid of the oil deposit on cylinder wall (stone hone...................... reassemble holding tongue carefully in left side of mouth. Put on the bell bottom pants, congratulate yourself for avoiding the capitalist ream and run her hard with good fuel.

 

Happy New Year!

 

Carefull with that hone. Cylinders are coated.

[richard100t]

Uh, bad idea: keep strong alkalis away from your aluminum components unless you want to see them dissolve before your eyes.

 

Try this little experiment:

 

Take a sheet of aluminum foil.

Spray it w/ Easy Off.

Stand back & count to 10.

Any holes in it yet? No? You cheated & used the heavy duty stuff, you rascal! Fine: give it another count of 10.

 

Now imagine that on your engine internals. Not a happy thought, is it?

I thought that the v11 motor was a cast iron block? Or do the cylinders have aluminum sleeves? I remember something about them being coated with nikasil or something, but its been a long time. I do agree that oven cleaner is probably not a good idea though.

[GuzziMoto]

If you soak aluminum parts in oven cleaner then yes they will dissolve. Eventually. But if you spray it on carbon encrusted aluminum parts or nikisil coated aluminum cylinders and wipe it off then you will be fine. Or don't use it. But TZ racers would use it to clean up engine parts when they could not get muriatic acid. Normal cleaners are not likely to have much effect. But as I said unless you are having engine issues due to excessive carbon build up then I would not worry about it. And I would be more concerned about build up on the back side of the valves, especially the exhaust valves, over a coating on the piston dome or some crusties around the rim of the cylinder above where the rings run.

To each his own.

[Tom M]

I found that a little carb cleaner sprayed onto a rag cleaned most of the crap at the top of my cylinders. To get them completely clean I used scotchbrite and carb cleaner. That combination didn't work on the piston domes, they're going to require something stronger.

 

When I dropped my heads off at a local shop for a refresh I asked the owner/racer who has built many engines what he does with nikasil bores when rebuilding and he said he uses WD40 and a hone wrapped with scotchbrite to break the glaze on the cylinder walls. I plan on following his advice when I put mine back together.

[The Monkey]

Carefull with that hone. Cylinders are coated.

 

My apologies Slavomir, and thanks Dan. True you shouldnt touch a Nikasil coating with either a stone hone nor emery cloth. Softer materials than the Nikasil such as a non metallic scourpad or an aluminum based ball hone can be used to clean or deglaze. My goof! More time about the diesels than this fine machinery. If you have been dumping some kind of softener onto the surfaces about the top of the piston take measures to ensure its removal from the rings and the cylinder wall. Wash your sump out too. Some of the elements in commonly available cleaners can wreak havoc in your mill.

[motoguzznix]

Slavomir

 

Sandblasting is no good idea on piston and head. Te sand causes deep grooves in the light alloy which is not desirable.

 

For removing the carbone deposits I always use stainless steel wool. Should be in every kitchen. Cleans good and the surface looks almost polished.

 

Polishing is a good idea for the combustion chamber surface as the heat will be reflected and enters piston and head in a smaller amount thus increasing the VE of the engine.

 

The deposits are not caused by the blown head gasket but by the worn valve stems and guides. Check this before reassembling!

[Slavomir Musilek (R.I.P.)]

Slavomir

 

Sandblasting is no good idea on piston and head. Te sand causes deep grooves in the light alloy which is not desirable.

 

For removing the carbone deposits I always use stainless steel wool. Should be in every kitchen. Cleans good and the surface looks almost polished.

 

Polishing is a good idea for the combustion chamber surface as the heat will be reflected and enters piston and head in a smaller amount thus increasing the VE of the engine.

 

The deposits are not caused by the blown head gasket but by the worn valve stems and guides. Check this before reassembling!

 

good idea!

 

I will clean pistons by letting them soak overnight in petroleum/technical benzin mixture and than clean them by soft felt polisher. Thanks for advice! Will check the valves too!

 

cheers

 

 

Slavek

[Tom M]

I cleaned up one my piston crowns last night with a wire wheel on my bench grinder, followed by a bit of scotchbrite. It worked great. This is how I used to clean up 2 stroke pistons way back when, but I was hesitant to do it on the Guzzi piston with the more complex crown. That said, I ordered a set of FBF pistons yesterday. I wanted to go with Mike Rich pistons but I'm done waiting for him to get enough orders to make running another batch economically feasible.