Putting Cylinders on Pistons - Oil or No Oil?

[pete]

Ok, I'm hoping to put my cylinders on tonight, but I'm a little confused as to whether I should use some engine oil or not.

The Clymer says to put some engine oil in the cylinders, but I have seen threads on here that say to do it dry...

What's the best option?

[Nessism]

I recommend just enough oil to keep the cylinder from rusting Pete. I don't think it matters much either way though.

[Big T]

Oil, it needs to have oil when it runs

[pete]

Cheers for the quick reply Ed, makes sense.

The guys who did the honing for me put a bit of engine oil in and cling wrapped them to preserve it for me, so I'll wipe that oil out and put a smear of some of the oil I have as I don't know what oil they put in.

[pete]

Oil, it needs to have oil when it runs

That makes sense too Big T, cheers

[Tom R]

I don't how much the shop cleaned up the bores after honing them; but you might want to scrub those cylinders out a bit more. I usually use hot soapy water and a scrub brush followed by wiping the cylinder walls with ATF and paper towels. If you have a high pressure steam cleaner - even better. Then oil. I'm always amazed at how much metal dust and shavings are still in there.

[Suzuki_Don]

Pete, don't neglect to space the rings correctly. I always oil the ring grooves and rings so they will rotate easily for correct spacing. I also oil the bores, particularly the chamfer on the bottom of the cylinders where the rings first enter the bore. As has been said, "you don't want to start the motor up dry", it needs lubrication until the pump can get the oil in there. I can't understand the thinking behind putting a motor together dry.

[KC1908]

I don't how much the shop cleaned up the bores after honing them; but you might want to scrub those cylinders out a bit more. I usually use hot soapy water and a scrub brush followed by wiping the cylinder walls with ATF and paper towels. If you have a high pressure steam cleaner - even better. Then oil. I'm always amazed at how much metal dust and shavings are still in there.

Pete,

Use the hot soapy water and wipe it out with paper as above. Honing leaves stuff behind and engineering shops usually just oil the sleeves afterwards.

Ken

[KC1908]

Pete,

I have ring compressors for bike pistons if you want to borrow them. Better then using small screwdrivers. I can take them to work in town and meet you somewhere.

Don't forget to put rags in the top case. Hate to drop a circlip when putting the pistons on the rods.

Ken

[pete]

Thanks for all the advice guys, I got them in tonight.

The guys did spray and blow it out before putting the oil in, but I got an old dish washing brush and kero and gave it an extra good scrub tonight before putting some oil in them again for assembly.

I did the difficult thing and used my fingers as ring compressors. Wasn't terribly easy but it worked ok.

And Don, yes, I spaced all the ring gaps according to the Clymer at around 120 degress.

I'm uploading pic's now but will update my rebuild thread in the morning as my eyes are a little tired at the moment.

PS: I didn't get the whole putting the cylinders on dry also, made no sense to me but I'm brand new at this so need to check all these things out, which is why I'm here after all

[sharpy]

Always put mine one with just a hint of oil around the base. You be admazed how much still gets scraped to the top when you wind it over. Built my Honda 900 proddy bike with a full rebuild and ran it in for a total 1.5 laps on a 2.4 klm course before full throttle and was a very quick bike. Knowing how i set the race engine up (loose) bearing wise helped.

[pete]

Cool stuff. Given the ring's scraping up and down the cylinders, it doesn't surprise me that a reasonable amount of oil would be moved with it now that you put it like that.

[argonsagas]

A general rule-of-thumb is to use oil every time you assemble parts that will move.

Since that is what they are supposed to do, the parts will begin moving sometime after assembly, and if there is no lubrication at that time then there will be abrasion.

If, for example, you assembled and installed the pistons dry, then started the engine, the pistons would move through several cycles before pumped oil could reach them. During that time abrasion would be inevitable.

Piston rings will move in their slots, over time, but they need lubrication intially, and so do the cylinder walls.

[pete]

See that's what I figured, which is why I couldn't understand the whole assemble it dry thing, but probably 99% of posters on here know more than I about this sort of thing, so I must ask...

[Agemax]

i wouldnt even contemplate building anything mechanical that moves, without any form of lubrication to give it a "head start". dont go mad but a bit too much in an engine wont hurt and will soon burn off any excess