Author Topic: Surface rust on freshly bored cylinders  (Read 4939 times)

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Offline q2418130103p

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Surface rust on freshly bored cylinders
« on: March 04, 2011, 05:19:58 PM »
So I spent a bit of time this morning scrubbing my freshly bored, honed, and bead blasted cylinders with hot soapy water.

The cylinder walls developed surface rust within an hour.  I put a coat of oil on them after I noticed what was happening.  I noticed that a brief rubbing took off most of the rust, so I figure a more thorough rubbing will finish the job considering the short amount of time.

I haven't had time to clean them completely yet, I was planning on doing it in the morning by rubbing them with oil and an old t-shirt till they are clean. 

So my question is two fold, and they also show my propensity for over-reaction in these matters:
1) When does surface rust become a larger problem (and I mean this both in terms of the amount of time it takes, and the degree of rust which matters).
2) Am I correct in thinking that I will get it all off by just rubbing it thoroughly with oil?
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Offline DarcyCB400F

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Re: Surface rust on freshly bored cylinders
« Reply #1 on: March 04, 2011, 05:31:49 PM »
Don't sweat it. Have cold beer and relax knowing no harm is coming your way.
Your oily rag is all they need. Just give them a nice oily coating and sleep easy knowing that the rust you see is no harm what so ever.

How about some pics anyway of your "new" engine???
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Offline q2418130103p

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Re: Surface rust on freshly bored cylinders
« Reply #2 on: March 04, 2011, 05:38:44 PM »
great, thanks for the info. 

Do you know, as a rule of thumb, how long cylinders can last before they heavily rust, or to what degree surface rust needs to be to actually be a problem? 

How much builds up on the cylinders walls when the bike is stored for the winter?  I store my car in a garage for the winter and generally only start it a handful of times.  I figure it is better to let it sit since I cant drive it anywhere to get it nice and hot.  There is always a nagging though in the back of my mind that the cylinder walls or building up crud.


I'll have pics in my build thread tomorrow (see my sig), if all goes well in the morning then the pics should be very cool.
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Offline bradweingartner

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Re: Surface rust on freshly bored cylinders
« Reply #3 on: March 04, 2011, 09:31:10 PM »
My 2 Cents.

Oil will penetrate into the surfaces of the sleeve and prevent the rust. Freshly bored cylinders however are 'virgin' and will rust right quick, especially after washing with soapy water. Also they are open to the atmosphere.

Now an assembled engine is oily, carbony and reasonably well sealed. Rust doesn't occur on the cylinder walls for a long long time in this condition assuming they are stored indoors in a fairly stable environment.

However, if you start the engine up and don't warm it up fully (aka, don't drive it more than 30min), you're actually introducing moisture INTO the engine that then can't escape.

It's better to just let it sit realistically speaking. If you are especially paranoid, use a engine fogging solution when you winterize it. I think I use Stabil brand fogging oil, no problems yet. But then again, I have one engine that literally sits outside in a snowbank all winter long every year and hasn't seized yet - fogged or not. (A free lawn mower that I hate and have been trying to kill for years...  ;D )

Offline bryanj

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Re: Surface rust on freshly bored cylinders
« Reply #4 on: March 05, 2011, 04:03:38 AM »
Just to ease your panic, many years ago when racing Triumphs( yes some did hold together long enough) a freshly bored set of barrels would be left out in the garden to "weather" then the rust lightly honed---this gave a cylinder that held a bit of oil and lessened the siezures but did alow a small amount of oil consumption, but then triumphs leaked most of it anyway so we didnt care
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Offline faux fiddy

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Re: Surface rust on freshly bored cylinders
« Reply #5 on: March 05, 2011, 04:14:32 AM »
( yes some did hold together long enough)

I heard about the air cooled  fiat cars. Most desired after market upgrade  was a net to catch parts.
^^^^^^^/l^^^^^^^^^^^^^^/l^^^
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<'  '  '   '  o .  . . . . . . .................(
 ' VVVVV'   ')))))____>-''''''''''''''''''\  l
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Offline bryanj

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Re: Surface rust on freshly bored cylinders
« Reply #6 on: March 05, 2011, 04:27:04 AM »
The net was to catch the chrome not parts!!
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline q2418130103p

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Re: Surface rust on freshly bored cylinders
« Reply #7 on: March 05, 2011, 05:12:31 AM »
My 2 Cents.

Oil will penetrate into the surfaces of the sleeve and prevent the rust. Freshly bored cylinders however are 'virgin' and will rust right quick, especially after washing with soapy water. Also they are open to the atmosphere.

Now an assembled engine is oily, carbony and reasonably well sealed. Rust doesn't occur on the cylinder walls for a long long time in this condition assuming they are stored indoors in a fairly stable environment.

However, if you start the engine up and don't warm it up fully (aka, don't drive it more than 30min), you're actually introducing moisture INTO the engine that then can't escape.

It's better to just let it sit realistically speaking. If you are especially paranoid, use a engine fogging solution when you winterize it. I think I use Stabil brand fogging oil, no problems yet. But then again, I have one engine that literally sits outside in a snowbank all winter long every year and hasn't seized yet - fogged or not. (A free lawn mower that I hate and have been trying to kill for years...  ;D )

I had been told something like this is the past, but it wasn't from a reliable source.  So I guess I wont bother worrying about it anymore.  Thanks.
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Offline Jordan

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Re: Surface rust on freshly bored cylinders
« Reply #8 on: March 05, 2011, 06:47:38 AM »
It is called flash rust, happens to all fresh steel, never heard of it being a problem.