Scotchbrite & Engine Work

Tech about stuff that doesn't fit in the above categories
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Frank
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Scotchbrite & Engine Work

Post by Frank » Thu Mar 12, 2009 8:29 pm

Reading a topic just posted by stroker (HIGH POWER PROPANE PLUS 2 YEARS), another BITOG forum topic (Scotchbrite--------NEVER !!) came to mind with regard to engine failure after a rebuild:

bbobynski wrote:NEVER USE SCOTCHBRITE TO CLEAN UP GASKET SURFACES OF AN ENGINE.

NEVER, EVER, EVER USE SCOTCHBRITE ON AN ENGINE. At least not one you want to run again for a long time.

Scotchbrite seems so benign but it is death to engines. Scotchbrite pads are nylon fibers with 40 micron particles of aluminum oxide in them. Scotchbrite dust leaves behind all those 40 micron particles hidden everywhere. Aluminum oxide is an extremely aggressive abrasive. It imbeds in the bearings and eats the crank....and other things.

Scotchbrite is the bane of the aftermarket re-man engine industry. There are lots of "new" re-mans ruined by cleaning up the old parts with scotchbrite pads and then installing them. Eats up the engine immediately. That is why many engines fail the main and rod bearings after a head job or other work...scotchbrite. People think it is because of coolant getting into the oil ruining the bearings or something when it was really the scotchbrite the mechanic used to clean up the parts... especially a Northstar engine where the block deck surface cleaning funnels the scotchbrite dust down the oil drain back passages.

If you cleaned up parts with scotchbrite you now have a HUGE cleanup job ahead of you cleaning up after the scotchbrite. You must make positively sure that none of the dust remains anywhere on any parts or got into the oil cavity. Hopefully the valley of the engine was covered if you used scotchbrite on the deck surface as if it drifted into the valley or into the pan your engine is toast.

I am very very serious about this. Scotchbrite has a very bad reputation in the industry as it seems like such an ideal cleanup method, seems so benign, yet can cause such extreme damage. Most mechanics in the know stay miles away from scotchbrite as it is harder to clean up after it than any labor it saves.
I'm not suggesting that Scotchbrite may caused stroker's failure and I started a new topic so as not to hijack his topic with a red herring.

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Steptoe
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Re: Scotchbrite & Engine Work

Post by Steptoe » Fri Mar 13, 2009 12:04 am

I'm not suggesting that Scotchbrite may caused stroker's failure
Will would suggest that it is a very good possiblity condisering his symtoms ....
Or they have used emery paper or steel wool...
It is ok IF EVERYTHING is dismantled, to clean off excess crap BEFORE chemical bath and before machining and final wash. Never after
If correct processs is used there is no reason at all, on a engine build to clean anything after machining and final wash other than to wipe with linen rags.
If not fully dismantling engine, say just replacing heads, the use of abrasivies is a BIG No No...elbow grease and razor blade.

The trouble is in workshops is this sort of stuff is left up to the new apprentice or labour, often with lack of instruction and supervision.
My Spelling is Not Incorrect...It's 'Creative'

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