Cleaning tops of pistons...

[petegardner_901]

Anyone with good ideas on how to remove carbon deposits without scratching the tops of the pistons?

 

I was told a brass wire brush in a drill is good but it leaves severe scratch marks...

[JohnD]

I use an old chisel, 1" so that it doesn't dig the corners in.

But a putty knife or paint scraper from a DiY would be fine.

Just don't hold it at a high angle so it digs in.

 

John

[Pete Lewis]

Best scraper I have for this is bone handled dinner knife, which had a blade snap many years ago

Its just one of those odd bits of kit that works nicely,

 

Stanley and razor blade scrapers dig into soft metals

after scraping use some thick oil in the bores and turn the crankslowly to drag any debris from down the

bores

old idea was to use an old ring to keep the ring of carbon around the edge of the crown, ive never found that worthwhile

[Colin Lindsay]

As John says a blunt paint scraper is better than a razor scraper. Keep a petrol-soaked rag handy to wipe the debris out of the bores. A soft kitchen scourer - not metal - soaked in oil also cleans them well.

[Leon]

i have a brass blade in a scraper set that works a treat. just a bit of time and care is needed not to scratch the piston crown. i find it harder keeping carbon from dropping down to the rings though than not scratching the piston. a nice little trick is to put the piton to be cleaned at the top and then pack round the piston with grease. after cleaning the crown you can back the piston dawn the bore leaving all the carbon that would have made it to the rings stuck in the greases at the top of the pots waiting to be removed.