Chromed Dome Piston

**Tue Jun 15, 2010 4:38 am » Post: #1 » Download Post**

I was at my mate's workshop last night and he has a stripped NSR250 dry clutch engine on the bench. The pistons look like they are nicasil plated (or something similar) on the dome down to the top ring recess. Does anyone know about these pistons? They are marked KV3 and look standard apart from the coating on the crown. I think the plating will stop damage from detonation. Any ideas?

**Tue Jun 15, 2010 5:12 am » Post: #2 » Download Post**

Ask George , he will tell you his story .

**Tue Jun 15, 2010 3:16 pm » Post: #3 » Download Post**

Later NSR pistons are coated down to the top ring.
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**Wed Jun 16, 2010 8:30 am » Post: #4 » Download Post**

Andy wrote:Later NSR pistons are coated down to the top ring.

Are spares available from Honda or Tyga? Sorry if this has been discussed before, but I have never seen a coated piston before, apart from my old KTM black Mahle ones. I think that a coated crown piston would out-perform a standard cast aluminium piston by far!

**Sun Jun 20, 2010 3:28 pm » Post: #5 » Download Post**

I managed to "borrow" the piston in question. Do the coated Honda pistons leave the factory with a mirror coating on like this, or has this one had special treatment?

**Mon Jun 21, 2010 1:23 am » Post: #6 » Download Post**

No, not quite the same/extreme, but coating piston crowns is nothing new.

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**Mon Jun 21, 2010 3:41 am » Post: #7 » Download Post**

What's the advantage of having a coated piston crown? Better flow? Less likely to accumulate carbon?

**Mon Jun 21, 2010 8:17 am » Post: #8 » Download Post**

You can use it to shave in when camping?
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**Mon Jun 21, 2010 9:11 am » Post: #9 » Download Post**

Major_Tom wrote:What's the advantage of having a coated piston crown? Better flow? Less likely to accumulate carbon?

If its a chrome coating then i guess chrome is hard so the piston should withstand detonation better?
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**Mon Dec 12, 2011 6:35 am » Post: #10 » Download Post**

Less surface area, so the piston absorbs less heat from the combustion, also there is less absorption of radiant heat from a shiny surface.

I wonder if it's worth smoothing the dome on cast pistons and polishing for a similar effect? So long as the piston isn't weakened, but you might have to remove a lot of material if the piston castings are rough.

**Mon Dec 12, 2011 8:35 am » Post: #11 » Download Post**

Nobody seems to be answering this intirguing question.

I've used teflon coated pistons in kart engines, but that just gave a little longer life...but chrome topped pistons...that's a new one on me.

Mike
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**Mon Dec 12, 2011 11:04 am » Post: #12 » Download Post**

If these are chrome plated, isn't there the risk of it flaking off? Not sure what the damage would be.

Dana
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**Mon Dec 12, 2011 12:17 pm » Post: #13 » Download Post**

Aluminum can be highly polished, so I don't see why they'd actually be chromed rather than having a polished or 'chrome' like finish.