What about polishing piston crowns?

[88-diamondblue]

Is there any advantage to polishing the crowns of the pistons? Any loss of compression due to doing this. The two things that I have read is that there is less heat retained in the piston and less carbon build up. This is on a 88 3.2. Same question for the dome of the heads any benefit. I have tried a search and have Wayne's book, that why the ?'s

Thanks,

[cgarr]

Not sure if there is any benefit to polish but I like to at least take off any sharp edges that could be points of high heat

[BReyes]

No, just perfectly cleaned, and as stated above. First time you run it there will be carbon build up.

Regards,

[88-diamondblue]

Was planning on removing the casting marks on the piston tops.

[ChrisBennet]

The stock 3.2 pistons are pretty smooth already. They don't even have any sharp edges to remove. I think there are better ways to spend your engine building time budget.
-Chris

[Jeff Alton]

I polished the last two sets I used, just for giggles. Wanted to see how hard it was. Did not take that long, probably no performance enhancement at all though!

Cheers

[88-diamondblue]

Chris, these are the casting marks I was going to remove. All the pistons have the same casting marks. Recommend just leaving them or are they areas that could create hot spots? Jeff, I thought I had seen some polished pistons in another thread.

Thanks everyone.

[911pcars]

I doubt any performance advantage, but polishing would provide less surface for carbon to cling to and perhaps reduce hot spots that might induce pre-ignition. However, a regular treatment from some internal water spray (engine running) may provide the same carbon reduction effect.

Sherwood

[afterburn 549]

agree with 911pcars- and one other PT the smoother it is the more heat it will reflect back rather then being a heat sink.
Ps I always make the inside of the combustion chamber (s) polished enough to see your self by.....is good for the cool list and cant hurt. (unless your fire coating the tops)

[stevepaa]

I did it to remove sites for carbon build up and ignition points.

How does one introduce water and what does it do then?

[911pcars]

"How does one introduce water and what does it do then?"

Steve,
Nice job with the polishing.

In the archives, Grady refers to it as the "rubbermaid solution." Basically, water is sprayed into the intake at around 1500-3000 rpm. The water scours the combustion chambers of carbon which exits out the exhaust.



Sherwood

[Jeff Alton]

I think the "Rubbermaid" solution refers to water being drawn in by the fan to cool the motor, not into the intake to get rid of carbon.....

Cheers

[911pcars]

"I think the "Rubbermaid" solution refers to water being drawn in by the fan to cool the motor, not into the intake to get rid of carbon....."

Jeff,
Yeah, I probably stretched that a bit, but the same or equivalent nozzle to lower the air temp. can also be used to introduce a water spray into the intake for the purposes of cleaning the combustion chamber and ports. A simple spray bottle could suffice for this purpose as well, but a continuous stream of spray is preferable.

Sherwood

[Jeff Alton]

Okay, got it now. I was a little confused (Normal for me). There have been some good threads on de-carbonning on the techinical forum.

Cheers

[88-diamondblue]

Ok, how do you guys that have polished the heads and pistons do it. What is the process to get to the mirror polish?

[afterburn 549]

I use dremel ,start with a big drum (big for dremel 1/2 inch?) and once the ruff stuff is gone use jewelers rouges....there are at least 3 grades of that.

[Jeff Alton]

I taped off the pistons and sanded them with 1000, 1200, 1500, 2000 (wet) and polished with a rouge. Each piston took around 20 mins total to do.

Cheers

[ChrisBennet]

I love you guys (piston polishers) but I think you're all nuts.
-Chris

[Jeff Alton]

Well, can't speak for all of us, but I am nuts....

[afterburn 549]

being crazy has always stopped from going insane or visa versa