When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello guys, been a while since I’ve worked on my engine project due to some health issues but now back to try to get the momentum going. While on a drinking day with a friend we got to talking about my pending project and the talk about pistons came up. He had seen how they looked out of the engine and had cleaned one up with the Dremel tool using the small delicate brushes
. That process took a good amount of time and had wire stuck on my shirt and face. Not fun, but he then said to blast it with soda. I’ve read on it a bit and seen a few posts on the 911 Rennlisters but had no luck finding 928 related posts. Can anyone advice on it if they’ve done so? Here a few pics of how one piston came when I cleaned with the small metal delicate brushed from Harbour frieght on my small Dremel tool.
I've had my pistons soda blasted. It removed all carbon and left the iron coating intact. Using any abrasive on the skirt like a scotch pad let alone a wire brush will damage the coating and dramatically shorten your engine's life.
The best way to clean the piston is to soak it in simple green for a few hours then use a toothbrush to remove the remains.
dont use anything more abrasive than a tooth brush
dont take them to the machine shop and have them cleaned in the parts washer as this soap will eat the iron coating.
dont use a wire brush or scotchbrite or blasting system unless your making a coffee table
The best way to clean the piston is to soak it in simple green for a few hours then use a toothbrush to remove the remains.
dont use anything more abrasive than a tooth brush
dont take them to the machine shop and have them cleaned in the parts washer as this soap will eat the iron coating.
dont use a wire brush or scotchbrite or blasting system unless your making a coffee table
amen! The carbon deposits are harder than the aluminum piston, so any mechanical method like wire brushes, even the cut little Dremel brushes, should never touch anything other than the top. Not the ring areas or the iron flash-plated skirts.
I’ve seen some recommendations for some spray gasket remover, but have not done any research on it.
———
A decade or so ago, a lister started buying used 928’s to break into parts. He had an eye on the prices that good used pistons were selling for, so was pulling them and “cleaning” them to make them pretty for sale. In that process he ruined every one, and enjoyed the wrath of folks who installed them and quickly ruined their blocks. That may be the root of Stan’s “coffee table” reference.
The shop I used (same one Greg uses) did it for ~$50 IIRC. It really isn't that expensive and it makes them and everything else spotlessly clean.
Yup. If the pistons are coming out anyway then soda is the way to go.
If the pistons aren't coming out then carb cleaner, tooth brushes and plastic tools work. But, it is time consuming and best done on a geared engine stand.