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Piston replacement

PostPosted: Sun Aug 15, 2021 3:20 pm
by Moulins1914
Hi, I've just removed my piston from my SIL barrel and it looks like a standard 3 ring Mahle(?) piston. The rings need replacing but the piston to bore clearance is OK. I was wondering whether to replace the piston with a better one so was after recommendations? Or to just replace the rings. Though I have read that if I replace the rings not to bother fitting the bottom ring?

Re: Piston replacement

PostPosted: Sun Aug 15, 2021 7:23 pm
by Scooterslag
Nothing wrong with a Mahle piston in a standard(ish) set up, been using them for years and their fine. I'd just replace the rings and pop it back together. Paul ;)

Re: Piston replacement

PostPosted: Sun Aug 15, 2021 9:01 pm
by Fast n Furious
It's always wise to carefully check the corner radii areas where the skirt joins the gudgen pin area for hairline stress cracks, to confirm if the piston remains servicable.
The 3 can, crack detection spray kit, which comprises of a cleaner, a penetrant and a developer, will show up any stress cracks as a thin red line. A big help if your eyesight is not the 20/20 it used to be.
Admittedly, this stuff is not a stock product in most lammy sheds and the downside is that the kit costs about £40. Although, you dont need the cleaner if you've already got some carb cleaner spray on the shelf, bringing the outlay down to about £25.
Twenty five quid would fare well toward the cost of a new piston I suppose............ Hmmmm. :?: