Rules Interpertation

[chuck baader]

My pistons, BMW 325e, do not have valve reliefs on the exhaust side. Due to a recent money shift, they now do. Changing pistons is not an option, but I would like to remove the sharp edges from the top of the piston. Viable options would be to scrape the offending metal, or light use of the die grinder to smooth things over. Opine, please. Thanks, Chuck

[JeffYoung]

If it is a "repair" returning it to stock, it's ok.

I can see that being hard to accomplish within 100% of the letter of the rule though.

But I wouldn't protest something like that, trying to fix the stock piston.

[Ron Earp]

I'd buff it down and go with it.

[mossaidis]

Also purchase new valve springs... just saying. :)

[chuck baader]

I don't think new valve springs are going to fix a 7000+ over rev on a 5600rpm motor. Anyway, stock (BMW) springs are NLA. They substituted the later "i" outer spring that is weaker than the original. One of my car's warts. Chuck

[MMiskoe]

Light use of the die grinder or sanding disk. I had reliefs like that for both intake & exhaust on all 6 pistons for one my Nissan motors. It was a donor motor that had lost its timing belt. I didn't do anything to the pistons and then ran fine.

Protesting you for that would be worth 30 lashes with washer bottle tubing before being told to go do something productive.

[mossaidis]

ugh, sorry to hear that.

[chuck baader]

Thanks, y'all...gonna try removal and not screw up pistons. Chuck

[joeg]

No problem with a very light clean-up.

I have a set of pistons just like that in one of my cars. The head was replaced with the entire valve train after the missed shift/ overrev/ timing belt jump.

With a new head, that motor runs quite strong!!l

[Mike Mackaman]

At the risk of public flogging, I have used a very sharp scraper to "cut" the raised part off and the dress it down as you said. This minimizes the junk getting where you don't want it. And I have run engines with way worse piston damage, and in much more challenging engine environments, like GT.

Mike

[chuck baader]

Yes, I was thinking of using a machinist tri scraper. Chuck