Join Date: Apr 2002
Thanked 3 Times in 3 Posts
Re: Oversize piston ring question.
The reason I'm asking all this is because I re-ringed my 258 about 3 weeks ago when I was trying to eliminate the horrible case of blow-by that I have. At that time my daily driver needed a fuel pump so I had to take my YJ everywhere.
If I got over 50MPH for any longer than about 5 minutes continuously, then I would literally start shooting oil out of the breather filter and around the PCV hose. If I went the 35 miles or so to my girlfriends house on the freeway, I would end up losing roughly a quart of oil during the round trip..most of that oil would be covering my entire engine.
Anyway, I'm trying to use my stock pistons in my 258 which has 170k miles on it. Just through normal wear, the bore has obviously been increased.
In this case, using a bore gauge, it's about .007" - .009" out which is pretty darn close to .010".
When I went down to Napa to ask them about ordering some piston rings, they asked if I needed standard or 10, 20, or 30 over.
I was thinking that the .010 rings would be good since my bore is almost that far out of spec. But that's when I started thinking about the actual physical size difference of the rings.
As for measuring the ring gap, what tool(s) do I need to measure that while the piston is in the bore?