Measureing oil control rings for wear
 

Hey guys, I'm trying to measure out my oil control rings but I think I'm going about it wrong.

The fsm states for no more than .020" but I'm reading like .070-.080 on all of mine. I'm confused cause one set is suppose to be from a 2,000 mile reman. Is there a different wear line I'm suppose to measure to or is it just the silver area?

Jarad

just the silver area, on the face that rubs the side iron.

I thought these were low wear parts that are not replaced? How often are they replaced in rebuilds?

the wear is along the inner circumference of each ring, look for the silver wear marks on the gold ring. It's on the side that rides along the iron surface (ie without the indentations).

Spec is less than 0.5mm wide, you'd be surprised at how many rings go out of spec. They're not cheap either.

Edit: I see j9 beat me to some of the above info ;).

We typically find we have to replace them on builds with around 90-100k miles or so.

yes, so not very often. lucky you i guess.

as an aside the guy who did the machine work on our race car engine, provided a really nice sheet that details exactly what he did, ie its like a build sheet. i think its fairly common in the piston engine world, but i've never seen it on a rotary. it gets kind of long, cause there are 12 side and corner seals and stuff, but at least when you got a rebuild you;d know you what you payed for.

I've pulled 200k+ engines apart where those were still in spec.

My first GSL-SE engine never smoked, but its rings were worn to about .060-.080, so maybe you're okay. It depends on if you plan on pulling it apart in 10,000 miles or 100,000 miles.

The service specs are weird... some of the specs are really conservative, well others (apex height!) are ridiculously slack. Not sure I'd bother putting an engine together with 7mm high seals unless I was doing an experiment and didn't plan on the engine running very long before pulling it apart again.

hmm never thought about it, but yeah i'd much rather use oil control rings worn double mazda's spec than 7mm high apex seals!

one failing is catastrophic, the other is mosquito abatement!

Maybe I'll ask some other shops their experience then ask the shop doing the work for me now...

They definitely can wear at different rates. I've torn down engines with very tight endplay clearance and the irons and metal control rings showed high wear after only 10k miles.