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-   -   Piston oil ring help EJ255 (

2manysubies 01-27-2013 03:27 PM

Piston oil ring help EJ255
OK, got everything back from machinist, put block together, checked all bearing clearances Check good. Got a set of new OEM rings from Vendor here (subaru dealer) top 2 rings,good end gap, installed on #1 Piston checked oil rings .006 gap, good to go, tried to put the bottom oil ring on, indexed, went to put the expander spring in, no joy, I don't think the "spring" is flattened enough, attempted to put the second(Upper) oil ring on... NO WAY! the "spring" is taking up too much room to even install ONE backup ring. Yes the pistons were cleaned spotless(using old ones)

I feel the need to give 'em a bump in the press in between 2 heavy metal plates to reduce thickness...IDK, never ran into this before.

Any suggestions besides get a set of forged etc... I'm open to.


Ring PN is:12033AB340

Max Capacity 01-28-2013 05:01 AM

I'd ask the machine shop for help. Or let them put them on.

heiche 01-28-2013 07:24 AM

This happened to me recently. Try putting in the expander ring FIRST, then the indexed top rail, then the bottom rail.

And you mentioned that the pistons are spotless. But are the grooves also spotless? You probably know this already, but you can break an old ring, and use it to scrape out the grooves (using the "unbroken" end of the broken ring). Also it's a good time to poke out any gunk in the relief holes that are in the oil control groove, if necessary.

2manysubies 01-28-2013 08:58 AM

Thanks guys, Yes the pistons are spotless, used the old ring trick,soaked in cleaner etc... I'm taking them to the machinist this morning.


GTTuner 01-28-2013 09:14 AM

Expander in FIRST, then the lower then upper rail.

Max Capacity 01-28-2013 10:04 AM


Originally Posted by 2manysubies (Post 4266233)
Thanks guys, Yes the pistons are spotless, used the old ring trick,soaked in cleaner etc... I'm taking them to the machinist this morning.


Yep, some things are best left to the experts...I'll learned that years ago.

2manysubies 01-28-2013 12:05 PM

Yes, expander then lower, that was what I was doing. For the benefit of those that don't know, I will now embarrass myself.

The upper Oil rail has a index tab on the ring. The lower does not, there for, if one does not look closely or chooses not to wear reading glasses(denial), one might miss the tab and try to install 2 upper rails with tabs into the same piston. Hence the "don't fit" deal. Goes to show you, ya learn something every day! Thanks for the help.


heiche 01-28-2013 12:29 PM

Ha! Yes, reading glasses are key to piston ring fitment.

wurkenman 01-28-2013 06:22 PM

Also make sure the expander is NOT overlapping itself. Pretty easy for it to "jump" the end and stack up.

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