The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Frenchy on 26.07. 2010 16:30

Title: Piston rings problem
Post by: Frenchy on 26.07. 2010 16:30
I found a set of new old stock rings.  The problem is that even though they've never been used, they're so old that the writing on the rings is gone.  The "T" or "top" that is usually written on them is no where to be found.  I've used a magnifying glass and can't find it!  How do I find out which way is right side up?  The rings I'm replacing are clearly marked, so I've tried lining them up and looking for a taper, but I can't see anything.  The top rings seem to be slightly rounded on top and sharper on the bottom of the ring, so I think I've got that one under control.  The oil ring didn't say that it needs to be right side up on the package (top and middle did say that they need to be top side up), so I think that one's fine.  It's the middle ring mostly that I can't figure out. 
Title: Re: Piston rings problem
Post by: bsa-bill on 26.07. 2010 16:54
not all rings are marked Frenchy and not all sets have tapered ones either.
The set I just used was (I hope) with out marking re top or any taper, ( I did look closely at the rings ), on the other hand the ones I put in some ten years ago did have a taper which I am pretty sure I got right, I think probably oil consumption would be a factor if you got them wrong.
Others with more knowledge and better eyes might like to put you and me right on this one
Title: Re: Piston rings problem
Post by: groily on 26.07. 2010 22:59
Don't reckon age alone will remove the word TOP - if nothing's visible, then probably they're parallel and no problem as to which way up they go. I've loads of rings of various ages and mileages all over the place, and with a strong glass I can make out the TOP marking on all rings that originally had it even after mega-miles. On NOS ones, it should be very clear if there's any marking on them.
AFAIK oil-control rings aren't an issue.
Agree with bill re oil consumption telling you if you put tapered ones in the wrong way up!
Title: Re: Piston rings problem
Post by: BSA_54A10 on 27.07. 2010 11:40
http://www.totalseal.com/TechPage.aspx#trGaplessPistRings (http://www.totalseal.com/TechPage.aspx#trGaplessPistRings)
Go here and read the tech pages, all you want to know about fitting rings
Title: Re: Piston rings problem
Post by: bsa-bill on 27.07. 2010 12:55
Nice link Trev - bookmarked to "bike info"
Title: Re: Piston rings problem
Post by: Frenchy on 27.07. 2010 14:45
Thanks for the help.  I'm just going to assume that they're parallel (despite the packaging instructing otherwise.)