The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Rgs-Bill on 17.12. 2012 21:48

Title: Re-ringing pistons of .040 with .060 over Hepolite rings
Post by: Rgs-Bill on 17.12. 2012 21:48
Hey you fellas, anyone who has tried this or has knowledge of some one who has, or just an engineering opinion of pro's or con's  of doing this.  Thanks in advance.
   Years ago a fella said he always used the next size up oversized rings, ex:  .040 over bore job with .040 over pistons, but use .060 over rings with the proper end gaps fitted.  Does any one out there have first hand info on such, or any opinion welcomed, from engineers or guys who have tried this, or racers, any one who could add to yes or no's on the   feasability of this method of fitting new rings only,  to .040 over pistons  ????

                    RGS-BILL
Title: Re: Re-ringing pistons of .040 with .060 over Hepolite rings
Post by: muskrat on 18.12. 2012 08:45
 G'day Bill, the general rule is no. The rings are made to fit the bore (round peg in round hole). To do what has been suggested to you would be like an egg (in shell) in an egg ring. So the ring would exert more pressure on the bore in sections and less in others.
 But in saying that I have done it and they lasted OK. Just don't tell anyone. *conf*
Cheers
Title: Re: Re-ringing pistons of .040 with .060 over Hepolite rings
Post by: kommando on 18.12. 2012 12:29
In a modern engine machined to tight tolerances it does not work, in an old engine where the bore is honed rough the rings wear so much as they bed in it makes no difference.

Have also done it too with no ill effects.