From owner-buick-rover-v8-archive@autox.team.net Mon Jan 8 16:54:45 2007 From: "jon" To: "rover V8" Date: Mon, 8 Jan 2007 15:57:38 -0800 Subject: piston rings My Rover (published by Rover) engine manual says "Position oil control expander ring joint and ring rail gaps all at one side, between gudgeon pin and away from left hand side of piston - viewed from front of piston." I know that gudgeon pins are really wrist pins, but my pistons are round and don't have sides. I can't make any sense of this. How do I position the ring gaps -- oil control and compression? Jon /// /// buick-rover-v8@autox.team.net mailing list /// From owner-buick-rover-v8-archive@autox.team.net Mon Jan 8 17:30:24 2007 From: "StagByTriumph@tscusa.org" To: jonnyaxt@iinet.com, buick-rover-v8@autox.team.net Date: Mon, 8 Jan 2007 19:33:13 -0500 Subject: RE: piston rings Hi John, Pistons have a "front" which is positioned to the front of the engine block. It is usually marked with an arrow, or text stamped into the top of the poston. That is in line with the wrist pin and aligns the underside oiling. Engine left is as you are sitting in the driver seat (left or right hand drive). Left as refered to in the manual is for the down side of the piston, or left side of the piston. This is so the gap is not sitting where fuel or oil might easily travel by gravity past the piston into the sump. If the gaps are on the up side, then fuel and oil will sit on the ring ready for the next start. Glenn Merrell President, TSC USA Original Message: ----------------- From: jon jonnyaxt@iinet.com Date: Mon, 8 Jan 2007 15:57:38 -0800 To: buick-rover-v8@autox.team.net Subject: piston rings My Rover (published by Rover) engine manual says "Position oil control expander ring joint and ring rail gaps all at one side, between gudgeon pin and away from left hand side of piston - viewed from front of piston." I know that gudgeon pins are really wrist pins, but my pistons are round and don't have sides. I can't make any sense of this. How do I position the ring gaps -- oil control and compression? Jon -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ . /// /// buick-rover-v8@autox.team.net mailing list /// From owner-buick-rover-v8-archive@autox.team.net Tue Jan 9 17:02:56 2007 From: "jon" To: , Date: Tue, 9 Jan 2007 16:05:59 -0800 Subject: Re: piston rings Sorry, but I still can't figure out "between gudgeon pin and away from left hand (thrust) side of piston". [The 4.0/4.6 section of the manual adds "thrust".] When I see the word "between", I expect to see "between x and y", that is, two items. The manual goes on to say "Position compression rings with ring gaps on opposite sides of piston between gudgeon pin and right hand side of piston -- viewed from front of piston." Note that there is no differenciation between the left and right bank. They seem to be saying that the gaps will be on the high side for one bank and on the low side for the other bank. My buick manual says "Position ends of expander above the piston pin where groove is not slotted." This does imply that the banks are treated differently, possibly agreeing with Glenn. But does Buick really want the gap at the front or back of piston, "where the groove is not slotted"? Both sides of my Rover pistons are slotted in the oil ring groove. Only above the ends of the pin (ie, front and back of piston) is the Rover oil control groove not slotted. A ford V-8 manual wants the expander gap at the very back of the piston for all eight pistons. All very confusing, except for what Ford wants: Ford shows a circle representing the top of the piston, and all the gaps shows on that circle, like the hands of a clock. Regarding left and right, the Rover manual (LRL 0164 and LRL 0004) explicitly says "viewed from front of piston", contrary to the norm of sitting behind the steering wheel. Jon ----- Original Message ----- From: To: ; ; Sent: Tuesday, January 09, 2007 6:05 AM Subject: RE: piston rings The orientation with respect to driver and front is correct, but I believe the reason is so that the gap is on the pressure side of the piston during the firing stroke (left is down on left bank and up on right bank after all) The gaps should be positioned in the 45 degree angle on the right side of the piston but not all in line. The object of this is SFAIK to reduce the chances of ring vibrations and subsequent breakage. ________________________________ From: owner-buick-rover-v8@autox.team.net on behalf of StagByTriumph@tscusa.org Sent: Mon 08/01/2007 19:33 To: jonnyaxt@iinet.com; buick-rover-v8@autox.team.net Subject: RE: piston rings Hi John, Pistons have a "front" which is positioned to the front of the engine block. It is usually marked with an arrow, or text stamped into the top of the poston. That is in line with the wrist pin and aligns the underside oiling. Engine left is as you are sitting in the driver seat (left or right hand drive). Left as refered to in the manual is for the down side of the piston, or left side of the piston. This is so the gap is not sitting where fuel or oil might easily travel by gravity past the piston into the sump. If the gaps are on the up side, then fuel and oil will sit on the ring ready for the next start. Glenn Merrell President, TSC USA Original Message: ----------------- From: jon jonnyaxt@iinet.com Date: Mon, 8 Jan 2007 15:57:38 -0800 To: buick-rover-v8@autox.team.net Subject: piston rings My Rover (published by Rover) engine manual says "Position oil control expander ring joint and ring rail gaps all at one side, between gudgeon pin and away from left hand side of piston - viewed from front of piston." I know that gudgeon pins are really wrist pins, but my pistons are round and don't have sides. I can't make any sense of this. How do I position the ring gaps -- oil control and compression? Jon /// /// buick-rover-v8@autox.team.net mailing list ///