Tracy,
As someone who uses 0-rings all the time in my work, I can vouch for the fact that when the O-ring gland (groove) is designed to proper specs they always look too big for the O-ring. The typical liquid O-ring groove for pressure only squeezes the O-ring 30%. (The O-ring has always looked to be too small to me!) I'm sure you had the manufacturers recomendations in hand when you sized the O-rings.
Bill Jepson
-----Original Message-----
From: Tracy Crook <lors01@msn.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Wed, 8 Jun 2005 16:59:46 -0400
Subject: [FlyRotary] Re: coolant leak
Yes they are.
I know about Ed's remark about them looking too small but we've sold over a thousand of these O-ring kits and never had a problem there. A LOT of work went into specifying and sourcing them. They are custom rings designed specifically for this application, not McMaster Carr parts. The McMaster TES rings are close but slightly too large (diameter) when at the high end of spec. They caused O-ring wall failure in several engines.
Tracy (love the Mazda SUV - Zoom - Zoom!)