[Mgs] Ring groove width tolerance

[Charles Hill]

Rick,

I don't have any Ford/Lotus references but all the ones I have suggest 
that .005" is the upper limit for piston ring side clearance.  Custom 
rings might be an alternative but the ring grooves in the pistons will 
have to be machined to true them up. New pistons may end up being a 
cheaper and easier alternative.

Regards,
Charles Hill

   On 12/7/2012 6:29 PM, Rick Lindsay wrote:
> Hello Friends,
>
> When it comes to technical issues beyond my knowledge, I turn to you guys, independent of the engine manufacturer.  The engine I'm building is a Lotus-Ford Twin Cam from a '65 Elan S2.  Here's the story and the question;
>
> Bore = 3.250"
>
> First compression ring = 0.083" ring groove width, ring is designed for 0.078" width.
>
> Second compression ring = 0.079" ring groove width, which is within spec.
>
> Oil ring = correct.
>
> Lotus specifies that the groove width limit is 0.080" but that's for a new engine.  My question is whether 0.005" is a little too large for an engine destined for mild street motoring (with a few moments of spirited driving tossed in).  Or am I going to have to source custom rings? :-o
>
> Thanks in advance for any and all advice.  Respond off-list if desired.
>
> -rick