Gary,
Many machine shops are critical of silicone bronze valve guides for the
reason you are experiencing. The solution is in properly sizing the new
guides after pressing them into place. The s-b guides require slightly
greater clearances because they expand and contract at different rates
than cast iron guides or valve stems. Apparently my machine shop knows
how to size them properly because I have had no problems with three
heads with s-b guides, the MG-TC and two below.
George Haynes
1965 TR4A, BRG, IRS, Surrey Top, Overdrive
1956 MGA, Dove Grey, live axle, soft top, Overdrive
|