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MG TD TF 1500 - Bronze valve guide clearance

My machinist does not have a ream to provide more than .002" clearance on the bronze valve guides installed for the exhaust valves. Does this seem enough to avoid seizing when they get hot? Should I look for another ream to give .003"?

TIA. Tom TD 22966, TD/C 10564
t lange

Tom, I think the exhaust valve clearance should be .004 to .006, with a max of .009 . Intake .002 to .004, with a max of .006 , measured with a dial indicator. Slide the valve out of the guide about 10 mm, then measure the guide to stem clearance with a dial indicator while rocking the stem back and forth. I could be wrong but I know I'm close. .002 on the exhaust in my estimation is way too close.
P.S. Jennings

Tom, the clearance with bronze/silicone should be .002 GREATER than the standard clearance. I think PJ's values are a bit loose, and may work with improved felpro seals. I used the numbers below with the standard seals.

Cast Iron 0.001-0.0015 inch (for comparison)
Bronze 0.003-0.004 inch (my installation)

The fitting height above the head is 0.945 for an XPAG

warmly,
dave
Dave Braun

This thread was discussed on 08/06/2010

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