I have removed the head from my '65 220Sb. I've disassembled it and feel a few of the valve guides should be replaced (I'll have a machine shop do the work). The parts book I have lists several replacement guides with different outer diameters. How do I determine which one I need? While I have it apart is there any sense in replacing all the guides (they're cheap)?

With-out removing & measuring all guides you wont know what size they are, unless the head hasn't been repaired before. In that case you will want std/1st repair size. If they are worn Replace them all!!

The guides are an interference fit. Original guides that had an outside diameter of 14.01mm need the slightly larger standard size 14.03 for a good second go round. The other sizes for repair of that guide would then be 14.2 and 14.4mm. These were originally designed for holes that were rebored after being ovaled out by guides that came loose.

The original guides and seals and rotators were updated in production over the years. A good, knowledgable machine shop can put the newer style guides, seals and spring rotators. Its a good investment.


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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician