Sorry , no idea here, but your good question raised another for the machine shop engineers amongst us. Are there different tolerances valve to guide for the different materials available -bronze manganese . iron etc.
To the OP - go to the minispares website and search for valve guides, they list the internal fit but no details on interference fit.
Taken from the iron guides Minispares Page
Quote:
hat tell tale puff of blue smoke when you first start is an indicator of worn guides or seals. Valve guides should be replaced with every valve job.
Sold individually, these are the original quality Cooper S guides for use in any head especially with chrome stemmed valves.
Also suitable for any of our plasma or heat treated competition valves when using unleaded petrol.
Not for Turbo exhaust valves as they have a 8mm internal diameter.
Should sit 0.550"from top of guide to valve spring seat.
Internal bore size after fitting should be about 9/32th (0.2812") but with modern day valves 0.2799" to-0.2804" is fine.
As most of our EN214N race valves are heat treated they can be used in these cast iron guiides which dissipate heat quicker than bronze but exhaust valves should be given a little more clearance.
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