Vendor valves undersized, proper clearance?

[Paperman]

Ordered a set of .015 over T style valves. Specs given we they were .327 stem. I planned to cut new guides with a 21/64 reamer (.328) and then a quick hone to get to proper size. The valves arrived and measure .3245-.3250.

Anyone see an issue running the valve a but looser than one typically would on a rebuild? I suppose its not a big deal was just surprised the valves were under by so much.

[RGould1910]

As you know Ford specs allow up to 8 thou clearance. That seems excessive but I've not had problems at 5 thou clearance. When I reamed valve guides on my 10, I cut them for 1. 5 thou clearance and had sticky valves. I'm sure I was passing oil thru newly installed rings which had not seated, but when I opened up the guides, the problem went away. I think at 3 thou clearance you're right on the money.

[George Hand]

When, I return home from Florida, I have a block to ream out. I had asked my brother (the machinist in the Family) to make me a "Sudo" valve head with a pilot hole with a clamp. I will clamp this over each guide prior to reaming. George

[TXGOAT2]

Guides that are too tight will lead to sticking valves as the engine warms up. Too much guide clearance allows the valves to slide on the seats and allows oil consumption and noise. Too much exhaust valve guide clearance also allows the valve to run hotter. Most oil consumption occurs at intake valves. Exhaust valves run hotter and are more likely to stick. The intake valve guides can be a little tighter than the exhaust valve guides. Oversize stems might require a little more clearance than standard size stems.

[Jerry VanOoteghem]

Guides that are too tight will lead to sticking valves as the engine warms up. Too much guide clearance allows the valves to slide on the seats and allows oil consumption and noise. Too much exhaust valve guide clearance also allows the valve to run hotter. Most oil consumption occurs at intake valves. Exhaust valves run hotter and are more likely to stick. The intake valve guides can be a little tighter than the exhaust valve guides. Oversize stems might require a little more clearance than standard size stems.

So, are you saying he has too much guide clearance or not enough?

[TXGOAT2]

That's general advice. Refer to Ford specs for specifics.

In my opinion, .003 is too tight for exhaust valves, and about right for intake.
For an engine that is expected to run at higher speeds and loads, such as a speedster engine or a TT engine, I'd go with .004 on intake and .006 on exhaust. New assemblies need some run-in time before running hard or fast. Avoid thick oil in Model T engines, especially with new assemblies.