Valve guide questions

[Rex_A_Lott]

I looked in a couple of the Model A books I have and couldnt find any reference to putting the split type guides in , and what is acceptable clearance.
I do have an old Motor manual that references flathead Fords from 35 to 46, and it called for .0025-.0045. I'm thinking those should be good numbers, since I still have the old tulip stem type valves and split guides.
Another thing that book said puzzled me...It said to put the split 90 degrees from the camshaft. I would have thought if there was any side-loading you would want the most surface area available from the guide, and put the split parallel to the cam. I didnt think to look at how the two were that I took out already , but when I get back on it I will pay more attention to how they were before I started. Obviously I am missing something here, so I would appreciate any comments or advice.

 

[d.j. moordigian]

I looked in a couple of the Model A books I have and couldnt find any reference to putting the split type guides in , and what is acceptable clearance.
I do have an old Motor manual that references flathead Fords from 35 to 46, and it called for .0025-.0045. I'm thinking those should be good numbers, since I still have the old tulip stem type valves and split guides. Are you asking about "valve stem clearance" or guide to
block clearance? If it is stem clearance,...I would consider .0045"
as worn out.
Another thing that book said puzzled me...It said to put the split 90 degrees from the camshaft. I would have thought if there was any side-loading you would want the most surface area available from the guide, and put the split parallel to the cam. I didnt think to look at how the two were that I took out already , but when I get back on it I will pay more attention to how they were before I started. Obviously I am missing something here, so I would appreciate any comments or advice.

That 90° is for V/8's.....so you can get the tool (bar)on the guide to
pull the guide down to remove the clip...
I think YOUR thinking is correct, on guide placement...

 

[Rex_A_Lott]

That 90° is for V/8's.....so you can get the tool (bar)on the guide to
pull the guide down to remove the clip...
I think YOUR thinking is correct, on guide placement...

Yes, I meant stem to guide clearance. I dont think there should be any guide to block clearance, maybe even a light press fit, since you have to have a tool to drive the old guides out.
I never thought about the tool for the V-8's, I have never torn one of those down. Thanks for that info.
I still cant see why but I paid attention as I took the rest apart, and they were consistently all 90 degrees to the cam...There's no way that was random, it was done on purpose, I'd just like to know why.

 

[ursus]

I always have mine set 90 degrees to the cam and marked as to which side faces out with a painted-on number for its position, in sequence. That way I know that it has been replaced in exactly the same position it was when the seats were ground. If somebody grinds your valves and returns the guides loose in a box then you have no point of reference because the guides are a matched pair and must be installed in the same position as ground. Make sure your machinist understands this and, if he gives that disinterested vacant stare, simply pick up your stuff and walk out the door before he has a chance to screw it up. Also, the valve should be able to fall by its own weight in the guide when installed, with a nice ringing sound to indicate full contact 360 degrees around. Just my experience...