valve guide wear limits

hey Guys,

I just broke down the spare head my son found local, I have not yet miced the stems, nor dug up my ball type hole gauges, but visually, pre soaking, eek, no scoring, but lets say it was on the extended oil change interval for a long time....

before I invest time into porting, how bad is guide replacement? how much guide wear can be inffered from stem wear?

 

Aftermarket performance guides are available for these models, but they are typically there for cooling purposes.

Although all components experience internal component wear, I don't recall seeing problematic guide/stem wear on these engines. I would expect these to wear faster if lubrication is neglected, but I also expect other parts to fail before these stems.

 

there is alot of feel and subjectivity using hole gages, that said, the biggest number i'm seein on the intake side is .2375

the valve is .2352


I can't find a spec table in my fac serv manual

 

All measurements with calipers, micrometers and bore gauges are subjective. But if the user is well trained, it is more accurate than tools like plasti-gauge

 

Appreciate the data, I imagine the clearance is essentially the same for the MZR.
Good info on measuring as well, brings back memories

 

It looks like all variations of this 4 cylinder Mazda engine have the same valve stem design.