[Scott Stoneburg]

Questions for the experienced / experts ... How difficult is it to install valve guides? I have micrometers, a lathe, a mill and a press. 2 guides came out and I has too much clearance on the valve stem. How much interference fit is needed to press in? I am just thinking about trying it myself, I am no stranger to checking and setting clearances or using my lathe. Thanks for the info

[steve25]

There's no majic to it.

Press the bad one out.

Chill the new ones in your freezer over nite and then hit them with some freeze spray just before you press them in so they shrink up in OD.

Just note that what you press them in with ( the needed tool ) that centers in the guide while it rest on top of the guide
It's critical that this driver does not contact too cloose to the ID of the valve guide hole especially if the guide is not iron because driving the guide in will pinch down the top of the guide somewhat.

With any guide replacement job, even if guide livers are use in the old guides at a minimum a touch up valve job will be needed especially if the whole guide has been replaced.
In such a case the guide may have moved .002"to .003" which you then times by 3.14 and you then your main valve seat could be off / shifted by .009"
Not a good thing!

[steve25]

Just note that if this is not a Pontiac head that some heads like BBCs with iron guides can only be pressedin and out in one direction since they have a slight taper to them.

[Scott Stoneburg]

Looking at the fit, the section of the guide identified with the yellow bracket slides in easily, there is maybe 1/2" that fits tight. But I can push/pull it out by hand. Shouldn't it press in the whole way? Or is that what you mean by tapered? What is the press for? .0003-.004 ?

[Scott Stoneburg]

Sorry, forgot the photo

[steve25]

No guide in a aluminum head should move by hand,

Since that’s taking place I would bet that the seat associated with those valves is moving around and that’s was beating up the valve guide by really slapping the valve around.

If this is the case then your lucky you cough this before the valve broke it’s head off and you lost the motor.

If you chuck up all the valves in your lathe do they spin true?

[Scott Stoneburg]

Originally Posted by steve25

No guide in a aluminum head should move by hand,

Since that’s taking place I would bet that the seat associated with those valves is moving around and that’s was beating up the valve guide by really slapping the valve around.

If this is the case then your lucky you cough this before the valve broke it’s head off and you lost the motor.

If you chuck up all the valves in your lathe do they spin true?

I have only #1 exhaust valve, that's the rocker that seized up and has the loose clearance. That valve is straight, I will check the others too now that you bring that up.

[PAUL K]

.002 interference fit works well. You should be able to swap out those guides with will and the equipment you have. But not sure how you will hone the new guide for correct valve stem clearance.

[Scott Stoneburg]

Originally Posted by PAUL K

.002 interference fit works well. You should be able to swap out those guides with will and the equipment you have. But not sure how you will hone the new guide for correct valve stem clearance.

What stem clearance should I be looking for ? I have a few inside cutters for my lathe

[mysticmissle]

you should check all your guides,

[PAUL K]

Originally Posted by Scott Stoneburg

What stem clearance should I be looking for ? I have a few inside cutters for my lathe

.0015 intake

.002 exhaust

[Scott Stoneburg]

Originally Posted by mysticmissle

you should check all your guides,

The others all felt solid by hand. I am thinking about doing all the exhaust guides.

[mysticmissle]

I had to replace around 10 in my pair if i remember correctly. mine werent loose, if i remember correctly, just overly worn according to my shop at the time. I think yours are likely of the same vintage. it is not uncommon

[Scott Stoneburg]

Originally Posted by mysticmissle

I had to replace around 10 in my pair if i remember correctly. mine werent loose, if i remember correctly, just overly worn according to my shop at the time. I think yours are likely of the same vintage. it is not uncommon

I had one overly worn, but that was the exhaust rocker that seized up and broke. One intake that was a little tight, the others all "felt good" I ordered an inside mic small enough to measure them,

[Skip Fix]

I know one machine shop that has a mini "dingle berry" hone for doing them.

[steve25]

Goodson supply hones.

You will need to rig up a way to flush the guide with Honing oil or at least ATF while honing.