I have an open valve block with one of the valve guides broken off a bit at the base. See photos. These guides are removable. However I suspect they are in there pretty tight especially after 100 plus years of service. I want to remove it but don't want to crack the block. Has anyone done this? Wondering if its a good idea or not.
Can it be drilled out?
It probably can Herb, but I want to save the guide. I plan on turning off the flange and replacing it with a washer of the same size. Then press it back in.
Makes you wonder how the guide lip was broken off to begin with.
Maybe somebody tried to force it in and that's what happened? If that's what happened it must be in pretty tight.
Could it be reamed out large enough to insert some type of sleeve to being it back to standard?
That may be an alternative before its drilled out or before some other type of attempt is made.
Maybe the safest?
Why not just make a new one?
Like Steve said. You can buy new cast iron guides, and if you can't find one that will work you can buy cast iron bar stock and turn your own.
Often when you press a bushing out of a hole, the hole is enlarged and the fit is loose if the same bushing is pressed back in. You could probably use some sleeve retaining compound if you really wanted to re-use the original bushing.
This looks like a exhaust valve guide, so I wouldn't try reusing the guide if it's pressed out since the temperature may get too high for sleeve retaining compounds as Loctite.
i would leave it be wont hurt a thing just a seat for the spring. charley
I was thinking the same thing Charley, but as you know the back of the flange is squared off to fit the shelf. Since the front is broken off, there are only the sides of the flange to support the spring. I am thinking the spring may want to bend. Maybe not. I'll try to call you.
Bob Bergstadt has NOS guides.
Any reputable machine shop would be able to remove the Guide and either find a match or manufacture a new one
I had to remove one of the guides from an '11 open valve block I was rebuilding several years ago. I drove that one out with a driver I made for the purpose and a hammer. Today, being a bit older and wiser, I would press the original valve guide out on a press.
The valve guides for the open valve block are, to the best of my knowledge, not currently available. Later style valve guides are, but they are straight sided guides, and really do not match what was used in an open valve block.
What I did was to buy a piece of cast iron round stock from McMaster-Carr, and I made a new one on my South Bend 9 lathe. They are not hard to make, and the guide hole for the valve can be drilled to the center line of the work piece. The outside of the guide can be machined around the center of the hole.
I suggest that you machine the diameter of the guide where it goes into the block to the exact same size as the old one, or maybe .001 oversize. This is just to be on the safe side. Really a light press fit of the guide into the block is all you need since once the valve is assembled in the block, the pressure of the valve spring will hold the guide in place on these early guides.
I hope this helps.
This doesn't address your issue, Richard, but does show an alternative method of dealing with valve guides on open valve blocks.
When the valve work was done on this block, the guides were replaced with straight side guides.
The old guides were bored out so that the spring seat portion was a slip fit on the new guides.
Why do you want to remove it? That missing chunk should be no problem at all?
I would leave it as is. On the underside where it is it would be almost invisible once everything was assembled. I have found many worse things in engines I have worked on (left by someone else, and sometimes again by me).
Those probably are not a "press fit". They are designed to be held in place by the valve spring. They should be snug, but little more than that.
I would maybe try a few light taps with a medium size hammer and soft punch of appropriate size. the piece may drop out easily. If that didn't work, and you are really concerned about the valve spring wanting to break? You could quickly make a custom step-sided washer out of a piece of appropriately size pipe. Just cut in from two sides with an offset close to what you need. Then a couple minutes on the grinder making the fit just right. Properly done, that would run for tens of thousands of miles, do no harm, and I would bet you a donut at the Auburn swap meet that nobody would ever notice it as long as it was in the assembled and running car.
Drive carefully, and enjoy, W2
Thanks for all the input. I was able to test the guide by tapping on a hammer and piloted punch. You could tell by the sound it wasn't in there tight. A few medium whacks and it began to move and in short order I had it out. I proceeded to machine the broken flange down to the size of the of the pressed in area of the guide,careful to remove the exact thickness of the flange. I'll make up the appropriate size washer and reinstall the guide with the washer in place.
Its a funny thing, you spend more time worrying thru something than it takes to do the job. ;^)