valve guide question

F

Fordestes

Well-known member
I am trying to install modern guides in my 30 engine, the block bores are a little larger on some guide bores (thumbs push on one ) and .0007 interference on others, What would be an easy way to tighten them?
I am thinking mabe a light knurl if possible on the o.d and then using some sort of locking compound or tossing them out in the rain and letting them rust a little, what would be a good locking compound , I know there is usually a locktite product for every occasion , but which one do I use , I realize there will be a lot of heat involved and I don't want them to work loose, I cant find any oversize guides . any suggestions would be appreciated. thanks, Fordestes
 
Use a valve guide knurling tool, it looks like a tube cutter with the cutter wheel replaced with a knurling wheel. Check with Goodson Tools.
 
motordr said:
Use a valve guide knurling tool, it looks like a tube cutter with the cutter wheel replaced with a knurling wheel. Check with Goodson Tools.
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so you are saying knurlize the guide bores? I am thinking about maybe a light knurl on the guides , I guess I'll just knurl the O.D of the guides and use some J.B.Weld, I don't care to use glue to put an engine together but I guess it will have to do, I am concerned about getting everything on center. thanks!
 
You are going to get some oil coming up the intake valve through the stem to guide clearance. The guide that is held in by the valve spring has a shoulder that fits against the hole that it pushes into. If you are concerned about oil coming into the combustion chamber via the intake valve guide, you could put some sealant there. Modern engines have a seal that fits the valve stem to keep oil from being sucked in to the engine, but the seal has a carefully designed fit to allow enough oil to pass to lubricate the stem.
 
Fordestes said:
so you are saying knurlize the guide bores? I am thinking about maybe a light knurl on the guides , I guess I'll just knurl the O.D of the guides and use some J.B.Weld, I don't care to use glue to put an engine together but I guess it will have to do, I am concerned about getting everything on center. thanks!
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No, you knurl the outside surface of the valve guide increasing the OD to obtain a press fit.
 
motordr said:
No, you knurl the outside surface of the valve guide increasing the OD to obtain a press fit.
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That is what I said , The guides are some hard stuff I just found out , I have since been able to reach someone who will hard chrome the O.D of the guides ,so mabe that way I can adjust to get a snug fit, I think a thumbs push is a little too loose for me, I am thinking about .002 interference should be ok. what do you think for interference fit. in the old days on some of the overhead engines we could buy oversized guides and sometimes tapered guides were called for, but those days are long gone. thanks for your input.
 
Well, you could make a guide out steel and put a bronze liner in it. Still, why not knurl the outside of the guide you have and drive it in! Knurling expands the diameter.
 
Fordestes said:
That is what I said , The guides are some hard stuff I just found out , I have since been able to reach someone who will hard chrome the O.D of the guides ,so mabe that way I can adjust to get a snug fit, I think a thumbs push is a little too loose for me, I am thinking about .002 interference should be ok. what do you think for interference fit. in the old days on some of the overhead engines we could buy oversized guides and sometimes tapered guides were called for, but those days are long gone. thanks for your input.
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With .002 interference you stand a chance of cracking the block when you try to press the valve guide in, I think .0005 oversize would be a better press fit. I used green Loctite (bearing and stud mount) on one of my valve guides that came out, after I knurled the OD a slight amount. The replacement guides are not as hard as one might think.
 
Its probably a cast iron guide. You can knurl the outside to tighten them up.
Works great. It may seem hard but they knurl easily.
 
oldspert said:
With .002 interference you stand a chance of cracking the block when you try to press the valve guide in, I think .0005 oversize would be a better press fit. I used green Loctite (bearing and stud mount) on one of my valve guides that came out, after I knurled the OD a slight amount. The replacement guides are not as hard as one might think.
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Green loctite , that is what I wanted to know, I finally got one knurled , I had a dull knurling wheels , swapped to new ones and that done the trick , cracking is what I was concerned about ,I'll go with .0015 ,with the knurled metal which most likely will flatten out a bit and leave me hopefully at about .001 . thanks
 
I did what you are contemplating one time on a friend's engine, a year or so later I again opened that engine for a different reason and found that one guide had slipped down nearly a full inch. The slip-ins are the best, they are like the originals but are one-piece.
 
Press-in guides may cause frustration because of the following:
1) The fit of press-in valve guides can vary from loose to tight
2) Press-in guides may become loose over time
3) Press-in valve guides put the cylinder block into tension and may cause a crack (Grey iron tensile strength is very weak compared to compressive strength)
4) Press-in valve guides don't have the .125 inch shoulder and the valve spring tension is less
5) A .125 inch washer is needed with press-in valve guides to restore valve spring tension
6) Some press-in valve guides are too long which makes valve spring installation very hard

The non-frustration alternate is one-piece slip-in valve guides with the shoulder
 
Terry Burtz said:
Press-in guides may cause frustration because of the following:
1) The fit of press-in valve guides can vary from loose to tight
2) Press-in guides may become loose over time
3) Press-in valve guides put the cylinder block into tension and may cause a crack (Grey iron tensile strength is very weak compared to compressive strength)
4) Press-in valve guides don't have the .125 inch shoulder and the valve spring tension is less
5) A .125 inch washer is needed with press-in valve guides to restore valve spring tension
6) Some press-in valve guides are too long which makes valve spring installation very hard

The non-frustration alternate is one-piece slip-in valve guides with the shoulder
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true story , I found out the old fashion way ( the hard way ) I already had some pieces on hand , so I went ahead and collected up the rest of the parts, as for the spring seats not being on the guides ,I am thinking about using some oversized keepers which are supposed to work in lieu of spring shims , I have a new package of 100 on hand and never opened them, Have you ever used them ? I was concerned about the guides falling out of place myself ,that is the main reason I have sought everyones advice and I must say there is a lot of good info on the subject , I appreciate your input it does make a good point ,I did not know the newer guides with the spring seats were available and I may go that route all I ever seen were the conventional guides thanks.
 
I'm dealing with this issue now myself with my BURTZ block. The modern valve kit sold by all the suppliers part number 6505M the valve guides are too small. Even knurling did not produce acceptable fit. My machine shop is going to procure some bronze guides and fit them into the block.
 
The slip-in guides are not a press fit and the fit should result in no detectable wobble when fully installed in the cylinder block.

If the guides wobble when installed, they are too loose.

The cylinder block dimensions are guaranteed to be correct per our warranty.
 
This is the kit that the guides have an interference fit.
 

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