Cracked valve guide, any advice?

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dgswinger

dgswinger

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Well I was taking my heads apart to clean them up and start to do a little port work when I found this crack at the top of the guide under the spring. Any opinions as to how to fix or is this fixable? Should I be concerned or is this ok? The heads aren't anything special just 587 casting 360 heads. Not sure if they are worth investing alot of money into, considering what's available now for small block heads. Take a look at the pics. It just appears to be cracked on the outside not into the guide yet. Any and all input is appreciated. Thank you.

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Those heads have had valve guides installed. They are usually 1/2 inch or 9/16 inch outside diameter The shop drills and reams the guide hole out then will press fit the replacement guide into place. This is when the damage you see will happen , if there is too much press fit. If your concerned, take them to a machine shop and have the possible loose cast iron removed.
 
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Not a problem, just have a shop install a replacement guide, problem solved.

Happened to me when I was tearing down a pair of heads with stuck valves, got a little too vigorous with a hammer knocking valves out.
 
If that head came into my machine shop I would replace the guide and make just the installed height is correct. With that being said you still need to spend a little time figuring out why was it damaged. Was it damaged when it was installed or was the installed height wrong and maybe the retainer hit it and cracked it. But whatever it's not the death of the head it's not a very expensive repair.
 
Thanks for the replys for some reason I didn't realize this would be a simple remove and replacement of the guide. I always over think things....
 
dgswinger said:
Thanks for the replys for some reason I didn't realize this would be a simple remove and replacement of the guide. I always over think things....
Click to expand...

Well, it ain't that simple. What I see is a knurled guide. The rest I can see are factory stock, and someone BEAT the valve out of it and cracked the guide.

All the guides should be replaced with .500 O.D. hardened guides. Then, the top of th guide should be machined for a POSITVE seal and trimmed for height.

For all this, you need a quality seat and guide machine.
 
yellow rose said:
Well, it ain't that simple. What I see is a knurled guide. The rest I can see are factory stock, and someone BEAT the valve out of it and cracked the guide.

All the guides should be replaced with .500 O.D. hardened guides. Then, the top of th guide should be machined for a POSITVE seal and trimmed for height.

For all this, you need a quality seat and guide machine.
Click to expand...

Na, just JB weld it. :D

If the heads are worth it, I have to agree with this.
Of course the guide job is going to flow over into the valves being redone, so take that into account on your total cost.
 
TrailBeast said:
Na, just JB weld it. :D

If the heads are worth it, I have to agree with this.
Of course the guide job is going to flow over into the valves being redone, so take that into account on your total cost.
Click to expand...


Damn, it's second nature to me, so I just ASSumed everyone would understand once you replace the guides you MUST do a valve job. Which adds to the cost. Then there is the potential that you don't have hard seats and those should go in after the guides.


It adds up quick.
 
yellow rose said:
Damn, it's second nature to me, so I just ASSumed everyone would understand once you replace the guides you MUST do a valve job. Which adds to the cost. Then there is the potential that you don't have hard seats and those should go in after the guides.


It adds up quick.
Click to expand...

I just thought I would mention it since the OP was asking about what to do about cracked guide insert.
 
yellow rose said:
Yeah, he said insert, but I don't see an insert in any of the pics he posted. One looks knurled, the rest I can see look like OEM.
Click to expand...

I thought that different one was possibly an insert because the cast is cracked but the inside isn't.
Carry on. :D

guide.jpg
 
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