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Discussion Starter #1
A friend of mine dropped an intake valve. The head has rail-type rockers, probably 67 head. One valve keeper was destroyed, other very slightly bruised. When the rocker and the valve spring were removed, we had difficulties getting the valve back up. We thought that the valve was bent. We got it finally up and it seems that there was a slight ridge in the valve or top of the valve guide. Now the valve can be turned easily and smoothly against valve seat and it doesn't feel like like bent valve. Is it possible just to replace keepers and then measure the gap between rocker and valve tip and if acceptable (as described in Tom Monroe's book), assemble it? Or is it mandatory to replace also rocker and retainer?

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Hmmm....I take it the head is still on the engine, yes?

You can try re-installing the spring, retainer and keepers and then do a leakdown test of the cylinder or just get an adapter to put compressed air in the cylinder and see where any leaks may be coming from...

Did one keeper or both keepers come out?

What did your friend see or hear at the time of the failure?

Remember, the valve can still turn freely but be bent in the area of the valve bowl below the seat and above the guide...doesn't take much to cause a leak...

Let us know what you find out...

Pat
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Did the rocker arm eat away the tip of the valve causing the rocker arm to hit the keepers? If this is the case then a new valve is necessary because the tip is too worn to just replace the keeper. With newer types of valves (still old) the tips of the valves are replaceable. You did not mention if this happened while driving but if it did your friend is lucky if the engine is all right. A valve that drops into a cyl can do terrible damage. Wouldn't want to think about it.
 
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Sounds like he got lucky. I had a valve head break off one time. Wedged between the piston and head. Caused the Rod to bend, and exploded the piston, cracked the cylinder wall. I trashed the whole engine. (Don't worry it wasn't a mustang)

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'67 Coupe project car (Did I say project car? I meant pile of rust)
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Discussion Starter #5
Yes, the head is still on. Leakdown test was exactly what we were thinking of after reassembly. Of course, all the other rockers have to be checked rather sooner than later.
Rocker was tilted sideways but still over the retainer. One keeper was still on place under rocker, I didn't see whether the deformed keeper was in place or lying around. A few metal shavings were on the head, we tried to get as much as possible away with a magnet.
Hearing: well, first he heard noise like misfiring (valve dropped?) or similar then more metallic sound (valve hitting rocker rail?).

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Discussion Starter #6
I don't think the valve has removable tip. It happened after he stopped to tighten exh header bolt and then after driving a few feet. Drove off (don't know whether just coasted or drove) and after that just a few attempts with starter. He was lucky, I agree, I remember our rally-Escorts (2.0 Ohc enginge) valve in three pieces with parts in water galleys. But still unlucky, he was picking the car up from winter storage, not a good way to start cruising season.

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Thanks for the update...

You might have dodged the bullet if the valve got stuck rather than dropping.....it sounds to me like that's what happened....

You'll know more from the leakdown....I'll keep my fingers crossed...life will be a lot simpler if the heads stay on...and less expensive, yes? *G*

Good luck!

Pat
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I'm now thinking that the rocker poped off the valve and was pressing on the retainer and chewing the keeper, this would cause the backfire and metal shavings. If the valve did fall thru you may have had piston slap causing the metalic noise. Valve might be ok. Check the tip like in monroe's book.
 
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