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Discussion Starter #1
I found this engine. Seller says it ran when installed but popped with throttle. The stem on one valve is mushroomed.

what would cause it to mushroom?

is it worth $500?

767357
 

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Stuck valve?, Tap it with a dead blow. Does it bounce? Poor quality? Contacting something in the chamber?
How handy and willing to take chance? May only need a valve job? Looks modified, if only the carb and intake.
 

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Typically, the rocker goes off the side of the valve, but this one already has guide plates. I avoided the whole issue by switching to 5.0 rockers and BOSS 302 fulcrums.
 

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Somethings wrong with the geometry on the #1 intake. Look at the shiny wear marks on the rocker stud down by the hex, that shouldn't be there. And someone will probably have a fun time getting that valve out. It's not worth the asking price.
 
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Somethings wrong with the geometry on the #1 intake. Look at the shiny wear marks on the rocker stud down by the hex, that shouldn't be there. And someone will probably have a fun time getting that valve out. It's not worth the asking price.
Extracting the valve is easy. Remove the head. Remove the springs. Grind around the tip with hand grinder. Valve falls off.
 

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Discussion Starter #8
I’m okay with a wrench and would be comfortable doing it. I just don’t want to buy an anchor for 500
 

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Extracting the valve is easy. Remove the head. Remove the springs. Grind around the tip with hand grinder. Valve falls off.
Yes, if you can get to the keepers
 

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#1 exhaust seems to have a different installed height ont he valve, could be something very simple. I see screw in studs & guideplates, so it could be a performance built set of heads. If it comes with the valve covers, intake and carb, you can't lose at $500.
 

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#1 exhaust seems to have a different installed height ont he valve, could be something very simple. I see screw in studs & guideplates, so it could be a performance built set of heads. If it comes with the valve covers, intake and carb, you can't lose at $500.
Yes, it looks like the valve for the #1 exhaust is for an early, non-rail rocker arm and the other valves have the taller stems for rail rockers. Offset wear marks looks like wrong length push rods.
 

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Yes, if you can get to the keepers
Too easy. Compress the spring, and the retainer goes downward, away from the mushroom. Then the keepers fall out. Not my first time at this particular rodeo.
 

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Too easy. Compress the spring, and the retainer goes downward, away from the mushroom. Then the keepers fall out. Not my first time at this particular rodeo.
And if the keepers are stuck: With the springs uncompressed, placing deep well socket on the retainer and giving it a quick rap with a hammer often pops them out. Granted, the mushroom should keep the valve from completely dropping, but one should have the piston up in the bore to stop it from going too far, just in case. It takes a little finesse and it's best to have a glove on so that you can hold the socket and the edge of the retainer so that keepers do not fly away and you do not pinch your hand between the spring and retainer.
 

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Discussion Starter #16
Thank you all. It comes with the intake and carb, valve covers. Any chance of the piston being damaged?
 

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VERY little chance of piston damage. Not "every" valve has a hardened tip and some have been known to mushroom , As others have already said pop off the spring and retainer , file or grind down the end of the valve until it slides out. Throw it away and get another. Make sure it has a hardened tip. Check the alignment on the rocker and valve stem , some guide plates are not correct and "skew" the rockers.
 
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