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Valves Hitting Pistons

J

jmbour66

Member
Hello to all,

Please take a look at the 2 pictures and let me know if this looks the Valves are hitting the Pistons. The engine was used for drag racing and I'm thinking that it was revved way too high for way too long. But as you can tell from other threads, I'm not an expert! :Mark
 

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  • Valve Kiss 2.jpg
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I don't see any obvious scratches in the piston, but if you think it's really been abused, I'd be looking at the valves. Do the faces of the valves look beat up, or do the valves seat all the way?? If a valve is bent, it probably won't seat well.

Smokey Yunick I ain't, so YMMV. :peter
 
This is what mine looked like when the gear drive grenaded and the valves hit:

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Last edited by a moderator:
"gotstang" said:
I don't see any obvious scratches in the piston, but if you think it's really been abused, I'd be looking at the valves. Do the faces of the valves look beat up, or do the valves seat all the way?? If a valve is bent, it probably won't seat well.

Smokey Yunick I ain't, so YMMV. :peter
Click to expand...

The Valves look good on the head, I will pull them from the head soon and check straightness.

I did forget to mention that a couple of push rods were slightly bent, which caused me to look at the pistons and valves.

The crank/and pistons operate very smooth with no binding or grinding.
 
Throw the heads back on with some play dough clay flattened out on top of that piston and rotate the crank a coupe of times. Then take the head off and check how far the valve indented into the clay. If it went all the way thru then you know for sure if the valves are hitting the pistons.
 
Bent pushrods could lead to lifter and cam issues. Pistons hitting valves could lead to cracked pistons, wrist pin issues, or rod and bearing issues. Without knowing how much the engine was ran with them hitting, it might lead to complete tear down to 100% comfortable running it.
 
Not sure if it's dinged or just carbon flaking off. Check it with the play-do to be sure.




BTW, nice usage of :Mark for a new guy!
 
"6t6red" said:
Throw the heads back on with some play dough clay flattened out on top of that piston and rotate the crank a coupe of times. Then take the head off and check how far the valve indented into the clay. If it went all the way thru then you know for sure if the valves are hitting the pistons.
Click to expand...

Dumb Question: When i put the head back on should I install the Push Rods etc.?
 
"jmbour66" said:
Dumb Question: When i put the head back on should I install the Push Rods etc.?
Click to expand...

Yes, things must be in proper setting/adjustment and moving to see if the valves hit.
 
"AzPete" said:
Yes, things must be in proper setting/adjustment and moving to see if the valves hit.
Click to expand...

Okay, Last DUMB question: Are these rocker arms adjustable or do they just get torqued to 20lbs like my other rocker arms.......
 

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Not adjustable. Touque to spec. And to mu eye, your pics look like valve contact - you're smart to check. However, I'd look damn close at the valves - a small bend can fatigue them, and then the head drops. The signs are then pretty easy to see :Mark
 
I decided to have the heads Soda Blasted so it will be a week or so before I get them back on the block and can do the "Play-Dough" check.

Thanks for all the help! :wor
 
Update: I removed all the valves in preparation for the soda blasting. All valves were straight and smooth.



Sent from my DROID2 GLOBAL using Tapatalk
 
I just realized that the springs on these heads are Stock, and the Cam is an E303.

Should I beef up on the springs, and if so does anyone have a recommendation?
 
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