Bent valve in a 360

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stansblue72

stansblue72

one of one 1953 ME!
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Anyone have any idea what might have caused this? Also the piston has a slight mark on it, not very deep but on the outside edge there is a burr. Otherwise the piston looks okay. Looks like we could remove the burr and it would be fine but would like some other opinions on it.

larry 160.jpg


larry 158.jpg
 
Piston is fine, clean of the sharp edges and it will be fine!

How does the combustion chamber, and seat look.
 
How old is the fuel?

Might have sugared up and stuck the valve.
 
The other pistons and valves are fine?

Are the heads fresh?

I'm guessing the valve seized up in the guide. Either guides are too tight or something similar.
 
Every thing else is fine, new fuel. It's a roller cam motor he just put a bigger cam in it. The guy we got the cam from thinks the valve springs are to weak.
 
LXguy said:
The other pistons and valves are fine?

Are the heads fresh?

I'm guessing the valve seized up in the guide. Either guides are too tight or something similar.
Click to expand...

Heads are fresh, Fresh fuel, #5 piston. Valve springs seem soft to me. I don't know how strong they should be but I can compress them with my hand. The heads came with the valve springs and I had a shop inspect and assemble. My cam has a .540 lift. Everything else is fine in the heads.
 
1st =valve float, spring breakage?


timing chain may have slipped?

seized guide at full lift?



Check the installed height on that one compared to the one next to it.
may have to [min .050 between coils 'bind room' at full lift] stick a .030-.060 VSI under the spring to get the psi back up.

but now that I'm reading it's a roller cam...get new springs and toss it back together.
 
Yup. The piston hit the valve. So either the spring can't control it good enough, or the guide didnt let it move easy enough. Either way, "everything else" is NOT ok. Make sure you smooth off the mark on the block too.
 
No marks on the block just the top of the piston. The head will be going back to the shop to get completely checked out. New stiffer springs might be a good idea too!
 
There's a nick in the picture. Right next to where the mark on the piston is...
 
that what this is? Looks like a nick where the bore is exposed from the head gasket... Bore is 4.00 and gaskets are 4.180. It hit the block, and that sharpie will get hot and might make it ping.

larry%20158.jpg
 
I see it now I was looking down the bore farther. When I run my finger around the inside I don't feel anything sticking in the bore. Do you think that small of a nick will cause problems? You got a good eye there moper!
 
Since you are running a larger cam did you check piston to valve clearance and check for spring bind? Advancing the cam will also cause clearances to close up.
 
Same thing just happened to me,mine was from a lifter retainer clip failure,it came half out and caused the lifter plunger to **** in the bore,instant solid lifter.Twenty minutes after I installed my new RHS heads,test drive around the block,worse yet is it bent a new valve in a new head.just plain bad luck.
 
They tested the valve springs and said the ones that where on the heads are way to weak for the cam that is in the car. On a note they knew all the cam specs. The place that did the heads is going completely go through them at no cost to us. Should be getting them back soon. Also getting new push rods.
 
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