Too close are

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1972ho
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Too close are

Post by 1972ho » Sun Mar 04, 2018 1:07 pm

Not hitting the piston but is this just to close
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Re: Too close are

Post by Newold1 » Sun Mar 04, 2018 5:31 pm

Yep, :I would agree! Too Close!

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Re: Too close are

Post by ProPower engines » Sun Mar 04, 2018 6:20 pm

Yup that is touching but only a couple thou.
Can you or do you have any need to advance the cam a couple degrees if that is an exhaust valve touching??
That will give you more room maybe about .050-.070 depending on the cam you have.But that will still be close but good enough without missing a shift.
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Re: Too close are

Post by Dutchman » Sun Mar 04, 2018 6:23 pm

Take .030 off the valve face and call it perfect. If the margin allows it

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Re: Too close are

Post by 1972ho » Sun Mar 04, 2018 6:38 pm

This is a intake valve and it’s already 4 degrees advance I’ve been thinking of having the valves ground down about .020.

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Re: Too close are

Post by statsystems » Sun Mar 04, 2018 7:14 pm

1972ho wrote:
Sun Mar 04, 2018 6:38 pm
This is a intake valve and it’s already 4 degrees advance I’ve been thinking of having the valves ground down about .020.

Do it like Dutchman said and take it off the face of the valve. It wont change the stem height.
Last edited by statsystems on Sun Mar 04, 2018 7:34 pm, edited 1 time in total.

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Re: Too close are

Post by englertracing » Sun Mar 04, 2018 7:31 pm

Send piston to Erik at rebco

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Dave Koehler
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Re: Too close are

Post by Dave Koehler » Sun Mar 04, 2018 8:06 pm

statsystems wrote:
Sun Mar 04, 2018 7:14 pm
1972ho wrote:
Sun Mar 04, 2018 6:38 pm
This is a intake valve and it’s already 4 degrees advance I’ve been thinking of having the valves ground down about .020.

Do it like Dutchman said and take it off the face of the valve. It wont change the stem height.
I think you meant geometry or pushrod length. Stem height and valve spring height will change as well as chamber volume IF it is super printed. Otherwise, no drama
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Re: Too close are

Post by 1972ho » Sun Mar 04, 2018 9:53 pm

Can’t the bottom side of the valve be ground/cut to decrease the margin so that the valve doesn’t move further into the head seat like facing the seat of the valve .I have new titanium intake valves with thick margins.

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Re: Too close are

Post by Dave Koehler » Sun Mar 04, 2018 10:14 pm

Ahh, was that what you guys wanted to cut? The chamber side of the valve?
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Re: Too close are

Post by statsystems » Sun Mar 04, 2018 10:46 pm

Dave Koehler wrote:
Sun Mar 04, 2018 10:14 pm
Ahh, was that what you guys wanted to cut? The chamber side of the valve?

Yes, chamber side of the valve.

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Re: Too close are

Post by Krooser » Sun Mar 04, 2018 10:50 pm

Have reliefs cut into the piston
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Re: Too close are

Post by Dave Koehler » Sun Mar 04, 2018 11:00 pm

At this point it probably isn't feasible for the OP to cut pistons. Maybe at tear down time.
Actually we don't know if this was a missed gear or a superstocker running on the edge.
We don't know if this is just a one valve problem or all 8.

FWIW I consider the valve face to be the side that contacts the seat.
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Re: Too close are

Post by Newold1 » Mon Mar 05, 2018 10:53 am

You could cut the valve face back depending on margin thickness but you should go back tot he valve rep. or manufacturer and let them tell you if you can take the amount you would like to off the face without WEAKENING the valve. Also from you pic it looks as though the edge of the valve is getting to close to the relief edge and that would not increase any clearance from cutting the face. Not knowing how hard and what rpms you are putting this valve train to, its hard to know how close to danger you are. If you are racing hard and revving above 6500 rpms you should keep that clearance at a minimum of .060" in my opinion. This is exactly why these clearances should be determined with clay on any engine such as this before its assembled for the first time. The piston top being clean and the head gasket looking unused would indicate this engine is in final assembly without being run. My advise is, its out, it can be broken down and the pistons and that relief can be cut easily and issue is over. Bite the bullet and do it right the first time! :wink:

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Re: Too close are

Post by Blakeslee » Mon Mar 05, 2018 2:28 pm

If you use a slightly thicker head gasket wouldn't that take care of the clearance issue without machining?

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