Valve Clearance - Number of cylinders

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I do number 1. If the valves are all the same height and the pistons/rods have been verified for deck clearance and I have too much clearance I just send it.

If it as close as I run mine (I think I’m .065 on the intake and .075 on the exhaust and the exhaust was dusting the carbon off the piston) then I check them all.

And I use clay and I don’t use checking springs. If you do, you will have more clearance than the light springs will say you do because all rockers (all good rockers I should say) have a higher than nominal ratio. This accounts for flex in the rocker.

I’m not a fan of running valves into pistons but I’m also not a fan of running too much clearance.

It hurts power.
 
Newbomb Turk said:
I do number 1. If the valves are all the same height and the pistons/rods have been verified for deck clearance and I have too much clearance I just send it.

If it as close as I run mine (I think I’m .065 on the intake and .075 on the exhaust and the exhaust was dusting the carbon off the piston) then I check them all.

And I use clay and I don’t use checking springs. If you do, you will have more clearance than the light springs will say you do because all rockers (all good rockers I should say) have a higher than nominal ratio. This accounts for flex in the rocker.

I’m not a fan of running valves into pistons but I’m also not a fan of running too much clearance.

It hurts power.
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Thank you
 
CudaTime49 said:
Do you use the checking springs?
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Just to be clear, I wasn’t saying not to use checking springs.

Most pistons today come with valve notches deep enough for way more cam than most guys need.

I also use the gasket and lash to calculate p/v clearance.

To that end, most guys can use checking springs and skip the clay. Just know if you do that and it says you only have for example only .075 on the intake with the checking spring, know you probably have another .020 at least because rocker flex isn’t accounted for.

When you start running your valves as close to the pistons as I do, then you need to use clay or you end up making your valve pockets deeper than they need to be.

And that hurts power.
 
I just pick and check one each bank... but the pistons, as said.. I'm mean, what cam lift are we talking here..
 
CudaTime49 said:
Do you use the checking springs?
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No.
But I'm not running triple springs or anything crazy heavy, either.
Most of my engines of late have been single with a damper or doubles. If doubles, I pull the inner springs and do my checks.
 
So am I wrong in getting cam at full lift, and measuring from there until the valve hits the piston? With a checking spring.
 
CRUZE 418 said:
So am I wrong in getting cam at full lift, and measuring from there until the valve hits the piston? With a checking spring.
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YES. The piston is a mile down the hole at max lift.

That’s your intake centerline number.

My junk goes in at 105 ICL. That means at 105 degrees AFTER top dead center the valve is it max lift.

You’d have to lift the valve 2 inches (that’s a WAG but you can measure that) for the valve to hit there.

Your valves will be closest to the piston 10 degrees before and after TDC.

What you are doing is checking your clearance in overlap with the piston around TDC.
 
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I thought that I had around 110 th's. Guess that I better get together with someone before I build my Hemi. I am not an engine builder, but have done several myself. Thanks for getting me off in the right direction. Will get it figured out now that I know.
 
When you check “P/V” clearance at full lift……..what you’re really checking is retainer to seal clearance.

The piston is inches away when the valve is at full lift.
 
Well, then, another dumb question. If the piston is inches away at total lift, why are we worried about the valve hitting the piston?
 
A good video with a visual representation of how, when, and why you check valve clearance.

 
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