Nicks Garage 383 build

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My non-expert two cents:

If Nick were closer and I wanted someone to dyno my engine, I'd be happy to take it to Nick.

If my engine was underperforming and I didn't know why, I'd take it somewhere else.
 
440 Mike said:
Quick question: If Nick's 383 has that little of exhaust valve to piston clearance and a lot of intake clearance, doesn't that indicate that the cam install is retarded?
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Nick posted this comment on video #2:

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Here is a little visualization:

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Looking down from the head to piston and cylinder bore.

Blue cap represents Intake valve at max cam lift, close to piston with piston at TDC.

Purple cap represents exhaust valve just beginning to come off its seat, high off the piston yet at TDC.

The aftermarket 2 cams probably have 2° advance ground into them.

Then the unknown, the degree of advance or retard added upon assembly.

Then also miss match of timing chain parts and gears giving an unexpected advance degree setting, throwing the formula off hence the picture at TDC.

See what others think....


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No mystery here imo.

The valve drop on an in line wedge head would always be less on which ever valve is bigger(The perimeter of the bigger valve is closer to the deck surface).

The pistons have no valve pockets.
Set piston at TDC, place head on block without valvetrain.
The intake valve will hit the piston at less lift than the exhaust.

The caveat would be, “unless there is a enough of a disparity between the intake & exhaust seat depths, and/or valve margin thicknesses to offset the difference in diameter”.
 
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He stated that the cam timing was checked & where it belonged in the vid, the 1st cam made more oats, & the 2nd(old comp retro HP grind that was in the engine prior) didn't find any real torque.....just lost hp...
 
Newbomb Turk said:
The only way that can happen is if the dyno operator is an idiot or a liar.

If you are using the same correction factor (and is should be STP and not the newer factors) there shouldn’t be 10 hp difference from corner to corner of the country.
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What is STP?
 
Gomer Pyle said:
A short stroke engine with a long rod ratio is tough to get valve to piston clearance, has no effect on CR.
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A shorter stroke with a relatively short rod is harder to get more compression from because there is less dwell time at TDC. The more dwell time, the more time to compress the mixture. I didn't say there was an "effect" on compression, just that one is harder to get compression from than the other. It's a physics thing. It's over my head, but it's true.
 
RustyRatRod said:
A shorter stroke with a relatively short rod is harder to get more compression from because there is less dwell time at TDC. The more dwell time, the more time to compress the mixture. I didn't say there was an "effect" on compression, just that one is harder to get compression from than the other. It's a physics thing. It's over my head, but it's true.
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A short stroke engine with a long rod ratio like the 383 has a very long dwell which is what make the valve to piston clearance more difficult, a longer stoke engine like the 440 has less dwell at the top, get a dial indicator and degree wheel and see for yourself.
 
Gomer Pyle said:
A short stroke engine with a long rod ratio like the 383 has a very long dwell which is what make the valve to piston clearance more difficult, a longer stoke engine like the 440 has less dwell at the top, get a dial indicator and degree wheel and see for yourself.
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I've degreed so many I've lost count. I'm not talking about a long rod. Did you see where I said "relatively short rod"? If you wish to continue the argument, please do so with the person in your mirror.
 
RustyRatRod said:
I've degreed so many I've lost count. I'm not talking about a long rod. Did you see where I said "relatively short rod"? If you wish to continue the argument, please do so with the person in your mirror.
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OK, so you mean like a 307 or 327 as a 383 has among the longest rod ratio's of any common V8. Sorry, won't bother you anymore.
 
Gomer Pyle said:
That + .020" is the NHRA blueprint spec for Stock and Superstock, an untouched 68-9 HP 383 is about .025" to .030" in the hole.
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You are wrong. I have had more than one untouched 383 in my shop, and they do indeed have a positive deck height
 
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