Deck height question

[Frankin_truck]

I got some good news today, the Machine shop called today and said they will have my block ready this coming week. (been waiting a couple months) He said they had to deck my block .003" just to clean up some marks. Does anyone know how much this will effect my compression ratio? How much protrusion would be idea for a high performance build? My Pistons fingers 16:1 with .075". Valve relief with grade D head gaskets

 

[Moneywellspent]

It shouldn't effect your compression ratio much. One thing I'd be more concerned about is your valve reliefs.

 

[Awenta]

Practically not at all. Plus the grade d hg will more than make up for it. I don't think you were getting within .003 of the valve anyway.

Need to know your camshaft setup

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[Frankin_truck]

Shit, I messed up I have grade c head gaskets. Must have typed d because It was on my brain as I was researching them. The Cam is a socal 6480 af, I don't think It requires the full .075" Vr I have in my Pistons so I should be good. Is there a ideal piston protrusion or does it just need to be in a allowable range ? I know lots of question about something that I shouldn't even worry about but I do...... Lol

 

[Awenta]

I thought the 6480 was standard fire?

It's also custom ground, no? So how did you get it ground?

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[Cknight199]

I thought the 6480 was standard fire?

It's also custom ground, no? So how did you get it ground?

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You can order them in both standard and alt firing order. "Custom ground" is referring to a specific grind that is custom to what the customer asks for, right?


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[mike diesel]

You can order them in both standard and alt firing order. "Custom ground" is referring to a specific grind that is custom to what the customer asks for, right?


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Correct.

 

[JRODS*LB7]

6480 is like .045 relief I believe?

 

[S Phinney]

You just need to remember any protrusion will take away from quench numbers. High performance engines you want right in the .030 quench range. Ideally the .008 range would get you in the right areas for most with c gaskets.

 

[Frankin_truck]

I thought the 6480 was standard fire?

It's also custom ground, no? So how did you get it ground?

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Its just a off the shelf cam i order it from DHD. You can order this one in a std. or af. firing order. i think it needs some where around .045'-.050' vr

 

[Frankin_truck]

You just need to remember any protrusion will take away from quench numbers. High performance engines you want right in the .030 quench range. Ideally the .008 range would get you in the right areas for most with c gaskets.

Thanks phinney thats what i was looking for :thumb:. i did a little looking and it seem .005"-.008" of piston protrusion is what most engine builder like to see. soon as i get my block back i will assemble it and measure

 

[Awenta]

Who is going to be putting it together and installing the camshaft?

You won't be mashing the valves with the piston.

Once you get it together you can measure the protrusion and calculate quench. Then you can see if you need d gaskets. But I really think it will be fine. .030-.035 is a good range like Phinney mentioned. Wouldn't want to go tighter than that.

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[Awenta]

Thanks phinney thats what i was looking for :thumb:. i did a little looking and it seem .005"-.008" of piston protrusion is what most engine builder like to see. soon as i get my block back i will assemble it and measure

Yup. Didn't see this post before I made mine. Should have refreshed.

Let us know how it goes. Math+multitasking is a no.

I know how you feel haha, I always over analyze.

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[Harbin_22]

Yup. Didn't see this post before I made mine. Should have refreshed.

Let us know how it goes. If it was at 008 and you decked 003 it leaves you at 005 still.

I know how you feel haha, I always over analyze.

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Wrong way. If you had .008 to start with and decked the block .003, you will gain protrusion. So now he will have .011 protrusion. I ended up with .012-.013 protrusion this go around and I haven't had any issues. 16.5:1 with C gaskets and 3388AF cam. No reliefs.

 

[Awenta]

Wrong way. If you had .008 to start with and decked the block .003, you will gain protrusion. So now he will have .011 protrusion. I ended up with .012-.013 protrusion this go around and I haven't had any issues. 16.5:1 with C gaskets and 3388AF cam. No reliefs.

Yup your completely right. Haha sorry. That's what happens when you try to multi-task.

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[TheBac]

Wrong way. If you had .008 to start with and decked the block .003, you will gain protrusion. So now he will have .011 protrusion. I ended up with .012-.013 protrusion this go around and I haven't had any issues. 16.5:1 with C gaskets and 3388AF cam. No reliefs.

I'd have to go back to my build thread to check, but those numbers sound familiar to my truck, too. (other than the cam)

 

[Chevy1925]

Mine is right in there as well but obviously not seeing the same power you are Kyle lol

 

[Fingers]

0.003" is about 1/4 point increase in compression.

These engines are very sensitive to volume changes.

 

[Frankin_truck]

0.003" is about 1/4 point increase in compression.

These engines are very sensitive to volume changes.

Good to know. When ordered my Pistons from you I had a hard time deciding on 16:1 or 16.5:1 Pistons. With the .003" off the deck looks like that puts me right in the middle at 16.25:1 whats difference in thickness between c and d head gaskets anyone?