Block Decking - Team Camaro Tech
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post #1 of 12 (permalink) Old Jan 10th, 10, 11:00 AM Thread Starter
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Charlie
 
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Block Decking

I am getting ready to drop my block off at the machine shop. Should I have them 0 deck it or leave .010"? Do you usually deck it to 9.000"? I calculated the static to be 10.3:1 and the dynamic to be 8.91:1 with 0 decking. If I have them remove .015" getting it to 9.010", the ratios drop to 10.06:1 and 8.71:1. Is it really going to make any difference? Should I leave some in case it needs to be decked in the future? Will have any issues with piston to valve clearance if a 0 deck or even by leaving .010"?

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #2 of 12 (permalink) Old Jan 10th, 10, 11:30 AM
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Re: Block Decking

I'm not a professional builder but I can't understand the practice of machining away irreplaceable cast iron (thus weakening the deck surface) and then building up the quench distance with thick gaskets. I always just have them decked to square and then pick the right head gasket to maintain .035-.040 quench. I've had good results with Fel-Pro 1094 shims (.016 thick) and the Mr. Gasket 1134 (.028). Ever notice how aftermarket blocks talk about extra thick deck surfaces? I'm sure a pro builder will offer a different view.
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post #3 of 12 (permalink) Old Jan 11th, 10, 07:49 AM Thread Starter
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Re: Block Decking

My understanding of decking is, by decking this allows you to have a greater control over the quench. By having a deck height of 9.025"(factory) you must you a .015" shim gasket to get a decent compression ratio. By decking to 9.000" or 9.010", you can run a .039" gasket and get a higher compression. If you run a flat top, 65cc head, 9.025" deck height and a .039" gasket, you will end up with a 9.56 static and a 8.28 dynamic. With a 0 deck you get 10.12 static and 8.76 dynamic, but this is just my understanding.

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #4 of 12 (permalink) Old Jan 11th, 10, 09:41 AM
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Re: Block Decking

Did my Dart m to 9.010 for your exact reasoning Charlie, leave some for next time. Also with Cometic MLS hi$ gaskets the surface finish is important, so the possibility of needing to touch up again in the future increases. Cometic can make you any thickness gasket you want if you can't find a shelf one to get what you need. Your deal I'd do 9.010 and a GM 10105117. Might make sure that gm gasket fits 350 bore, I never have set one on a 350 just on a puny 305 and didn't remember to write down the gasket I.D.

But I heard a guy say he uses that one on 350's. It is an .028 gasket. That 10105117 # is from memory so I hope I got it right. At summit it has an "nal" prefix. They (summit) say it is for 350 but only 4.00 id

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post #5 of 12 (permalink) Old Jan 11th, 10, 05:36 PM
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Re: Block Decking

Charlie,
I personally like leaving the pistons about .005" down. Help for future "oops's" if you know what I mean. I really dont think that the difference is worth worrying about for the average engine.

Now .... did you actually mock the engine up and check the deck hgt before sending it to the machine shop ?? If not ... shame on you Parts vary a lot more than you think and without a mockup first, you cannot just "zero deck" a block and be sure it will be correct.

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post #6 of 12 (permalink) Old Jan 11th, 10, 06:31 PM
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Re: Block Decking

I like what BILLK said whats your intake close at because from static to dynamic looks pretty close ?
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post #7 of 12 (permalink) Old Jan 12th, 10, 04:10 AM
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Re: Block Decking

I wouldn't deck a block either. Unless I'm looking for another 1/2 HP, I would spend the money towards balancing, then a good set of heads, in this order.

The most I would do is to 'hone' the deck and heads with a Norton India stone and WD40 or ATF to remove the broach marks providing a smooth surface for the steel shim gaskets to seal.

Remove the dowel pins and reduce their diameter for a slip fit.

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post #8 of 12 (permalink) Old Jan 12th, 10, 06:57 AM Thread Starter
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Re: Block Decking

Quote:
Originally Posted by BillK View Post
Charlie,
I personally like leaving the pistons about .005" down. Help for future "oops's" if you know what I mean. I really dont think that the difference is worth worrying about for the average engine.

Now .... did you actually mock the engine up and check the deck hgt before sending it to the machine shop ?? If not ... shame on you Parts vary a lot more than you think and without a mockup first, you cannot just "zero deck" a block and be sure it will be correct.
Bill, I haven't sent the block out just yet. When I bought the parts, the guy had in the advertising what was done to the block(line bored, fresh .040" overbore), but didn't have anything about decking so I assumed it was stock height, but we all know what happens when you assume. I posted this because I wanted to get an idea of what I should do WHEN I send it to the machine shop. I was thinking of leaving some for a rainy day, but I wanted to get some opinions 1st. Thanks for that. My only issue with mocking is, the heads I will using are still on the current motor. The block is another 350 block, but the heads are the current aluminum AFR's I am running now so that is going to make this a little hard.

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #9 of 12 (permalink) Old Jan 12th, 10, 07:00 AM Thread Starter
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Re: Block Decking

Quote:
Originally Posted by ssdoug View Post
I like what BILLK said whats your intake close at because from static to dynamic looks pretty close ?
According to the Keith Black compression calculator, they say take your intake closing measurement and add 15* to that. My intake valve closes at 38*ABDC so that would make 53* when typing into the calculator.

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #10 of 12 (permalink) Old Jan 12th, 10, 07:04 AM Thread Starter
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Charlie
 
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Re: Block Decking

Quote:
Originally Posted by Everett#2390 View Post
I wouldn't deck a block either. Unless I'm looking for another 1/2 HP, I would spend the money towards balancing, then a good set of heads, in this order.

The most I would do is to 'hone' the deck and heads with a Norton India stone and WD40 or ATF to remove the broach marks providing a smooth surface for the steel shim gaskets to seal.

Remove the dowel pins and reduce their diameter for a slip fit.
The reason I was going to deck it was so I didn't have to run a thin head gasket. I have had good results with the FelPro 7733PT2(.039" thick). I want to be able to run this head gasket and still get the compression in the 10:1 range. If I deck the block to .005", I will have a static of 10.18 and a dynamic of 8.81. That is right where I want it. If I don't deck it, I will have to run a thin head gasket and I don't want that. Both because I haven't had luck with them and also because I just feel more comfortable with more gasket there.

What is the purpose for making the dowels slip fit?

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #11 of 12 (permalink) Old Jan 12th, 10, 07:22 AM
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Re: Block Decking

Making the dowel pins slip fit allows you to install them without a hammer/punch preventing mushrooming the pin and to have a clear passage of the deck if you are to 'hone' the deck for better gasket sealing. Just something I've learned over the years.

Good luck with your deck. I've never felt/noticed any difference between having a 0.040" quench and a 0.060" quench.

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post #12 of 12 (permalink) Old Jan 12th, 10, 09:13 AM
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Re: Block Decking

Quote:
Originally Posted by BillK View Post
Charlie,
I personally like leaving the pistons about .005" down. Help for future "oops's" if you know what I mean. I really dont think that the difference is worth worrying about for the average engine.

Now .... did you actually mock the engine up and check the deck hgt before sending it to the machine shop ?? If not ... shame on you Parts vary a lot more than you think and without a mockup first, you cannot just "zero deck" a block and be sure it will be correct.
X2 on what Bill said. A quick 4 corner mock up or with all pistons in place, will let you know where you are at as for PIH.
I did and found variances, block was not square, had one piston .020 in hole and in other corner it was like .015, then another .025.
I had the block cut to make all even and parallel with crank centerline. I ended up with about.001 in the hole, made the differance up with a .039 gasket.

Took motor down later and inspected piston tops, I notice a better combustion pattern and no signs of piston hitting anywhere.

Don
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