That's true, but one should not be done without the other, IMO. What's the reference for anything with the block deck? The crankshaft center line.
How much decking is to much?
- Thread starter Cope
- Start date
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That's true, but one should not be done without the other, IMO. What's the reference for anything with the block deck? The crankshaft center line.
You would think the machine shop would be smart enough to ask the question ...do you want the block square...deck heights even....LOL
Many years ago, I asked the machine shop to square the deck...he decked the block the same amount on each side...yeah...still have .008 difference between the sides and a few thousand from front to back....changed machine shops....
but the 360 ran for 10 yrs ..ran a best of 10.31....and since I squared the deck...had nothing but problems with it.... so you never know...
Many years ago, I asked the machine shop to square the deck...he decked the block the same amount on each side...yeah...still have .008 difference between the sides and a few thousand from front to back....changed machine shops....
but the 360 ran for 10 yrs ..ran a best of 10.31....and since I squared the deck...had nothing but problems with it.... so you never know...
nm9stheham
Well-Known Member
I know it's not funny.. but that is funny.... yes, you never know. Tnx
dibbons
Well-Known Member
It is a little complicated when using a custom small block crank (2.96" stroke), custom rods (6.298" center to center length) and old school TRW pistons (This is the 305 motor I am building),
I told the one machine shop to set the TRW L2322 dome pistons to .017 above the block deck (rated up to 12:5 to 1 compression). When they got there, one deck was still not cleaned up, so they made a small second pass. I am glad they did not remove any more material from the other bank that had already cleaned up with the pistons set at my specs. I can either run two different head gaskets, or not worry about it and run the same gasket (after verifying piston to head clearance, of course).
The second machine shop is working on a factory 340 high compression motor (flat top pistons). They cleaned up both decks on the this second block, but like I said, one side needed two cuts. When I assemble the rotating components on the second motor, I will see how the piston deck height compares, bank to bank. Should be interesting to see if both blocks were "off kilter" in the same way. Regardless, I don't want either shop taking off extra material (that I could never recover) from the cylinder block deck surface. And if the specs differ by only about .005", that still seems to be much closer to blueprint specs than the factory output.
One more factor to consider is the final compression ratio of the L2322 pistons in the first motor (de-stroker). According to the on-line compression calculators, de-stroking will lower compression about 1.5 points, depending on combustion chamber volume.
I told the one machine shop to set the TRW L2322 dome pistons to .017 above the block deck (rated up to 12:5 to 1 compression). When they got there, one deck was still not cleaned up, so they made a small second pass. I am glad they did not remove any more material from the other bank that had already cleaned up with the pistons set at my specs. I can either run two different head gaskets, or not worry about it and run the same gasket (after verifying piston to head clearance, of course).
The second machine shop is working on a factory 340 high compression motor (flat top pistons). They cleaned up both decks on the this second block, but like I said, one side needed two cuts. When I assemble the rotating components on the second motor, I will see how the piston deck height compares, bank to bank. Should be interesting to see if both blocks were "off kilter" in the same way. Regardless, I don't want either shop taking off extra material (that I could never recover) from the cylinder block deck surface. And if the specs differ by only about .005", that still seems to be much closer to blueprint specs than the factory output.
One more factor to consider is the final compression ratio of the L2322 pistons in the first motor (de-stroker). According to the on-line compression calculators, de-stroking will lower compression about 1.5 points, depending on combustion chamber volume.
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MOPAROFFICIAL
Oogliboogli
To each his own.
moper
Well-Known Member
I did it when I was much more ignorant. There are better ways to achieve a performance goal than using a machine you have access to. Especially if it's not setup or equipped to do automotive engine work.
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