Do you need to zero deck the block

On a SC eng do you need to zero deck the block or can you leave it in the hole to help drop the C ratio, or will the hurt the quench...or dose the SC eng even care...

Most people don't deck to zero. They leave a little there so if the next time the block is exposed there is material to cut if there is a problem on the block surface. I like the zero deck so I can get as small a quench zone as possible but then again I'm am amateur and probably don't know what I'm doing anyway.

YOu are right tim... on both instances....

So if you don't zero deck the block, how much are or should i leave it in the hole.

My pistons were .025 in the hole, I had .020 removed off the top of the block. I left .005 in case it ever has to be done again.

I think zero-decking is more about optimization and balance.

I like it, because I want my individual cylinders to be as alike as possible and the rotating assy as balanced as possible.

But the others have brought up valid points.

Zero decking has lttle to do with cylinder balance, or optimization. That is accomplished with a cut of any amount, that removes enuf stock to clean up deck surface of block, parallel with the crank, and perpendicular (90* from one deck to the other) with bores. ZD just implies removing enuf stock to put piston crown flush with the block deck surface, when piston is a TDC.

Zero decking has lttle to do with cylinder balance, or optimization.


Sure it does. You just made a mistake in regards to how I was using the word balance.

Obviously it has nothing to do with balance in the way that mallory metal has to do with balancing a crankshaft. Perhaps I could have chosen a better way to phrase my post.

Regardless; I'm talking about making each cylinder as much alike it's sisters as possible. Zero decking gives me a nice, flat surface that is a consistant distance from the crankshaft centerline. This means that with a rod of "X" length, the centerline of the pin is always "Y" distance from the deck surface in every cylinder. If I have a consistant distance there; it makes it easier for me to tighten up the quench to .025-.030 without worrying of one of the pistons is going to kiss the head because of some tiny amount of core shift in the casting sand in 1995.

As to whether this affects the optimization of an engine; I would respond that this is simply an integral part of blueprinting an engine, and I wasn't aware that the value of blueprinting was in dispute.

Sure it does. You just made a mistake in regards to how I was using the word balance.

Obviously it has nothing to do with balance in the way that mallory metal has to do with balancing a crankshaft. Perhaps I could have chosen a better way to phrase my post.

Regardless; I'm talking about making each cylinder as much alike it's sisters as possible. Zero decking gives me a nice, flat surface that is a consistant distance from the crankshaft centerline. This means that with a rod of "X" length, the centerline of the pin is always "Y" distance from the deck surface in every cylinder. If I have a consistant distance there; it makes it easier for me to tighten up the quench to .025-.030 without worrying of one of the pistons is going to kiss the head because of some tiny amount of core shift in the casting sand in 1995.

As to whether this affects the optimization of an engine; I would respond that this is simply an integral part of blueprinting an engine, and I wasn't aware that the value of blueprinting was in dispute.

I think you misunderstood him. Any time that the deck is 'cleaned up' you will have the same result. When they come across with that big flycutter, if its properly setup, it will do exactly what you are talking about at the point of minmum cleanup. My deck only took .006 and the cylinders are still 'balanced' as you refer to, even though they are .019 in the hole.

I think you're saying that I am using the term "zero-decking" incorrectly.

If that's true, I see you're point and you may be right.

A deck surface can be "trued up" without being zero decked, and I tend to use the term "zero deck" generically.


In any case, unless I misunderstood the guy I was just responding to; he misunderstood ME and thought I was talking about balancing the engine in the rotating mass sense.


I wonder how confused I will be before the thread is over...?

I think you misunderstood him..

:) Yea, I knew precisely where he was coming from. No misunderstanding there.

Any time that the deck is 'cleaned up' you will have the same result. When they come across with that big flycutter, if its properly setup, it will do exactly what you are talking about at the point of minmum cleanup. My deck only took .006 and the cylinders are still 'balanced' as you refer to, even though they are .019 in the hole.

Tough to state it any better than that. :)
Decking, as a machining procedure, does not automatically imply 'zero' decking.

My pistons were .025 in the hole, I had .020 removed off the top of the block. I left .005 in case it ever has to be done again.

A nice option is made available, when a thick enuf gasket is used. Zero decking can be performed initially, yet additional stock can still be removed later if needed/desired, thus having pistons out of the hole a little, as is done with the LSx enignes.