Is there any reason not to have zero deck height?

Post by **seanyb505** » February 28th, 2008, 9:49 am

For some reason when I started researching I got the idea it wasnt that great of an idea to deck the block that much. Now Im seeing a couple people actually shoot for zero deck height. Is there anything wrong with taking .0495 off the block?

Post by **jsawduste** » February 28th, 2008, 11:28 am

A loaded question with many variables. Taken at face value the only thing that would change is your valve train geometry. Length of the cylinder head bolts is another question. Though I suspect there is enough latitude here.

Post by **Flash** » February 28th, 2008, 11:36 am

No problem at all just as long as you quench is at least .045 your safe.( .002" below deck and and a .043 head gasket = .045"

The reason some don't deck the block, or don't thing is a good idea, is those that will spend the extra cash for the custom piston.

If the piston set up further in the bore it will stop sooner at the bottom(More piston skirt supported at BDC (Bottom Dead Center)

for those of us, that will be using stock 4.0L piston..........Decking the block will make "0" affect on this.

Flash.

Post by **Flash** » February 28th, 2008, 11:40 am

jsawduste wrote:A loaded question with many variables. Taken at face value the only thing that would change is your valve train geometry. Length of the cylinder head bolts is another question. Though I suspect there is enough latitude here.

Good point, I hadn't even thought about the head bolt

and yes if you deck more then a several thousands of the deck.......You will be buying shorter push rods or shimming the rocker arms for proper preload at the lifter.

Flash.

Post by **jsawduste** » February 28th, 2008, 11:55 am

Flash, please don`t travel down the road of shimming stock rocker arms.

Post by **seanyb505** » February 28th, 2008, 12:38 pm

I knew about the valvetrain....my shim kit actually arrived yesterday. Even if I go to zero deck Im still sitting pretty at 9.23 CR. Would bolts have to be altered? Ill be using the 258 rods, so zero deck can be acheived by decking the block .0495", I just didnt know if it was safe or not.

Post by **Flash** » February 28th, 2008, 2:26 pm

seanyb505 wrote:I knew about the valvetrain....my shim kit actually arrived yesterday. Even if I go to zero deck Im still sitting pretty at 9.23 CR. Would bolts have to be altered? Ill be using the 258 rods, so zero deck can be acheived by decking the block .0495", I just didnt know if it was safe or not.

I Don't know?????? ask you machines and let us know what he recommends, or how much you can get a way with before shorter bolts are needed??????

Hmmm i have never heard of any one talking about shortening or replacing with shorter bolts????????

A some point this could be important.

Here's another question.........How thick is the deck?????

Flash.

Post by **seanyb505** » February 28th, 2008, 8:02 pm

Im going off of what is listed on the stroker calculator for deck height, which I dont have on this computer so I dont know off the top of my head.

Post by **Shark** » March 2nd, 2008, 6:33 pm

shorter head bolts shouldnt be a big deal. just take a chop saw and cut off the machined deck height. grind down the rough edges. the stock bolts are plenty long. dont think there would be a problem with losing too much of their strength.

Post by **4point6** » March 22nd, 2008, 10:38 am

jsawduste wrote:Flash, please don`t travel down the road of shimming stock rocker arms.

What is wrong with using shims? I was planning on using these to compensate for decking the block 0.040 +/-:

http://store.summitracing.com/partdetai ... toview=sku

Says they work with the 242. I'd like to not go with custom pushrods, but if shims are bad news, then I'll have to reconsider.

Post by **seanyb505** » March 22nd, 2008, 10:43 am

I was poking around the hesco site the other day and the have different length pushrods for around 40 a set. What are the lengths of the stock rods?

Post by **4point6** » March 22nd, 2008, 11:40 am

seanyb505 wrote:I was poking around the hesco site the other day and the have different length pushrods for around 40 a set. What are the lengths of the stock rods?

My FSM says 9.640" - 9.660", 5/16" diameter

Post by **seanyb505** » March 22nd, 2008, 12:22 pm

The ones I would see being most relevant are 9.5" and 9.547", and you would need to take .093" off the head and block combined to make the most use out of the 9.547" rods. Thats a lot to take off, it looks like if I were to go to zero deck and take .015 from the head the shortest I could go with would be 9.575". I dont need to go to zero deck, so by taking .045 from the block and .015 from the head I would only need a .060 shim for each rocker, and since I have that exact size I think Im ok. But now with the production of the KB pistons which can use the 4.0 rod, Ill have to see which direction regarding zero deck height I take based on price.

Post by **SIXPAK** » March 22nd, 2008, 12:38 pm

I have in the past decked over .090 on a HIGH [14+] comp motor without issue. Adjust push rod lenght as needed.

Post by **seanyb505** » March 22nd, 2008, 5:45 pm

Im sure its possible; I was referring to my particular build.

Is there any reason not to have zero deck height?

Is there any reason not to have zero deck height?

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