no more p28 pistons
 

I want to do away with my tired p28 pistons and exchange them for a higher compression piston. Can anyone direct me to a piston that requires no modification to the block and isn't going to have a valve clearance issue inside of a d16z6. I would prefer an easydirect replacement.Sorry in advance for the noob question.

RE: no more p28 pistons
 

are you looking for a stock piston? or like aftermarket pistons with higher compression

RE: no more p28 pistons
 

Im looking for direct replacement that needs no block modification and will give me a higher compression.

RE: no more p28 pistons
 

D16A6 pistons with everything else stock will yeild a 10.4 to 1 compression ratio but I suggest you go slightly over bore to clean the cyl walls up.

http://www.knology.net/~jediklc/dcalc.htm

RE: no more p28 pistons
 

What do you mean by clean the cylinder walls up? The block i bought has brand new p28 pistons and rings and has just had the walls honed. What whould be reason for boring the cyl walls?

RE: no more p28 pistons
 

I did not know it was a freshly machined block, mybad

RE: no more p28 pistons
 

I would like to istall the d16a6 pistons onto my stock rods myself. Any beefier direct replacement rods that i can rape from another engine that will work with these pistons that do not require block modification?

RE: no more p28 pistons
 

Best thing I can tell you on that is to just buy a set of aftermarket alum rods or have a stock set bead blasted. You dont need forged rods for what you are doing but if you wanted to add some so that maybe you could spray a little later it would go along way.

RE: no more p28 pistons
 

Price on bead blasting the rods?

RE: no more p28 pistons
 

That calculator can be a little tricky. You have to calculate your own piston to deck height or it will be inaccurate.

Try this one. http://zealautowerks.com/dseries.html It calculates the piston to deck height for you.

Compression with A6 pistons will be about 9.96:1.

An interesting option I'm looking into right now, but may be too much for you is PDN (98-00 GX pistons). The displacement of the dome on them is unknown at this time, but from my searching I'd estimate it's about 4-5cc, which would yeild a high 11/low 12 comp ratio. An interesting thing about them is they use a 21mm wrist pin unlike D16s which have 19mm wrist pins. LS rods have 21mm wrist pins also. This allows for a direct replacement with LS rods with only minor machining to make them fit. I'm not sure how much stronger these rods are, or if it'd even matter in a N/A setup. But it's just something I'm looking into at this time.

RE: no more p28 pistons
 

That sounds awsome. Would the LS rod and PDN piston combo have any valve clearance issues? If so how would I fix the valve clearance?

RE: no more p28 pistons
 

Not sure. The pistons will sit about 0.02" in the block, but the dome is about 0.1" high on them.

RE: no more p28 pistons
 

I have a d16z6. Can anyone tell me if a LS rod and PDN piston combinationis going tohaveproblems with valve clearance? If so, could you you tell me how I would go about fixing thatproblem.Unless you have a better high compression piston-rod combo that would be better suitable for my engine.

RE: no more p28 pistons
 

Eh, I'm a gluten for punishment I guess. I just mentioned that combo because of the rods.

An easier method would be to use P29/PM7 pistons with your stock rods. They will clear, and yield a minimum of about 12:1 CR with an OEM Z6 gasket. You can adjust higher or lower with a thicker or thinner gasket.

:edit: Cometic makes headgaskets in any thickness, btw.

RE: no more p28 pistons
 

Would it be advisable to shot peen my stock rods? And do you know about how much that would cost?

RE: no more p28 pistons
 

shot pening is not expensive...about $30 per rod around here and I'm sure if you look hard you'll find cheaper. Also have the seams ground out.

RE: no more p28 pistons
 

Thanks alot for the answers everyone.

RE: no more p28 pistons
 

keep in mind however that the a6 pistons has the valve releifs in the wrong spot. so milling the head/deck or the use of a high lift cam will require you to clay the motor for clearance. ive seen a6 pistons in a y8 along with the crower stg 3 clash rather nicley in the form of 8 bent valves. however i have built a few z6's with pm7 pistons and crower stg 2's with no issues. worste case you have to fly cut the pistons which isnt very expensive.

RE: no more p28 pistons
 

at some poitn or another someone posted numbers for GX pistons...i'll see if i can find 'em later.

RE: no more p28 pistons
 

PMS or PDN?

RE: no more p28 pistons
 

Here are some P29's that I decided not to use because I'm using a lot of nitrous and wanted H Beam rods and forged pistons...
They are + .040" and fit stock rods with no modifications.. As Kedawei said; You can fudge the compression ratio by using different head gaskets...

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