triple L

iTrader: (14)

Hey evom,


I've had this project going on for about 9 months... saved up and collected all the necessary parts to do the 2.3 stroker kit... i've taken the longblock to a local performance shop to have it cleaned, honed, decked, hot tanked and had the head ported and polish and 3 angle valve job resurface... i finally went and got the block back from the shop because they took way too long (6 months)...

i tore down the whole block to inspect the piston rings and clearance on the rods and seen that they had notch it up pretty well around the areas to clear the rods... after doing so i went and installed everything back together cleaned it up pretty well and wrench it down to torque specs to my finding that the pistons had A LOT OF PLAY SIDE TO SIDE... to where when i start to crank it you can actually see the pistons move side to side....

this is my first time building the motor so i am no professional but to my understanding this is not normal....

please fill me in with any inputs and tips i am thinking they had the block honed down too much since my pistons are standard size 85mm will i still be able to use these pistons or go a bit larger!? the motor will be seeing in the 600s awhp

thanks for any reply and stay safe!!

Bcity

Wussup triple l , what's the piston to bore clearance ? Answer that and we can help.
Everyone's standard for "A LOT" will always be different .
So let me rattle off.
Pistons rock , stroker pistons rock more , 2.3l has the most extreme side loading of the piston because of the stroke, angle, rod ratio and reduced dwell.
You haven't mentioned the actual pistons you purchased, so more rattle.
Manufacturers recommended piston to bore clearance differ.
so your choice of piston could have a large amount of recommended clearance.
for example Ross pistons have recommended as little as 0.006" not up to 6.
wiseco/Cp/mahle/tomei I'd give a MINIMUM of 0.0035" and then hks again recommend even less.

This brings me to another point, piston to wall clearance isn't just determined by manf recom, INTENDED APPLICATION and the experience of the machinist will also change the clearance.
Last but not least what was the condition of the bore ? Maybe it took an extra thou to clean round and parallel.
so I'd pop the pistons out and measure the piston to bore clearance ( if you don't know how, type 2.3l build there's heaps or just call your machinist and ask them how much clearance it has)
you could also just measure the rock , tdc piston, dial indicator, zero measure 4 point cross Section, find average of the 4 measurements ( depth or zero deck) then place D/I on thrust side and rock piston. This will give you an idea if it's smoked
The crown is also significantly smaller than the skirt so what may seem as a excessive amount of rock might just be a trick of the eye.


Oh almost forgot was it torque plate honed with upgraded head bolts ?
I've seen L19s close the bore up to 0.0018" so you'd have to reinstall the torque plate to get the p/b clearance to repeat depending on where you measure.
Thrust axis don't tend to close , usually they close across the head bolt axis.


Hope that helps G/L cuzzie

triple L

iTrader: (14)

that helped a lot i will measure the piston to bore clearance and post soon

JohnBradley

iTrader: (30)

Wiseco has 2 sides to the spec sheet that comes with the pistons. 0.0035" is just the starting point not the end point. PTW really is determined by 2 things, Alloy used and power expected. 2618 will be different than 4032, a 300hp motor can run tighter than a 900hp motor. Once you know what that is, which is most likely as easy as calling the machine shop, it can make things easier to determine. If they come back with some crazy number then it will be pretty obvious.

Aby@MIL.SPEC

iTrader: (161)

piston clearances are generally determined by taking the diameter of the piston near the bottom of the skirt.

piston clearance is not determined by the piston crown to cylinder wall.

besides, if you measure the skirt of a piston, it's not round. There is actually a bit of "cam" built into the skirt.

the top of the piston has a lot of room, due to expansion from the heat. so yeah, if your looking @ the piston crown & see the ring, because there is ~.010/.020 clearance, thats fine... this is the part of the piston that expands the most, so the extra clearance is needed.

Bcity

Who ever said PTW was measured at the crown ?

Aby@MIL.SPEC

iTrader: (161)

sorry, my assumption.

that is why I said what i said.

sounds like you have it covered....

okevolutionVIII

iTrader: (71)

Did the shop give you a build sheet for clearances or did you even give them a piston to match up the PTW clearance you wanted? I bought a "built" 2.3L from Top Level Performance a few years ago and had to rebuild it myself after it locked up before ever starting. I would pull all the pistons and see what's going on. Like everyone said, the PTW clearance depends on the piston material and the max power in mind. For example, I did my std. Wisecos at .004 after finding my "built" block to have been at .002(wouldn't have ran long if it didn't lock up).