It's a pretty simple process. Std bore is 4.055. The pistons are manufactured to fit in a 4.055 bore.
If you bore the block +.020 you finish the cylinders at 4.075.
Likewise for +.040, finish the cylinders at 4.095.
yes that is tradition over sizes... so you saying that a 4.095 bore runs a ~.001" piston clearance!?!?!?! i know the .060 hyperpnuetestic over BBC piston i put in a BBC had a clearance spec of .0015-.0035"
For a high heat application we normally add an extra .001 to the finished bore size to allow for additional expansion.
If I recall correctly Adam's original motor broke a crank and the cracked the main webs in the block. Someone with more time to spare than I, can probably find the original posts.
yep lost the injector first weeknd of oct 07 right before texas diesel nationals.. made 6galon of fuel and oil mix JD came up and brought me oil to change on the side of the road then followed me back to santa clarita I5/sr126 are loaded the truck up on the trailer and towed it home... i call pat that night while siting almost to garmon CA he siad it was safe to drive all the way home like such... you were working on you stroker kit and asked if you could have my ripped crank for inspection... then joked
about welding up the web and selling it back into service got the dealer to instal 8 new inectors at the same time the 126 valley and your area was burning chased water in oil problems after that including head gaskets and water pumps... then 12-24-07 lost the engine.
Adam found a used block that had burnt a piston and due to $$ concerns wanted to re-use a set of used std pistons. The block was too badly damaged to use std bore pistons again and knowing $$ was tight I made him a deal on some +.020 and all the machine work.
yep foudn a used 06 lbz block, cank, cam that had split a piston.. the plan was to see if it was possilbe to save the std size bore delip the piston and reuse them pending on depth of gouge in the wall. i droped it out monday(10-25-08) morning prior to hollowen 08.. it it was to be bored out you were to use cast pisotns.. it was to get main studs, head studs, keyed crank and camshaft, balanced, mains honed/bored, and block deck/squared up... asked if you woudl be able to get it done by cob friday... you said yes, i asked if it doesn there goign to be anyone here to work on it while you are at sema.. you said yes the one or 2 guys were staying behidn to take care of orders and loose ends... we shook hands and i left.. tues day you called me said need to go .020 over gouge was .010 deep. i gave the ok
We bored and honed the block to +.020 and during final wash discovered a divot in one of the cylinders with the burnt piston hadn't completely cleaned up.
yep got a call 11-11-08 that everything was ready... after it sat in the shop for ~2 weeks and we found the gouge was still there after it was loaded up in the back of my truck.. and inculding the piston the were not to be in the build(new mahle hyper coated pistons with vavle relieves) in which you said that the balance was difference on them bewteen oem cast .020 and the mahle hyper pistons..
Adam was under some sort of deadline to get this engine assembled and move out of CA, we had a discussion about why he couldn't assemble the engine this way, I apologized for the delay and informed him the bore isn't right and would not leave my shop until it was right.
between the wrong pistons, 2 week delay, then finding a .010 gouge still in the wall...after it was loaded on my truck... was VERY disapointing.. so off the block came. asked what you were goign to do with pistons.. you said you had .040 cast pistons... i asked about rebalanceing.. you weighed the .020 and then .040 and found a substanial weight difference. asked if you were going to rebalance... you said no we will cut the .040 down to weigh the same as the .020s... too bad it did leave the shop wrong.. gouge was still there. when assembled those soem one couldnt keep one word and blamed Sema.. like it came and did a sneak attack on your business... and you werent ready for it... thuse why it took almsot 3 weeks.. which is the time i told you i had to get the machine work and anything else that went wrong fixed before i head back east...
So we bored/honed the block to use +.040. The bore size in the block should measure 4.095 to 4.096 with out wear.
The pin bore in a cast Duramax piston is offset by .030. This is to reduce side load on the skirts of the piston.
Installing pistons in a reversed direction would change the offset by a total of .060 resulting in additional side loading of the skirt and additional cylinder/piston wear.
if this is so importent... then why are the new aftermarket pistons have 0 offset? still never answer that question
I stand behind the machine work 100%.
so whats piston to bore clearance? if all 8 cylinders are shot and all bearings are shot... from improper clearances... like i told you when i asembled it i had low .002X" clearance on the mains and rods
I can't control the cleanliness of the assembly or the conditions in which it was run. Did the air cleaner do an effective job of keeping debris from being ingested into the engine? Was it removed for the occasional drag race or sled pull?
Guy
