Boring Out A Motor
 

Anyone have a rough estimate how much this would cost. I think making a 5.9 a 6.2 adds bout 100 hp but not sure. thanks

i think there has to be a better way to get a 100 hp then boring out your engine

is there any purpose other than just trying to add extra hp? and the reason boring adds the extra hp is b/c it bumps compression ratio, which meants that any other mods have to be take into consideration... nitrous, timing, big boost numbers... its going to lift the head that much easier.

i could be wrong but they dont make oversise pistons you just bore it 30 over and sleve it back to stock but like i said i could be wrong

i think i've seen the pistons floating around... they're odd sizes... gassers typically being bored .030 and .060 while the cummins is like 20 and 40 (dont hold me to that) i saw a 40 over piston and just thought that was an oddball size

could be it too idk:c:

my bud down the street has a 2nd gen twelve valve thats bored 30 over and it runs like a bat out of hell

most cummins do run liek a bat out of hell bud... i guess the point is; yes its possible; but it isnt an upgrade most opt for. since the 5.9 is a parent bore block if the cylinder gets scored you have to bore it like a gasser opposed to say a wet cylinder liner replacement. yes it will make the truck run better and result in higher power numbers. problem is as stated before boring out the engine will increase the compression ratio, with a higher compression ratio you have to be weary of higher boost pressures, nitrous and above stock timing. the head will be much more prone to lifting. if you wanna drop the change go for it; just dont go crazy with the timing or boost pressures. for example some competition trucks will lower their compression ratio so they can force more air into the cylinder for better oxidization of the supplied fuel while maintaining safe cylinder pressures.

i think cummins over bore sizing is metric, yes you can get oversize pistons from cummins...i work for a diesel machine shop in e-town an w just bored oout a 24v. the pistons cost about $1200 an boring it out wasn't cheap either, but don't ask me to many prices i just rip the stuff apart an put it back together...i dont think timing or bost will be a really big factor with a good set of head studs, an oversize head gasget, or even get your piston tops shaved daown like .005"-.010", but make shure you talk to your machine shop, they can help you with all that kinda stuff

Check the compression height on the replacement pistons,if it is like the gassers the piston manufacturers lower the comp height to make up for the overbore.This is on stock replacement pistons only.