Need pistons....

[HHhuntitall]

I lost a head gasket last week on my '03, and the ensuing loss of water got the #6 piston. I don't know if it'll clean up with a hone, so I'm thinking new pistons. I'm gonna have to pull it to sleeve it, so I'm wondering about oversizing it, instead. Any help please. I have no real experience with the HPCR lowers. I intend to ring the head, maybe the block, depending on input from you guys, and head studs. SO, let me have it.

 

[sag2]

Are you sure you lost a head gasket or did you have a bad injector and melted #6?

If you caught it soon enough you can hone and go with a stock piston. Otherwise sleeve it and go with stock piston.

 

[HHhuntitall]

It definitely lost a head gasket. The white cloud that it emitted as I was pulling over even SMELLED like antifreeze. The injectors and nozzles still looks fine, even under the microscope. I've been going to magnaflux it, but I'm too depressed. It's got DDP 60 hp nozzles on it. It's kinda strange how the gasket went, as it was well under 40lbs boost. The cold temperature might have contributed, but it still shouldn't have done it. #@$%! I did buy this truck used, with 50,000 on it in '05, so I suppose it could have had a problem from the previous owner, but it's been running VERY well until this, with no oil usage or other signs of any premature wear. I was looking for pistons as I'd like to have the bore, but I don't know much about building up the HPCR. That's why I'm asking... ... ... ...

 

[JWadford]

if you pull it, sleeve it, all six pistons from cummins for about 1000 with the sleeve, blown mine up twice and a buddies once.

 

[Diesel Power]

No need to sleeve it, take it to a machine shop check the bore first, if it needs over bore up to 4. 060 do it!! buy one piston and run it if your really tight on cash. The bigger bore in one cylinder wont amount to squat, but it will keep that cylinder cooler..... now if it need's more than a . 040 over bore then, sleeve it.



I build racing engine all the time so i have a bit of expirence. if you dont feel comfortable doing this yourself, i may be able to offer you some help, feel free to call.

 

[JWadford]

Dont run one overbore piston and the rest stock, your engine will be out of balance, and the one overbore will run hotter due to more surface area and a thinner cylinder wall, if you bore it, bore them all, or just sleeve the one and hone the rest, i build engines too. Cheaper now might be twice as much sooner than later.

 

[Diesel Power]

Dont run one overbore piston and the rest stock, your engine will be out of balance, and the one overbore will run hotter due to more surface area and a thinner cylinder wall, if you bore it, bore them all, or just sleeve the one and hone the rest, i build engines too. Cheaper now might be twice as much sooner than later.

Wrong!! These engines are internally ballanced, the piston size makes no difference in the ballance... . were talking a difference of say 20-30 grams. . Not saying it's what i would do in a race engine, but in a street truck you will never know the difference.



The bore will run cooler because the bore being bigger will alow for more airflow, anyone that has spent any time on a flowbench knows this. besides the walls are . 250-325 thick!!! Bet you knew that too... . a . 040 over bore would only equal . 020 on each side, that equals nothing, barley 1 cubic inch. :-laf



The bigger bore senario was only if he was tight on cash, otherwise sleeve to standard.

 

[JWadford]

Wrong!! These engines are internally ballanced, the piston size makes no difference in the ballance... . were talking a difference of say 20-30 grams. . Not saying it's what i would do in a race engine, but in a street truck you will never know the difference.



The bore will run cooler because the bore being bigger will alow for more airflow, anyone that has spent any time on a flowbench knows this. besides the walls are . 250-325 thick!!! Bet you knew that too... . a . 040 over bore would only equal . 020 on each side, that equals nothing, barley 1 cubic inch. :-laf



The bigger bore senario was only if he was tight on cash, otherwise sleeve to standard.

ya sure dude throw 20-30 grams at that speed and it becomes pounds you have a companion cylinder that you already know about im sure that weighs less now so now no matter how you do it it is still out of balance. :-laf, also the one cubic inch, do you have any idea how much pressure difference that one cubic inch creates, simple math, 4. 02 bore at only 100 psi would create 1269 pounds of pressure pushing down on the crank journal, bore it . 040 over and it becomes 1294 pounds and that is just using a measily 100 psi which a combustion event is wayyyy more, do the math before you say it doesnt make a difference, you must build checker auto engines.

 

[HHhuntitall]

Let me end the arument there, I'm not going to overbore one cylinder and not do the others. I learned my lesson there on Chrysler RB and Wedges a long time ago, when we were experimenting with firing order on cranks and compression ratios..... I know the rpm will be under 8,000, but I still don't think I like the idea of the one slug being heavier than the others, be it one or two grams or not, even at 1500rpm. Especially when the compression ratio is 19. 5:1 instead of 10. 8:1. I think it's a short term gain, and while the crank will probably handle it, as it's forged(and tough as hell), I'm not gonna want the long term loss(when the crank breaks!). I don't know what it will take to clean up, probably only . 20 over, but I haven't measured it yet. I'm putting it off. Regardless, you're getting off the topic a little, as I'm looking for tougher, better-made, aftermarket pistons, and if there are any for the HPCR, overbored, etc. Please keep to that, if you don't mind. I'm going to build it right, as I'm keeping the truck. It's paid for, and I'll spend the money on the motor. I'm going to go about it right with a new cam, bearings, ported/fire-ringed heads, and a new turbo, too. Not to mention the filter housing off an 855 Big Cam. But now I'M getting off the subject.

 

[HHhuntitall]

OH, AND, thanks for the input, wheither I agree with it or not!!

 

[JWadford]

OH, AND, thanks for the input, wheither I agree with it or not!!

sorry to rant, didnt want to see something bad happen to your truck.

 

[chipster]

ya sure dude throw 20-30 grams at that speed and it becomes pounds you have a companion cylinder that you already know about im sure that weighs less now so now no matter how you do it it is still out of balance. :-laf, also the one cubic inch, do you have any idea how much pressure difference that one cubic inch creates, simple math, 4. 02 bore at only 100 psi would create 1269 pounds of pressure pushing down on the crank journal, bore it . 040 over and it becomes 1294 pounds and that is just using a measily 100 psi which a combustion event is wayyyy more, do the math before you say it doesnt make a difference, you must build checker auto engines.

The simple math according to cummins, in the service manual for `06 dodges, is you can run std. . 020 , or . 040 over pistons in any combination in the same engine. if it needs to go more than . 040 over, sleeve it and go back to std. if cummins says it`s ok to run different size pistons in the engine I believe `em and would not worry about all the personal theory being espoused here. read the service manual and learn something from cummins. there`s no reason to throw away 5 good pistons, and bore 5 good cylinders just to feel good. it`s easy to recommend going all new when it`s someone elses money. cummins dosen`t see it that way. :-{}

 

[HHhuntitall]

Yes, and by cummins spec's this powerplant is 305hp at the flywheel, but when I dyno'ed it last month, it was 373hp, 720ftlbs torque, at the rear wheels with no programmer, and with the TST on 2(where is is run for fuel mileage), it was 410hp, and 905ftlbs. Elevating cylinder pressures will cause devastating effects on crank and journal wear, I would fear. I'd believe Cummins, as well, if this engine would be stock. However, with what I want to do, I'm afraid to bore just one cylinder, as I'm sure you understand. I have no intentions of throwing away ANY pistons, though, as I've got a fleet of these trucks, as well as many earlier generations. Seeing as I'm going to keep this truck for awhile, God willing, I'm going to keep all parts, especially when you don't know when something will be going "BANG!" Thanks for the input...

 

[JWadford]

The simple math according to cummins, in the service manual for `06 dodges, is you can run std. . 020 , or . 040 over pistons in any combination in the same engine. if it needs to go more than . 040 over, sleeve it and go back to std. if cummins says it`s ok to run different size pistons in the engine I believe `em and would not worry about all the personal theory being espoused here. read the service manual and learn something from cummins. there`s no reason to throw away 5 good pistons, and bore 5 good cylinders just to feel good. it`s easy to recommend going all new when it`s someone elses money. cummins dosen`t see it that way. :-{}

i work on cummins engines in blast hole drills and mining equipment, a small vibration leads to major destruction, not trying to push your buttons but as most skilled technicians know what the book says and reality are two different things, it cost 70 dollars for a sleeve and 90 dollars for installation, and 226 dollars for a piston with rings, a crank is 1200 dollars new from cummins, i think rings are 25 dollars a piston,i have built and blown up several different engines from cat, cummins,international,ford,mopar, and chevrolet, honestly every engine i have seen when one piston is larger has had some sort of problems, mainly vibration, so yes i learned something from all of my expieriences with engines, i am simply trying to avoid a situation where a powerstroke or duramax might have to tow him home. MERRY CHRISTMAS

 

[Diesel Power]

The simple math according to cummins, in the service manual for `06 dodges, is you can run std. . 020 , or . 040 over pistons in any combination in the same engine. if it needs to go more than . 040 over, sleeve it and go back to std. if cummins says it`s ok to run different size pistons in the engine I believe `em and would not worry about all the personal theory being espoused here. read the service manual and learn something from cummins. there`s no reason to throw away 5 good pistons, and bore 5 good cylinders just to feel good. it`s easy to recommend going all new when it`s someone elses money. cummins dosen`t see it that way. :-{}

Yea but what does cummins know anyway... ... ... ... ... :-laf



I mean i've only been building race/street/and towing engines for almost 20 years, but what do i know.....

 

[JWadford]

Yea but what does cummins know anyway... ... ... ... ... :-laf



I mean i've only been building race/street/and towing engines for almost 20 years, but what do i know.....

if you wouldnt do it in a race engine then why a street modified engine??? cause cummins did it in a 115 h. p. generator. :-laf

 

[Diesel Power]

if you wouldnt do it in a race engine then why a street modified engine??? cause cummins did it in a 115 h. p. generator. :-laf

Because in a race engine you have a customer with plenty of options and money to spend on the BEST parts availible.



DD engines are mostly owned buy folks who are barley getting by, with very little options, so cost and time is a big concern for them...

 

[chipster]

Yea but what does cummins know anyway... ... ... ... ... :-laf



I mean i've only been building race/street/and towing engines for almost 20 years, but what do i know.....

Cummins knows that you wouldn`t be able to measure the difference in power with one cyl . 020 larger than another. also its really easy to make the . 020 or . 040 piston weigh exactly the same as a std piston. that will eliminate any vibration. I`ve seen many chevy and dodge engines in heavy duty trucks and motor homes with high miles towing heavy trailers with miss matched pistons ,from the factory,and NO problems. I`ve been building the same type of engines, race, street, and towing for 50 years. I`ve been `round the world, been to some redneck picnics, and seen a couple goat roping contests. But I don`t think I`ve seen all there`s to see when it comes to engines. I keep learning something every day. Merry Christmas!!:-laf

 

[Diesel Power]

Cummins knows that you wouldn`t be able to measure the difference in power with one cyl . 020 larger than another. also its really easy to make the . 020 or . 040 piston weigh exactly the same as a std piston. that will eliminate any vibration. I`ve seen many chevy and dodge engines in heavy duty trucks and motor homes with high miles towing heavy trailers with miss matched pistons ,from the factory,and NO problems. I`ve been building the same type of engines, race, street, and towing for 50 years. I`ve been `round the world, been to some redneck picnics, and seen a couple goat roping contests. But I don`t think I`ve seen all there`s to see when it comes to engines. I keep learning something every day. Merry Christmas!!:-laf

Exactly!



Merry Christmas to you as well.

 

[JWadford]

Cummins knows that you wouldn`t be able to measure the difference in power with one cyl . 020 larger than another. also its really easy to make the . 020 or . 040 piston weigh exactly the same as a std piston. that will eliminate any vibration. I`ve seen many chevy and dodge engines in heavy duty trucks and motor homes with high miles towing heavy trailers with miss matched pistons ,from the factory,and NO problems. I`ve been building the same type of engines, race, street, and towing for 50 years. I`ve been `round the world, been to some redneck picnics, and seen a couple goat roping contests. But I don`t think I`ve seen all there`s to see when it comes to engines. I keep learning something every day. Merry Christmas!!:-laf

all the while you can make it balanced by weight you can never balance the pressure difference in the hole that is larger. no matter how much you know, you cant change or balace that part of it, that is what i was getting at, merry christmas to you too