LBZ piston replacement

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redneckbuckeye

Member
Mar 27, 2008
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Sheridan, IN.
What would be envolved in replacing the pistons and rods on a LBZ before they went boom. I am looking at the most economic way to do this. I realize the engine would hve to be pulled heads and all accessories on the top of the motor. Would you have to have the cylinders delipped or any other machine work. What does a set of lb7 cut and coated pistons run versus a forged set.
Ballbark doing the tear down and labor myself what are we looking at for money invovled.
 
ripmf666

ripmf666

Active member
Sep 20, 2006
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Wentzville Mo
Rods and Pistons with rings and pins are around 4918.00 shipped, You will nee dto have the block tq plate honed and the setup balanced.If you stay with main bolts and not main studs you will need new bolts from GM and side bolts all cost around 50 bucks for all 10 mains and 10 side cap ones, Most of the gaskets and the head gaskets and sealent will run with the bolts I said above total is 530 area, The forged pistons are 2500 bucks just alittle more then the LB7 that are cut and coated the pretty sure the mahle forged ones are not coated on top and there is not hard proof on daily drive life.your going to havd 530 in head studs, with you doing all the work yourself you will have around 8000k in parts and machine work mybe just a hair less, You will have 60 hrs of work in pulling the motor tearing it down and rebuilding it and installing it back in your truck.Look at a few of my post and you can see I posted alot of pics from my rebuild and lots of part #'s heres a link http://www.duramaxdiesels.com/forum/showthread.php?t=5608&page=3
http://www.duramaxdiesels.com/forum/showthread.php?t=6679
 
JOHNBOY

JOHNBOY

< Rocking the Big Single!
Aug 30, 2006
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Saegertown, Pa
redneckbuckeye said:
Thanks for the info, does it save you any money if you do the replacement before a failure, or is it better to just hope you get lucky.
Click to expand...

Depends. If you spilt a piston or bend a rod and hurt the block it will cost more. If you just blow a hole in the piston and the cylinder can be honed to clean up and not bored it really is about even.

I still would rather build it, before I break it. It is best to buy another short block and build it so you dont have so much truck down time. It costs more up front but you can get your money back out of the stock long block when you install the built engine. Building the engine in the truck is what I did. I regret it honestly. I should have built another motor then swapped. Builds always take longer then planned.
 
NelsonDiesel

NelsonDiesel

Formerly StewieTuned
May 8, 2008
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www.NelsonDiesel.com
i am looking into a repair "before" a catastrophic failure. I am only considering fresh rings, LBZ or LMM rods and necessary work/parts to put it back together :) . i am a long way from this but it is in my mind.....

I am a firm believer in fixing things before they break....
 
slowlmm

slowlmm

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Mar 2, 2008
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StewieTuned said:
i am looking into a repair "before" a catastrophic failure. I am only considering fresh rings, LBZ or LMM rods and necessary work/parts to put it back together :) . i am a long way from this but it is in my mind.....

I am a firm believer in fixing things before they break....
Click to expand...

Not me dont fix wht aint broke :D but then im a dummy with work/race truck with a broken motor :D
 
slowlmm

slowlmm

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Mar 2, 2008
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Imo do the rods at the same time or wait untill you can afford them, lbz rods will hold 600 rwhp no prob but as you go up you take more chance of a failure. your saveing 2400 + $ inetailly but if you window your block and damge your new pistons you will be into it for alot more then that. and plus all the time to rebuild again
 
custom8726

custom8726

Active member
Feb 25, 2008
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Upstate N.Y
JOHNBOY said:
Depends. If you spilt a piston or bend a rod and hurt the block it will cost more. If you just blow a hole in the piston and the cylinder can be honed to clean up and not bored it really is about even.

I still would rather build it, before I break it. It is best to buy another short block and build it so you dont have so much truck down time. It costs more up front but you can get your money back out of the stock long block when you install the built engine. Building the engine in the truck is what I did. I regret it honestly. I should have built another motor then swapped. Builds always take longer then planned.
Click to expand...


I am learning this now:rolleyes: And you are correct:thumb:
 
SmokeShow

SmokeShow

Well-known member
Nov 30, 2006
6,818
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Lawrenceburg, KY
so to change the rods and pistons, and nothing else, the block HAS to go to the machine shop? Exactly how necessary is that? Thinking along the lines of running this engine one year, then tearing down to build appropriately the following winter.

Basically want to take pistons and rods out and put used cut lb7s with fresh rings and new rods and go. If I have the rods and pistons balanced, do they have to balanced with the crank?


I want to know what trent did to get his done for less than $5k! :thumb:
 
wdino73

wdino73

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Sep 25, 2009
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Versailles, Ky
Now boyz you know everyone has their own little opinion an everyone thinks their right, LOL, If u don't have deep pocket u have to be smart common sense goes along way, It all depends on what your going to do with the truck after the build. what Hp an Torque you want to run, and boost. That will tell where u need to start, that's my littlle opinion.
 
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SmokeShow

SmokeShow

Well-known member
Nov 30, 2006
6,818
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Lawrenceburg, KY
quite literally, I'm building a grenade. I'm gonna push it way harder than it should be and only need it to last a year. Just can't afford the charger, and dual cp3s and build the engine all out in the beginning. So, engine is gonna have to be as simple as absolutely possible.

It might not be possible, I don't know. I'm probably just gonna buy a seperate block and crank and build it up correctly from there. ;)


C-ya
 
RENODMAX

RENODMAX

Dead Wrong
Mar 4, 2008
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Yes Mitch the Dmax needs to be balanced with crank, balancer AND flywheel iirc. However if someone is running a motor that wasn't balanced I'd assume they'd have their rods damn near the same weight ;). The stock motors are nowhere near balanced I'll tell you that much.
 
RENODMAX

RENODMAX

Dead Wrong
Mar 4, 2008
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hes talking about balancing the rotating assembly when he switches rods and pistons. not boring/honing the block
 
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