LB7: Motor Build thread

LBZ

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Jul 2, 2007
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I might be wrong, but I thought most of the balance is done with the piston assembled on the rod and then the weight is removed from the piston.

Good question though!
 

sweetdiesel

That's better
Aug 6, 2006
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I might be wrong, but I thought most of the balance is done with the piston assembled on the rod and then the weight is removed from the piston.

Good question though!


all my pistons weigh the exact same.


wieght is removed from crank.......
 

zfuller123

StarLite Diesel
Sep 2, 2006
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www.starlitediesel.com
Yep let me know when it's time.. if you can give me a week or two notice.. if it's gonna be before the end of december (are there even races down there during december?) - i still have avacation day to use up for travel before the years over so would love to spend it on vegas :)
 

TrentNell

Finally underway !!!!!
Jul 7, 2008
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Man , finally got the cylinder heads done and on the motor , if anyone ever pulls there heads off i would advise getting them checked out or doing it yourself before you re-install , these heads came off of a running and drivable truck ( not mine ) and i found 7 bent valves, most slightly but enough to bind on the seal , and 2 that were very bent .

Had alot more pics of the heads and motor but my phone quit emailing on me so :rolleyes: , and had pics of the quite large pile of powder coated parts too , i will update them later .
 

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TrentNell

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Jul 7, 2008
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more pics , they dont do justice to the color of the powder coat or how deep the color looks
 

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TrentNell

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Jul 7, 2008
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.........
 

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LBZ

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X2 after weighing all the piston/rod assembly's , the differnce wasnt enough for my own opinion to worry about removing material .

all my pistons weigh the exact same.


wieght is removed from crank.......

Crank weight removal I know about, but remember Josh H's issue with his machinist drilling into his pistons? What was that about? I thought that was to get each piston/rod the same weight or maybe it was just someone doing something they shouldn't have...
 

JoshH

Daggum farm truck
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Feb 14, 2007
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I might be wrong, but I thought most of the balance is done with the piston assembled on the rod and then the weight is removed from the piston.

Good question though!
When an engine is balanced, you must weight each rod and make the rods all the same weight. They will be balanced so the big end and the small end are within 1 gram of each other, and ideally the whole rod weight will be within 1 gram of each other, on a good balance job. Then each piston, piston ring, wrist pin and clip set is matched to within 1 gram of each other (the rings, pin and clips should all be the same, so it doesn't matter what if they get mixed from one piston to the other). Then bob weights are assembled to match the weight of each rod piston combo and they are attached to the crank throws and the balancer and flywheel/flexplate are attached to the crank. The crank is then spun on a crank balancer and weight is removed or added where the machine says to.

Crank weight removal I know about, but remember Josh H's issue with his machinist drilling into his pistons? What was that about? I thought that was to get each piston/rod the same weight or maybe it was just someone doing something they shouldn't have...
My problem was when the machine shop was balancing the pistons the guy drilled into the bottom of the pistons to remove weight from the heavier pistons, and on the heavier pistons he hit the oil cooling gallery. I had Guy balance my replacements and he removed the weight from the wrist pin (chamferred the inside diameter on each end similar to how the LBZ wrist pins are) and engraved the pin and piston so I knew for sure which pin went with which piston. That allowed the removal of less material since steel is more dense than aluminum, and it kept from removing any material from the piston.
 
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dordtrecht5

Regular Cabs Rock
Jul 21, 2009
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When an engine is balanced, you must weight each rod and make the rods all the same weight. They will be balanced so the big end and the small end are within 1 gram of each other, and ideally the whole rod weight will be within 1 gram of each other, on a good balance job. Then each piston, piston ring, wrist pin and clip set is matched to within 1 gram of each other (the rings, pin and clips should all be the same, so it doesn't matter what if they get mixed from one piston to the other). Then bob weights are assembled to match the weight of each rod piston combo and they are attached to the crank throws and the balancer and flywheel/flexplate are attached to the crank. The crank is then spun on a crank balancer and weight is removed or added where the machine says to.

Thanks for the clarity. That is how I did it on an old Super Stock gas car back in the day, but because I am mostly ignorant about diesel hot rodding, I didn't know if it was done differently or not.
 

TrentNell

Finally underway !!!!!
Jul 7, 2008
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Getting close now , other than I put the intake manifolds on wrong and have to flip them :rolleyes: , oh well easy fix and at least i noticed now . still have abit before its done I wont drop the motor untill i get my new twins but really all i have left is accessories , wiring , and fuel lines and such .

Pics arent the best quality , cell phone is way easier than breaking out the camera .
 

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duratothemax

<--- slippery roads
Aug 28, 2006
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wow Trent!!! Im not gonna lie...when you posted up the first pics of the green parts.....I really wasnt crazy about it.

But now that I see them all on the engine/together...that looks sweet! Nice job.
 

TrentNell

Finally underway !!!!!
Jul 7, 2008
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wow Trent!!! Im not gonna lie...when you posted up the first pics of the green parts.....I really wasnt crazy about it.

But now that I see them all on the engine/together...that looks sweet! Nice job.

Thanks Ben , there will be a fair bit of black to break it up , and like I said earlier in the thread the pics dont do it justice , nor does the poor lighting , I like it so far and its a color combo i haven't seen before so that makes it better for me . Plus the color was chosen to go with my black twin piping , I havent even decided what color the new set is going to be .
 
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ChevyDieselLLY

Whats A Budget???
Apr 1, 2008
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very nice Trent. i like it alot.

i think you should keep your new twins looking like your old ones, black tubing with the chrome covers. i think it will go very nice with the motor.