Question: LLY Motor Build

JoshH

Daggum farm truck
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Feb 14, 2007
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If you think you will put a cam in eventually, you might as well do it while you're building. It will be a lot easier to do it while the motor is out and apart.
 

ChevyDieselLLY

Whats A Budget???
Apr 1, 2008
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Just my opinion:

Rods (Id prefer Crower)
Cut LB7/LLY pistons (coated tops?)
Main studs with line hone
Head studs with torque plate hone
Crank balanced w/SoCal dampner
(minimum) 70% injectors
Remanned stock heads with stronger springs
Stock cam
Dual CP3
Bigger Twins (sorry...only real way to make it "streetable" is twins)

New -- Rings (Mahle), Bearings (Clevite H series), Headgaskets (GM "C") Flywheel/balancer bolts & Gaskets/Orings (whatever you couldnt salvage), Oil pump
Key crank, cam & oil pump, weld water pump


Theres probably some stuff in there that I forgot. Building a Duramax always costs more than you budget.

very nice list you have Tom.
 

TheBac

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Apr 19, 2008
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very nice list you have Tom.

Yeah...its a "wish" list, as in "I sure wish I had the money to afford that list." :rofl:



I agree on the retainers and pushrods if going to an aftermarket cam and heads. Do LLYs have to worry about injector retainers (ala LB7), too?
 
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Akdiesel

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Aug 23, 2009
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Not as far as I know...and yeah when I go with aftermarket heads and a cam I'll be finishing up all the odds and ends
 

JoshH

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I'll keep everyone updated.

Josh are there any issues with running an aftermarket cam and stock heads?
The only thing you might want to do with the heads is swap in a set of upgraded springs and retainers if you are going to run an aftermarket cam. I still have stock castings and valves and just upgraded the springs and retainers with parts from SoCal. If you run a big cam, you will have to have valve reliefs cut in the pistons.

stock pushrods i believe is the only issue. i was told they break.
I am still running stock pushrods and have had no problem with them. I'm sure I'm not the only one either.
 

Akdiesel

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Aug 23, 2009
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Thanks Josh...i think for now I'll be sticking with stock heads and stock cam...but I will be going back through as $$ allows
 

Akdiesel

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Aug 23, 2009
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Well nevermind man...did some thinking guess it'll just be the turbo for now...didn't think about the stock C not being able to keep up with those 100 overs
 

JShe8918

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Feb 17, 2009
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I say if your going to do it once do it right the first time. 700 to 800 i would think that is getting close to girdle territory, but that is just my opinion. Go on and do the cam atleast. It is alot more cost effective to do it all at once unless your doing the work yourself and don't mind the down time. Also the stock heads seem to do decent i "heard" treat is or was running stock heads with springs.

I'm in the process of setting up my LLY build. Just trying to go keep her reliable for when i do lay the power to her. Hoping twins, dual cp3, with big nozzles. My goal is the same as yours no higher than 850 with 760 being my goal.
 
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paint94979

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Sep 18, 2006
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I say if your going to do it once do it right the first time. 700 to 800 i would think that is getting close to girdle territory, but that is just my opinion. Go on and do the cam atleast. It is alot more cost effective to do it all at once unless your doing the work yourself and don't mind the down time. Also the stock heads seem to do decent i "heard" treat is or was running stock heads with springs.

What have you seen that would warrant the use of a girdle in an 800hp truck?
 

Akdiesel

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Aug 23, 2009
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Thanks man. I have a deployment to Afghanistan coming up in Jan/Feb time frame so I may hold off on the build till after as i don't want to get it built by early fall and then have a nice brand new motor sitting for 7 months. That's why i'm not going to risk wadding the motor up by running dual C's and 100 overs with the 475 just yet....figure I'll do the 475...build the motor then do the injectors and dual Cs
 

JShe8918

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Feb 17, 2009
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Maybe i shouldn't say my opinion. But from what i have read. Like stated i am in the process of setting up a build with dimitri and i am leaning towards doing a girdle. Rather be safe than sorry and always over build is my thoughts. But when spending 10K on a build what is another 800 to 1000 for a girdle?