Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!

1 - 15 of 15 Posts

·
Registered
Joined
·
41 Posts
Discussion Starter · #1 ·
Well I picked up my first lb7. The PO said motor was knocking, had some brass flakes in the oil so he pulled it. He owned a landscape business and got swamped with work so he was unable to fix it.
Here's what I know/was told:
Motor is said to have 223k on it
Has been sitting since may of last year
PO didnt know anything about the injectors, if they've been replaced or not
Rod and main bearings have some wear but nothing looked serious

My plans:
Lbz rods(sitting on the shelf)
Studs
P&P heads
50% over injectors
66mm turbo
Built trans
Efi
Supporting mods etc.

As you will see, I'm pretty much taking over someone else's unfinished project. The motor looks like a mess, I'm mechanically inclined and all but this seems a little intimidating since im new to duramaxes lol. Are there any good write ups or manuals that would be able to help me out? Any tips or tricks I should know about before tearing into everything?





Thanks,
Eric
 

·
Premium Member
Joined
·
3,633 Posts
ill get our lb7 guy over here for ya he will help ya out the best he can! btw i wouldent bother with a port and polish heads, aint worth the money spent for the little gain it has
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #3 ·
I've heard mixed reviews on p&p'ing duramax heads.
Some say do it, others say nay. My girlfriend had her heads ported on her efi tuned 04. Claims there was a difference but I'm not so sure. My teacher always said money spent on the heads is money well spent, but we were talking mostly gassers. I just don't want to be in the same spot I am with my Cummins. Had the head fire ringed and studded and slapped it on, one of my biggest regrets was not getting it ported, I thought about pulling it to have it done but it has taken a lot of abuse so why break something that works.
 

·
Registered
Joined
·
4,924 Posts
Duramax heads flow amazingly well in stock form. If your not doing an all out 1000+ horse motor build, then skip the port and polish. And even then, it is a toss up.

What are your hp plans for the truck?
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #5 ·
Just looking for a street/strip kinda deal. Something still streetable but will put people in their place when the need arises. 600 seems like the comfortable operating area for people with lbz rods, so I'll probably get some tuning from Rob or Kory and try to get somewhere around there.
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #7 ·
I'm around that right now on mine... I've been thru 4 transmissions in less than 6 months. Any time I put the hammer down in 5th it just chews all the teeth off of the gears. Pretty annoying, these nv4500s suck. Haha
 

·
Registered
Joined
·
4,924 Posts
I'm around that right now on mine... I've been thru 4 transmissions in less than 6 months. Any time I put the hammer down in 5th it just chews all the teeth off of the gears. Pretty annoying, these nv4500s suck. Haha
My 01 cummins also was a 5 speed. I laid down 604 hp and 1290tq. Never once had an issue with my trans. It saw 604 hp multiple times everyday for a year before i sold the truck. nv4500's are stout until parts start getting replaced in them. New venture doesnt make parts for the nv4500 anymore so there all cheap chinese copies that are terrible. Once they have been opened up and remand, there quality is gone.
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #9 · (Edited)
Yup i agree. I lost 3rd gear last fall. Took out all the other internal gears and trans completely locked up. Bought a remanned from a dealer, either way id be looking at cheap aftermarket replacements, I would have more in parts than I would with a new trans, plus the new trans came with a better warranty (3yr 300,000 mi).... it would be nice if I could get them to last 3 months or 3,000 miles.... I busted my 5th and counter shaft gear earlier this week which really made me want to get the ball rolling with this project. But looks like I got lucky, all the pieces stayed out of the gears and I have an OEM 5th gear I took off my original trans. Should be back on the road by Tuesday.

That wasn't even all of them.




It is missing more teeth along the top as well
 

·
Registered
Joined
·
7,376 Posts
As far as the LB7 goes, I agree with no P&P. It definately a waste of money for a 600HP goal. It wouldnt be in my plans even for 700hp.

Your going to have some dry seals from that motor being out for so long. The CP3 is something I would remove and have inspected or rebuilt for the miles it has on it. They tend to weaken and lose the holding power towing or racing in higher gears. Plus your seal on that could be bad. I would also replace the waterpump while the motor is out. If your doing LBZ rods you will have all new bearings, so I wouldnt worry unless you find issues with the crankshaft.

The injectors are a bigger issue as I'm sure you know. If you want the very best go with Exergy's. The bigger the better for the motor, and injectors. Probably up to 60 overs I would say. Rob and Kory wouldnt tune for more than the motor could hold, so you won't use the full potential of the bigger injectors. However being open for shorter time, and flowing fuel easier will keep temps down, and lessen the chance of them cracking. So 50 overs like you said should be good for everything.

Are you planning on pulling the heads and replacing the headgaskets? If so plan on doing ARP studs in the heads. You dont need the more expensive ones for 600hp. As you will see they are for 650+ applications.

Hope this helps some.
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #11 ·
I gotta pull the pistons to put the rods in so the heads gotta come off. Buying new bearings, rings, head gaskets,water and oil pump. Gonna have the motor balanced for the added weight of the lbz rods.

Will my cp3 handle 60 overs? Don't people run lbz cp3s on their lb7s to help keep up with bigger injectors in the higher rpms? Would I need the whole pump or just the fpr?


Should I throw an aftermarket cam in while its out and right there?
 

·
Registered
Joined
·
7,376 Posts
The LB7 pump is capable of making the same as the LBZ, the difference is the FPR. So you could keep yours and put the LBZ fpr on it. But if it needs work just get the LBZ pump if it's easier for you. Add a lift pump to your list.

I know your stock cam will do fine, but I have not personally seen a Duramax motor with a aftermarket cam. DmaxChris is running one, so I'm sure you could ask His opinion on that and get a solid answer.
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #13 ·
Lift pump, gauges, exhaust, traction bars, sleeves,etc.

I'll look into a cam. What about heavier valve springs and push rods?

How hard is this motor to tear apart and reassemble... well mostly reassemble, I have a big tote full of random nuts bolts and pieces he already took off. Any detorquing sequence on the heads?
 

·
Registered
Joined
·
7,376 Posts
As far as the heads are concerned, you dont NEED to do anything unless your going for more than 800hp. If you want to get a cam it may help in some way, but your stock LB7 cam will perform very well with no failures for your HP goal. Same for springs and pushrods. Everything needs a good inspection because of the metal/brass in the oil.

With the motor out like that it should be easy to tear apart. and re-assemble. You can take pics of the bolts and nuts seperated from eachother, and I'm sure we can help you with where they should go. There is a detorque sequence for the heads. It's opposite from the torque sequence. I believe its from the outside to the middle to remove them, top and bottom bolts on each end, and work in to the center.
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #15 ·
What about pistons? Should I get them Cut/coated? I just want to do as much as I can while its out.
 
1 - 15 of 15 Posts
Top