L5P interchangeability?

Leadfoot

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Dec 27, 2006
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I know there are a few internal changes (such as the reluctor being placed in the rear) as well as a few external changes (doing away with the second motor mount bosses), but was under the impression that the basic footprint remained the same. Just curious if an L5P shortblock could be swapped in as a service replacement for a blown LBZ in a daily driver?

I guess the biggest hurdle would be if the reluctor can be made to work (not sure of tooth counts) with an extension or adapter harness, and if everything else will bolt up.

Not that they are available yet, just wondering if it will be possible when they are.

Now that they've been out for a few months and I assume certain shops have at least started to play with them....
 

02greysixer

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Jun 4, 2011
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I feel like the bigger hurdle will be making the denso fuel system work with older trucks electronics or making Bosch parts fit the new engine. Unless blocks are similar enough heads could interchange

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JoshH

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The taller deck will make it extremely difficult requiring a lot of custom fuel lines and intake pieces. That is assuming the earlier heads will bolt on to the new block.
 

Leadfoot

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I feel like the bigger hurdle will be making the denso fuel system work with older trucks electronics or making Bosch parts fit the new engine. Unless blocks are similar enough heads could interchange

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I was thinking/hoping the older upper end could be used so there would be no issues with fueling or electronics.
 

Leadfoot

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The taller deck will make it extremely difficult requiring a lot of custom fuel lines and intake pieces. That is assuming the earlier heads will bolt on to the new block.

We run standard deck intakes on tall deck big block chevy's with spacers all the time. Spacers on the Y bridge or even a custom Y bridge would seem to be the only issue (maybe feed lines to the rails as well if there isn't enough movement in the stockers). It sounds as if there are extra bolt holes as the new heads have more, but I'm assuming if they kept the old pattern old heads should still bolt up.

Y bridge spacer and custom rail lines would be a pretty cheap price to pay for "what is said to be" a MUCH better bottom end especially for someone with a damaged block.

Edit: possibly longer pushrods as well to compensate for deck height, but again a minor issue and if your swapping over the upper end your doing the work anyways (not an extra step).
 
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2004LB7

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What voltage do the denso injectors work at? Maybe they will work with one of the earlier year ecm/fcim

The other item would be the HPFP regulator. How close is it to the Bosch one and would it play nice with the ecm?

I think everything else could probably be made to "work"

I am sure you can plumb in a Bosch compatible pressure sensor, a cam and crank sensors, etc.
 

Leadfoot

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Dec 27, 2006
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Revisiting this as more time has passed and I think some people didn't read or misinterpretted what I was asking.

I was wondering if someone loses a bottom end on a previous generation light duty DMax (LB7, LLY, LBZ, LMM, or LML) such as a broken crank/rod/piston, if they could take THEIR top end with THEIR ORIGINAL injectors, harness, CP3, fuel lines, rails, etc. etc. and swap it on to an L5P (electronics/injector compatability would be a non-issue). Their original electronics and injectors, etc. etc would work the same as they did before so no need to reinvent the wheel.

From what I've gathered the L5P adds bolt holes for the additional head bolts of the L5P heads, but the original holes still line up, so heads should be bolt on. It is a taller deck though which would require longer pushrods (easy enough and you have the heads off anyways) and a y-bridge spacer or custom bridge (again shouldn't be too tough as we already have vendors making aftermarket bridges).

The thing I'm most interested in and could be the biggest problem would be due to the relocation of the reluctor wheel and tooth counts. Is the count similar to that of any of the previous generations and/or is the sensor compatible or will an older sensor work. Without the reluctor working (whether it be putting the old sensor in and extending the harness), or making the new sensor work with "tuning", it's a moot point.

The reason I ask is that while injectors due go bad and CP3's sometimes fail, overall the top end seems to be pretty good, it's the bottom end (crank and pistons mostly) that seem to be suspect even with high dollar cranks. It seems the L5P may be an alternative for those of us who want more power for daily driving and weekend warrioring without as much fear of a broken crank. If we have to buy a block anyways, might as well get one that "seems" to have fixed several issues that we tend to worry about.

The big question is what type of reluctor wheel do they use (is it similar in size and tooth count to a previous gen) and will an previous sensor work, or is the L5P sensor the same or can one be adapted to work? I'm pretty sure Banks knows the answer, just wondering if any of our board engine builders and tuners have had a chance to see what's going on with the new bottom ends yet?



What voltage do the denso injectors work at? Maybe they will work with one of the earlier year ecm/fcim

The other item would be the HPFP regulator. How close is it to the Bosch one and would it play nice with the ecm?

I think everything else could probably be made to "work"

I am sure you can plumb in a Bosch compatible pressure sensor, a cam and crank sensors, etc.
 

countrycorey

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Jan 30, 2010
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I don't know if you would be asking for issues with not using the two outer head bolt holes and how that would affect/distort the block once assembled.

If youre going to go through the trouble or effort, why not try to swap in a long block or complete engine?

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NC-smokinlmm

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May 29, 2011
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It's going to be difficult no matter what without the stock file to use as a base tune and I think getting that is going to prove the hurdle. GM invests an obscene amount of money, time and manpower into building the tune file so I doubt any performance company could pull off a tune without it...
 

2004LB7

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I dont think the question was for using the engine along with its ECM but more for using the long block as an upgrade to the older blocks.taking advantage of the new crank, rods, etc

I still think someone needs to test the denso injectors with an LMM ECM to see if the whole engine less its ECM could be swapped into an older truck
 

Leadfoot

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I dont think the question was for using the engine along with its ECM but more for using the long block as an upgrade to the older blocks.taking advantage of the new crank, rods, etc
Exactly

I still think someone needs to test the denso injectors with an LMM ECM to see if the whole engine less its ECM could be swapped into an older truck
That would be nice if possible. How different physically are the injectors? If the LBZ ECM can't control the denso injectors, could the LBZ injectors fit in L5P heads and what about connectors? Also is the reluctor going to be an issue?
 
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Leadfoot

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Dec 27, 2006
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It's going to be difficult no matter what without the stock file to use as a base tune and I think getting that is going to prove the hurdle. GM invests an obscene amount of money, time and manpower into building the tune file so I doubt any performance company could pull off a tune without it...

Using the LBZ upper end would negate any tuning issues.
 

Leadfoot

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Dec 27, 2006
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I don't know if you would be asking for issues with not using the two outer head bolt holes and how that would affect/distort the block once assembled.

The stock LBZ heads with the 2 fewer bolts still hold a butt-load of power especially on a street machine, so a non-issue for what I and many others would be looking for

If youre going to go through the trouble or effort, why not try to swap in a long block or complete engine?

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Because right now the L5P uses a completely different injector setup. If it COULD be controlled by the older ECM's it would be even better as you could bolt in a complete long block, but that doesn't look promising at this point.

One question that might hinder is the fact the reluctor wheel is moved and I'm not sure if the plug for the sensor is the same or what the tooth count/spacing is. That's kinda the information that will dictate what is/isn't possible. I was hoping somebody had some insight.
 

RPM Motorsports

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I've tried twice to get hold of an L5P from Banks like he has listed for sale, so I can attempt to run one on older electronics. He used to respond to FB messages, but seems he's not even doing that any more. Would be a fun project to play with on the engine stand.
 

2004LB7

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looks like one may be able to shoehorn in a previous a gen injector. good information

from here:http://www.trucktrend.com/how-to/engine/1702-a-peek-inside-the-duramax-l5p/

039-6.6l-duramax-l5p.jpg


"The Denso G4S Gen III solenoid-type injectors (left) are new to the Duramax engine. The top-mounted solenoid and fuel inlet, along with 0.7677-inch (19.5mm) body diameter, make it distinctively different from its counterpart. Denso’s Mini-Sac nozzle provides 830 cc of fuel per minute through seven holes and a 180-degree spray angle. The tip of the nozzle protrudes 0.059 inch (1.5 mm) into the cylinder. The hold-down bracket assembly is redesigned for the new injector."
 

THEFERMANATOR

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You may be able to swap the timing cover, do some machining, and swap in the reluctor up front and forget about the rear one. Or you can always go external with a reluctor.
 

Leadfoot

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Dec 27, 2006
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It's been a few months and I know a few shops (other than Banks) have started to look at these. Just wondering what everyone's thoughts are on shortblock retrofit. Biggest hurdle seems to be the reluctor but I'm sure someone will figure it out (possibly a plug & play solution). Pushrods and Y-bridge also a concern but should be "easy" fixes.