Motor Build Qs

[insane3639]

Hello all, im looking at buying a Dmax and with the school i plan on going to they give me the option to build that motor if I want to. I plan on building the motor just a mild one. What im looking at is on the LB7 when is it necessary to shave the pistons? and to what CR? and if shaving pistions and lowering CR with this relatively low boost is it necessary to put it better rods? What im looking at is a mild build with a BD turbo or similar which is like 45psi max, or possibly twins if money is sufficient. I would tune it myself with EFI live and also throw on some other bang for your buck goods. Just looking for a good Daily Driver that tows well.

Thanks for the help.

 

[duratothemax]

The "basic" garden variety "budget" dmax build consists of:

-delipped (NOT anything taken off the top, just take the lip off of the bowl ( with a .1875" radius) LB7/LLY pistons

-crower, carillio, R&R/TTS, or Howards rods

-keyed [stock] crank

-keyed [stock] cam

-stock heads and stock misc valvetrain stuff

-arp head studs

-balance the rotating assembly

-new stock bearings, seals, rings

I dont know what else im forgetting but thats the basic idea. Doing aftermarket rods is key if you want to be run over 675rwhp or so (thats the ROUGH long term reliable limit for LBZ rods, LB7/LLY rods about 100rwhp less). Of course stock rods arent gonna flat out break the second you go over that power level; the stock dmax rods give you lots of warning (they can bend a lot without breaking) before something catastrophic happens. Basically nothing is guaranteed over those hp levels. It might last 10,000 miles at >675 rwhp, or it might last 1,000 miles...

general consensus is ~16.0-16.5:1 is a good CR to shoot for in a daily driver that will see a wide range of temperatures.

they arent really hard engines to build in my opinion; just follow the service manual as there ARE some particular non-standard procedures, and triple check everything and you'll be fine.

someone else can add on to my post as im sure im forgetting some things....

ben

 

[duratothemax]

EDIT: If im interpreting your post/ideas correctly, I think you are kinda underestimating the dmax for the goals you are setting...if you are running a BD turbo and a single cp3 with a big EFILive tune, you'll be fine with a 100% stock engine. Even the stock head bolts will be fine at 45psi.

BIG turbos and dual CP3's is when you start running on borrowed time, like 700+ rwhp and 11 second quarter miles...

ben

 

[Osubeaver]

they arent really hard engines to build in my opinion; just follow the service manual as there ARE some particular non-standard procedures, and triple check everything and you'll be fine.

someone else can add on to my post as im sure im forgetting some things....

ben

From a guy that knows nothing about building an engine and is looking to have a local, reputable, gasser shop build one:

What are the non-standard procedures? Cliff's Notes version.

 

[othrgrl]

Ben pretty much hit it on the head with a budget build. Lowering the compression ratio is not at all necessary - when the pistons get delipped you lose a little compression, but that's not why you delip them. Rods, head studs, keyed crank and cam, and delipped pistons are the basics. Also as Ben said if you are going to run a BD turbo (there are much better options by the way) and a single CP3 then you don't even need to go into the motor. You could get up to about 600hp with the right S366 charger and a single CP3 and still have a truck that can tow heavy loads just fine. A nice setup for 750+hp is rods, keyed, delipped, studded with 40% over injectors, dual fuelers, and an S472 charger. If you have more to spend stage 1 or stage 2 heads, a cam, intercooler, headers, ect are all good things to add.

 

[insane3639]

Thnanks for all that info! I know their are some better turbos but where is a good place to look for them i was looking at II or FPE or possibly MPI twins in money was sufficient

 

[Bako_Dmax]

Building your own twins is not hard if you have the right tools and some patience. There is lots of info and pics on here for DIY twins. You will save a ton of money and can get some serious hp and keep it very streetable:thumb:

 

[duratothemax]

You could get up to about 600hp with the right S366 charger and a single CP3 and still have a truck that can tow heavy loads just fine. A nice setup for 750+hp is rods, keyed, delipped, studded with 40% over injectors, dual fuelers, and an S472 charger. If you have more to spend stage 1 or stage 2 heads, a cam, intercooler, headers, ect are all good things to add.

yep exactly! :thumb:

 

[duratothemax]

From a guy that knows nothing about building an engine and is looking to have a local, reputable, gasser shop build one:

What are the non-standard procedures? Cliff's Notes version.

ring orientation, piston orientation and alignment, PTW/bearing clearance, and rod/cap orientation.

 

[SmokeShow]

Does it go without saying that one would need to have the block at least cleaned, checked for trueness, and honed or is that not necessary really if it still looks alright when torn down?


C-ya

 

[insane3639]

Does it go without saying that one would need to have the block at least cleaned, checked for trueness, and honed or is that not necessary really if it still looks alright when torn down?


C-ya

Not a bad idea to do that i would say it may just save you in the long run it only looked ok

 

[moore428]

Have the heads ported. More air in, more air out = more power without all the other bullshit involved.

 

[SSchmi5519]

What would a S472 do to stock internals?

 

[othrgrl]

What would a S472 do to stock internals?

With enough fuel it would reduce their lifespan drastically. It is a 2.8 charger capable of over 50 PSI of boost and over 750hp. If you don't get greedy with the tuning or try to push everything to the limit you could run it on a stock motor without a problem.