We've built several LS12s so far. One went into a suburban, and another went into 3/4 scale P-51.
We have a bunch of LS parts still laying around from those previous jobs so we're putting together some 12s for ourselves! The process gets refined each time we do it making it a little easier each time hah
We figured out how to section two stock cranks/cams and create our own firing order, and we cut out about 12 grand in crank/cam creation costs.
Love the responses! Glad there are a bunch of LS enthusiasts interested!
I started taking pictures of this build a little later than I should have, so i'll try and illustrate everything we do as best as possible
Originally Posted by Bazman
God bless the hot rodders like you in this world! That is as pure as it gets. Love to know more.
I guess the engine would have realistic capacities ranging from 8L to 11L depending on bore, deck height, and stroke combo?
An LS3-12 would become a 9.3 - YES PLEASE
This block we have was sleeved to 4 inch with stock stroke, so its 545 cubic inch (8.9L)
The goal for this build is to experiment and enable us to build an entire LS12 with essentially two stock motors (crate or supplied)
Now onto the process
The hardest parts are paring together the block, heads, crank and cam.
(this isn't the block we're using, its just one that we have for mockup)
The block is cut through the center of the bore inbetween the lifters (on this design). After skinning both halves, then you line them up and weld. You weld inside and out, and install a wet sleeve on those two cylinders to cover it. Between the ribbing and the additional deck, the weld is just as strong as the original cast block.
For the heads, you pair them together and cut one cylinder off each side
Similar process, the big trick is pairing them together straight and lining up bolt holes/dowel pins.
For the crank, we also saw off both ends and pair it together in the middle of the journal.
This build we are NOT designing the crank like a 12. The firing order is set up so it is like a V16 minus four cylinder. We plan to push this crank and see just how much power we can make on it. We save a lot of money and time not making brand new cranks ourselves, so we're giving this a whirl
Esstienally the same for the cam, pair it up/line it up, and weld through the center cam support journal. We are sending this off to be reground.
Incredible, I love seeing machining stuff like this, it's amazing what you can do with the willingness to attack the hurdles. How does the firing order get changed with the crank design now? IIRC an inline 6 or V12 is very well balanced harmonically due to evenly spaced firing pulses, are you getting the same effect using this arrangement as opposed to an engine designed from the outset to be a 12 cyl?
__________________ '13 Chevy Sonic - Wifey's car.
'08 350Z Nismo - Test pipes and bottle, 12.5@114
'84 GMC 1500 RCLB - future LS recipient
'93 Toyota Tercel - 35mpg daily beater
'06 Cobalt SS - project racecar