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We recently fired up our first prototype V12 LS1, and I thought forum members might be interested in some of the challenges we met along the way and how they were overcome. We certainly have learnt a lot by reading this forum over the years, so would like to contribute.
Firing order and balance
There is much debate online over if a 90 degree V12 is “balanced”. Theoretically any angle V12 will balance just fine as it is really just two straight 6s. What you do get with a 90 degree V is an odd-fire engine, where the power is unevenly distributed over the engine rotation.
For firing order we went with the left bank in the usual straight 6 order, (1, 5, 3, 6, 2, 4) and the right bank in a reversed straight 6 order and obviously had to make a camshaft to suit.
Water Leaking
We had heard of this being a challenge (actually on this forum) and it certainly was. The biggest issue is sealing between the lifter galleries and the water jacket. For our first engine we tapped and fitted an M16 internal hex grub screw, with a generous amount of thread sealer.
Starting
With 8.55 litres of high compression goodness, this is one tough engine to crank over. We had been warned, so put a lot of effort into ensuring the engine was line bored perfectly, and all tolerances were spot on. We are sure this helped, as we did get it running with a stock starter, but burnt out 3 in the process.
A high torque starter was the solve on this challenge.
Head Gaskets
Obviously nobody makes a head gasket for a V12 LS engine, so we had to make them ourselves. We chose to go with copper to get started, and so far this has worked well. We are also talking with some of the manufacturers of MLS head gaskets.
Engine Management
An ECU that is capable of running an odd-fire V12 with waste spark was an expensive exercise just a few years ago. Thankfully the new Haltech Elite 2500 had all the configuration we needed and is available for a quite reasonable price. Stand alone EFI software has come a long way recently too, so the configuration and startup tune all went much more smoothly than expected.
Waiting to hear it run
This project has been ongoing for a number of years, and we really didn’t want to get too excited before it was running. There were a lot of things that could and did go wrong but we finally have a reliable, running engine! A well known magazine is coming by in the next few days to shoot a video, as soon as that is released we will post here for all to hear
We will keep our site updated with the latest progress http://v12ls.com
Curious, are you working with the people in this other thread?
Not as yet, but we would love to work with those guys. I am sure we could learn from eachother. I have reached out privately, so as not to hijack their thread and can't wait to see how that one goes with the blower on it!
Street Machine magazine just posted a video of it running on their Facebook page. It is just a teaser shot on a cell phone, there is more to come soon.
Did you have that crank shaft custom made or is it cut and welded?
The crank is a custom billet piece made to our design. We really wanted to ensure good balance for a decent redline and reliability.
I am really curious what it would take to have a 1 piece block made.
Just time and money 1FastBrick. We are sure this block can be taken quite a bit further anyway though. At 717HP with a mild spec camshaft this is more than most street cars can put down anyway. We will find out I suppose when we get it into a car in the next few months
And which crank is it? 3.268"(4.8L) or 3.622"(5.3-6.2L)?
We based everything off a 5.7 LS1, same bore, stroke etc. It was really tempting to go for a stroker seeing as we built a completely custom crankshaft but we wanted to keep as many variables to a minimum with all the other new things going on with this build.
I was curious on the block as I know it's not cheap and it's probably time consuming to cut 2 blocks to make one.
I know to have the tooling made to cast the blocks is really expensive. But If it turns into something, It might be easier. I know the LS1 blocks are no longer made but LS2 blocks as well as LS3 blocks are.
We based everything off a 5.7 LS1, same bore, stroke etc. It was really tempting to go for a stroker seeing as we built a completely custom crankshaft but we wanted to keep as many variables to a minimum with all the other new things going on with this build.
I'm sure there's numerous ones with blown motors and trans, just rotting away because the owner's pipe-dream of getting it fixed faded decades ago... go pick em up cheap...
Fullboost.com.au have posted up a youtube video of our initial dyno pulls.
We are really happy with 717hp, with cathedral port heads, a mild cam and pump gas friendly compression. But most of all we are happy with the engine balance and smoothness right up to where we expected power with that cam to taper off.
One small issue we came across was that more crank case ventilation is needed. I suppose we should have expected that!
We also had some fuel distribution issues, and have had many questions on why not direct port injection. The real reason is that we already had the TBIs and wanted to get this concept proven as soon as possible so we can keep developing. We had a personal goal of making more than the Hellcat and did not expect to do that with a "test" intake and exhaust on.
SEMA just selected us as semi-finalists in their launchpad competition! This is a huge honor for two guys who have put everything we have into proving this concept even works, and we really need your help. Please vote and share the link around in support of the only LSx innovator in the competition.
V12 LS1 - First fire up and challenges 
