alamantia

iTrader: (10)

I have been reading a lot about people having great sucess purchasing a new bare LS2 block and building their own motor. If I read correctly the bace LS2 is 364 cubic inches with a 4.00 bore and 3.62 stroke. I'm noticing that 402 is a popular displacement build. Is there a paticular reason I hear 402 so much? Arent their rotating assemblies available for other stroker variations? I also hear that boring a LS2 can only be done up to 0.010" so if I was to purchase a brand new block and not bore it what stroker options would I have aside from a 402 kit?

Thanks in advance for any insight on this

slow trap

iTrader: (22)

some people put in a 4.1" stroke to make it a 412-414 but most stick with a 4"

Steve - Race Eng

iTrader: (1)

The working cylinder wall length on the LS2 block is 5.450". That length makes it difficult to use greater than 4" stroke length and have a reasonable life expectancy for the pistons. The piston is pulled to the wrist pin at bottom dead center leaving very little skirt support.

I had Darton make the replacement dry and MID liners 5.800" long which will support up to 4.25" strokes. The Darton dry liner will go out to 4.190" bore normally aspirated = 468 cubic inches at 4.190" and 4.250" stroke or 455" at 4.125" stroke. Most of my customers opt for a 454 at 4.185" bore and 4.125" stroke. The 4.125" stroke will give longer life on the street.

You can bore most LS2 stock blocks to 4.030" by the way. Any new block should be vibratory stress relieved whether replacement sleeved or not. Then do your finish machine work. Cylinder walls, bearing bores will remain a lot rounder and decks will remain flat if you follow this procedure.

Steve

355ss

iTrader: (9)

Who does the vibratory stress relief, and what is the process? I am assuming that stock engines and gm crate engines are not stress relieved. So some engines that are built new are being shipped with cylinders that are .005 out of round? I just purchased a new L92 block and was looking into have the stress relief done.

Steve - Race Eng

iTrader: (1)

Brand new castings, forgings, weldments whether aluminum or iron have residual stresses from manufacture. This includes, blocks, heads, brake rotors, cranks, etc. Also, any time you machine a part you are also putting stress in the part.

You should not find your bores out of round until you run the engine. The stresses are reduced during the running, heating and cooling process. If you took your engine apart, you would find the bores out of round.

Vibratory stress relief reduces the stress in the block or part, so it moves around very little or not at all after running. I use a Stress Relief Engineering Formula 62 stress relief machine which vibrates the block or whatever at it's natural harmonic frequency. Harmonic vibratory stress relief has proven to be the most efficient method of vibratory stress relief. It takes about an hour for a block.

You can find more info at Stress Relief Engineering's web site:
http://www.stressreliefengr.com/

Steve

Randy WS6

iTrader: (69)

Ive been running a aluminum LS2 418 for a 11 month now with no problems at all and a lot of wot runs with a 250 shot pro fogger n.o.s. its a 4.030" bore & 4.100" stroke & 6.125 rods. you can see some of the build pics in my sig.