LS 2 clearences
Thread Starter
Teching In
Joined: Sep 2011
Posts: 40
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From: calgary alberta
LS 2 clearences im building an LS2 from an 06 vette and going twin turbo. can anybody help me with piston to wall clearences, ring gap , main & rod brg clearences'
eagle rods. je forge pistons.stock crank. thanks.
eagle rods. je forge pistons.stock crank. thanks.
TECH Apprentice
Joined: Jan 2008
Posts: 366
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From: Gladstone, Queensland, Australia
the most important thing is bore finish and torque plate honing, the last engine I built runs no baffles in rocker covers and just small breathers does not breath a drop filters are dry nor use oil as i chose a machinist that new what he was doing 99% of breathing issues is related to bore finish, it has to be a very fine cross hatch the more shiny the bore the better lol should look like a mirror, its harder to do with low nickel content in bore (will never look like a motorbike bore). She wont breath and push oil everywhere if its not right, if the bore is to coarse it will hold oil in the cross hatch and get past the rings, breathe and burn. You can go wide on the ring gaps and a little looser on bore clearance and still not have breathing issues. I see race engines 15:1 comp with near 30 thou ring gaps and 8 thou plus ptb clearance and have good leak down numbers and no breathing or blowing oil out rear mains. there like this as they sit on 8500 rpm constantly but have no issue at all so dont stress on ring gap just follow recommendations from the ring pack and get a good competition hone.
I'd go .002 on the rods and try for .0015 on the mains as the block grows when warmed up. Mine ranged from .0012 on the front to .0017 on the rear. Whatever JE recommends on the pistons, go with it. F.I., I'd go at least .024 on the top and .026 on the second. My Wiseco pistons called for .004 and I went .026 and .028 on my rings. Havent put the supercharger on it yet. Just NA for now.
Thread Starter
Teching In
Joined: Sep 2011
Posts: 40
Likes: 0
From: calgary alberta
the most important thing is bore finish and torque plate honing, the last engine I built runs no baffles in rocker covers and just small breathers does not breath a drop filters are dry nor use oil as i chose a machinist that new what he was doing 99% of breathing issues is related to bore finish, it has to be a very fine cross hatch the more shiny the bore the better lol should look like a mirror, its harder to do with low nickel content in bore (will never look like a motorbike bore). She wont breath and push oil everywhere if its not right, if the bore is to coarse it will hold oil in the cross hatch and get past the rings, breathe and burn. You can go wide on the ring gaps and a little looser on bore clearance and still not have breathing issues. I see race engines 15:1 comp with near 30 thou ring gaps and 8 thou plus ptb clearance and have good leak down numbers and no breathing or blowing oil out rear mains. there like this as they sit on 8500 rpm constantly but have no issue at all so dont stress on ring gap just follow recommendations from the ring pack and get a good competition hone.
talked to my engine builder and he said he can do that . thanks for the imput
Thread Starter
Teching In
Joined: Sep 2011
Posts: 40
Likes: 0
From: calgary alberta
I'd go .002 on the rods and try for .0015 on the mains as the block grows when warmed up. Mine ranged from .0012 on the front to .0017 on the rear. Whatever JE recommends on the pistons, go with it. F.I., I'd go at least .024 on the top and .026 on the second. My Wiseco pistons called for .004 and I went .026 and .028 on my rings. Havent put the supercharger on it yet. Just NA for now.
found specs for my pistons. i will use that thanks
TECH Apprentice
Joined: May 2009
Posts: 323
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From: NW AR
Also you MUST properly hold oil on the cylinder wall or suffer bore wear.
As mentioned before the manufacturer will supply a card with the pistons that give you the spec for boring them. Going turbo is going to dictate different clearances on the piston and rings.
