Factory flat top piston for LY6?
#1
Factory flat top piston for LY6?
What factory flat top piston could I use to raise the compression on a stock LY6, and how much will it bump up the compression?
I know the LQ9 has flat tops but I'm not sure if the valve notches will be in the right position.
Thanks
Jarhead
I know the LQ9 has flat tops but I'm not sure if the valve notches will be in the right position.
Thanks
Jarhead
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Pancho96 (09-22-2022)
#3
Thanks
I saw an old Car Craft dyno report where they used an LQ9 short block and put on L92 cyl heads and a .570 lift cam. They used clay on the piston tops to check PTV clearance and had no problem at all.
Anyone know how much the piston swap would raise the compression?
Thanks
Jarhead
I saw an old Car Craft dyno report where they used an LQ9 short block and put on L92 cyl heads and a .570 lift cam. They used clay on the piston tops to check PTV clearance and had no problem at all.
Anyone know how much the piston swap would raise the compression?
Thanks
Jarhead
#5
Thanks for the info BES.
So you had to cut intake valve reliefs to clear?
What lift and duration are you running?
My plan was to find some stock flat tops to replace the factory LY6 pistons to raise the compression a point or so.
I believe the LQ9 and LS2 pistons are about the same although the LS2 has a narrower compression ring.
Yes I have considered milling the heads to increase the compression but I want to use a .570 or so lift cam and I don't want piston to valve issues.
Thanks
Jarhead
So you had to cut intake valve reliefs to clear?
What lift and duration are you running?
My plan was to find some stock flat tops to replace the factory LY6 pistons to raise the compression a point or so.
I believe the LQ9 and LS2 pistons are about the same although the LS2 has a narrower compression ring.
Yes I have considered milling the heads to increase the compression but I want to use a .570 or so lift cam and I don't want piston to valve issues.
Thanks
Jarhead
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#8
8 Second Club
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I fully intend to cut .050" from my L92 heads, I dont think I will need to mill the intake, but I will need to oblong the bolt holes. should give me 11.0:1 with a .040" gasket and stock LY6 shortblock.
YES I will need to cut valve releifs in the pistons, probably around .100" like BES did
YES I will need to cut valve releifs in the pistons, probably around .100" like BES did
#9
Thanks for the input 3pedals I do like your Camaro and how it runs.
Low 11s is pretty impressive.
So how big is your "small" cam?
I plan a combo pretty much like yours, an Ly6 with a carb, cam and headers.
I've never been good at shifting a manual tranny so I'm going to run a powerglide or T400.
Jarhead
PS With that 120 speed I think you'll get into the 10s.
Low 11s is pretty impressive.
So how big is your "small" cam?
I plan a combo pretty much like yours, an Ly6 with a carb, cam and headers.
I've never been good at shifting a manual tranny so I'm going to run a powerglide or T400.
Jarhead
PS With that 120 speed I think you'll get into the 10s.
#11
TECH Fanatic
iTrader: (24)
just over 11 to 1 with a .054 cometic gasket.
my SS went a best of 10.93 at 126 1.44 60 ft, 6 speed car, 3820lb raceweight. and I shift it 7700.
the small attention to details (morel lifters, hollow stem intake valves, manley nextek spring) all show up on the dyno and at the track.
good luck on your L92 setup
my SS went a best of 10.93 at 126 1.44 60 ft, 6 speed car, 3820lb raceweight. and I shift it 7700.
the small attention to details (morel lifters, hollow stem intake valves, manley nextek spring) all show up on the dyno and at the track.
good luck on your L92 setup
#12
Thanks a bunch for the information.
I just bought a set of LS2 pistons and rods from a member here and I will put them in my LY6 when I get it.
If I've figured it right I should end up with about 10.9 to 1 compression without milling the heads which is about where I want to be.
Jarhead
I just bought a set of LS2 pistons and rods from a member here and I will put them in my LY6 when I get it.
If I've figured it right I should end up with about 10.9 to 1 compression without milling the heads which is about where I want to be.
Jarhead
#13
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Thanks a bunch for the information.
I just bought a set of LS2 pistons and rods from a member here and I will put them in my LY6 when I get it.
If I've figured it right I should end up with about 10.9 to 1 compression without milling the heads which is about where I want to be.
Jarhead
I just bought a set of LS2 pistons and rods from a member here and I will put them in my LY6 when I get it.
If I've figured it right I should end up with about 10.9 to 1 compression without milling the heads which is about where I want to be.
Jarhead
#14
Thanks, I was basing the 10.9 to 1 estimate off of the Car Craft dyno test where they used a LQ9 shortblock and said the the head ccs of an LQ9 and L92 was the same and the compression would stay at 10.9 to 1.
I guess 10 to 1 isn't bad and will run great on 93 octane pump gas.
My plan is to start like 3 Pedals did, stock shortblock LY6 with MSD controller,carb and headers, using the stock cam with a new timing chain and front cover to replace the VVT stuff.
Then after running awhile, pulling it down for a new cam, ported heads and the LS2 pistons and maybe milling the heads to up the compression some more.
Jarhead
I guess 10 to 1 isn't bad and will run great on 93 octane pump gas.
My plan is to start like 3 Pedals did, stock shortblock LY6 with MSD controller,carb and headers, using the stock cam with a new timing chain and front cover to replace the VVT stuff.
Then after running awhile, pulling it down for a new cam, ported heads and the LS2 pistons and maybe milling the heads to up the compression some more.
Jarhead