Quench question
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Joined: Sep 2009
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From: Frozen Tundra, WI
Quench question Is the ideal quench any different for a carb vs. fuel injection??
The idea is to make it as tight as possible without the piston hitting, correct??
If stock gasket thickness is .051 compressed, I should be able to run an .041 gasket without any worries?? Shift rpm is only 5500 but it will not be EFI.
The idea is to make it as tight as possible without the piston hitting, correct??
If stock gasket thickness is .051 compressed, I should be able to run an .041 gasket without any worries?? Shift rpm is only 5500 but it will not be EFI.
You are on the right track, you just have to be careful of a few things....
Most LS engines use a positive deck clearance (not 100% certain on LQ4 & LQ4) meaning that the piston extends a few thousandths above the deck surface at TDC. Older Gen I small block chevy's were well below the deck unless the block had been machined.
Aside from that, you need to have a little room for the pistons to rock at TDC. You can measure with a dial indicator on opposite sides of the pin (intake side vs. Exhaust side) but this distance should be minimal.
Lastly, you do need a little room for error and stretch as RPM's increase. With your 5500 rpm shift points, you should be fine for this exercise. Once you have changed parts in the bottom end though, it would be safer to measure, especially if you plan to push the limits.
Good luck!
Most LS engines use a positive deck clearance (not 100% certain on LQ4 & LQ4) meaning that the piston extends a few thousandths above the deck surface at TDC. Older Gen I small block chevy's were well below the deck unless the block had been machined.
Aside from that, you need to have a little room for the pistons to rock at TDC. You can measure with a dial indicator on opposite sides of the pin (intake side vs. Exhaust side) but this distance should be minimal.
Lastly, you do need a little room for error and stretch as RPM's increase. With your 5500 rpm shift points, you should be fine for this exercise. Once you have changed parts in the bottom end though, it would be safer to measure, especially if you plan to push the limits.
Good luck!
Thread Starter
TECH Resident
Joined: Sep 2009
Posts: 859
Likes: 2
From: Frozen Tundra, WI
Thread Starter
TECH Resident
Joined: Sep 2009
Posts: 859
Likes: 2
From: Frozen Tundra, WI
Is that a lot of slop in the bore??
I can still see some of the hone marks in the cylinder.
Found this - hopefully all the html works (I'm on my phone).
https://ls1tech.com/forums/advanced-...-rock-tdc.html
Stock pistons cold rock about .020 ish as in if one side is pushed sideways it may go .010 out of the hole and then .010 in the hole when rocked the other way. Forged pistons have generally more rock when cold. Some of the wiseco and Diamond LS1 specific stuff is still only like .020-.025 where as some traditional forgings and skirts can be much more like .030-.040 even so it all depends. When hot these all rock much less. It looks like your clearances should all be fine, but hopefully some solid tech will prompt more discussion. At 5500rpm, I can't see where you could have any issues.
https://ls1tech.com/forums/advanced-...-rock-tdc.html
Originally Posted by racer7088
Originally Posted by the_merv
How much Piston Rock should there be at TDC?I have a 6.0l Block, 4.000" Bore with Eagle 4.000" Crank & 6.125" Rods. I just pulled the Heads cause I have bad Rings, I'm wanting to make sure that I don't have excessive Piston Rock.
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Thread Starter
TECH Resident
Joined: Sep 2009
Posts: 859
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From: Frozen Tundra, WI
Thanks for the link. That clarified some things.
My "little fella" cam duration is only 210 int, 218 exh, .531 lift with 114 LSA.
I am fairly certain there should be enough piston to valve clearance, with only .020 removal of gasket and head (total), but if anyone thinks otherwise please let me know.
My "little fella" cam duration is only 210 int, 218 exh, .531 lift with 114 LSA.
I am fairly certain there should be enough piston to valve clearance, with only .020 removal of gasket and head (total), but if anyone thinks otherwise please let me know.
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