LS1 heads on LS2 block - Which HG?
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LS1 heads on LS2 block - Which HG? Like the title says, LS2 block (stock 4.000" bore), LS1 heads (3.898" I believe?)
I've searched, and from what I've come up with, I need a head gasket with at least a 4.000" dia., but I shouldn't use the using the 1041 due to too much open space. So the question is, should I go with the GM MLS for the 6.0 or the 5.7? Or does it matter? I'm not sure what the sizes are on those gaskets.
I've searched, and from what I've come up with, I need a head gasket with at least a 4.000" dia., but I shouldn't use the using the 1041 due to too much open space. So the question is, should I go with the GM MLS for the 6.0 or the 5.7? Or does it matter? I'm not sure what the sizes are on those gaskets.
6.0 MLS gaskets unless the chambers have been opened up to more than 4.030"... unless they are early LS1 castings (with the notches in the deck.) In that case you will need early 6.0 truck graphite gaskets. As 405HP_Z06 stated, the gaskets MUST be slightly larger than the larger of the two, the bore or the chamber.
Thanks,
Shane
Thanks,
Shane
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Quick follow-up.
Is it possible to have the gasket too large for the bore? I've searched and haven't found a definitive answer.
Example: Stock bore LS1 (3.910"), 243 heads w/ a stock 64.45 cc chamber. Can you use a gasket such as the Fel-Pro 1041 w/ a bore size of 4.1"? Is the combustion path fouled up with the slight gap?
Is it possible to have the gasket too large for the bore? I've searched and haven't found a definitive answer.
Example: Stock bore LS1 (3.910"), 243 heads w/ a stock 64.45 cc chamber. Can you use a gasket such as the Fel-Pro 1041 w/ a bore size of 4.1"? Is the combustion path fouled up with the slight gap?
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Verdad Gallardo Quick follow-up.
Is it possible to have the gasket too large for the bore? I've searched and haven't found a definitive answer.
Example: Stock bore LS1 (3.910"), 243 heads w/ a stock 64.45 cc chamber. Can you use a gasket such as the Fel-Pro 1041 w/ a bore size of 4.1"? Is the combustion path fouled up with the slight gap?
Is it possible to have the gasket too large for the bore? I've searched and haven't found a definitive answer.
Example: Stock bore LS1 (3.910"), 243 heads w/ a stock 64.45 cc chamber. Can you use a gasket such as the Fel-Pro 1041 w/ a bore size of 4.1"? Is the combustion path fouled up with the slight gap?
Cometic offers custom gasket services with a short turn around time. This is an option if you can't find something.
I probably wouldn't need custom cometics. I would go with the standard 3.910" .040 cometic gaskets. My only concern is the price!
That's why the Fel-Pro 1041 is attractive. It's a .043 gasket, but for about 1/3 the cost. The only problem is the bore size. I'm just wondering if that additional space in the oversized gasket bore is going to mess up the combustion path/power production/etc. The amount of additional cc's in the chamber from the oversize gasket is pretty small.
Fel-Pro bore = 4.135"
Cometic = 3.910"
Head gasket volume of the 3.910 bore = 7.87cc
volume of the 4.135 bore = 8.8 cc
This equates to a difference of CR of .01 !
So..... It looks like the only real difference would be in the flame path/travel???
That's why the Fel-Pro 1041 is attractive. It's a .043 gasket, but for about 1/3 the cost. The only problem is the bore size. I'm just wondering if that additional space in the oversized gasket bore is going to mess up the combustion path/power production/etc. The amount of additional cc's in the chamber from the oversize gasket is pretty small.
Fel-Pro bore = 4.135"
Cometic = 3.910"
Head gasket volume of the 3.910 bore = 7.87cc
volume of the 4.135 bore = 8.8 cc
This equates to a difference of CR of .01 !
So..... It looks like the only real difference would be in the flame path/travel???
Why not just stock GM MLS gasket for the LS2? LS2 uses 243 castings, which were previously installed on the LS1 in the Z06. Shouldn't be an issue. Plus, they're WAY cheaper than Cometics.
Because the stock gasket is .053 thickness compressed.
The cometic is .040 thickness compressed.
The thinner gasket increases compression from 10.34 to 10.67 on a stock-cube LS1 with 243 castings (64.45 chambers).
That could result in 5 hp more at the crank.
If the Fel-Pro .040 gasket would work, that's a pretty good deal for $ per HP.
The cometic is .040 thickness compressed.
The thinner gasket increases compression from 10.34 to 10.67 on a stock-cube LS1 with 243 castings (64.45 chambers).
That could result in 5 hp more at the crank.
If the Fel-Pro .040 gasket would work, that's a pretty good deal for $ per HP.
I probably wouldn't need custom cometics. I would go with the standard 3.910" .040 cometic gaskets. My only concern is the price!
That's why the Fel-Pro 1041 is attractive. It's a .043 gasket, but for about 1/3 the cost. The only problem is the bore size. I'm just wondering if that additional space in the oversized gasket bore is going to mess up the combustion path/power production/etc. The amount of additional cc's in the chamber from the oversize gasket is pretty small.
Fel-Pro bore = 4.135"
Cometic = 3.910"
Head gasket volume of the 3.910 bore = 7.87cc
volume of the 4.135 bore = 8.8 cc
This equates to a difference of CR of .01 !
So..... It looks like the only real difference would be in the flame path/travel???
That's why the Fel-Pro 1041 is attractive. It's a .043 gasket, but for about 1/3 the cost. The only problem is the bore size. I'm just wondering if that additional space in the oversized gasket bore is going to mess up the combustion path/power production/etc. The amount of additional cc's in the chamber from the oversize gasket is pretty small.
Fel-Pro bore = 4.135"
Cometic = 3.910"
Head gasket volume of the 3.910 bore = 7.87cc
volume of the 4.135 bore = 8.8 cc
This equates to a difference of CR of .01 !
So..... It looks like the only real difference would be in the flame path/travel???
Unfortuneately, there is no perfect head gasket out there. Compromises are made in the interest of product coverage and commonality which ultimately affect the user. I had the same delimma a short while ago on my head/cam swap.....
I completely understand the cost issue. The affects of head gasket bore size on flame front propegation is probably an argueable subject; however, for our purposes here there is not an issue that will cause a catastrophic loss in combustion efficiency. The only other small issue is the difference in head gasket technology when comparing the Fel-Pro 1041 v. a MLS. Assuming the gasket surfaces are properly prepared, the MLS is a better gasket than the graphite/composition core of the 1041.
Unfortuneately, there is no perfect head gasket out there. Compromises are made in the interest of product coverage and commonality which ultimately affect the user. I had the same delimma a short while ago on my head/cam swap.....
Unfortuneately, there is no perfect head gasket out there. Compromises are made in the interest of product coverage and commonality which ultimately affect the user. I had the same delimma a short while ago on my head/cam swap.....
"for our purposes here there is not an issue that will cause a catastrophic loss in combustion efficiency"
- Maybe not Catastrophic, but enough to negate the additional power from the higher compression?
"the MLS is a better gasket than the graphite/composition core of the 1041."
- Where does the Cometic come into this discussion? It's got a reputation for poor sealing quality if both surfaces are not perfect and copper spray isn't used.
Is the bottom line for this discussion that the priority should be placed on proper sealing vs. better quench?
(Sorry to beat a dead horse, but the MLS costs $30, and the Cometics are $180. That's a big difference!)
Cometic isn't the only company that manufactures MLS head gaskets for the LS1 engine. The Fel-Pro 1041 is NOT a MLS gasket.
In the above case, the $30 gasket you reference and the $180 Cometic's are both MLS. The question is whether the gasket dimensions fit your needs.
Because the stock gasket is .053 thickness compressed.
The cometic is .040 thickness compressed.
The thinner gasket increases compression from 10.34 to 10.67 on a stock-cube LS1 with 243 castings (64.45 chambers).
That could result in 5 hp more at the crank.
If the Fel-Pro .040 gasket would work, that's a pretty good deal for $ per HP.
The cometic is .040 thickness compressed.
The thinner gasket increases compression from 10.34 to 10.67 on a stock-cube LS1 with 243 castings (64.45 chambers).
That could result in 5 hp more at the crank.
If the Fel-Pro .040 gasket would work, that's a pretty good deal for $ per HP.
