which gasket to run? TEA stage II LS6 heads
07-24-2008, 08:59 AM
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which gasket to run? TEA stage II LS6 heads I just bought a set of TEA stage II ls6 heads. I am putting them on my stock bottom end 3.90 bore motor. My pistons, IIRC, are out of hole .007. The heads have been milled to 61cc. I have valve reliefs already which are aroung .065 deep.
Here is a link to the post with info on the heads. They have 2.04 int and 1.55 stock exh valves but flow great. I do not know what the valvle drop on them is. https://ls1tech.com/forums/showthrea...hlight=ls6+tea
My cam is a comp XEr 232/236
comp cams XEr grind 3726r/3728r 114+4
base circle ?
duration at .050 232/236
duration at .006 281/285
valve lift .595/.601
lsa 114+4
ICL 110
Intake open 6* BTDC
Exhaust close 0* TDC
Intake closing point 70.5
I have two gaskets to choose from handy. The factory MLS @ .054 thicknes 3.910 bore or my already used once Cometics @.040 thich with a 3.970 bore. I used these for my old heads which were opened up to unshroud the 2.05 int valves.
Which gasket would be better for my application (street car using 93 octane) and what are my Dcr/SCR and quench figures with either setup.
thanks in advance
Mike
Ps my old heads will be up for sale soon
Here is a link to the post with info on the heads. They have 2.04 int and 1.55 stock exh valves but flow great. I do not know what the valvle drop on them is. https://ls1tech.com/forums/showthrea...hlight=ls6+tea
My cam is a comp XEr 232/236
comp cams XEr grind 3726r/3728r 114+4
base circle ?
duration at .050 232/236
duration at .006 281/285
valve lift .595/.601
lsa 114+4
ICL 110
Intake open 6* BTDC
Exhaust close 0* TDC
Intake closing point 70.5
I have two gaskets to choose from handy. The factory MLS @ .054 thicknes 3.910 bore or my already used once Cometics @.040 thich with a 3.970 bore. I used these for my old heads which were opened up to unshroud the 2.05 int valves.
Which gasket would be better for my application (street car using 93 octane) and what are my Dcr/SCR and quench figures with either setup.
thanks in advance
Mike
Ps my old heads will be up for sale soon
07-24-2008, 09:06 AM
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also, other than the effects on quench and SCR/DCR. Is there any downside to running a gasket with a little more bore diameter than is needed. The Cometics are 3.970 vs 3.910 for the stockers. Will this crevace cause other issues with performance?
Mike
Mike
07-25-2008, 08:19 PM
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I ran the #'s with the both gaskets. My quench is .047 with the stock gasket and a scr of 11.08 and dcr of 8.40. If I use the cometic (.040) I get a quench of .033 and scr of 11.455 and dcr of 8.676. Any issues between the two choices
Mike
Mike
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07-27-2008, 07:24 AM
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So if I am reading this right, you guys are saying I should just use the cometics
Seriously though, why not the desire to run the cometics with the lower quench and bump in compression they offer. I appreciate the recomendation everyone has given, and will take the advice. I am just curious as to the reasoning beind sticking with the stock MLS. Running the compression numbers, I get 11 to 1 using my old heads(64cc's) with the .040's and the same using the stock mls with these heads (61cc). So no gain in compression from the smaller chamber and stock gasket but a drop in quench. Just curious.
Mike
Seriously though, why not the desire to run the cometics with the lower quench and bump in compression they offer. I appreciate the recomendation everyone has given, and will take the advice. I am just curious as to the reasoning beind sticking with the stock MLS. Running the compression numbers, I get 11 to 1 using my old heads(64cc's) with the .040's and the same using the stock mls with these heads (61cc). So no gain in compression from the smaller chamber and stock gasket but a drop in quench. Just curious.
Mike
07-29-2008, 12:48 AM
#10
You need to make sure you measure how far out the hole the pistons come, INCLUDING rock at absolute TDC, at the top of the piston...
So, even out the piston as much as you can, then set it flush to the block, raise it till its at max height using a dial indicator plum to the top (12 o'clock position) of the piston, then push on the bottom of the piston to rock it up. This will give you a better indication of how far out the hole the pistons are really going as the motor is running.
With my particular setup, the pistons were out the hole .018, without rock, when the motor was built, the rock wasn't accounted for, so 51thou cometic were used. Fast forward 8K miles, and coolant in my oil, i pull the heads, and come to find out, all the pistons on one side of motor is hitting the heads. I re-measure the quench distance, including the piston rock, and my quench went from 33 thou quench, to 20thou!!! The other sides quench including piston rock was 25thou!!!! In the end, I had to order custom 71thou gaskets, to get me to 41/46 thou quench distances, and will never run a quench distance that tight for reliability reasons.
In the end, I would recommend running the MLS gaskets, if the 40thou gaskets are giving you a compression height of 33thou. In fact, if you're thinking of cometics, just get the 51thou cometics with a bore of 3.91 (if you're still at stock bore diameters), you can just call and tell them that you need that, and they will make it specific for you. Then you will have a quench distance of 44thou, with the proper bore diameter, and be happy.
Adrian
So, even out the piston as much as you can, then set it flush to the block, raise it till its at max height using a dial indicator plum to the top (12 o'clock position) of the piston, then push on the bottom of the piston to rock it up. This will give you a better indication of how far out the hole the pistons are really going as the motor is running.
With my particular setup, the pistons were out the hole .018, without rock, when the motor was built, the rock wasn't accounted for, so 51thou cometic were used. Fast forward 8K miles, and coolant in my oil, i pull the heads, and come to find out, all the pistons on one side of motor is hitting the heads. I re-measure the quench distance, including the piston rock, and my quench went from 33 thou quench, to 20thou!!! The other sides quench including piston rock was 25thou!!!! In the end, I had to order custom 71thou gaskets, to get me to 41/46 thou quench distances, and will never run a quench distance that tight for reliability reasons.
In the end, I would recommend running the MLS gaskets, if the 40thou gaskets are giving you a compression height of 33thou. In fact, if you're thinking of cometics, just get the 51thou cometics with a bore of 3.91 (if you're still at stock bore diameters), you can just call and tell them that you need that, and they will make it specific for you.
Then you will have a quench distance of 44thou, with the proper bore diameter, and be happy.Adrian
08-13-2008, 02:48 PM
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LS6 block honed to 3.95" bored, stock crank, Eagle H-beam rods, Weisco Forged pistions, blue printed, balanced, by PER Race Engines, all ARP hardware, TEA Stage II LS6 Heads, milled to 59cc Static compression 11.3:1, 24x/24x, .62x/.62x @112+2 LSA. FAST 92mm intake/TB, FASTTOYS lid, RPM Level 4 T56 with upgraded bronze sliders, all new hydraulics, LS7 Clutch, 42lb/hr injectors, Kooks 1 7/8" x 3" headers, Corsa Catback, Z06 MAF, Meizer water pump, Powerbond undedrive pulley, Racetronix fuel system.
Right now, I'm just waiting for the motor, and a few of the other misc. parts. The main studs came in today, so the motor should be ready by the end of the week.
Wish I had the money do the a Moser M9 and Tubular front set up this year, but I dropped way to much on this projet this year, so it won't be til next year before i can address those issues and add a little bit of nitrous, or get to the track for that matter.
The car is a 2002 Z28.
Right now, I'm just waiting for the motor, and a few of the other misc. parts. The main studs came in today, so the motor should be ready by the end of the week.
Wish I had the money do the a Moser M9 and Tubular front set up this year, but I dropped way to much on this projet this year, so it won't be til next year before i can address those issues and add a little bit of nitrous, or get to the track for that matter.
The car is a 2002 Z28.
