[ZexGX]

Originally Posted by 94cobra69ss396

I come up with 10.33 with a .044 quench which is great. The engine should run strong. However, if you do go with a blower don't drop the compression by adding a thicker head gasket. A 64cc combustion chamber will drop the compression down to about 9.75 and would keep the .044 quench. That's a little high but with an intercooler or meth injection it won't be. Better yet would be a set of AFR's with 72cc combustion chambers which would give you 8.97:1.

Believe it or not, I didn't even bother to do calculations to figure out quench distance. Definitely do not want to use a headgasket thicker than 0.051" anyways. Stock cylinder heads for these are 66.67cc - and I still have the stock unmilled heads from that motor, so in theory I could port those and then mill them X amount when I go boost to get the desired chamber size, or just fork out the cash for some nice ones. Every now and then I see a halfway-decent set going for sale on 'Tech for between $500 and $1000.

[94cobra69ss396]

A stock 66.67 combustion chamber would give you 9.47 compression which is still blower friendly.

[ZexGX]

Originally Posted by 94cobra69ss396

A stock 66.67 combustion chamber would give you 9.47 compression which is still blower friendly.

I think the main concern with going over 66.67cc was the dynamic compression ratio with the cam I have... Made it a ridiculously low DCR.

[SkunkLookingCar]

Congrats on getting the engine together. What alloy are the pistons. 15psi might be a bit high for 4032 (ask enkivette) but 2618 will be able to handle the cylinder pressure. The valve reliefs look like they get pretty close to the edge of the piston which can be a stress riser. The thermal coating will help quite a bit though. The coating slows the annealing process that happens to all aluminum pistons when the temperture rises. Microhardness surveys of used pistons show the area of the piston where the valve reliefs come to the edge are the first areas to soften and the coating will keep the heat out of the metal keeping the piston stronger, longer. I agree with 94cobra69ss396 statement about the compression ratio and his suggested solutions.

[ZexGX]

Originally Posted by SkunkLookingCar

Congrats on getting the engine together. What alloy are the pistons. 15psi might be a bit high for 4032 (ask enkivette) but 2618 will be able to handle the cylinder pressure. The valve reliefs look like they get pretty close to the edge of the piston which can be a stress riser. The thermal coating will help quite a bit though. The coating slows the annealing process that happens to all aluminum pistons when the temperture rises. Microhardness surveys of used pistons show the area of the piston where the valve reliefs come to the edge are the first areas to soften and the coating will keep the heat out of the metal keeping the piston stronger, longer. I agree with 94cobra69ss396 statement about the compression ratio and his suggested solutions.

Thanks. They are 2618 aluminum alloy. I had the coatings done after-the-fact since I bought the pistons NIB from someone and saved $300 over MSRP, so I took that savings and put the $300 towards coatings from Embee Performance. Not the most well known coating facility, but they are the largest local aerospace coatings company that caters to racing teams. Apparently they do the coatings for Ross and some other piston manufacturers.

This thread is a good read when it comes to forged engine longevity: http://www.ls1tech.com/forums/advanc...ged-motor.html
Maybe not the best piston choice for my power level, but I care more about them not cracking than slow oil consumption increases (unless it gets BAD...).

I am not capable of assembling/balancing a SHORTblock on my own, so I just bought all the parts necessary (except for the main studs) and had JMS Racing Engines (a shop in El Monte) purchase the main studs & do the line hone/balance/assembly the shortblock. My friends and I reassembled it from the head studs up.

[SkunkLookingCar]

Originally Posted by ZexGX

Thanks. They are 2618 aluminum alloy. I had the coatings done after-the-fact since I bought the pistons NIB from someone and saved $300 over MSRP, so I took that savings and put the $300 towards coatings from Embee Performance. Not the most well known coating facility, but they are the largest local aerospace coatings company that caters to racing teams. Apparently they do the coatings for Ross and some other piston manufacturers.

This thread is a good read when it comes to forged engine longevity: http://www.ls1tech.com/forums/advanc...ged-motor.html
Maybe not the best piston choice for my power level, but I care more about them not cracking than slow oil consumption increases (unless it gets BAD...).

I am not capable of assembling/balancing a SHORTblock on my own, so I just bought all the parts necessary (except for the main studs) and had JMS Racing Engines (a shop in El Monte) purchase the main studs & do the line hone/balance/assembly the shortblock. My friends and I reassembled it from the head studs up.

Good stuff. I'd say your bottom end is up to the task.

[enkeivette]

Centrifugal is the way to go! ATI (Procharger) has some CARB legal kits, not sure about for the F-Body... but I'm sure they do.

Don't forget to open up those ring gaps if you're planning to blow in it that hard! Also, moly rings tend to lose strength with pinging, while stainless rings don't. That's why I went with Total Seal stainless my second time around. Juuust a thought.

And yeah, 15 psi on 4032 is pushing it. You'll need to intercool without question, and pull timing. 2018 is the way to go. But if you already bought the pistons, just be sure to run it intercooled.

[ZexGX]

Got it running on Sunday. Runs very good. Tune is set to 22* of timing and pig-rich for safety. No detectable oil blowby whatsoever after the first initial startup "puff" even when following the GM factory new car engine/driveline break-in procedure. Very little to no piston slap (WAY less than a stock LS1... for now...). It's throwing two knock sensor codes and a MAF code (P0101, so it's on SD tables), regardless of the MAFs I tried (32k stock, or 92k descreened which was verified working). It's either a grounding issue or a tune issue (probably grounds/wires). Will be trying a few things tonight with the grounds. Sounds very healthy and idle vibration is way smoother than stock. Valvetrain noise stands out less than stock as well. The 42lb injectors are louder than the valvetrain. I guess that's a good thing. Rocker arms were torqued properly and 7.325" pushrods were used. Pulls just as hard as a stock LS1/T56 car through first and second. T56 car doesn't have 3rd or 4th so I couldn't do any testing through those gears.

Oh, and I got 21MPG on the drive back, that's all with a safe base tune and going WOT a few times, and speeds ranging from 65-75 for most of the way. I know it's rich because it backfires every once in a while on deceleration when holding a gear.

Changed the oil after the first ring-seating adventure. Cut open the filter with a bandsaw. Lots of metal dust but very few to no slivers or chunks. Awesome.

Originally Posted by enkeivette

Centrifugal is the way to go! ATI (Procharger) has some CARB legal kits, not sure about for the F-Body... but I'm sure they do.

P1SC is the CARB legal F-body kit, D1SC is the more popular one. I'm only planning on Vortech because I may get a deal on one from a friend.

Originally Posted by enkeivette

Don't forget to open up those ring gaps if you're planning to blow in it that hard! Also, moly rings tend to lose strength with pinging, while stainless rings don't. That's why I went with Total Seal stainless my second time around. Juuust a thought.

Mine are Total Seal brand, but they are not stainless steel. I figure by the time I can afford to go boost, the ring gaps will have opened up enough to handle the boost.

Originally Posted by enkeivette

And yeah, 15 psi on 4032 is pushing it. You'll need to intercool without question, and pull timing. 2018 is the way to go. But if you already bought the pistons, just be sure to run it intercooled.

Already posted that they're 2618 alloy, and an intercooled setup was always the plan.

[ZexGX]

YouTube - ‪It's...

gutted cats bolted on temporarily for first startup/break-in, x-pipe not hooked up for this video

[Shaolin Crane]

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