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Looking to build a motor that will put down 500 RWHP through a T56 and built 8.8.
Got a LS2 short block for a decent price because it had a failed rod bearing.
I've purchased some LSA heads for a decent price already.
I was going to buy a complete rotating assembly but found a couple pieces locally. Just trying to save a few bucks. Would like some opinions on the parts available to me.
Compstar LS2 Stroker Crank and H beam Rods - Lightly used
$1000 US
Wiseco K464X05 Piston Kit - New
Chevy LS -3cc Dome 4.005" Bore
$850 US
I know I should find pistons that will give me a compression bump while having valve reliefs so I can run a bigger cam with the LSA heads. Would this get me going in the right direction?
Looking to build a motor that will put down 500 RWHP through a T56 and built 8.8.
Got a LS2 short block for a decent price because it had a failed rod bearing.
I've purchased some LSA heads for a decent price already.
I was going to buy a complete rotating assembly but found a couple pieces locally. Just trying to save a few bucks. Would like some opinions on the parts available to me.
Compstar LS2 Stroker Crank and H beam Rods - Lightly used
$1000 US
Wiseco K464X05 Piston Kit - New
Chevy LS -3cc Dome 4.005" Bore
$850 US
I know I should find pistons that will give me a compression bump while having valve reliefs so I can run a bigger cam with the LSA heads. Would this get me going in the right direction?
Thanks for any help.
According to my numbers, those pistons will give you just over 11:1 compression with a stock .051" head gasket assuming they have a .000" deck height. A .041" thick Fel Pro 1161 series head gasket would bump that up to just over 11.3:1 which is what I would do. Here are my numbers:
Combine that with the right LS stroker camshaft for your application, some good 1 7/8" headers and you should reach your goal no problem.
For compression I was aiming for 10.7:1 which is what stock is for the LS3 or a bit higher. I don't plan on using forced induction.
There wouldn't be any issue running those pistons with the rod and crank mentioned? I've never spec'd pistons to cranks/rods before.
Thanks
Jake
Here is what you need to know
Deck height of LS block = 9.240"
Stroke 4"/2 = 2"
con rod length 6.125"
piston height 1.115"
Total = 9.240" so zero deck height
Now you can use any of the compression calculators available. input your valve release size combustion chamber size and head gasket thickness and you're set.
According to my numbers, those pistons will give you just over 11:1 compression with a stock .051" head gasket assuming they have a .000" deck height. A .041" thick Fel Pro 1161 series head gasket would bump that up to just over 11.3:1 which is what I would do. Here are my numbers:
Combine that with the right LS stroker camshaft for your application, some good 1 7/8" headers and you should reach your goal no problem.
It's weird how I used the Wallace racing calculator with the same info and got almost a point higher.
From the looks of it, I put in an -3cc volume for a dome. You have a -3cc volume for a valve relief. Not sure which is correct.
Originally Posted by KW Baraka
I run 12:1 compression with no issues; even during afternoon rush-hour, summertime traffic in South Texas (100+ degrees).
With a properly spec'ed cam and optimal quench (.035" to .040").....12:1 in a daily driver = no sweat.
KW
Sure you can run it without issues, plenty of people do. You just don't really see a gain because of how much timing gets pulled to keep it from pinging on those hot summer days. Especially if you actually race it.
It's weird how I used the Wallace racing calculator with the same info and got almost a point higher.
From the looks of it, I put in an -3cc volume for a dome. You have a -3cc volume for a valve relief. Not sure which is correct.
.
It appears that the Wallace calculator needs a positive number for a dish or valve relief whereas ours uses a negative number input for a dish or valve relief.
How can you ensure proper quench? Is that based upon the cam.. Who should I see to spec out a proper cam setup for me. Thanks for the info.
Jake
Quench is basically the clearance between the piston and cylinder head. Stock LS engines usually have the pistons .005-.007" out above the deck of the block at TDC so a stock .051" thick MLS gasket gives you .044-.046" quench distance.
When your machinist builds your engine, he can cut the deck of the block so that your pistons stick further out and reduce the quench distance. Most prefer .035-.040" as a good safe quench, but others have run less. When you run tighter than .035", you really need to make sure you have accurate measurements because you run the risk of the pistons hitting the head.
It appears that the Wallace calculator needs a positive number for a dish or valve relief whereas ours uses a negative number input for a dish or valve relief.
Yeah I noticed that, I'm just curious whether the piston has a dome or not. It's listed as a -3cc dome, so I calculated it as such. However, Wiseco's catalog says it should give you about 11.3:1 with a 68cc chamber.
Yeah I noticed that, I'm just curious whether the piston has a dome or not. It's listed as a -3cc dome, so I calculated it as such. However, Wiseco's catalog says it should give you about 11.3:1 with a 68cc chamber.
Their compression rating is kind of generic. You notice it shows the compression as 11.3 for all of the bore diameters from 4.000 to 4.075. Just in that small bore size range can account for nearly 4 tenths of a point.
I also see that the compression height of that piston is .005" in the hole unless you deck the block.
Lastly, they do not specify the head gasket dimensions. So, there is another variable.
It's weird how I used the Wallace racing calculator with the same info and got almost a point higher.
From the looks of it, I put in an -3cc volume for a dome. You have a -3cc volume for a valve relief. Not sure which is correct.
Sure you can run it without issues, plenty of people do. You just don't really see a gain because of how much timing gets pulled to keep it from pinging on those hot summer days. Especially if you actually race it.
Is one calcaulator taking heat expansion into consideration ?
Is one calcaulator taking heat expansion into consideration ?
I doubt it. I think it's just as speedtigger said, a negative volume means a dome for the wallace racing calculator and a dish for the cam motion calculator.
What would be the general consensus on the compression ratio? Should I take a bit off the block to ensure straightness and run the thinner head gasket? I don't want to sacrifice too much PTV clearance for the cam.
12-27-2016, 08:25 AM
Help with LS2 Stroker Build 
