6.0 4.030 build stock rods cranks. Piston issues&cr
08-19-2018, 09:33 AM
#1
6.0 4.030 build stock rods cranks. Piston issues&cr Our builder is building a 370" 6.0 for us and said he is using flat top pistons.
We are using stock crank stock rods. New pistons.
he said that the compression with 64cc heads will be 10.5, and I'm a little confused because I would think ls2 flat tops with no reliefs had like 11.0 and this is .030 block and why the compression could be less.
does anyone have any insight on this.
also what piston could we use to drop into the stock stoke rods 3.662 6.098 and achieve about 11.5.
will these diamond tsp pistons fit. https://www.texas-speed.com/p-5905-d...roke-20cc.aspx
we are gonna be using prc 225 or tfs cast 220, ported fast 92 or ob 102
thanks
We are using stock crank stock rods. New pistons.
he said that the compression with 64cc heads will be 10.5, and I'm a little confused because I would think ls2 flat tops with no reliefs had like 11.0 and this is .030 block and why the compression could be less.
does anyone have any insight on this.
also what piston could we use to drop into the stock stoke rods 3.662 6.098 and achieve about 11.5.
will these diamond tsp pistons fit. https://www.texas-speed.com/p-5905-d...roke-20cc.aspx
we are gonna be using prc 225 or tfs cast 220, ported fast 92 or ob 102
thanks
08-19-2018, 06:03 PM
#2
I believe using stock length 6.098 inch rods greatly limits piston selection. Moving to an aftermarket rod that is 6.125 opens up piston selection and you should be able to basically get the desired 11 to 1 compression with much less hassle. Opening the bore up adds volume and decreases compression if everything else remains basically the same.
Likewise heads can be milled some to increase compression but the piston to valve clearances become tighter with flat top pistons and cam selection more limited. Also there is a point where excessive milling to heads can cause alignment issues with intake manifold.
When I've had motors build, given the cost involved for everything else going with an aftermarket rod made sense. The stock rods are good but a nice set of stronger aftermarket rods can be had for a pretty reasonable price.
I'm sure others with direct experience hand building their own motors can explain better in more detail on specific piston choices with stock rods. The piston in the TSP looks like a reasonable starting point to me.
Likewise heads can be milled some to increase compression but the piston to valve clearances become tighter with flat top pistons and cam selection more limited. Also there is a point where excessive milling to heads can cause alignment issues with intake manifold.
When I've had motors build, given the cost involved for everything else going with an aftermarket rod made sense. The stock rods are good but a nice set of stronger aftermarket rods can be had for a pretty reasonable price.
I'm sure others with direct experience hand building their own motors can explain better in more detail on specific piston choices with stock rods. The piston in the TSP looks like a reasonable starting point to me.
Last edited by 99 Black Bird T/A; 08-19-2018 at 06:15 PM.
08-19-2018, 09:33 PM
#3
I've been trying to look like crazy. Have to wait till tomorrow to speak to builder.
but I believe wiseco and diamond make a piston for stock rods a direct displacement. But idk about the floating and non floating pins and all that not that smart lol
Jason
but I believe wiseco and diamond make a piston for stock rods a direct displacement. But idk about the floating and non floating pins and all that not that smart lol
Jason
08-22-2018, 10:09 PM
#4
Theoretically....
I get 11.16 with 64cc heads, flat top 0cc, 4.030 bore, 3.622 stroke, 6.098 rods, .052 gasket, and pistons .005 out of the hole, assuming something like cometic part number CGT-C5014-052 that has gasket bore diameter of 4.150
Use these gaskets: Cometic MLS Head Gaskets H1295SP5051S
Use these pistons: https://www.briantooleyracing.com/cu...tock-rods.html
You'll be at 0 out of the hole and compression of 11.57:1
In a perfect world where theoretical = actual measured some 0.053 gaskets at that 4.030 gasket bore diameter puts you at exactly 11.50:1
Your engine builder will need to actually measure how far the pistons are coming in or out of the hole and they based the gasket selection on whatever will get you closest to 11.50.
I get 11.16 with 64cc heads, flat top 0cc, 4.030 bore, 3.622 stroke, 6.098 rods, .052 gasket, and pistons .005 out of the hole, assuming something like cometic part number CGT-C5014-052 that has gasket bore diameter of 4.150
Use these gaskets: Cometic MLS Head Gaskets H1295SP5051S
Use these pistons: https://www.briantooleyracing.com/cu...tock-rods.html
You'll be at 0 out of the hole and compression of 11.57:1
In a perfect world where theoretical = actual measured some 0.053 gaskets at that 4.030 gasket bore diameter puts you at exactly 11.50:1
Your engine builder will need to actually measure how far the pistons are coming in or out of the hole and they based the gasket selection on whatever will get you closest to 11.50.
Last edited by 5.7stroker; 08-22-2018 at 10:56 PM.
08-22-2018, 11:36 PM
#5
Going thru the same questions from a friend in Las Vegas with stock length rods and pistons already purchased, with a 5.7. I've got to call and see what there using for piston calculations is it in the hole or @ 0 deck height & gasket thickness used etc..... He has 243's 65cc heads that has had work done by A.I. for 2.02 valves. So I'll get the basic info tomorrow and work from there and see what's the recommended max lift before P/V clearance becomes a issue = Flycutting. He's wanting a track only little 5.7 for a track car. Thinking @ 60cc that would net me around 11.4 with it @ 0 deck height and .041 thick 3.980 bore gasket. Rough numbers but thinking close to actual numbers so he can have the machine work done.
Found this still need the calculations for gasket thickness and where the piston sits @ the deck, also if the block has been decked etc.
Found this still need the calculations for gasket thickness and where the piston sits @ the deck, also if the block has been decked etc.
- Piston Top Type: Dome Top
- Bore: 3.903
- Stroke: 3.622
- Rod Length: 6.098
- Compression Height: 1.335
- Compression Ratio: (65cc) 10.7
- Dome Volume: 4.0
- Rings: 1/16 1/16 3.0
- Rings Included: Yes
- Pin Type: Chromium Alloy Steel Straight Wall
- Pin Diameter: .927
- Pin Length: 2.500
- Pin Wall: .150
- Pin Weight: 117
08-22-2018, 11:46 PM
#6
I think we are gonna spend the money on diamond 11510 pistons, use factory gen4 rods and crank, arp bolts.
those pistons with 64cc will do 11.1cr with 62cc 11.4.
He picked up prc 225 heads 62cc, plan on .040 gaskets should be 11.7, also got a vengeance ported 92 fast and a ls2 tb.
we plan on a custom grind, ms4/btr4/streetsweeper/polluter style cam. I tried to spec my own but waiting to hear what the gurus say, 236,242 113+2. 49*ivc 56*evo 13* overlap.
this is going in a c5.
I want 505-525rwhp 460ish tq.
thanks guys
those pistons with 64cc will do 11.1cr with 62cc 11.4.
He picked up prc 225 heads 62cc, plan on .040 gaskets should be 11.7, also got a vengeance ported 92 fast and a ls2 tb.
we plan on a custom grind, ms4/btr4/streetsweeper/polluter style cam. I tried to spec my own but waiting to hear what the gurus say, 236,242 113+2. 49*ivc 56*evo 13* overlap.
this is going in a c5.
I want 505-525rwhp 460ish tq.
thanks guys
08-23-2018, 12:10 AM
#7
I'm just copying 2* 5.7 builds both over 500rwhp (he's running a Vic Jr & 4150 TB). Wish I could get the compression higher. Gonna give C a call and talk it over to finalize some things. Vegas is a hr back so he still may be up, he's 31 though so I'd think he's up.
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08-23-2018, 12:37 AM
#8
optimum compression will make night and day difference on loving a big cam or not and also making the power where you need it.
Hope y'll have fun and do what you want
08-23-2018, 10:35 AM
#10
Yea I'm past the thought of fly cutting:
..004+ @ TDC with .051 gasket with deck set @ 9.240 no deck of short block would = around 11.0
Going with .041 thick gasket and milling the heads to 60cc makes around 12.0 compression which is what I was hoping for.
P/V Clearance for mock up needs to be .080 for the intake and .100 exhaust. I've done his spec's he can have the work done.
Cam will be a Darth like solid roller on E85 for a 01 Camaro. C* has a 4l60 trans with I'm thinking stock rear end gearing. We'll look at gearing 3.73+ and stall once the cam is done. I asked C was this for the race car he said it's to replace the old 5.7 in his Camaro he has a 6.0 short block for the race car that runs a 355 sbc now and he still uses. Wants to use Ls3 heads for it later down the line. That's for another day. Going to look into intakes now.....He has a Ls6 intake and thought about the Vic Jr -4150. He says he not spending $1500 with Fast nor Msd. I'm looking at the Holley low profile 102 sniper as I write.
So I'll get the basic info tomorrow and work from there and see what's the recommended max lift before P/V clearance becomes a issue = Flycutting.
Going with .041 thick gasket and milling the heads to 60cc makes around 12.0 compression which is what I was hoping for.
P/V Clearance for mock up needs to be .080 for the intake and .100 exhaust. I've done his spec's he can have the work done.
Cam will be a Darth like solid roller on E85 for a 01 Camaro. C* has a 4l60 trans with I'm thinking stock rear end gearing. We'll look at gearing 3.73+ and stall once the cam is done. I asked C was this for the race car he said it's to replace the old 5.7 in his Camaro he has a 6.0 short block for the race car that runs a 355 sbc now and he still uses. Wants to use Ls3 heads for it later down the line. That's for another day. Going to look into intakes now.....He has a Ls6 intake and thought about the Vic Jr -4150. He says he not spending $1500 with Fast nor Msd. I'm looking at the Holley low profile 102 sniper as I write.