SRP pistons...
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Joined: Oct 2002
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From: somewhere south of normal
SRP pistons...
Does anyone have SRP flat tops (-5cc), part# 138089, in their 383 stroker..? I built my short block last fall and I'm now ready to complete the build. But I've found conflicting info regarding the CR with these slugs. Summit catalog states 11.8:1 with 64cc chambers. JE website states 11:1 with 64cc chambers, and 10.3:1 with 70cc chambers. I tend to trust the JE info over Summit, but I need to know for sure. I have not spoke with any tech support so far.
If the 10.3:1 is correct, I will be ordering Dart Pro-1's with 215 runners and 72cc chambers, and should have a CR around 10:1 (approx). I am very comfortable with this CR for a street performance engine.
Short block has Eagle forged crank (#435037505700), internal balance, and Eagle H beams (#5700B3D).
If the 10.3:1 is correct, I will be ordering Dart Pro-1's with 215 runners and 72cc chambers, and should have a CR around 10:1 (approx). I am very comfortable with this CR for a street performance engine.
Short block has Eagle forged crank (#435037505700), internal balance, and Eagle H beams (#5700B3D).
Burning Brakes
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From: Upland Ca
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From: Unreconstructed, South Carolina
Calculate CR yourself ... handly & accurate CR calculator first introduced here by Lars:
http://www.campbellenterprises.com/R...o%20calculator
No matter who calculates static CR ... you, summit or JE ... you must know how far piston down in hole (deck height), gasket thickness, dome volume, chamber volume. The calculator tool is very handy to run "what if?" scenarios.
SRP 138089 ... 4.030" bore, CH =1.425", DV = -5cc, for 5.7" rod with 3.75" stroke. This will sit 0.025" down in hole of a stock 9.025" block. If your block had, say 0.015" machined from decks, then it will sit 0.010" down in hole. Down in hole depends on how much, if any, the block's been decked.
One of the thinnest gaskets for use with alum heads is Victor Reinz 5746 ... it is 0.026" thick ... a felpro 1010 is 0.039"... felpro 1003 is 0.041".
Run the scenario w/ stock deck and 0.039 gasket and 72cc heads ... static CR very close to 9.7:1 ... at 0.010 down in hole and 0.039 gasket it'll be very close to 10:1. If block was zero decked (piston level with deck) and 0.039 gasket it's very close to 10.2:1.
Scenario w/ stock deck and 0.026 gasket & 72cc heads ... CR very close to 9.9:1 ...at 0.010 in hole it's very close to 10.3:1.
http://www.campbellenterprises.com/R...o%20calculator
No matter who calculates static CR ... you, summit or JE ... you must know how far piston down in hole (deck height), gasket thickness, dome volume, chamber volume. The calculator tool is very handy to run "what if?" scenarios.
SRP 138089 ... 4.030" bore, CH =1.425", DV = -5cc, for 5.7" rod with 3.75" stroke. This will sit 0.025" down in hole of a stock 9.025" block. If your block had, say 0.015" machined from decks, then it will sit 0.010" down in hole. Down in hole depends on how much, if any, the block's been decked.
One of the thinnest gaskets for use with alum heads is Victor Reinz 5746 ... it is 0.026" thick ... a felpro 1010 is 0.039"... felpro 1003 is 0.041".
Run the scenario w/ stock deck and 0.039 gasket and 72cc heads ... static CR very close to 9.7:1 ... at 0.010 down in hole and 0.039 gasket it'll be very close to 10:1. If block was zero decked (piston level with deck) and 0.039 gasket it's very close to 10.2:1.
Scenario w/ stock deck and 0.026 gasket & 72cc heads ... CR very close to 9.9:1 ...at 0.010 in hole it's very close to 10.3:1.
Thread Starter
Pro
Joined: Oct 2002
Posts: 708
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From: somewhere south of normal
Originally Posted by jackson
Calculate CR yourself ... handly & accurate CR calculator first introduced here by Lars:
http://www.campbellenterprises.com/R...o%20calculator
No matter who calculates static CR ... you, summit or JE ... you must know how far piston down in hole (deck height), gasket thickness, dome volume, chamber volume. The calculator tool is very handy to run "what if?" scenarios.
SRP 138089 ... 4.030" bore, CH =1.425", DV = -5cc, for 5.7" rod with 3.75" stroke. This will sit 0.025" down in hole of a stock 9.025" block. If your block had, say 0.015" machined from decks, then it will sit 0.010" down in hole. Down in hole depends on how much, if any, the block's been decked.
One of the thinnest gaskets for use with alum heads is Victor Reinz 5746 ... it is 0.026" thick ... a felpro 1010 is 0.039"... felpro 1003 is 0.041".
Run the scenario w/ stock deck and 0.039 gasket and 72cc heads ... static CR very close to 9.7:1 ... at 0.010 down in hole and 0.039 gasket it'll be very close to 10:1. If block was zero decked (piston level with deck) and 0.039 gasket it's very close to 10.2:1.
Scenario w/ stock deck and 0.026 gasket & 72cc heads ... CR very close to 9.9:1 ...at 0.010 in hole it's very close to 10.3:1.
http://www.campbellenterprises.com/R...o%20calculator
No matter who calculates static CR ... you, summit or JE ... you must know how far piston down in hole (deck height), gasket thickness, dome volume, chamber volume. The calculator tool is very handy to run "what if?" scenarios.
SRP 138089 ... 4.030" bore, CH =1.425", DV = -5cc, for 5.7" rod with 3.75" stroke. This will sit 0.025" down in hole of a stock 9.025" block. If your block had, say 0.015" machined from decks, then it will sit 0.010" down in hole. Down in hole depends on how much, if any, the block's been decked.
One of the thinnest gaskets for use with alum heads is Victor Reinz 5746 ... it is 0.026" thick ... a felpro 1010 is 0.039"... felpro 1003 is 0.041".
Run the scenario w/ stock deck and 0.039 gasket and 72cc heads ... static CR very close to 9.7:1 ... at 0.010 down in hole and 0.039 gasket it'll be very close to 10:1. If block was zero decked (piston level with deck) and 0.039 gasket it's very close to 10.2:1.
Scenario w/ stock deck and 0.026 gasket & 72cc heads ... CR very close to 9.9:1 ...at 0.010 in hole it's very close to 10.3:1.
I will be using the thinnest gasket I can find, in order to get my quench where I would like it to be. Even with an .026 I think it will be too wide. I may disassemble the block yet, and have it decked so as to get the quench around .040.I'm about to get out the DCR calculator to see where I'll be with the cam that I want to use, with duration @ .294 I & .302 E.
