Questions regarding PRC Stage 2.5 heads and milling
#1
Questions regarding PRC Stage 2.5 heads and milling
So I will be sending in my 243s to PRC to have a mild port along with having them milled and have a few questions.
I currently have a Gen 4 LMG 5.3 with OE 243 heads, Crane 210/218---.551/.551---116+2LSA---110ICL cam, Stock flat top pistons, 051" MLS head gaskets.
I would like to have the PRC Stage 2.5 done to the heads, have the heads milled down to 58CC Combustion Chamber (.0036" Milled give or take), using Ferrea 2.02" Intake and 1.575" Exhaust valves. Also going to a .040" head gasket to achieve a 11.12:1 Static CR and a 8.15:1 Dynamic CR.
My question is will I run into any PTV clearance issues or any issues of any sorts with this combo?
I want to stay away from Fly Cutting the pistons. SO if something needs to be changed let me know. I can have the heads shaved .030" to be at 59CC's if needed.
Thanks in advance
I currently have a Gen 4 LMG 5.3 with OE 243 heads, Crane 210/218---.551/.551---116+2LSA---110ICL cam, Stock flat top pistons, 051" MLS head gaskets.
I would like to have the PRC Stage 2.5 done to the heads, have the heads milled down to 58CC Combustion Chamber (.0036" Milled give or take), using Ferrea 2.02" Intake and 1.575" Exhaust valves. Also going to a .040" head gasket to achieve a 11.12:1 Static CR and a 8.15:1 Dynamic CR.
My question is will I run into any PTV clearance issues or any issues of any sorts with this combo?
I want to stay away from Fly Cutting the pistons. SO if something needs to be changed let me know. I can have the heads shaved .030" to be at 59CC's if needed.
Thanks in advance
#4
I have used 3 different calculators and came up with 11.1-11.2:1 Static and 8.15-8.21:1 on Dynamic.
I am using a 3.780" Bore, 3.622" Stroke, Cylinder head Gasket Bore of 3.92", Head gasket thickness of .040", 58cc Chamber, Stock Gen 4/L33 Flat top pistons 0.00CC , -.006 Piston Deck Clearance out of hole.
Cams ABDC is at 74.0, 0 Boost at Sea Level.
Did I miss something or didn't calculate something right?
I am 100% Sure on cam specs, looking at cam card now. Crane Cams # 1449051
Factory specs on Static CR is 9.95:1 with stock 64.45CC 243s and .051" head gasket.
I am using a 3.780" Bore, 3.622" Stroke, Cylinder head Gasket Bore of 3.92", Head gasket thickness of .040", 58cc Chamber, Stock Gen 4/L33 Flat top pistons 0.00CC , -.006 Piston Deck Clearance out of hole.
Cams ABDC is at 74.0, 0 Boost at Sea Level.
Did I miss something or didn't calculate something right?
I am 100% Sure on cam specs, looking at cam card now. Crane Cams # 1449051
Factory specs on Static CR is 9.95:1 with stock 64.45CC 243s and .051" head gasket.
Last edited by 07NBSChevy; 05-17-2016 at 08:04 PM.
#6
http://www.rbracing-rsr.com/compstaticcalc.html
http://www.wallaceracing.com/dynamic-cr.php
I used RBRacings thing and came up with 11.2:1 SCR with a 59cc Camber and .040" head gasket, then used Wallace Racing for the DCR and came up with 8.21:1
Does this sound right for a 59cc chamber? The 58cc with these calculators puts me above the DCR I would like to be at.
http://www.wallaceracing.com/dynamic-cr.php
I used RBRacings thing and came up with 11.2:1 SCR with a 59cc Camber and .040" head gasket, then used Wallace Racing for the DCR and came up with 8.21:1
Does this sound right for a 59cc chamber? The 58cc with these calculators puts me above the DCR I would like to be at.
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#8
TECH Junkie
iTrader: (5)
You're using duration and valve events at 0.050...that's not going to be accurate. Plus, that number should be 39 + 15 so 54 if you're going by that. Idk where you got 74 from.
You need to look at the advertised duration at 0.006
11.2 SCR with 272 advertised duration and 114ICL is about 8.53.
Although it's confusing, you're saying 116+2 but the ICL is 110?
You need to look at the advertised duration at 0.006
11.2 SCR with 272 advertised duration and 114ICL is about 8.53.
Although it's confusing, you're saying 116+2 but the ICL is 110?
#10
TECH Addict
Its probably 116+4. I have a 222/226 115+3 .600 lift and PRC 5.3 heads 58cc on a 5.3 LM7 and i have no issues.
Last edited by gagliano7; 05-18-2016 at 11:47 AM.
#16
Redtan, i do appreciate your replys and knowledge on this. I am still trying to understand all this cam stuff.
Based off all the info on the cam I gave you minus the ICL, what would be the best chamber size to achieve the closest to 8.2:1 dynamic compression.
Based off all the info on the cam I gave you minus the ICL, what would be the best chamber size to achieve the closest to 8.2:1 dynamic compression.
#18
TECH Junkie
iTrader: (5)
Based off all the info on the cam I gave you minus the ICL, what would be the best chamber size to achieve the closest to 8.2:1 dynamic compression.
I would shoot for something like 8.5-8.6 DCR. That could be achieved by milling off 2-3ccs of the heads.