Looking for head specs... Milled 853 cc #s
01-29-2013, 08:19 PM
#1
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Looking for head specs... Milled 853 cc #s I have 853 castings. I am porting them. Polishing the exhaust side.
Everyone is saying to get 243s or 799s . Its pointless to me to spend 500 on heads then pay another 600 getting them worked, then another 500 in springs, retainers and keepers, and then a trunion kit...VALVES, .. Holy **** guys, you seriously spend $2000 on stock heads?????? Wwooooowwww. You can buy complete aftermarket heads for that....not my idea of why you would mod stock heads, im on a budget.
That being said, i am keeping my 853 castings and having them worked. I have a friend who has his, by the same machinist im using, flowing 300 in/ 220ex @ .600 lift. He only milled his .005 for a surface reassurance.
How much needs to be milled for a 64cc chamber like a 243?
Stock 853 is already a 67cc head. I wouls assume not much to get to 64??
Chime in if you know your stuff.... Thanks
Everyone is saying to get 243s or 799s . Its pointless to me to spend 500 on heads then pay another 600 getting them worked, then another 500 in springs, retainers and keepers, and then a trunion kit...VALVES, .. Holy **** guys, you seriously spend $2000 on stock heads?????? Wwooooowwww. You can buy complete aftermarket heads for that....not my idea of why you would mod stock heads, im on a budget.
That being said, i am keeping my 853 castings and having them worked. I have a friend who has his, by the same machinist im using, flowing 300 in/ 220ex @ .600 lift. He only milled his .005 for a surface reassurance.
How much needs to be milled for a 64cc chamber like a 243?
Stock 853 is already a 67cc head. I wouls assume not much to get to 64??
Chime in if you know your stuff.... Thanks
01-31-2013, 01:31 PM
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I just had mine done and not exactly sure what the combustion chamber size was when it was done. But they were milled around .018 to get the compression up a bit. Hope this helps and make sure to check PTV clearance.
01-31-2013, 01:48 PM
#3
I have 853 castings. I am porting them. Polishing the exhaust side.
Everyone is saying to get 243s or 799s . Its pointless to me to spend 500 on heads then pay another 600 getting them worked, then another 500 in springs, retainers and keepers, and then a trunion kit...VALVES, .. Holy **** guys, you seriously spend $2000 on stock heads?????? Wwooooowwww. You can buy complete aftermarket heads for that....not my idea of why you would mod stock heads, im on a budget.
That being said, i am keeping my 853 castings and having them worked. I have a friend who has his, by the same machinist im using, flowing 300 in/ 220ex @ .600 lift. He only milled his .005 for a surface reassurance.
How much needs to be milled for a 64cc chamber like a 243?
Stock 853 is already a 67cc head. I wouls assume not much to get to 64??
Chime in if you know your stuff.... Thanks
Everyone is saying to get 243s or 799s . Its pointless to me to spend 500 on heads then pay another 600 getting them worked, then another 500 in springs, retainers and keepers, and then a trunion kit...VALVES, .. Holy **** guys, you seriously spend $2000 on stock heads?????? Wwooooowwww. You can buy complete aftermarket heads for that....not my idea of why you would mod stock heads, im on a budget.
That being said, i am keeping my 853 castings and having them worked. I have a friend who has his, by the same machinist im using, flowing 300 in/ 220ex @ .600 lift. He only milled his .005 for a surface reassurance.
How much needs to be milled for a 64cc chamber like a 243?
Stock 853 is already a 67cc head. I wouls assume not much to get to 64??
Chime in if you know your stuff.... Thanks
With that said, it takes roughly .006" of milling to remove 1cc. To get from 67cc to 64cc, you're going to need to remove at least .018".
01-31-2013, 01:55 PM
#4
Yea, $2000 no ******* way dude
Brand new heads, valves springs etc $1400
http://texas-speed.com/p-1391-prc-st...ted-heads.aspx
Brand new heads, valves springs etc $1400
http://texas-speed.com/p-1391-prc-st...ted-heads.aspx
02-01-2013, 12:17 AM
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Yea, $2000 no ******* way dude
Brand new heads, valves springs etc $1400
http://texas-speed.com/p-1391-prc-st...ted-heads.aspx
Brand new heads, valves springs etc $1400
http://texas-speed.com/p-1391-prc-st...ted-heads.aspx
Martin@tick calculated a 10.26:1 comp ratio on my setup if I were to run just a .040 gasket. if I mill another .018 off I might have to go with slightly less lift on my cam and take the milder lobe of 234/238 .609 lift for p to v clearance but my comp should be up a bit.
ill ask him and see, thanks for the input guys.
02-01-2013, 11:31 AM
#7
TECH Senior Member
IMO a 234 cam with .018 mill will need to be measured for PTVC. Depending on LSA/ICL it could or not clear. (but by what margins).
So bottom line, you'll need to measure.
And lift has next to nothing to do with PTVC. Max lift occurs close to or at BDC. (BDC is bottom dead center and is when the piston is the furthest in the bore at the bottom so no contact with valves can be possible at that time)
Many people confuse .050 lift capabilities with tappet lift.
So bottom line, you'll need to measure.
And lift has next to nothing to do with PTVC. Max lift occurs close to or at BDC. (BDC is bottom dead center and is when the piston is the furthest in the bore at the bottom so no contact with valves can be possible at that time)
Many people confuse .050 lift capabilities with tappet lift.
