|
Author
|
Topic: stock valve springs
|
streetstang67
Gearhead Posts: 397
From: SC, USA
Registered: Nov 2002
|
posted 02-09-2004 04:13 PM
   
I'm about to get a cam, but I dont want to change valve springs. First off, I dont really know whats involved, and second, it seems complicated. Either way, it would be nice to keep the same stock springs with the cam change. Right now I'm thinking about the XE256H and a similar specialty cam, the lift for both is around .474-.477. Can I keep my stock valve springs(the engine was rebuilt less than 5000 miles ago)? What are the chances for one to break?------------------
'67 coupe: 289 bored .030 over, c-4 tranny
Holley 600 carb, edelbrock performer intake, Crane XR-i ignition, hooker comp headers, dual flowmaster exhuast C-4 (stock) 3.55s with traclok
IP: Logged |
Moneymaker
Administrator Posts: 25883
From: Lyons, IL, USA
Registered: May 99
|
posted 02-09-2004 04:20 PM
Ask you engine builder for an honest answer.
You need 90 lbs or so on the seat with that cam. If he used the old springs, then you need new ones.------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,& '04
First SS/MA in the TENS!
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
IP: Logged |
indyphil
Gearhead Posts: 2398
From: Senoia, G.A. USA
Registered: Jul 2002
|
posted 02-09-2004 04:22 PM
I dont think the question is so much about durability (although they will give up eventually) but more about valve float. A bigger cam will accelerate/open the valve faster - then the spring cant keep the valtrain together so the valve hangs open this is bad for the valve, the seat and performance. Comp cams will be able to tell you which springs are needed for which cams and people often refer to them by Seat force (how much force is needed to lift the valve off the seat) Im no expert so I dont want to guess, some real experts on here might know if stock springs will be OK with the 256 cam but I would imagine they will be OK.
------------------
'68 coupe 289 C code
66 heads, edel 600cfm carb, performer intake, dual exhaust http://www.geocities.com/ottouk_77/68mustang.htm
IP: Logged |
capri man
Gearhead Posts: 6417
From: doerun, ga.
Registered: Nov 2000
|
posted 02-09-2004 04:24 PM
did you install new springs when the engine was built? do you have any idea what the closed seat pressure is on the springs?------------------
mike r
racing is real
everything else is just a game.
81 capri-7.47 @90mph 1/8
1.54 60 ft. http://www.angelfire.com/ny5/billswebsite/pg06.html
IP: Logged |
indyphil
Gearhead Posts: 2398
From: Senoia, G.A. USA
Registered: Jul 2002
|
posted 02-09-2004 04:25 PM
I Was writing my lame reply while alex was actually writing something informative.  ------------------
'68 coupe 289 C code
66 heads, edel 600cfm carb, performer intake, dual exhaust http://www.geocities.com/ottouk_77/68mustang.htm
IP: Logged |
capri man
Gearhead Posts: 6417
From: doerun, ga.
Registered: Nov 2000
|
posted 02-09-2004 04:27 PM
dang, alex and phil answered while i was typing. i think i got a new set that came off of some gt40p heads here somewhere. dont know the specs on them though. maybe someone here can tell us.------------------
mike r
racing is real
everything else is just a game.
81 capri-7.47 @90mph 1/8
1.54 60 ft. http://www.angelfire.com/ny5/billswebsite/pg06.html
IP: Logged |
Moneymaker
Administrator Posts: 25883
From: Lyons, IL, USA
Registered: May 99
|
posted 02-09-2004 04:32 PM
quote:
Originally posted by capri man:
dang, alex and phil answered while i was typing. i think i got a new set that came off of some gt40p heads here somewhere. dont know the specs on them though. maybe someone here can tell us.
Those will work. ------------------
Alex Denysenko
Co-Administrator and Moderator NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA & SS/MA National Record Holder '00,'01,'02,'03,& '04
First SS/MA in the TENS!
IHRA division 5 Superstock Champion
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28 The Barry of BarrysGrrl Quote #1: "I never met a magazine mechanic I liked."
Quote #2: "Make sure brain is in gear before engaging mouth!"
Quote #3: "If you can't run with the big dogs, stay on the porch!"
www.moneymakerracing.com
IP: Logged |
capri man
Gearhead Posts: 6417
From: doerun, ga.
Registered: Nov 2000
|
posted 02-09-2004 05:00 PM
i found them. i got all the retainers and locks also. if you need them just let me know.------------------
mike r
racing is real
everything else is just a game.
81 capri-7.47 @90mph 1/8
1.54 60 ft. http://www.angelfire.com/ny5/billswebsite/pg06.html
IP: Logged |
Mustangsandmore Forums
