Weak springs?
#1
Member
JUNIOR BUILDER
Thread Starter
Join Date: May 2007
Posts: 83
Weak springs?
Hi,
I have a Crane TR-272/4167-2S-10 cam in my 509.
The cam card says:
1967-UP CHEVROLET V-8 396 THRU 454 CU.IN.
MODERATE COMP. ONLY, GOOD UPPER R.P.M.
TORQUE & H.P., HIGH COMP. RATIO REQUIRED
INTAKE @CAM 4167 @VALVE 708
EXHAUST @CAM 4167 @VALVE 708
TIMING OPENS CLOSES ADV DURATION
@ .0195 INTAKE 45 BTDC 85 ABDC 310 °
TAPPET LIFT EXHAUST 88 BBDC 48 ATDC 316
@ .050 INTAKE 29 BTDC 63 ABDC 105 °ATDC 272 °
TAPPET LIFT EXHAUST 72 BBDC 26 ATDC 115 °BTDC 278
RECOMMENDED RPM
RANGE WITH MATCHING COMPONENTS
MINIMUM RPM 4400
MAXIMUM RPM 7800
VALVE FLOAT 8500
So not a street cam, but not a pro-stock cam either.
The valve spring recommandation:
Crane-99876
LOADS:
CLOSED 160 LBS @ 1.968 OR 1 31/32
OPEN 490 LBS @ 1.308
I have installed them on 1.950" which gives 160-180lbs seat pressure new. Few questions. Is this enought as the rpm at finish line is about 7000? Should I upgrade the springs? Spring recommadations for 1.55 size? Heads are with 2.19/1.88 stainless steel valves. I had about 50 runs on new springs and lifters when we took it apart. Springs are now 150-180lbs at the seat. Valve seats and lifters seems to be fine.
I have a Crane TR-272/4167-2S-10 cam in my 509.
The cam card says:
1967-UP CHEVROLET V-8 396 THRU 454 CU.IN.
MODERATE COMP. ONLY, GOOD UPPER R.P.M.
TORQUE & H.P., HIGH COMP. RATIO REQUIRED
INTAKE @CAM 4167 @VALVE 708
EXHAUST @CAM 4167 @VALVE 708
TIMING OPENS CLOSES ADV DURATION
@ .0195 INTAKE 45 BTDC 85 ABDC 310 °
TAPPET LIFT EXHAUST 88 BBDC 48 ATDC 316
@ .050 INTAKE 29 BTDC 63 ABDC 105 °ATDC 272 °
TAPPET LIFT EXHAUST 72 BBDC 26 ATDC 115 °BTDC 278
RECOMMENDED RPM
RANGE WITH MATCHING COMPONENTS
MINIMUM RPM 4400
MAXIMUM RPM 7800
VALVE FLOAT 8500
So not a street cam, but not a pro-stock cam either.
The valve spring recommandation:
Crane-99876
LOADS:
CLOSED 160 LBS @ 1.968 OR 1 31/32
OPEN 490 LBS @ 1.308
I have installed them on 1.950" which gives 160-180lbs seat pressure new. Few questions. Is this enought as the rpm at finish line is about 7000? Should I upgrade the springs? Spring recommadations for 1.55 size? Heads are with 2.19/1.88 stainless steel valves. I had about 50 runs on new springs and lifters when we took it apart. Springs are now 150-180lbs at the seat. Valve seats and lifters seems to be fine.
#4
Senior Member
RACING JUNKIE
Join Date: Sep 2007
Location: Belleville, IL
Posts: 658
http://cranecams.com/index.php?show=...01&lvl=2&prt=5
According to Crane's website, you don't have enough spring.
According to Crane's website, you don't have enough spring.
#5
Your spring part # should be 99886, not 99876. Big difference. If it were me I would set the heads up with a PAC 1246 spring, but at least get the correct springs. If you are limited to a 1.55 spring, a PAC 1225 would work much better than what you have.
#7
Senior Member
RACING JUNKIE
Join Date: Sep 2007
Location: Belleville, IL
Posts: 658
Maybe they figured out that it wasn't enough spring and revised the website and new cam cards?
If you can fit a 1.56" spring, go with a PSI CT1227
http://www.psisprings.com/index.php?...ask=view&id=17
If you can fit a 1.56" spring, go with a PSI CT1227
http://www.psisprings.com/index.php?...ask=view&id=17
#8
Senior Member
RACING JUNKIE
Join Date: May 2006
Posts: 2,044
This is copied from the original post, very confusing.
1967-UP CHEVROLET V-8 396 THRU 454 CU.IN.
MODERATE COMP. ONLY, GOOD UPPER R.P.M.
TORQUE & H.P., HIGH COMP. RATIO REQUIRED
Moderate comp only, then high comp required? wt?
I'd go with the springs recommended from crane they know whats best for their cams, or go with a comparriabled set with them same seat pressure, same installed height and coil bind.
Goodluck, Charles
1967-UP CHEVROLET V-8 396 THRU 454 CU.IN.
MODERATE COMP. ONLY, GOOD UPPER R.P.M.
TORQUE & H.P., HIGH COMP. RATIO REQUIRED
Moderate comp only, then high comp required? wt?
I'd go with the springs recommended from crane they know whats best for their cams, or go with a comparriabled set with them same seat pressure, same installed height and coil bind.
Goodluck, Charles
#9
Senior Member
RACING JUNKIE
Join Date: Sep 2007
Posts: 4,137
Originally Posted by cepx111
This is copied from the original post, very confusing.
1967-UP CHEVROLET V-8 396 THRU 454 CU.IN.
MODERATE COMP. ONLY, GOOD UPPER R.P.M.
TORQUE & H.P., HIGH COMP. RATIO REQUIRED
Moderate comp only, then high comp required? wt?
I'd go with the springs recommended from crane they know whats best for their cams, or go with a comparriabled set with them same seat pressure, same installed height and coil bind.
Goodluck, Charles
1967-UP CHEVROLET V-8 396 THRU 454 CU.IN.
MODERATE COMP. ONLY, GOOD UPPER R.P.M.
TORQUE & H.P., HIGH COMP. RATIO REQUIRED
Moderate comp only, then high comp required? wt?
I'd go with the springs recommended from crane they know whats best for their cams, or go with a comparriabled set with them same seat pressure, same installed height and coil bind.
Goodluck, Charles