Maximum Valve Spring Pressure

mannymen · 02-05-2012, 02:33 PM

What is the safest / maximum spring pressure one can run in a SBC with press-in studs?

Thanks
Manny

Paul Precht · 02-05-2012, 04:07 PM

They tend to pull out or break with the stock springs.

mannymen · 02-05-2012, 06:57 PM

"They tend to pull out or break with the stock springs"

Under what kind of conditions does this occur in?

above or under 6500?
over 300 lbs open pressure?

tj310 · 02-05-2012, 07:31 PM

Problems occur with stock rocker arms if they pinch the stud at full lift, shorter pushrods may help, we used to run stock Z28 springs.---Trevor

mannymen · 02-05-2012, 08:52 PM

Paul,

Thanks for the info. My plans are to use a set of stock 441 heads 1.94 - 1.50 (press in stud) with z28 springs and aftermarket roller tip or full roller rockers. For some limited street time and some bracket racing.

The camshaft will be in the ballpark of

327 / 350 hp cam

or something similar below

Camshaft Lift: .450 Intake /.460 Exhaust
Flat Tappet Duration @ .050" (222°Int/222° Exh)

Paul Precht · 02-05-2012, 09:07 PM

Some heads might be fine but there is an inconsistency from head to head and stud to stud. If the heads have a good history a slight step up from stock should be OK

Tom keedle · 02-05-2012, 09:47 PM

i've had the studs "pinned" before, might be an alternative for ya...

rustbucket79 · 02-05-2012, 11:13 PM

You're not going to break studs with that cam/spring combination, and you shouldn't be pulling studs either. If you want a guarantee, drill the stud bosses with a 1/8" bit and install hardened roll pins, or have a shop pull the studs and tap them for repair studs. (shoulderless studs)

trmnatr · 02-09-2012, 01:42 AM

Quote:

Originally Posted by Tom keedle

i've had the studs "pinned" before, might be an alternative for ya...

All studs should be pinned or screw in studs and guide plates

Harry 6674 · 02-09-2012, 11:53 AM

Quote:

Originally Posted by trmnatr

All studs should be pinned or screw in studs and guide plates

The cost is cheap compared to popping off a retainer. I found that out a long time ago.

02-05-2012, 02:33 PM	#1
mannymen Senior Member Join Date: Apr 2003 Posts: 728 Likes: 5 Liked 13 Times in 7 Posts	Maximum Valve Spring Pressure What is the safest / maximum spring pressure one can run in a SBC with press-in studs? Thanks Manny __________________ N/A

02-05-2012, 04:07 PM	#2
Paul Precht Senior Member Join Date: Dec 2001 Location: Elysburg, Pa Posts: 731 Likes: 355 Liked 320 Times in 119 Posts	Re: Maximum Valve Spring Pressure They tend to pull out or break with the stock springs.

02-05-2012, 06:57 PM	#3
mannymen Senior Member Join Date: Apr 2003 Posts: 728 Likes: 5 Liked 13 Times in 7 Posts	Re: Maximum Valve Spring Pressure "They tend to pull out or break with the stock springs" Under what kind of conditions does this occur in? above or under 6500? over 300 lbs open pressure? __________________ N/A

02-05-2012, 07:31 PM	#4
tj310 Member Join Date: Sep 2009 Location: Dresden On. Canada Posts: 460 Likes: 0 Liked 0 Times in 0 Posts	Re: Maximum Valve Spring Pressure Problems occur with stock rocker arms if they pinch the stud at full lift, shorter pushrods may help, we used to run stock Z28 springs.---Trevor

02-05-2012, 08:52 PM	#5
mannymen Senior Member Join Date: Apr 2003 Posts: 728 Likes: 5 Liked 13 Times in 7 Posts	Re: Maximum Valve Spring Pressure Paul, Thanks for the info. My plans are to use a set of stock 441 heads 1.94 - 1.50 (press in stud) with z28 springs and aftermarket roller tip or full roller rockers. For some limited street time and some bracket racing. The camshaft will be in the ballpark of 327 / 350 hp cam or something similar below Camshaft Lift: .450 Intake /.460 Exhaust Flat Tappet Duration @ .050" (222°Int/222° Exh) __________________ N/A

02-05-2012, 09:07 PM	#6
Paul Precht Senior Member Join Date: Dec 2001 Location: Elysburg, Pa Posts: 731 Likes: 355 Liked 320 Times in 119 Posts	Re: Maximum Valve Spring Pressure Some heads might be fine but there is an inconsistency from head to head and stud to stud. If the heads have a good history a slight step up from stock should be OK

02-05-2012, 09:47 PM	#7
Tom keedle Senior Member Join Date: Dec 2008 Location: Berthoud, Coloraduh Posts: 695 Likes: 13 Liked 8 Times in 7 Posts	Re: Maximum Valve Spring Pressure i've had the studs "pinned" before, might be an alternative for ya...

02-05-2012, 11:13 PM	#8
rustbucket79 Junior Member Join Date: Aug 2004 Location: Canada Posts: 45 Likes: 0 Liked 0 Times in 0 Posts	Re: Maximum Valve Spring Pressure You're not going to break studs with that cam/spring combination, and you shouldn't be pulling studs either. If you want a guarantee, drill the stud bosses with a 1/8" bit and install hardened roll pins, or have a shop pull the studs and tap them for repair studs. (shoulderless studs)