Valve spring rated lift vs camshaft lift? - Vintage Mustang Forums
 
Thread Tools
post #1 of 7 (permalink) Old 05-14-2019, 06:02 AM Thread Starter
Senior Member
 
russosborne's Avatar
 
Join Date: Aug 2003
Location: Glendale Arizona
Posts: 1,888
Question Valve spring rated lift vs camshaft lift?

Question.

If a spring is rated for say .550 inch lift, what would a safe cam lift be for that spring. I am assuming I shouldn't go for a cam lift right at the spring rating. Or any spring rate, is there a percentage I should leave as a safety factor?

I don't want to totally waste the spring lift either. Obviously I could go WAY under, but would like to go as close as possible without having to worry about it breaking.

Avoiding breakage would be really good. :-)

Thanks,
Russ

RIP Mallory, Abby, and Sadie. And now Casey. :-( We miss you girls.

79 Pinto Hatchback. Fully caged, 8inch 4:10 gears. 351W. Aftermarket Tremec T5 (1352 251), Going to be a fun cruiser.

74 Pinto Wagon.
On maybe permanent hold.

72 Ranchero GT w/351Cleveland & automatic. Although this wasn't supposed to be a project car it seems that it has become one. Stupid rusted out California floor pans.
russosborne is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old 05-14-2019, 06:26 AM
Senior Member
Supporting Member
 
gordonr's Avatar
 
Join Date: Oct 2015
Location: Virginia Beach
Posts: 418
As a builder you should be looking for a spring bind spec of .050 to .080". You should pull a few springs and check the install height to verify what you have anyway as well.

1969 Mach 1 S code...2nd owner
gordonr is offline  
post #3 of 7 (permalink) Old 05-14-2019, 06:49 AM Thread Starter
Senior Member
 
russosborne's Avatar
 
Join Date: Aug 2003
Location: Glendale Arizona
Posts: 1,888
Uh, thanks, but what are you telling me?
Sorry, no clue.
Russ

RIP Mallory, Abby, and Sadie. And now Casey. :-( We miss you girls.

79 Pinto Hatchback. Fully caged, 8inch 4:10 gears. 351W. Aftermarket Tremec T5 (1352 251), Going to be a fun cruiser.

74 Pinto Wagon.
On maybe permanent hold.

72 Ranchero GT w/351Cleveland & automatic. Although this wasn't supposed to be a project car it seems that it has become one. Stupid rusted out California floor pans.
russosborne is offline  
 
post #4 of 7 (permalink) Old 05-14-2019, 10:32 AM
Senior Member
 
Join Date: Oct 2015
Location: Anaheim
Posts: 1,117
What he is saying is , if you have a cam with NET lift ( not gross , before lash) of .550 , you look for a spring that "coil binds" ( goes solid) at .600-.630 compression from the installed height. For example if a spring coil binds at 1.200 you would want an installed height of 1.800-1.830 so that you have .050-.080 more than the net cam lift. Having more spring "travel" is mot necessary and can have a negative affect . Then you have to select a spring that has pressures compatible with your cam at those specific heights. Add to that the fact that there will be "some" pressure variation in a set of 16 that can only be found with a spring pressure tester. Preparing a set of heads for a performance application can take hours.
Randy

'66 GT350H-3 time cover car - Car Craft July'77,Modified Mustangs and Fords Feb2011 ( w/article), Mustang Monthly June 2014. Bracket raced by me for the last 44 years. Yes it is a real one.
'68.5 R code GT fastback
'67 Ranchero 408W -427 glass hood
'78 F350 "Oleynik" car hauler
Ford Experimental parts collector
GT350HR is offline  
post #5 of 7 (permalink) Old 05-14-2019, 10:48 AM
Senior Member
 
maladezo's Avatar
 
Join Date: Jul 2015
Location: Californication
Posts: 1,060
Garage
I like to double check everything. Squeeze a spring and measure height while bound. Measure installed spring height, adjust with shims if needed.

'67 coupe, 390, 4spd.
maladezo is offline  
post #6 of 7 (permalink) Old 05-14-2019, 07:15 PM Thread Starter
Senior Member
 
russosborne's Avatar
 
Join Date: Aug 2003
Location: Glendale Arizona
Posts: 1,888
Thanks.
Not a true performance build, but sounds like something I can do.
Main reason for the question is I am looking at different cheaper aluminum heads that come with the springs installed. Most have 0.550 springs installed.
So quick take I am getting is in this case I would be wanting to stay below 0.500 on the cam just to be safe without needing to worry?
Putting better springs in is always an option.
Not going anywhere radical, don't want to get into piston to valve clearance issues.

If this engine is even usable. That's a different can of worms.

Thanks
Russ

RIP Mallory, Abby, and Sadie. And now Casey. :-( We miss you girls.

79 Pinto Hatchback. Fully caged, 8inch 4:10 gears. 351W. Aftermarket Tremec T5 (1352 251), Going to be a fun cruiser.

74 Pinto Wagon.
On maybe permanent hold.

72 Ranchero GT w/351Cleveland & automatic. Although this wasn't supposed to be a project car it seems that it has become one. Stupid rusted out California floor pans.
russosborne is offline  
post #7 of 7 (permalink) Old 05-14-2019, 08:50 PM
Senior Member
 
awhtx's Avatar
 
Join Date: Sep 2011
Location: The Hill Country of Central Texas
Posts: 8,812
Quote:
Originally Posted by russosborne View Post
If a spring is rated for say .550 inch lift, what would a safe cam lift be for that spring.

I would assume that if a company says their springs are rated for .550" lift then that's exactly what they mean- you can safely use a camshaft and rocker arm that provides up to .550" lift. In other words the safety factor before reaching coil bind is included in their number.
awhtx is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Vintage Mustang Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Cam Advice Quicksilver66 Vintage Mustang Forum 30 02-27-2019 10:02 PM
Recommendation on valve spring tool maxx424 Vintage Mustang Forum 17 02-22-2019 09:49 AM
1966 A Code 289 valve spring dimension fstbac Vintage Mustang Forum 3 01-27-2019 10:30 PM
Power Steering Valve Spool Centering Spring Cap RayTada Vintage Mustang Forum 1 10-06-2018 06:42 PM
Valve spring question evans1 Vintage Mustang Forum 6 08-31-2018 10:44 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome