Vavletrain's weak links
02-10-2009, 12:50 PM
#1
TECH Resident
Thread Starter
iTrader: (10)
Join Date: May 2005
Location: Long Island, NY
Posts: 835
Likes: 0
Received 0 Likes
on
0 Posts
Vavletrain's weak links logically, everything should be replaced for high RPM motors... but how much can everything take...
What RPM will each STOCK part break:
What RPM will each STOCK part will cause valve float:
Whats the biggest cam before each STOCK part will break:
Whats the biggest cam before each STOCK part will cause valve float:
- Hydrolic Lifters
- Pushrods
- Rocker Arms
- Springs
- Retainers
- Locks
- Valves
What RPM will each STOCK part break:
What RPM will each STOCK part will cause valve float:
Whats the biggest cam before each STOCK part will break:
Whats the biggest cam before each STOCK part will cause valve float:
- Hydrolic Lifters
- Pushrods
- Rocker Arms
- Springs
- Retainers
- Locks
- Valves
Last edited by greatskiiiier; 02-10-2009 at 03:50 PM.
02-10-2009, 03:10 PM
#3
If a cam goes in there Replace.....
Pushrods w/ Properly measured Chromoly
Springs
You can reuse the retainers if you stick with Beehive springs, go to Ti if using a Dual coil spring.
Lifters when you kill them, alot of that has to do with spring pressure.
Stock rockers last a long while, only on high rpm set ups do I see people opt for Jesel.
Valves and locks should not need replacing.
It really depends on what your goal is.
Pushrods w/ Properly measured Chromoly
Springs
You can reuse the retainers if you stick with Beehive springs, go to Ti if using a Dual coil spring.
Lifters when you kill them, alot of that has to do with spring pressure.
Stock rockers last a long while, only on high rpm set ups do I see people opt for Jesel.
Valves and locks should not need replacing.
It really depends on what your goal is.
02-10-2009, 03:53 PM
#4
TECH Resident
Thread Starter
iTrader: (10)
Join Date: May 2005
Location: Long Island, NY
Posts: 835
Likes: 0
Received 0 Likes
on
0 Posts
so with say PRC .660 springs, which have and open pressure of 390lbs would need new lifters due to the extra force required to open the springs?
so is it better to get springs rated for .600 for a .595 lift cam, or would prc .660 be the best
so is it better to get springs rated for .600 for a .595 lift cam, or would prc .660 be the best
02-11-2009, 08:47 AM
#5
Teching In
Join Date: Nov 2007
Location: Detroit Metro
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
Stock valvetrain components are for the stock valvetrain (exception is the rockers). If you are going to run a bigger spring with more RPM then you need better lifters among other things.
02-11-2009, 12:28 PM
#7
TI retainers w/ compatible locks and seats for the springs
Chromemoly pr's
That is the only absolute requirements.
Now for the optional, recommended replacements
LS7 lifters
LS2 timing set
ported oil pump
Optional performance repalcements
Yella Terra rockers
Trending Topics
02-11-2009, 12:32 PM
#8
TECH Resident
Thread Starter
iTrader: (10)
Join Date: May 2005
Location: Long Island, NY
Posts: 835
Likes: 0
Received 0 Likes
on
0 Posts
ok... but do you need such a stout spring for say a .595 lift cam? would it have an advantage? higher RPM without valve float? last longer?.. compared to say a spring rated for .600 lift
02-11-2009, 12:36 PM
#9
What cam are you thinking about running?
02-11-2009, 06:36 PM
#11
TECH Resident
Thread Starter
iTrader: (10)
Join Date: May 2005
Location: Long Island, NY
Posts: 835
Likes: 0
Received 0 Likes
on
0 Posts
ya that what i figured... im kinda looking at PRC 2.5 5.3s an they come with .660 springs.. and im looking to go with roughly a 228 .590 cam but figured id see if its worth replacing anything now while i try and save up funds
02-12-2009, 05:06 PM
#15
TECH Senior Member
iTrader: (18)
Join Date: Jun 2002
Location: NW Houston, TX
Posts: 10,036
Likes: 0
Received 0 Likes
on
0 Posts
But those are the advertised specs on the spring. You wont know exactly what the spring can take untill you get the springs you plan to use and have them measure to see where they coil bind. Also there is deflection in the valvetrain, not to mention its a hydraulic set up.
02-13-2009, 07:14 AM
#16
Teching In
Join Date: Nov 2007
Location: Detroit Metro
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
Anybody who changes out springs should use an installed height micrometer to verify the setup. I suppose if you do a true drop in (stock everything on the valve side; valves, locks, retainers, seats) then you can probably get away with not checking them if you know the factory specs.
If you want to learn more, please take the time to read this: CransCams on Valve Springs
Ken
