Valve springs with this?
07-18-2005, 05:37 PM
#1
TECH Regular
Thread Starter
iTrader: (23)
Join Date: Jun 2005
Location: TN
Posts: 437
Likes: 0
Received 0 Likes
on
0 Posts
Valve springs with this? How long will my 918's last with a 617/630 lift cam?
Long enought to break my motor in say 2000 miles not twisting it above 4000 for the first 1000 and not over 5000 for the last 1000? I just don't have the money to invest in new springs when i just bought this set of 918's and haven't even used them. And by the way they are for sale and have only been installed not ran.
Any suggestions?
Thanks
JON
Long enought to break my motor in say 2000 miles not twisting it above 4000 for the first 1000 and not over 5000 for the last 1000? I just don't have the money to invest in new springs when i just bought this set of 918's and haven't even used them. And by the way they are for sale and have only been installed not ran.
Any suggestions?
Thanks
JON
07-18-2005, 08:48 PM
#4
Launching!
Join Date: Jun 2005
Location: longview, tx
Posts: 202
Likes: 0
Received 0 Likes
on
0 Posts
It's possible that the springs may coil bind at that lift. I'd definitely be a checkin to see before I put them on but I wouldn't waist the effort, personally. Get the springs you need before you lunch your motor over some springs.
07-19-2005, 05:01 AM
#5
TECH Resident
iTrader: (3)
Join Date: Nov 2002
Location: Pewee Valley,Ky
Posts: 824
Likes: 0
Received 0 Likes
on
0 Posts
918 spring
installed height 1.800" @130#
coil bind is 1.085 giving .715 of lift before coil bind. leaving .085 of clearence at .630 lift
Comp recommends a max lift of .600 but they have been used to .625-.650; Valve float would be the biggest issue at high rpms as seat pressure at .630 would be only about 330#'s
So yes you can do what you are asking, but if breaking in a new motor why not spend $250ish on springs more suited to that cam? you will be pissed if you damage a new setup because you skimped a bit on springs.
installed height 1.800" @130#
coil bind is 1.085 giving .715 of lift before coil bind. leaving .085 of clearence at .630 lift
Comp recommends a max lift of .600 but they have been used to .625-.650; Valve float would be the biggest issue at high rpms as seat pressure at .630 would be only about 330#'s
So yes you can do what you are asking, but if breaking in a new motor why not spend $250ish on springs more suited to that cam? you will be pissed if you damage a new setup because you skimped a bit on springs.