Moparchat - Home of MOPAR enthusiasts worldwide!



Go Back   Moparchat - Home of MOPAR enthusiasts worldwide! > Technical Forums > Performance Talk

Click here to search for Mopar cars and parts for sale.


Reply
 
Thread Tools Display Modes
  #1  
Old 11-17-2008, 03:26 PM
rampage_82 rampage_82 is offline
Inactive User
 
Join Date: Dec 2007
Location: Mountainair NM
Posts: 657
Default Valve springs ????

Ok I am gathering parts to build my 440 again. The cam I've decided on is the 308 Magnum Comp Roller... 23-742-9. The recommended springs according to Comp is the 929-16. I can't believe these are the correct springs, as they seem way to weak.. I.E. 148lbs @ 1.88"installed and 432lbs @ 1.23"open. What looks like a better spring to me would be the K-Motion K-1100, which is 230lbs @1.9"installed and 555lbs at 1.25"open.... Even the K Motion springs seem a little on the light side on the open, cause this cam will only have .555" lift after the valve lash is taken out, so 1.9" - .555" would = 1.345" and that would only have 507lbs open pressure. However the comp springs would only have 387lbs open. Has anyone used this cam and what valve spring did you use....any opinions here...
Reply With Quote
  #2  
Old 11-17-2008, 03:40 PM
rampage_82 rampage_82 is offline
Inactive User
 
Join Date: Dec 2007
Location: Mountainair NM
Posts: 657
Default

I really think on a roller cam weak springs would be detrimental. I need this thing to last this time, cause the motor was ruined last time, cause I wiped 2 Comp cams, the first I wiped during breakin, the second lasted about 3 races, and the third cam which held up fine was a Lunati, however it didn't run as well, and my bearings were toast by this time anyways. That is why I'm insistent on a roller, plus I don't like hyd. lifters (roller or flat tappet) anyways. This is about the last chance I get to play with my race truck, cause my wife wants more kiddo's, and they outrank the race truck for some reason...lol
Reply With Quote
  #3  
Old 11-17-2008, 07:27 PM
crisser crisser is offline
Inactive User
 
Join Date: Oct 2005
Location: lafayette,la
Posts: 521
Default

Why not run the Comp 938`s? 204 @ 1.9 and 516 @ 1.25? Seems strong enough for a STREET roller. Those lobes are not as agressive as a true race roller lobe. Do you have the valvetrain parts to operate at these pressures with some reliabality? Once you get in the 500`s and up, you`ll need good parts.
Reply With Quote
  #4  
Old 11-17-2008, 07:34 PM
crisser crisser is offline
Inactive User
 
Join Date: Oct 2005
Location: lafayette,la
Posts: 521
Default

By the way, isn`t the lash factored in when they give lift specs?
Reply With Quote
  #5  
Old 11-18-2008, 12:31 AM
rampage_82 rampage_82 is offline
Inactive User
 
Join Date: Dec 2007
Location: Mountainair NM
Posts: 657
Default

The lash factor isn't usually factored in the lift specs...but I will double check this..Yes I already have the valvetrain parts ... hardened shafts, Crane Gold Rockers, Comp pushrods .080 wall 7432-16, the heads 906 factory castings can take up to .700" lift (they were built and ported by Dan Dvorak), however the flow stalls after .550" lift. Right now the springs are for the Hyd. cam... 120lbs @ 1.9" and 300lbs @ 1.4" open. the coil bind is at 1.15". I was looking at the Comp 938 springs, but was wondering if there was a reason why they recommended the 929's??? Is there anything wrong with the K-Motion springs?
Reply With Quote
  #6  
Old 11-18-2008, 12:58 AM
crisser crisser is offline
Inactive User
 
Join Date: Oct 2005
Location: lafayette,la
Posts: 521
Default

Quote:
Originally Posted by rampage_82 View Post
I was looking at the Comp 938 springs, but was wondering if there was a reason why they recommended the 929's??? Is there anything wrong with the K-Motion springs?

They do recomend the 938`s on that cam.
No, nothing wrong with the K-Motion spring.
It looks like you`re trying to get a 600# spring for that cam, and while it won`t hurt, I don`t think they are necessary for a street roller lobe.
Reply With Quote
  #7  
Old 11-19-2008, 11:12 AM
rumblefish360's Avatar
rumblefish360 rumblefish360 is offline
Moparchat Bronze member
 
Join Date: May 2000
Location: C
Age: 57
Posts: 11,120
Default

Go to the valve springs listed in "RED" as they are the preimum (SP) part to use.
Reply With Quote
  #8  
Old 11-19-2008, 11:48 AM
aarracer aarracer is offline
Inactive User
 
Join Date: Mar 2007
Location: British Columbia
Posts: 891
Default

rampage 82

You may wish to try a full flow oil filter with this build. This WILLl stop all remnants of failure (should this happen again)from contaminating the rest of your engine!
Reply With Quote
  #9  
Old 11-23-2008, 05:47 AM
451Mopar 451Mopar is offline
Inactive User
 
Join Date: Sep 2000
Location: Aurora, Colorado
Age: 59
Posts: 1,831
Default

Quote:
Originally Posted by rampage_82 View Post
The lash factor isn't usually factored in the lift specs...but I will double check this..Yes I already have the valvetrain parts ... hardened shafts, Crane Gold Rockers, Comp pushrods .080 wall 7432-16, the heads 906 factory castings can take up to .700" lift (they were built and ported by Dan Dvorak), however the flow stalls after .550" lift. Right now the springs are for the Hyd. cam... 120lbs @ 1.9" and 300lbs @ 1.4" open. the coil bind is at 1.15". I was looking at the Comp 938 springs, but was wondering if there was a reason why they recommended the 929's??? Is there anything wrong with the K-Motion springs?
The cams are specified with zero lash. When I degreed my Comp roller cam off the lobes all the duration points were as advertised, and peak lift was as specified (maybe plus 0.001"?). My cam was custom ordered 264/264 @ 0.050" duration using the HXL lobes (fairly agressive / high lift) that should yeild 0.714"/0.714" valve lift @1.6:1 rocker ratio. This was ground on a wider 112 lobe seperation angle.
I went overkill on valve springs using the PAC Racing 1325 springs installed at #250@2.00", and about #700 open pressure. I have not used these springs before, but they were recommended. I hope they are as good as I was lead to believe, because they are pricy at $538.00 /set, not to mention the additional $400 for Ti Retainers, Machined ChroMoly locks, and spring seats.

The reason I am building a new engine is I dropped a valve, possably due to old weak valve springs.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
valve springs darkside Performance Talk 4 10-10-2006 12:04 PM
valve springs ok lvlrlvlopar Performance Talk 4 08-23-2002 12:43 PM
Valve Springs ROBGTS Performance Talk 2 01-07-2002 12:58 PM
077 valve springs 70gtx Performance Talk 1 11-16-2000 08:56 AM
Valve Springs slepr1 Performance Talk 3 06-06-2000 12:27 AM




All times are GMT -4. The time now is 01:28 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
. . . . .