Springs for HotCam
Thread Starter
Racer
Joined: Jan 2001
Posts: 322
Likes: 0
From: Liberty Township OH
Springs for HotCam
I have an LT4 and am planning to install a HotCam and port & polish the head.
Should I install a double spring or stay with the standard LT4 single spring? I know that the double spring would require machining the head, but it will be off anyway. Cost is the concern. I can replace the LT4 springs & keepers for $36. The double springs (CompCam PN 986-16), keeper, retainer, and shimkit will run $190. Plus I'll have to spend another $50 on machining the head.
So, is the double spring setup worth $250 for the HotCam? What will the advantage be? Is the stock LT4 spring unsafe at 6400 RPM? Will I be able to get more revs with the double spring, or does power drop off after 6400.
Should I install a double spring or stay with the standard LT4 single spring? I know that the double spring would require machining the head, but it will be off anyway. Cost is the concern. I can replace the LT4 springs & keepers for $36. The double springs (CompCam PN 986-16), keeper, retainer, and shimkit will run $190. Plus I'll have to spend another $50 on machining the head.
So, is the double spring setup worth $250 for the HotCam? What will the advantage be? Is the stock LT4 spring unsafe at 6400 RPM? Will I be able to get more revs with the double spring, or does power drop off after 6400.
Melting Slicks
Joined: Apr 2001
Posts: 2,474
Likes: 1
From: Drive it Like You Hate it Cincinnati OH
Re: Springs for HotCam (Polar LT4)
I have the lt4 springs with my hot cam. we're doing a hot cam kit in a buddies 94 lt1 right now.... I don't know of any problems with the lt4 springs. I'm sure the double springs are better, but is the cost worth it??? ..not for me right now.
:cheers:
[Modified by FoolCrzy, 12:43 PM 1/30/2003]
:cheers:
[Modified by FoolCrzy, 12:43 PM 1/30/2003]
Melting Slicks
Joined: Oct 2002
Posts: 2,896
Likes: 349
From: Smithfield VA
Re: Springs for HotCam (Polar LT4)
I have always thought that the stock LT-4 spring was on the edge for use with the Hot cam. I think coil bind is for the spring is not much more thatn the .525 lift of the Hot Cam. There is a GMPP dual valve spring that will fit in the LT-4 head with no modifiaction that is good to .555 lift or so. I forgot the p/n though. They are pretty inexpensive too.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Re: Springs for HotCam (FoolCrzy)
What are everyones thoughts on seat pressures for the HOT Cam?
From another thread....
TEA will machine LS1/6 locators for use on an LT4 with CompCams 941 springs. The 941 springs have ~130# closed seat pressure @ 1.78 and ~350#open.
I think the LT4 springs are fine with an LT4 that only sees occasional high rpm use. Of course knowing my driving style...different springs are probably smart. The question is, can I behave and wait a year in order to get better hardware when I pull the heads for porting?
Anyone?
From another thread....
TEA will machine LS1/6 locators for use on an LT4 with CompCams 941 springs. The 941 springs have ~130# closed seat pressure @ 1.78 and ~350#open.
I think the LT4 springs are fine with an LT4 that only sees occasional high rpm use. Of course knowing my driving style...different springs are probably smart. The question is, can I behave and wait a year in order to get better hardware when I pull the heads for porting?
Anyone?
Thread Starter
Racer
Joined: Jan 2001
Posts: 322
Likes: 0
From: Liberty Township OH
Re: Springs for HotCam (96GS#007)
I spoke w/ Jeff Koop today. He said that the GM dual springs have too much pressure - they will prematurely wear valve train components & may collapse the lifters. He suggested that if you want to use those springs to convert to mechanical lifters. Also said that the LT4 HotCam is just fine w/ the LT4 springs.
Melting Slicks
Joined: Oct 2002
Posts: 2,896
Likes: 349
From: Smithfield VA
Re: Springs for HotCam (96GS#007)
I think it would be a good idea to upgrade. Here I found the info on the GMPP Dual valve spring:
P/N - 00330585
1.397" Diameter
140# seat pressure @ 1.75"
325lb/in rate
1.15" solid height
I ran this spring until I upgraded to a cam that had .595 lift. They cost ~$5 each. You would need to get the L98 spring seat too.
P/N - 00330585
1.397" Diameter
140# seat pressure @ 1.75"
325lb/in rate
1.15" solid height
I ran this spring until I upgraded to a cam that had .595 lift. They cost ~$5 each. You would need to get the L98 spring seat too.
Melting Slicks
Joined: Oct 2002
Posts: 2,896
Likes: 349
From: Smithfield VA
Re: Springs for HotCam (Polar LT4)
I ran these springs on my engine, w/ stock LT-4 valvetrain, for 30K miles with no problems. I also know of many other people running them with no problems. They are recommeded for use by a couple different head guys.
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