Ltx Solid Roller Spring Pressures?
10-03-2013, 11:08 PM
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Ltx Solid Roller Spring Pressures? Thinking about switching to a solid roller in my 383 lt4 and need to know what kind of spring pressures I should be looking for? Gonna probably be a high .650-.690 lift cam. Any help?
10-04-2013, 07:37 AM
#2
There is a lot more to spring choice than cam lift. If you thought this was all the info you needed to post I suggest you find a professional to sell you a package and don't question their judgement..
In an extreme example a friend has a solid roller that sees over 8000rpm in a 400 smallblock over .800 lift and it runs less seat pressure than most of us run on hydraulic grinds. It is an oversize cam bore in the block, the rockers are I think over 1.8 ratio, the valves titanium and the cam carefully developed with the use of a Spintron in order to loft the valves in a controlled manner hence the spring pressure under 140 on the seat.
It is still a 23 degree smallblock though so it is very similar to a LT1 right?
Even just around here you will find guys running vastly different pressures on similar lift cams due to things like how aggressive the lobe is, if they are using a lightweight valve like the stock LT4s or a hollow Feria and titanium retainers. Are they using a stock pcm and limited to 7000rpm or aftermarket management and going to 7800rpm. Then there are even two schools of thought on valvespring pressure the oldschool crowd still believes in a LOT of pressure and some guys are setting things up to utilize a lot less pressure these days.
In an extreme example a friend has a solid roller that sees over 8000rpm in a 400 smallblock over .800 lift and it runs less seat pressure than most of us run on hydraulic grinds. It is an oversize cam bore in the block, the rockers are I think over 1.8 ratio, the valves titanium and the cam carefully developed with the use of a Spintron in order to loft the valves in a controlled manner hence the spring pressure under 140 on the seat.
It is still a 23 degree smallblock though so it is very similar to a LT1 right?
Even just around here you will find guys running vastly different pressures on similar lift cams due to things like how aggressive the lobe is, if they are using a lightweight valve like the stock LT4s or a hollow Feria and titanium retainers. Are they using a stock pcm and limited to 7000rpm or aftermarket management and going to 7800rpm. Then there are even two schools of thought on valvespring pressure the oldschool crowd still believes in a LOT of pressure and some guys are setting things up to utilize a lot less pressure these days.
10-04-2013, 07:49 AM
#3
There is a lot more to spring choice than cam lift. If you thought this was all the info you needed to post I suggest you find a professional to sell you a package and don't question their judgement..
In an extreme example a friend has a solid roller that sees over 8000rpm in a 400 smallblock over .800 lift and it runs less seat pressure than most of us run on hydraulic grinds. It is an oversize cam bore in the block, the rockers are I think over 1.8 ratio, the valves titanium and the cam carefully developed with the use of a Spintron in order to loft the valves in a controlled manner hence the spring pressure under 140 on the seat.
It is still a 23 degree smallblock though so it is very similar to a LT1 right?
Even just around here you will find guys running vastly different pressures on similar lift cams due to things like how aggressive the lobe is, if they are using a lightweight valve like the stock LT4s or a hollow Feria and titanium retainers. Are they using a stock pcm and limited to 7000rpm or aftermarket management and going to 7800rpm. Then there are even two schools of thought on valvespring pressure the oldschool crowd still believes in a LOT of pressure and some guys are setting things up to utilize a lot less pressure these days.
In an extreme example a friend has a solid roller that sees over 8000rpm in a 400 smallblock over .800 lift and it runs less seat pressure than most of us run on hydraulic grinds. It is an oversize cam bore in the block, the rockers are I think over 1.8 ratio, the valves titanium and the cam carefully developed with the use of a Spintron in order to loft the valves in a controlled manner hence the spring pressure under 140 on the seat.
It is still a 23 degree smallblock though so it is very similar to a LT1 right?
Even just around here you will find guys running vastly different pressures on similar lift cams due to things like how aggressive the lobe is, if they are using a lightweight valve like the stock LT4s or a hollow Feria and titanium retainers. Are they using a stock pcm and limited to 7000rpm or aftermarket management and going to 7800rpm. Then there are even two schools of thought on valvespring pressure the oldschool crowd still believes in a LOT of pressure and some guys are setting things up to utilize a lot less pressure these days.
I don't remember exactly what my pressures are but they are right around 225 seat/ 525 open. EDIT: just to clarify, 225/525 is not very much for a solid roller, it's more or less average. You can go through the COMP catalog and look at some Sprint Car camshafts and look at the springs they recommend, and the pressures will be way higher.
10-04-2013, 08:39 AM
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Spring pressures are going to depend entirely on your cam profile. No one here can tell you what you should run. That should be a conversation between you, the makers of your cam and your engine builder.
10-04-2013, 10:51 AM
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Springs are always critical, but they're especially important on a solid roller setup. Get the wrong/weak springs and you'll find out stuff starts blowing up real fast.. and it doesn't take much with an aggressive solid.
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10-04-2013, 12:25 PM
#8
Ramp rate is a lot more important then lift for spring selection.
My springs are 260 seat ~740 open, because even though my cam is "only" .73x lift, the lobe is pretty aggressive right off the base.
My springs are 260 seat ~740 open, because even though my cam is "only" .73x lift, the lobe is pretty aggressive right off the base.
