Determining what valve spring pressures are needed.

[TheSilverBuick]

In relation to my other threads about valve lift for a street engine....

As I'm thinking more and more about getting a new cam for the Skylark, and having the heads gone through and ported I want to know more about valve spring pressures.

In other threads we discussed around .550" being a good upper limit for lots of miles, but I am still thinking of going with more than that. The next question is what are the expected valve spring pressures needed at that lift for 6,000rpm? Is there a general rule to follow? I don't have all the valvetrain weights. What about at .650" lift? I'm trying to get a feel of how radically the valve spring pressures need to increase per amount of additional lift. My follow question to this will be at what point do I worry about longevity of the hydraulic roller lifters (might be the limiting factor here) and roller rockers.

Current set up:
I'm going to leave it up to the guy refreshing the heads on if I re-use the same springs if I go under .650" lift, which is the lift TA rates them up too.
Current springs are dual rated at:
O.D. 1.385
125 lbs @ 1.900
275 lbs @ 1.400
Coil Bind 1.060
plus 0.075" shim.

.525" Lift.
Installed height: 1.870" @ 135lbs,
Full valve lift: 1.345" @ 330lbs
per the spec sheet from when TA assembled the heads.

And if my google math is right it would be 464.3lbs at .650" lift using the same springs, which I have no idea if that is enough or not or if that is too much for a hydraulic roller or if that is detrimental to the longevity of all the rollers. I'm talking over 10,000 miles per year.

Thoughts?

[TC]

The 330lb open seems kind of lite, the Springs I got for the hydralic roller for my LS1 are 470lbs open and 129lbs closed......

[TheSilverBuick]

The 330lb open seems kind of lite, the Springs I got for the hydralic roller for my LS1 are 470lbs open and 129lbs closed......

You probably have more lift than I do, as well as turn a bit more rpm.

[TC]

You probably have more lift than I do, as well as turn a bit more rpm.

It should top out about 6800rpm and the cam I'm running has .617/.624 lift.... Weren't you talking about running around .600 lift??

[TheSilverBuick]

Right and those specs are my current springs of .525" lift and 6,000rpm tops.

[BBR]

My thought is to ask TA

[TheSilverBuick]

My thought is to ask TA

The issue is they don't seem to have any customers that run the miles I do. The ones that have the kind of lift I'm thinking about only run their cars 1,000-2,000 miles a year, at least from the response I got from V8Buick and Buick engine builders. They aren't used to high miles OR lift much over .500", let alone both.

[squirrel]

put a blower on it, keep the mild cam and weak valve springs.

[dieselgeek]

Randal, we can always mock it up on a spintron! only cost probably $8,000 to figure out what $800 valvetrain parts to run.

[TheSilverBuick]

Randal, we can always mock it up on a spintron! only cost probably $8,000 to figure out what $800 valvetrain parts to run.

It's a Buick, it's $2,000 valve train!

[realsteelfreak]

Contact this guy, Carl

http://www.wegnerautomotive.com/aboutus.htm

He use to make the Buick program go in Cup and Busch back in the day, maybe he can help more with your cam and spring questions .

[Scott Liggett]

Have you talked to the tech guys at Comp Cams. They deal with more cars and set ups than anybody.

[prostreet34]

Randal, not sure if it's relevent, compairing solid roller sbc to hyd. roller BB Buick. But this is a real combo, actually togeather, in a car that is actually runs. ( I think you know what I mean ).

Solid street roller (tight lash) .248/.254 @ .050 .576/.582 lift
I set springs up @ 155 seat/410 open.

9,000 miles later, just before 2012 DW, had 12 @ 133-138 and 4 @ 128-132
also pulled the lifters had 3 that were starting to spread around the pin. Sent them Comp. replaced 3 and rebuilt the rest.

So in 9,000 miles the only thing I've done is a set of springs and some lifters. I think I'm going to switch from Comp. to Isky lifters next time I pull it apart.

I know Buicks are a different deal. with valvetrain weight, etc. but thought the spring press. lost over miles driven might help.

Jason

[milner351]

That's good info Jason - thanks for sharing real world data. How often do you check / set lash with a solid roller?

[prostreet34]

That's good info Jason - thanks for sharing real world data. How often do you check / set lash with a solid roller?

I run the valves every oil change 1,000-1,500 miles. They never realy move, sometimes I'll chase .001"-.002" (T&D 1.5 shaft rockers)

Jason