Cyl Head Experts - Valve Spring Setup Question

[mopowers]

I have a hydraulic roller cam that I plan on running for a mild street cruiser - 230/236 @.050", .544"/.555" on a 110. Comp is calling for 120-150 lbs seat and 300-380 lbs open pressure. The heads are from trick flow and come with "hydraulic roller" springs and have 155 lbs at the 1.950" installed height and 391 lbs open - slightly outside of the range provided by Comp.

Questions:
1. Should I consider installing +.050" locks to soften the spring a little, or would you run them as-is? I believe adding .050" to the installed height would put me at 134/370 lbs by my math (427 lb/in springs).
2. Also, will these pressures be okay with stock hydraulic roller lifters?

 

[Newbomb Turk]

Run them as is. 150/390 is a nice compromise. I try and hit 170/410 but you can’t always get it.

 

[TT5.9mag]

Second vote for run it as is.

 

[RustyRatRod]

Leave it right there.

 

[GTX JOHN]

Another vote for run it as it is.

 

[RustyRatRod]

You have to remember, valve sprAngs lose some tension after break in, so they will probably be spot on.

 

[mopowers]

Thanks guys. Any idea why Comp specs lower pressures (120-150 seat and 300-380 open)? For nearly the same cam, Howards calls for 120-140 and 350-375 - still lower than where I'm at. I'll send 'em though.

You have to remember, valve sprAngs lose some tension after break in, so they will probably be spot on.

I should've mentioned - the springs are lightly used. I measured the pressures of all of them and they ranged from 148-158 at the measured installed height (which also varied by about .025")

 

[TT5.9mag]

Thanks guys. Any idea why Comp specs lower pressures (120-150 seat and 300-380 open)? For nearly the same cam, Howards calls for 120-140 and 350-375 - still lower than where I'm at. I'll send 'em though.

Ask 10 camshaft guys the same question and you’ll get 329 different answers. Don’t overthink it.

 

[RustyRatRod]

Ask 10 camshaft guys the same question and you’ll get 329 different answers. Don’t overthink it.

Too late for that. It's done overthunk.

 

[mopowers]

Run them as is. 150/390 is a nice compromise. I try and hit 170/410 but you can’t always get it.

Thank you, I appreciate it. Is the limitation generally the stock lifters, or cam material? Mines a ductile iron SADI core. Sounds like it's better to err on the side of having more pressure than not enough. I'm curious where the ceiling usually is and what happens with too much spring pressure - Lifter bleed down?

 

[Bewy]

I have used +050 & - 050 keepers a few times. I never found a set that makes a 050 difference, more like 0.035". So keep that in mind.

 

[Newbomb Turk]

Thank you, I appreciate it. Is the limitation generally the stock lifters, or cam material? Mines a ductile iron SADI core. Sounds like it's better to err on the side of having more pressure than not enough. I'm curious where the ceiling usually is and what happens with too much spring pressure - Lifter bleed down?

They hydraulics limit how much pressure you can use.

A long time ago I had a Cam Dynamics solid roller that was ground on a cast iron core.

It would take about 500 pounds over the nose. When I tried to go to 600 it started to flake the cast iron off the nose.

I thought a SADI core was a steel cam with a cast iron gear. It’s been so long since I’ve used one I forgot.

 

[mopowers]

They hydraulics limit how much pressure you can use.

A long time ago I had a Cam Dynamics solid roller that was ground on a cast iron core.

It would take about 500 pounds over the nose. When I tried to go to 600 it started to flake the cast iron off the nose.

I thought a SADI core was a steel cam with a cast iron gear. It’s been so long since I’ve used one I forgot.

That's good to know. When I called Oregon Cam, Ken recommended not going over 320-ish open on a reground cast iron core. I know quite a few folks who do it successfully though. From what I've read, the (SADI) austempered ductile iron cores are quite a bit stronger.

btw- I was able to swap springs around to narrow the seat pressure spread to 154-155. I'm happy with that. Now I just need to buy another set of seals. Not sure the ones I popped off are usable, even though they're brand new.