Valve springs

[408 Nova]

How do you know how much spring you need?

[mag2555]

My crystal Ball is at the shop getting a tune up and oil change, so I need to ask what kind of Cam are you running, lol!

[BillK]

If the information isn't on the cam card or in the catalog I either call or e-mail the cam manufacturer and ask them. I don't like guessing or going by internet hearsay.

[1972ho]

If it’s a compcam that normally give you the spring part number for the camshaft you order,mine gave me two spring options and I just looked up the number in there spring catalog and told me the spring height and pressures at that from top to bottom.

[frnkeore]

Ben Herheim at Howards, gave me this chart for their SB roller cams.

[steve cowan]

Ben Herheim at Howards, gave me this chart for their SB roller cams.

Is that chart representing seat load ?

[steve cowan]

How do you know how much spring you need?

My opinion is cam company as a starting point but it all depends-
Application
If you change rocker ratio
Rpm
Weight of components etc
Sometimes it is trial and error and it really is a loaded question.
I think having more spring is safer than not enough.

[frnkeore]

Ben Herheim at Howards, gave me this chart for their SB roller cams.

Is that chart representing seat load ?

No, it all open pressure. I don't know why it has .600 close at the same pressure but, it is just as it was sent to me, when I inquired about spring pressure, when ordering a SBF cam.

I also inquired on this forum, regarding spring pressures for the SBF I was building. There is a program that will predict pressure. A member on this forum offered to run it for me, and I got the results. It was 2 or 3 years ago and I'm sad to say, I've forgotten who it was but was very greatful to him. but, although it included most perimeters, it was put down by many, saying it didn't have enough info. But, it did have more info than most anyone gets, when they are giving recommendations on this forum. Here is the form.

[Mummert]

There are enough guys here to guess pretty good if you have some cam specs, type of engine, max rpm , and weight of some of they key valvetrain parts.

[408 Nova]

Asking for sb2.2 heads with 2.18/1.60 titanium valves, .937 link bar lifters, solid roller cam with 55 mm bearing journals, drag race only, no more than 9,000 rpm.

.430 or so lobe with 2.10/2.00 I/E rockers.

I haven't ran the engine yet, and just want to make sure I don't have too much spring on the heads consistent with reliability of the valvetrain and the ability to follow the lobes.

The heads have PAC 1356's on them. 300 lbs on the seat at 2.1" installed height, and 1002 lbs at 1.2".

[steve cowan]

I can't offer a spring package for your application but I helped a friend for a few years in B/GAS AUTOMATIC superstock in Australia
358ci pro stock truck engines.
SB2 heads,jesel keyway lifters 9500rpm etc.
Between rounds we would check springs
420lb seat intake - 400lb seat exhaust
Not saying you need this but just some information.

[408 Nova]

I can't offer a spring package for your application but I helped a friend for a few years in B/GAS AUTOMATIC superstock in Australia
358ci pro stock truck engines.
SB2 heads,jesel keyway lifters 9500rpm etc.
Between rounds we would check springs
420lb seat intake - 400lb seat exhaust
Not saying you need this but just some information.

Good information. Thanks!

[Mummert]

Are you going to dyno the engine or go straight to the car with it?
If you are going to to try and run as little spring as you can I would get it on the dyno. There will be some signs if the valve train is getting unhappy. Shape of the power curve, fuel flow, A/F will start showing signs, so it can be rectified quickly.

[Turbobuick6]

Asking for sb2.2 heads with 2.18/1.60 titanium valves, .937 link bar lifters, solid roller cam with 55 mm bearing journals, drag race only, no more than 9,000 rpm.

.430 or so lobe with 2.10/2.00 I/E rockers.

I haven't ran the engine yet, and just want to make sure I don't have too much spring on the heads consistent with reliability of the valvetrain and the ability to follow the lobes.

The heads have PAC 1356's on them. 300 lbs on the seat at 2.1" installed height, and 1002 lbs at 1.2".

I would say you have a good spring on your heads for your combo.

[408 Nova]

Are you going to dyno the engine or go straight to the car with it?
If you are going to to try and run as little spring as you can I would get it on the dyno. There will be some signs if the valve train is getting unhappy. Shape of the power curve, fuel flow, A/F will start showing signs, so it can be rectified quickly.

Yessir, gonna throw it on the dyno.