Valve spring question

Posted By: cbarracuda

Valve spring question - 08/10/11 10:09 PM

What will be the right seat presion on a hydraulic roller camshaft with 220 duration at 0.50 and 5.20 lift. I have two sets of springs, one with 130 seat and 330 open and another set with 165 seat and 390 open. Are any of those ok or any other suggestion?
thanks

Posted By: Cab_Burge

Re: Valve spring question - 08/11/11 05:19 AM

Quote:

What will be the right seat presion on a hydraulic roller camshaft with 220 duration at 0.50 and 5.20 lift. I have two sets of springs, one with 130 seat and 330 open and another set with 165 seat and 390 open. Are any of those ok or any other suggestion?
thanks

I would look at the amount to coil bind first and use the one that was at least or close to .080 from coil bind

I did one 426 street hemi motor with a hydraulic roller cam and lifters and used 165 lbs on the seats and 375 to 390 lbs opended, motor revs good and pulls hard to 7000 RPM, maybe a little higher

The customer wants it shifted at or below 6800 RPM, so that is where it gets shifted at by him. it is a 4.25 stroke

Pulls like gang busters

Posted By: cbarracuda

Re: Valve spring question - 08/12/11 02:54 AM

The ones at 165 are K Motion 800 and they are good up to 700 lift installed at 1850. To get the 165 I will have them at 1900 and on the spring tester, when I go 1900-520(camlift), I have a reading of 390. This is a retro fit lifter and they are heavy, I was worrying that it would be to much pression for the hydraulic mechanism, but since your experience says it's ok then I will go ahead and installed those springs. Thanks

Posted By: HardcoreB

Re: Valve spring question - 08/12/11 04:40 PM

To properly answer your question, it would help if you gave all pertinent information including application. Unless your just throwing together parts you have laying around and have no longevity or performance expectations. (I.E.-it is what it is)Based on your question, you don't fully consider valvetrain as a 'system'. This can lead to bigger problems ($). Measure all the springs and be familiar with their typical load losses before selection time. As was mentioned you should pick a spring that runs near C/B. Production stuff can be engineered to run at 1mm from C/B. I've run 'racy' springs below 1.5mm.

Posted By: Crizila

Re: Valve spring question - 08/12/11 05:29 PM

As a starting point, I would look at what the cam manufacturer recommends for that cam and lifters. That will get you in the ball park. Yes, you should look at the valve train as a system for your final spring rate choice. Installed height, rpm range, valve train component weights, all need to be considered.

Posted By: cbarracuda

Re: Valve spring question - 08/13/11 01:53 AM

Quote:

To properly answer your question, it would help if you gave all pertinent information including application. Unless your just throwing together parts you have laying around and have no longevity or performance expectations. (I.E.-it is what it is)Based on your question, you don't fully consider valvetrain as a 'system'. This can lead to bigger problems ($). Measure all the springs and be familiar with their typical load losses before selection time. As was mentioned you should pick a spring that runs near C/B. Production stuff can be engineered to run at 1mm from C/B. I've run 'racy' springs below 1.5mm.

We are not talking production stuff. If you read the first post you will find all the information you need. Comp cams recommends 140 seat presion but the lifter seems to be a little heavy because it's a retro fit lifter hydraulic roller for a 302 and that's why I tried to go a little higher like 165 seat. That's all

Posted By: dodgeboy11

Re: Valve spring question - 08/13/11 02:28 PM

On the spring tester, coil bind the springs a few times. This will typically drop the pressure just a bit so you have an idea what you'll be working with after it has run for awhile.
I like to run about .120" away from coil bind with new springs. This way on a freshen up you can stuff up to .060" shims in there and still be ok. Running far from the springs coil bind isn't necessarily bad, but it tells me that it's the wrong spring for the job if it's over .120" away.

Posted By: cbarracuda

Re: Valve spring question - 08/13/11 10:15 PM

Thanks