Valve Spring durability

[akrt]

I'm am going through my motor. I'm having the heads CNC ported. I'm going to change my cam to something a little bit bigger. I currently have a .736 lift cam with 285 duration at .050. I am going to go to a .785 lift cam with 296 duration at .050. Though these are drag race specifications, my car is mainly street driven. I know the faster and higher lift on the cam lobes, the faster the valve springs wear out. Anyone have any experience with cam/valve springs for this amount of lift that street drove theirs, and how long your springs lived? I've got a valve spring pressure tester. I plan on running the springs for a bit and testing them against their brand new specifications and retest them again and again every several weeks to see if they fall off very quickly. Obviously, I'm concerned about longevity. Bad oil pressure, bad rod bolts and bad valve springs kill engines. . .

 

[HEMI-ITIS]

The seat pressure an over the nose pressure sure makes a diff on longevity!

 

[Yatzee]

I'm am going through my motor. I'm having the heads CNC ported. I'm going to change my cam to something a little bit bigger. I currently have a .736 lift cam with 285 duration at .050. I am going to go to a .785 lift cam with 296 duration at .050. Though these are drag race specifications, my car is mainly street driven. I know the faster and higher lift on the cam lobes, the faster the valve springs wear out. Anyone have any experience with cam/valve springs for this amount of lift that street drove theirs, and how long your springs lived? I've got a valve spring pressure tester. I plan on running the springs for a bit and testing them against their brand new specifications and retest them again and again every several weeks to see if they fall off very quickly. Obviously, I'm concerned about longevity. Bad oil pressure, bad rod bolts and bad valve springs kill engines. . .

Every manufacturer of finished heads with valves installed will give you an idea of the max cam you can use with the installed springs. Surpass their recommendations and your going to be buying new springs to ensure proper valve operation. Figuring it out on your own will be more of a "trial and error" operation. Get it wrong and you end up with either valve float or worn/broken parts. Find out what springs a manufacturer uses for your type of application and clone their engineering for the spring values. If you go heavier the collets will have to be of top quality but usually come with a spring kit. The intention with spring application is to have enough tension to close the springs at high rpm operation but no more than that.

 

[68 HEMI GTS]

You may want to look at providing some spring oiling to help longevity.

 

[akrt]

Many factors are involved in choosing the right valve spring for your engine. Installed height, seat pressure, open pressure, coil bind etc. following the manufacturer's recommendation for springs for drag racing is fine if you're drag racing. I'm street driving mine. Many more miles than just drag racing so I don't know how well the springs hold out befor they need replacing. I'm seeking some advise from someone that actually uses these large cam profiles on the street..

 

[dieseldazzle]

Many factors are involved in choosing the right valve spring for your engine. Installed height, seat pressure, open pressure, coil bind etc. following the manufacturer's recommendation for springs for drag racing is fine if you're drag racing. I'm street driving mine. Many more miles than just drag racing so I don't know how well the springs hold out befor they need replacing. I'm seeking some advise from someone that actually uses these large cam profiles on the street..

Call for hemis only I think he has customers that do.

 

[Challenger340]

What I would like to know is what benefit you are expecting from the larger Camshaft ? and on what Heads/Engine ?
No SERIOUSLY here ?
Just getting the Heads CNC Ported and the extra Flow is NO assurance of actually making more power ? or being able to slice off the "best" area under the power curve. Nonetheless, the V/Spring slew rate or frequency all factors to efficiency, with thermal stabilization of the spring alloy critical to longevity in the street environment, not to mention adequate Oil Flow over the Spring duration operation for cooling.
Yep, we've run 550# to 650# rate Springs on the street PLENTY, and made them live, with a few guys in excess of 940hp @7200 rpm on pump gas(KB Hemi's)
But my question remains....
What benefit are YOU expecting going from 285* @ .050 to 296* @ .050 ? and what do your Heads Flow ?

 

[akrt]

Is this some kind of joke? Questions are answered with questions? Have I stumbled on to one of those "let's see how important I can make myself seem" forums? Slew rate? Why not talk metallurgy and installed height along with harmonics within the valve train.. Why not talk about if you have enamel or urethane paint on your car while we're at it? Makes about as much sense in answering my question, which no one has answered. Including YOU. I'm not asking if a group of guys have, since you're backing up your statements with "we're". Speak for yourself or let someone with actual experience speak. Otherwise you're just wasting time and space and revealing your ego's needs...

 

[Challenger340]

Yep, you are right !
When trying to answer YOUR question..... I might just as well try asking if you have enamel or urethane paint on your car ?

My sincerest apologies.
Rest assured, there is no mileage in this for me, (nor anyone else I suspect who can answer from the street experience you requested ?), here on the internet answering your questions for free. (I get PAID very well to do so at work)
nor
in "seeing how important I can make myself seem" as you put it ?

I wish you the best of luck with that Spring Tester, and your Lifter Trunions.... please carry on.

 

[akrt]

I've always viewed being a Mopar enthusiast as being part of a brotherhood. I can't imagine not helping my fellow Mopar enthusiasts. If there's something in my experience that can help someone else, I gladly and freely offer my advise. If I don't have an answer to a post, I don't respond. If you can't answer because you don't know the answer or that you do know the answer but won't share it because of how well you are paid makes no difference to me or anyone else who might benefit from said question. Better left unsaid, in my opinion. You're a Mopar guy. I'm a Mopar guy. I like you already. In responding to your questions: my motor is 588ci. Indy Legend heads. Currently stock ports that flow 350cfm. Once ported, will flow 440cfm. The current camshaft makes too much torque down low as I run 12.5" ET Street tires that spin like crazy. I'm looking to move my torque band higher up in the RPM range. I have super stock springs and a pinion snubber. Will install cal tracs at some point this summer. Also my power tends to level off after 5,500 rpms. I realize ladder bars may be in my future... I'm just trying to make my car faster.

 

[66Satellite47]

Well my two cents worth. Big cams like you're talking about are hard on valve springs. I believe today's springs are better than what I ran years ago... but that size cam is pretty sure to hurt springs. Interesting combination, kills the tires but still runs out of pull at 5500. I'd sure consider another cam profile that may not make so much torque & kill the tires but runs a bit more than 5500 rpm, but doesn't get up into the lift level cam you're talking about.

 

[mopar 3 B]

Is this some kind of joke? Questions are answered with questions? Have I stumbled on to one of those "let's see how important I can make myself seem" forums? Slew rate? Why not talk metallurgy and installed height along with harmonics within the valve train.. Why not talk about if you have enamel or urethane paint on your car while we're at it? Makes about as much sense in answering my question, which no one has answered. Including YOU. I'm not asking if a group of guys have, since you're backing up your statements with "we're". Speak for yourself or let someone with actual experience speak. Otherwise you're just wasting time and space and revealing your ego's needs...

We try to due our best for the most part. No two engines are alike even when built in the same shop by the same person. The questions being asked where no more stupid than yours.
And yes metallurgy matters even if you do not think so. That is why it is continually tested from the foundry to a finished product.
You asked a very vage question. Honestly I have seen more valve spring failure due to driver error than any other cause.
It always amazes me when one thinks a race engine will last for street use.

 

[Jeremiah]

Manley Nextek, Isky RAD/RAD+, higher end PSI and higher end PAC springs all offer many endurance springs. Assuming a 2" installed height and 280 lb on the nose and 750 @ .775 lift I'd guess that the Isky 9999-RAD might fit the bill. You could use a +.050 retainer and/or +.050 locks to dial in the spring of your choice. To further refine things you will have choices of spring seats/cups from .050 and thicker. Getting the valve train geometry dialed in would be a good place to start. From the you could check a few retainers for rocker arm clearance, etc while getting an idea of where the installed height ends up.

You oil system modifications will be dependent on the block, heads, and rocker arms you decide to use. If you have not ordered rocker arm I'd be asking what installed height and spring diameter is utilized.

Maybe I missed it, what are the desired valve spring pressures? Quality valve springs/roller lifters/etc., good geometry, and lots of oil should work for 5-10k+ miles if you keep an eye on it. As mentioned keeping an eye on the spring pressures is very important.

 

[IQ52]

Yep, you are right !
When trying to answer YOUR question..... I might just as well try asking if you have enamel or urethane paint on your car ?

My sincerest apologies.
Rest assured, there is no mileage in this for me, (nor anyone else I suspect who can answer from the street experience you requested ?), here on the internet answering your questions for free. (I get PAID very well to do so at work)
nor
in "seeing how important I can make myself seem" as you put it ?

I wish you the best of luck with that Spring Tester, and your Lifter Trunions.... please carry on.

Having a limited experience with Challenger340 I feel safe in saying that he may well have more answers, than many of you all put together, can come up with questions. It's a shame to lose his experience here. He has way more than me for sure, and I've run a 900 HP 500" stroker on the street with an .800" lift cam.

 

[akrt]

I don't know what's vague about "Anyone have any experience with cam/valve springs for this amount of lift that street drove theirs, and how long your springs lived?" I do think it's "stupid" to answer a question with a question. Anyone who has run a combo that is similar would also benefit from an actual answer. If you have to ask, you probably don't get it. Of course, if you read closely, you can see I never once mentioned valve spring failure. That wasn't my question. I'm not running a 383 or a 440 with a .484 lift. Complete different animal. It should be clear I'm not running a "Race engine" on the street. Virtually none of the Hemi racers use the Indy Legend Head for the track. They usually opt for something bigger, like the Indy 1-RA6 which use a 2.40 intake valve and flow beyond 525 CFM and 14-1 compression. My engine has headers. Does that make it a race engine? If I run my stock Chrysler V6 Lebaron Convertible down the race track, does that make it a race car? Yeah, seems ridiculous. Anyone can take a statement and twist it. Just look at this thread for evidence. Hemi-itis, 68 Hemi GTS and Jeremiah, I thank you for your impartial, drama free advise. Also, if "I've run a 900 HP 500" stroker on the street with an .800" lift cam" is true, but you don't care to add to the knowledge base of everyone who reads this thread, then why even take the time for a non response?

 

[vintage chromoly]

Wow!

 

[IQ52]

I'm wounded to the core.

And I think you've done nothing but make your traction problem worse. I'd work on the suspension first.

Best of luck there akrt.

 

[akrt]

My apologies if I'm coming across as a jerk or worse. I am very much "to the point" person and most people aren't. Yeah, I could work on my suspension, or a many number of things. I was simply looking for information specific to my question. If I've offended you, I ask your forgiveness.

 

[Challenger340]

In this day and age, and for many, many years, we(my Shop, I OWN IT) have been able to exceed 900 HP and 765 Ft/Lbs Lbs Torque on a 572 HEMI using:
* 91 Octane Pump Gas
* .640" Intake and .617" Exhaust NET Valve Lift, sub 285* @ .050 Roller Cam
* Good for 6,000 miles street driving with NO ISSUES (we just freshened it after 5 years, and bumped it up past 940hp)

Does the above in some way illustrate to you from my world the WHY I was ASKING:
* What benefit are YOU expecting going from 285* @ .050 with .736" Lift.... to a 296* @ .050 Cam with .785" Lift ? and what do your Heads Flow ?

Just my opinion....
but while I would agree you probably DO need some Head work...
and,
that potentially you may benefit from a new Roller Cam Profile for extended Street reliability.....
IMHO
you require neither 296* @.050.... nor .785" Lift to stop spinning the Tires with Leaf/Snubber on Street Asphalt = suspension.

 

[akrt]

I didn't want to list all that went with my question due to the length. Background: my car has a 4.625 stroke and a 4.5 bore. 12.5-1 Pistons, unported Indy legend heads, comp cams .736, [email protected]. Builder that does a lot of Indy work suggested this can as it had good torque down low. He was correct. Tons of torque. When I say it falls off at 5500 it's still pulling real hard, but it doesn't go any faster spinning higher or not. I figure I could use better port flow and a different cam to move the torque peak higher up the rpm scale while giving me additional power. I realize more cam/ compression etc doesn't always equate to more power, but usually, it does. With more air in, additional cam to help fill it. I always say that if I'm paying for bigger ports, I damn well better use all of it..