Darin Morgan, Valve Springs and coil bind.

[Speedy Goomba]

Darin,
if you dont mind me asking, when you set up your valve springs, i understand you work from coil bind backwards.
How far from coil bind do you set them? (how much clearance between the coils).

I understand that the springs will bounce off the spring seat less when set-up in this manner.

Does the seat pressure concern you guys at all, or do you just worry about the open pressure and the seat pressure lands where it lands? Do you worry about the pressure at all, or just achieve what you can with the springs that you have?

[Darin Morgan]

Does the seat pressure concern you guys at all, or do you just worry about the open pressure and the seat pressure lands where it lands? Do you worry about the pressure at all, or just achieve what you can with the springs that you have?

There is no pat answer for the proper procedure to set up valve springs. There are guide lines you should follow such as not taking the coils to bind and trying to set it up close to the manufactures recommendations. I always tell people that .050 away from coil bind is as tight as I would ever run a spring. I have never seen ( at least with the engines I have worked with) a spring that benefited from running it tighter than .050. Some springs like to be farther away from coil bind than others. On a Pro Stock engine they are about .120 away from coil bind. It depends on, the spring design, the camshafts lobe design, valve train weight and the amount of loft your are trying to control. The valve train weight and loft usually come into play with engine that operate at extreme engine speeds at or around 9000-10000rpm but Nextel Cup engines use these techniques as well.
To answer some of your questions, yes we do worry about both the open and closed pressures but the seat pressure much less than the open. In a perfect world the spring would have little pressure at close and about 1200 over the nose but this is not a perfect world so we have to set them up at about 425 on the seat to get that over the nose pressure and the proper rate to control the valve action. I wish I could get 200 on the seat and 1200 over the nose but they cant make a spring with that rate. An engine design is an exercise in compromise and that goes double for the valve train! The only way to learn what makes a particular engines valve train work is to get on a Spin Tron and the dyno and work it out over time. otherwise, you go off the camshaft and spring manufactures recommendations.

General rules of thumb,

(1) Don't get any closer than .050 to coil bind.
(2) As far as Seat pressure goes, A little too much will not hurt you but too little will DESTROY you!
(3) Follow the manufacture recommendations first before you venture out on your own. I say this because if you pick the wrong spring for a camshaft you will induce resonance into the valve train and hurt parts. Even if the spring has more pressure than what the manufacture wanted you to run! I cant count how many times people purchased some wiz bang HIGH pressure spring only to discover that its rate and coil design induced resonance some where in the power band and beat everything to death! Spring design still rates as a black art in my book.

[Speedy Goomba]

Darin,
Thanks! This is a wealth of information and it's much appreciated.
Brian

[Wolfplace]

Darin,
Thanks! This is a wealth of information and it's much appreciated.
Brian

HI Brian,,
Do the "rules" sound at all familiar??
Pretty much the same thing I been preachin on the other board even though I have received a bunch of flack for it a few times from people who like to tell me how cheap they can buy a set of springs from Joe Smucks mail order house

Wasn't it you that I said something like if you ever saw a Spintron test it would be damn near enough to make you want to quit buildin these things??

When you see the springs come off the heads & retainers & dance around like they were made of Jell-O it kinda makes you wonder how these poor things live at all & in road race, circle track or any endurance stuff or any application where you happen to use a spring that has a "fuss point" where the engine stays for very long it can get ugly real fast.

I don't have access to a Spintron but was privileged to attend some testing being done at one of the cam manufacturers & came away realizing that a spring can be very happy at say 7500, go nuts at 8000 & be happy again at 8500 & the same spring with a different push rod may exhibit completely different results
This is why it's a good idea to discuss your spring choice with the cam designer or someone who has had known results in the same type of application instead of picking a spring because it's cheap & has about the same published specs,,

[Speedy Goomba]

In a year or two when i change to a roller cam in my motor, i plan on use PSI or isky tool room gold stripe springs. I plan on talking to both, PSI/Isky and a particular guy at Comp that i have in mind when picking out a spring. I believe that the Isky tool room gold stripe are infact PSI springs, so i may as well cut out the middle man and speak with PSI.

I've never beat you up over recommending good valvetrain parts. I usually recommend using good valvetrain parts, as a valvetrain failure is usually expensive. If you look at my recent posts on the camaro board, you'll find i was suggesting that Eric68 use PSI or Isky Tool room gold stripe springs on his motor, since his current springs were causing the motor to break up at high rpms (They were wayyyy wrong).

And of course, everyone jumped all over me for that advice, because of course, i'm "crazy" But you and me both know alot of people on the other board are terrible at dealing with eccentric personalities.

And BTW, i've taken your tip on the super 7 degree valve locks, and plan to use them when i switch over to roller. And also i plan to use 3/8" pushrods, on a tip from you. Unless i take the opportunity and use shaft rockers as well, in that case i'll probably use a 7/16 pushrod, if it'll work(fit)

Mike, dont think that i ignore your advice when i ask more then one persons opinion. I take alot into consideration when specing out parts for my upcoming projects.

[Speedy Goomba]

Decided to create a screen name, this is a good website!

[Wolfplace]

Brian,
That wasn't directed at you. If it sounded that way I apologize. I have never seen you recommend crap parts & have seen you take the same flack only more so for telling someone to do it right the first time

You are correct, the outer Tool Room is wound by PSI but Isky does their own testing & has their own specs on the springs & supposedly has their own surface treatments etc.
I don't have a clue what they are doing but I can tell you after going to the RAD series, spring life has doubled.
Have not broken one in 2 years. & the retainers are very happy when you remove them except for where the damper hits them & we are changing them only once a year on the little 332 that normally sees about 9400 with regularity going up & down in the gears in a road race environment.

On PSI unless you are planning on buying a ton of them I believe you will have to purchase them from CV Products now as they are supposed to be the sole distributor.
If I can help you on the Isky stuff just hollar.

[Speedy Goomba]

Thanks Mike!

When i get ready to buy the isky springs in a year or two i'll give you a hollar!

[Darin Morgan]

I don't have access to a Spintron but was privileged to attend some testing being done at one of the cam manufacturers & came away realizing that a spring can be very happy at say 7500, go nuts at 8000 & be happy again at 8500 & the same spring with a different push rod may exhibit completely different results
This is why it's a good idea to discuss your spring choice with the cam designer or someone who has had known results in the same type of application instead of picking a spring because it's cheap & has about the same published specs

I had a truck puller who purchased some Raptor heads and he wanted the PSI spring upgrade. It has always worked well for cams with .960 lift and above. Those springs have always lasted twice as long as the 948 springs in this particular engine. In this case it was a disaster! The customer took the engine to 9000 then dropped it back to about 8100 and held it there for some time. No big deal right? WRONG! That's EXACTLY the point these springs go into resonance with that push rod, rocker, camshaft combination! In a Drag Race application its no big deal because they go though that point so fast. Holding the engine at that point exacerbated the problem ten fold. He was destroying parts right and left so I sent him some Comp 948 springs and the problem was fixed. I am sure every engine builder on this message board could tell similar stories.

[J-Rod]

This was posted on Corvetteforum by Walt Donovan. Walt is an engineer for Jesel.


Springs aren't made for a specific lift (or cam or rocker ratio) but.....

When you add more lift you do two things to tax the ability of the spring to control the system.
1) You increase acceleration in the same proportion that you increase lift, and
2) you must set up the spring taller to account for the extra lift. Doing this naturally decreases the seat pressure.

You have one saving grace in that most spring manufacturers have their heads up their .... (well nevermind). Anyway, the spring makers mostly claim their springs should be set up at least .075 from coilbind. They are slowly pulling their heads out though. They used to cringe if you set up their springs less than .100 from coilbind. Have the laws of physics changed so that springs can be set tighter?

Remember this, the further the open lift spring is from coilbind, the lighter the force over the nose, the more chance to slam the coils together. I set circle track springs at .035 from CB, prostock at .050 from CB. The only reason the PS springs need so much room is that these heavy triples get very tight just before CB and put extreme loads on prods.

If you get numbers on your springs you can estimate what difference shimming would make. Take the mfrs numbers of installed ht, seat pressure, rate, and distance from CB. If a given spring is 120# @ .085 from CB and you want to squish it to .035, you are adding .050 shim. This .050 times a rate of 344# per inch is 12#. Add this to the 120# seat and you see 132# on the seat. Same thing for adding lift while maintaining distance from CB. Add .050 to your installed ht DECREASES seat pressure by 12#. Anyway, all this means nothing unless you know what shims are and where to put them.

[Wolfplace]

This was posted on Corvetteforum by Walt Donovan. Walt is an engineer for Jesel.


Springs aren't made for a specific lift (or cam or rocker ratio) but.....

When you add more lift you do two things to tax the ability of the spring to control the system.
1) You increase acceleration in the same proportion that you increase lift, and
2) you must set up the spring taller to account for the extra lift. Doing this naturally decreases the seat pressure.

You have one saving grace in that most spring manufacturers have their heads up their .... (well nevermind). Anyway, the spring makers mostly claim their springs should be set up at least .075 from coilbind. They are slowly pulling their heads out though. They used to cringe if you set up their springs less than .100 from coilbind. Have the laws of physics changed so that springs can be set tighter?

Remember this, the further the open lift spring is from coilbind, the lighter the force over the nose, the more chance to slam the coils together. I set circle track springs at .035 from CB, prostock at .050 from CB. The only reason the PS springs need so much room is that these heavy triples get very tight just before CB and put extreme loads on prods.

If you get numbers on your springs you can estimate what difference shimming would make. Take the mfrs numbers of installed ht, seat pressure, rate, and distance from CB. If a given spring is 120# @ .085 from CB and you want to squish it to .035, you are adding .050 shim. This .050 times a rate of 344# per inch is 12#. Add this to the 120# seat and you see 132# on the seat. Same thing for adding lift while maintaining distance from CB. Add .050 to your installed ht DECREASES seat pressure by 12#. Anyway, all this means nothing unless you know what shims are and where to put them.

With all due respect to Mr. Donovan, I feel their is more to springs than pressure, & distance from coil bind & it sounds like he might have been answering a specific question.

When I take an engine & pick up 12 HP just changing pushrods & most of the little goofy dips in the torque curve go away that I assumed were from spring surge at different RPM's or when I just change from one spring of the same basic advertised rate, pressure & bind height to another of seemingly equal specs,, or even to a slightly lesser pressure & now the retainers no longer look crap after just dyno time & they start lasting all season in an endurance deal it tells me there is more to springs than just the advertised numbers in the catalog.

I can't speak for Pro Stock except for what I have been told but in some limited circle track applications where you are using a cam that is actually designed to "loft" the valve higher than the designed lobe it would probably not be a good idea to run the spring at .035 from coil bind.
I personally don't feel using coil bind to stop the valve lift is the best idea in most applications.

Also, being further from coil bind really has no effect on nose pressure unless you are referring to the same spring.
You can change springs to a higher rate, set it .100 from coil bind & end up with the same pressure.
I think you will find that the main reason the cup guys are running over 9500 now is because of advancements in springs, pushrod design & the fact they are running specific combinations of cam, lifter, pushrod, rocker, spring, retainers & valves & they are living because they know where not to run the engine.
If you change anything in this combination of parts without the benefit of Spintron data you may find a point in the RPM range where things tend to get very unhappy & if this happens to be where the engine spends any length of time,,, ugly things will happen

[ChrisU]

Has anyone given thought to the theory of cancelling resonant frequencies by setting up the spring so the coils make contact with each other at peak lift? Consider a tuning fork for instance. Not to suggest that we introduce coil bind, but in the dynamics of the spring itself....

I hate to look at the spring in terms of 'coils' in the discussion, as we tend to look at them as seperate entities, when they are really one.

I'm not suggesting it hasn't been considered, but I'd like to know if it's a valid theory.

This would suggest that having too much left in the spring would not be a desireable situation, in a high rpm application.

[J-Rod]

I was quoting Walt. I'm sure he has his reasons for what he does, as do others. I simply quoted a post he had made. I don't think its the be all or end all, but working for Jesel I think he has some insight into valvetrain dynamics.

As for Circle Track. I don't think when he referred to Circle Track he was referring to launcher cams. That is whole other animal. We use them in some lift limited drag racing series, and the rules there are differnet than others when it comes to spring setup.

But, I guess I could send him an email and see if he wants to post up why he does what he does...

As for the resonant frequency of a spring. I have seen published information which touts the advantages of a ovate beehive spring to help reduce resonant frequncy based partially on the shape of the spring, but also due to the shape and winding of the coils.

Several cam designers I know hate beehive springs though, but I do find it intersting that varying the shape of the spring is supposed to have some positive effect on harmonics. But, like anything in nature everything has a certain resonant frequency. If you find that frequency, its a good place to avoid as it tears up stuff if you sit there.

[EngineTech1]

What do some of you like to see for clearances between the i.d. of the different coils in the spring pack to the o.d.'s of the different lands of the retainers and i.d. locators? I know how I have been setting up this particular fitment but was wondering what others use as guidelines and what kind of results you have seen. Also what do some of you consider to be the most important things to consider when setting up a solid reliable valvetrain, encompasing all included components of the valvetrain and cylinder head/ engine combination, I know this is a really involved area of discussion and I am more looking for a sort of a 5 or 10 most important things to keep in mind or look at.

[EngineTech1]

Another question I have is without the benefit of a spintron what indicators can you look for on the dyno as signs of valvetrain related issues such as float, or bounce, and harmonics related problems in the valvetrain? Are there specific indicators to look for or monitor or is it more of an A / B testing situation?