Going to start putting my cylinder heads together and am going to order my valve springs. In the camshaft listings for my cam if you move over on the cam selection page you will see the spring part number they recommend for the cam, which just so happens to be the same as my previous combination.

So...I go to the specs on the springs and check the numbers to be sure. The installed height for my springs on my heads are 1.875 intake and 1.900 exhaust +/- a few thousandths. the same as listed for the springs.

The math:
1.900" - .666" lift = 1.234"...Whats the catch----The spring recommended by the manufacturer binds at 1.225". Since you should always have at least 0.050" preferably 0.060" of safety factor...all I would get "theoretically" is .009".

There is good news though, on page 310_311 the springs are listed again by installed height and part number. The spring is tagged as "max lift = .550" which totally makes sense and is consistent with my math check.

It would be very easy for someone to just get the part number from the cam listings and put them in, what a big surprise that would be after a couple of miles..... :(

I didn't use the recommended spring in my last combination with a 288AR cam because I already had a new set that were a little stiffer and calculated out with all the right numbers and safety factor.

This is not meant to bash any company because typo's exist everywhere in everything...Just meant to send a message to not take anything for granted and check out EVERYTHING when it comes to clearances and compatibility of engine components.

graemlins/beers.gif

Tom,
Good point. Many years ago when I was putting together my motor, I ordered my rings at 4.375" bore. 454 +.125" They arrived and that is what the box said they were. Upon installing and setting the ring gaps, they were all too wide. I took them back to the machine shop, he measured them for me and said that they were wrong. Said it happens in about 1 per every 1000 boxes. Figures I had to get them. Then my springs were wrong also. But I did not notice like you did. I installed them and ended up with about 8 broken rocker arms and bent pushrods due to coil bind. Never assume! I always measure everything now.

Head gaskets can be the same way. I used a nominal .020" head gasket that upon removal turn out to be .015". Since this was a race engine and going for a tight quench, that missing .005" cause the pistons and heads to meet. Only minor, fixable damage but it could have been much worse. Always a good idea to measure everything.

check twice, bolt once, that's what I say. smile.gif

There will never be a substitute for double checking with your own fingers and eyes.

Think about this, with a hydraulic cam you wouldn't see this putting the engine together, even you were supicious. The lifters collapse with no oil in them, it wouldn't look bad at all. Fire it up, drive it down the road, ka-boom.

Tom

wisdom = the ability to learn from other people's experience.

My Dart heads suffered from this problem. Dart's spec sheet said "max lift .620" and also gave the part number for the Comp springs they used. I decided to double check and pulled out the comp catalog; good thing I did. For the springs Dart used, the comp book said "max recommended lift .550" -- oops. If someone took Dart on their word they would have a BAD case of coil bind. :rolleyes:

I also check all my new valvesprings for pressures/rates... I've got a box with a few mismatched springs before.

You're right on the money here... ALWAYS double check things, even new stuff right out of the box.

If we're talking about Comp's specs - squeeze the spring to coil bind (vice is good but I use two plates to buffer the spring from the jaws) and measure back from there.

Not real confidence builder.


MAT

Follow-Up -

Comp Cams has now said that their 929 spring is a little light for roller cams like the XR292R and the 288AR that I have used. They are saying about 20 pounds more would be good. They have also said that the street grinds are a little softer than their race billet cams.

What springs did you end up using? I ended up using Comp 953 springs with my .663 lift Bullet roller and pressures and clearances worked out fine. Just curious. Fronm their specs in the Comp catalog, those 929 springs didn't look like they'd be sufficient.

Randy

Yes Randy,

I used the Congo Rollers from Competition Products, $149. I installed them at 1.950 to get the seat pressure down to 190-200. I will be installing a new set again. I have to go and admit, this was the third season on the set that is in there. The lifters will remain for a second season.

I am running the XR292R cam with Dart Heads. The springs I am running are 205# seat and 555# at .660" lift. No problems and I will be taking the intake off this month to replace the lifters and get the old ones rebuilt (yearly). Comp is recommending the comp 954 springs which is spec out at 223# @1.900" and 537# at 1.25 (.650" lift) comparable to what I am running now. Both Comp and my machinist said that these would work the best. Also with a typical loss of 15# of seat almost immediately that would bring it to 208# which is right where I am at. I am also going to be buying the LSM Spring Tester to test the springs while I am adjusting valves at the races
http://www.lsmproducts.com/images/pc-100.jpg

FWIW I'm also running the 953 CC springs with my XR-286 grind roller. The spring rate is 496lbs/in and the height is 1.900. Seat pressure at 1.990 is 162. Mine are installed at 1.875" so the seat/open pressure is 175/505 respectively. The thing I really like about these springs is the coil bind is at 1.085. So at an install height of 1.875 and max lift of .666 I've got .124 before coil bind. IMO the springs should live longer because they're not operating as far into the duty cycle as a spring with a higher coil bind might be.

my $0.02

Ken, that was my thinking exactly. Do you drive your setup on the street much? How has your spring/valvetrain life been?

Randy

Ken,

That is exactly what I did too. I will post the specs up a little later.

I just ran in to the exact situation on my 383.
Its got about 3500 miles and 20 passes at the track. I used springs recommended by Crower and never checked. Last weekend I bent a valve. Today my machine shop checked and all the springs. On the exhaust side they were only .030 to bind on the .518 lift. Two of the springs were down to 70 lbs of seat presure and caused the float.

Originally posted by ToyzRMe:
Ken, that was my thinking exactly. Do you drive your setup on the street much? How has your spring/valvetrain life been?

Randy Randy,

I seldom drive my car on the street, not because it's "unstreetable" but rather because I'm lazy. When I race I run Hoosier skinnies in the front and full slicks out back. It's too much of a hastle to switch four wheels on and off the car twice a week (race every Saturday most of the year, sometimes more often). I think that this setup would work fine on the street, idling and all. I've got nearly 100 passes on this set of springs. I checked the spring pressure about 4-5 weeks ago and they were all reading within 5lbs of where they were when they were installed at the beginning of this year. I will run on the springs and lifters all of next year and I'm hoping to make close to 200 passes next season.

I have a 70 396 with a solid lifter cam with 560 lift. I called Comp Cams and they recomended the single spring that has a .530 lift max. spec. Called a couple days later got another guy and he said that was the spring I needed.The .530 spring would be fine with .560 lift. Scares me. Any suggestions on springs? Thanks Steve

The spring I decided to run is 1.550 diameter with 230 lbs at 1.880 and 650 lbs at 1.150 with coil bind at 1.080. Springs average 575 lbs per Inch....I first verified these numbers using 2 different spring pressure testers at 2 different machine shops. They were both within 10 lbs either way. I installed them at 1.950" which gave me 190 on the seat and 570 open with my .660/.666 lift. with a coil bind of 1.080 and a compressed height of 1.284, this left me with .204 before coil bind. well above the .060 min. recommended. And as ken pointed out first, it just seemed to me that I should get a more reliable lifespan out of the spring.

The CC recommended spring only would give me .034" of clearance to coil bind. and 150# on the seat...that just didn't sit right with me...No thanks.

A rule of thumb is that springs can lose 3% to 8% of their rate after a little use. so at 190lbs - 6% = 178 lbs it is ok. A little extra spring pressure without getting crazy is ok for a roller anyway and we are not talking big numbers here anyway.

My buddies Pontiac Heads for his 580" BBC motor had the machine shop guys cowering in the corner after his springs were installed with a hydraulic press, it just happened that the cylinder heads were between THEM and the nearest EXIT!...too funny!


Steve, what cam do you have? and part number if possible, maybe I could help.

Ken,

You had mentioned that you checked the springs 4-5 weeks ago and they were all within 5lbs of each other.........what method do you use to check the pressure?

Originally posted by Rumblin70SS:
Ken,

You had mentioned that you checked the springs 4-5 weeks ago and they were all within 5lbs of each other.........what method do you use to check the pressure? Tony,

I use a Moroso hand held spring tester. What I meant was that the spring readings I took recently were within 5lbs of what they were when the springs were first installed. The Moroso hand pull spring tester has an advertised margin of error of +/- 5%, I think it may actually be higher. What's important is to get a reading when the springs are new using the tool of your choosing and then repeat those measurements periodically using the same tool/method. When the springs get weak enough that valve float occurs the MPH will typically drop off. The idea is to be ahead of that curve if possible to avoid any damage from valve float.

Originally posted by mc71454:
....I installed them at 1.950" which gave me 190 on the seat and 380 open with my .660/.666 lift . And as ken pointed out first, it just seemed to me that I should get a more reliable lifespan out of the spring.MC71454, just a thought here; in effect it would seem you`re open pressure is only about 358#`s. That` Hyd F/T pressue!
I would be more concerned with lifter "toss".
While it might initially look as though you`ll improve spring life the lifters themselves could get hammered to death.
And then valve float sets in and that will kill a set of springs as you know.

I would add some more pressure,...Just a suggestion

Originally posted by BigRed-L72:
</font><blockquote>quote:</font><hr />Originally posted by mc71454:
....I installed them at 1.950" which gave me 190 on the seat and 380 open with my .660/.666 lift . And as ken pointed out first, it just seemed to me that I should get a more reliable lifespan out of the spring.MC71454, just a thought here; in effect it would seem you`re open pressure is only about 358#`s. That`s Hyd F/T pressure!

I would be more concerned with lifter "toss".
While it might initially look as though you`ll improve spring life the lifters themselves could get hammered to death.
And then valve float sets in and that will kill a set of springs as you know.

I would add some more pressure,...Just a suggestion </font>[/QUOTE]

I have no idea why that XX posted...Sorry! graemlins/clonk.gif

Steve, the springs you want are the L88 type that Tom here used to wheel on Ebay. The whole setup was around $110, springs, locks , reatiners, should be around 115 seat, 330 open at .560 lift. .560 lift max. ( Although I use then now with a cam netting out .580 on the exhaust.)

Tom, I'd pick up a spare set if I didnt get some Comp 924s for free.

Oh, and to go with Tom's idea, never ASSUME the springs set you have is right. Check the pressures.

BIG RED - Thanks for pointing that out

I corrected the error in the description. What I meant was that my springs give 380 MORE pounds of pressure between closed and open - making it 190# initial pressure + 380 MORE # open (.660x 575 ) = a total of 570# open..My Bad with the way it was described. Thanks Again

I have the Flu and a fever ---- oops !!

Gene, I am a little confused :confused: remember I have the Flu and it really sucks

Gene, never mind, I get it now..Sorry, I wouldn't trust myself to check tire pressure right now..

Ken,

Thanks for your information, I do appreciate it. I just bought the same tester last weekend and plan on testing all the springs before I drop my big motor in the car.........