[bubba68ss]

This is the second valve spring that has broken on my 396 with comp xe262 cam. They are stock springs and i dont know how old they are but they seem to be fresh clean breaks usually in two spots. My car just started running bad at idle (warming up) so i pulled the valve cover as i knew what it might be.
Why would i be breaking springs? Would this explain why my motor is so noisy (besides the fact that it is a XE cam...) at higher rpm's? Are they just worn out?

 

[66rat]

Do yourself a big favor and relpace all the springs ASAP, before one lets go of the valve and destroys the engine. I can't explain why they are breaking, too many variables involved, but replace them with the manufacturer's recommended springs. I've seen many engines die because of broken valve springs.

Rob

 

[1Fast7D]

They are stock springs

Did you check for coil bind and the rest of the valvetrain geometry when the cam was installed???

 

[M.Maner]

Listen to 66rat! I suspect your springs are in coil bind. CC recommends always replacing springs especially on big block chevy's. The good news is you have not destroyed the motor yet. The bad news is I suspect your cam is now junk. If these springs are failing from fatigue you may be OK,as far as the cam goes,but if there failing from coil bind,your cam is probably going flat and you may find bent pushrods and other damage,this is probably the reason for the noise.Never install a performance cam with old springs,your just asking for a disaster.

 

[bracketchev1221]

Exactly what he said!!

 

[Hi-po SS 454]

Bubba , very surprised you didn't go witht the cams matching springs with proper installed height per manufacture. They stress, NOT to use stock springs. So far your lucky.. Time for tear down Dude !!!

 

[Jerry Briggs]

Never, Never install a performance camshaft without matching springs. Jb

 

[bubba68ss]

Definatley wasnt having coil bind, lift is 504" 510" on the cam and with the spring fully compressed i can put a piece of thin cardboard between the coils with no problem. All my pushrods are spinning freely still and the pushrods arent bent. I will have the springs tomorrow.
How do i install the springs at their right heighth? I know how to change the springs but do i need shims or anything like that?

 

[Hi-po SS 454]

Have never set spring installed height myself, but you'll need to know the manufactures suggested installed height for that spring and cam. You'll need shims, and you'll need the tool to measure the height correctly. I'm sure others here can be more detailed on this procedure.

 

[pukes66]

Ask my 454 in my 1 ton 4x4 about using the wrong valvesprings!! Do yourself a favor and replace every spring and retainer with the Comp Cams reccomend parts. If you cannot afford too replace these componets, keep saving!! You will be money ahead. This is the voice of experience talking.

 

[bubba68ss]

if all the pushrods are spinning, the cam is probably good right?

 

[bubba68ss]

i did a next day delivery order on the correct springs and i should get them tomorrow. I have about 8K miles on this motor and cam and havent lost a lobe yet. about 4K miles ago i tore engine apart to put in new pistons and the lifters and cam were in great shape. The lifters had a nice circular pattern on the bottom and the lobes were very smooth. i think the springs are just fatigued and old. You guys got me worrying about a ruined cam! NOOO!
Ill replace the springs tomorrow and should be good to go.

 

[Bob West]

How do you get correct installed height with the heads on the motor? That has to be fun.

 

[bubba68ss]

Im guessing you just put one on and measure it and shim it until it is right, then shim all the rest of them the same way?

 

[66rat]

A valve spring height mic would be ideal for setting the spring height. I think their about $60 bucks. If you don't want to spring (no pun intended) for that, you could cut a piece of pipe to the correct length and use that to set up your shims. Personally, I would check every valve for the correct height. Use the rope thru the spark plug hole trick to support the valves while changing out the springs.

HTH,

Rob

 

[BillsCamino]

Chris,
I've got a valve spring mic that you're welcome to borrow.
If interested, PM me your address and I'll get it right out to 'ya. :thumbsup:

 

[Guest]

I use a 2"+ long finish nail, my "dics" and my dial calipers, a good flat file or my bench grinder and two cheap hardware store soft springs.

Install the valves using the soft springs and cut the nail close and then keep filing until it fits and measure the nail and you have it.

Don't forget the hard .015" thick seat wear shims to keep the damper from chewing the cast-iron seats up.

pdq67

Best Car Insurance | Auto Protection Today | FREE Trade-In Quote

 

[bubba68ss]

I just got my springs today but it doesnt say anywhere what height they should be installed at. The Comp website is worthless too. Anyone know of a chart with the listings? Theyre comp 911-16 springs

 

[BillK]

Chris,
Comp catalog says 1.900"

 

[bubba68ss]

Thanks alot Bill