Valve stem seals with .500 lift?

[RSpengler]

I read somewhere that on vortec heads, the retainers crash down onto the valve stem seals with more than .465" lift? Is this true, and how do you cure the problem? My vortecs are at the shop being assembled as I type and I need to know if I need to call off the build, before its all assembled... Im going to be using the comp 412 cam, and stock height springs and stem locks, is all well or no? Also, the springs I am using are Crane springs with an inner damper, I also just read teh damper must be removed to accomodate the seals??? Argh....
-Rob

 

[E-Rue]

Re: Valve stem seals with .500 lift?

i usually run into issues at .530" of lift. not sure where you got the 465 number unless it came from someone using different style parts than i am. its not a complicated matter to machine down the pedistal where the valve seal goes. any compitant machine shop will have the tool/ability. once thats done you will have the clearance you need. anything larger than .560 lift tho, and id recommend using a valve thats .100" longer than stock. im in the process of setting up a vortec head right now with 560" of lift and all LS1 valve train components. its an interesting experiment for sure. using the 1.7 ratio shaft mounted rockers is proving to be a real task, as they are designed around a completely different installed height.

e

 

[dgoodhue]

Re: Valve stem seals with .500 lift?

.465 might be what the stock springs bind at.

 

[E-Rue]

Re: Valve stem seals with .500 lift?

the best thing to do is assemble your heads with your choice of valve train components and measure the distance from the bottom of the retainer to the top of the valve seal. as long as this measures more than the total lift of your cam, then you should be fine.

another thing to consider is coil spring bind. check the coil bind rating on your spring using the card that comes with them, against the lift number of the cam you have chosen (multiplied by the rocker ratio). always double chack everything once you have the head on the motor, by rotating the motor over with the valve cover off to be sure there are no interferance issues.

another thing to watch is piston to valve clearance. the valves should never come in contact with the pistons. a small piece of clay in the fly cut area of the piston will gauge clearance. assuming you have any. lol

anything can be compensated for, you just have to remember not to get in a hurry, and always double check all your clearances BEFORE you fire up the motor. might be a headache to look at everything, but i assure you its worse to find out AFTER you fire it up.

e

 

[93ty475]

Re: Valve stem seals with .500 lift?

I read somewhere that on vortec heads, the retainers crash down onto the valve stem seals with more than .465" lift?


I also just read teh damper must be removed to accomodate the seals??? Argh....
-Rob

Where did you read this info, if you dont mind me asking? any links?

thanks,

 

[RSpengler]

Re: Valve stem seals with .500 lift?

Lots of places, I pulled the .465 number from memory, I thought it was from the S-series forum, but not sure. I searched the forums here, and couldn't find an exact number when interference occurs. As for the dampner removal, I read that in a post here as well.
-Rob