BAD-HABIT

I bought a new set of L31 Vortec heads from GM before I put my motor together 2 years ago. I have approx 70hours on the motor now. My question is this....After speaking to a guy who used to work at the shop (it went under early this year)that assembeled my heads (replaced the springs,keepers and retainers) I was told that he didn't think the guy who did my heads machined the heads down for the needed type of valve seals.....Now every thing I have read about the Vortec heads states that they need this done for anything over 480-490 lift. Im pushing 495 and 505 now.....What kind of damage will this do to my heads/engine if the seals were not correct? How can I tell if this has been done or not? I really don't want to take the heads off to check or correct the problem since money is real tight. But Iv'e got to much invested to let it go with out knowing.

Thanks
Randy
"Bad-Habit"

Iggy

I believe you'd be hitting the valve guides with the retainers (not the oil seals) or reach coil bind (if the spring pockets weren't machined too). In which case you'd be bending pushrods, screwing up the rockers, lifters, and possibly the cam too. Either way you would have known it by now.
Everything I've read about modifying the Vortec heads is that the guides have to be machined and the spring pockets have to be machined to a larger diameter to fit aftermarket/stronger springs.

Check out Chevy High Performance magazine. Their web site carries an extensive selection of 'how to" and free access to all their tech articles.
The had an article on modifying the Vortec heads for high lift. It's titled.. "It's a spring thing" .

cstraub69@comcast

If he put an umbrella type seal on the guide and the clearance is not enough, the seal would be pinched between the top of the guide and the bottom of the retainer. Now on some retainers the valve locks protrude out the bottom. If the latter is the case you stand the risk of pushing the locks out and dropping a valve. Not good.
You can see if the seals are coming apart pretty easily. Pop the valve cover off and look inside of the springs. The seal could be black, green, white, gray. See if they have any tears. Also you can rotate the engine over manually with the plugs out while checking to see how close the retainers gets to the top of the valve guide.

I would think after 70 hours your okay, if the interferance was drastic it would have come apart already, but for a sane mine, I would check.

Chris

traviss

My vortecs when put together the retainers were hitting the seals at .460" When i did mine a few years ago, I had to have the guides machined down to run .542 lift. Then you run a small crane teflon seal. There should be around .060" clearance between the seal and retainer at max lift, when being setup.