I have my 062 vortecs in the mill set up to cut the valve guide bosses down to clear my valve springs, and furnish a .530 I.D positive valve seal. I intend to machine the small (.550" dia.) and large(.840") step of the boss down to leave only the height of my seal plus 1/16" at .530" dia. Since I'm removing such a substantial portion of the valve guide boss, I thought I should confirm with the community whether or not this is wise. Would someone kindly advise me what is typically done in this case? The heads are intended for a mild street machine with approx .520" lift (thumpr)
Could someone also advise on a approximate rpm to run the comp cams cutter (4726) at? I was assuming 80-100rpm or so...
Thank you for your input.
Vortec valve guide boss machining
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Re: Vortec valve guide boss machining
Run beehive springs/retainers (comp 787-16 iirc), they hit the seal around .585" (how my head checked anyways) which does away with machining your guide bosses and lightens up the valvetrain in one step.
installed height was @ 1.75" for my set of stock 062's with the comp retainers.
A set of pac 1215's will get ~ 120 seat @ 1.75, though being oem heads best check your specific heads for installed/clearances.
installed height was @ 1.75" for my set of stock 062's with the comp retainers.
A set of pac 1215's will get ~ 120 seat @ 1.75, though being oem heads best check your specific heads for installed/clearances.
Re: Vortec valve guide boss machining
Several companies carry "drop-in" spring/retainer combos for your needs. Straub Technologies and Alex's Parts are 2 off the top of my head.
Good Luck!
Good Luck!
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Re: Vortec valve guide boss machining
Ditto. Fyi, I have run the blue LS-6 GM springs and comp 26918s with the #787 comp retainer on 4.3 and 5.7 vortecs. Although, if I was buying today, I'd look at 1215 or 1218 PAC. Howards also has a beehive. I've found that with stock valves and the #787 retainer, a +.050" lock is needed to get near 1.800". Esp with the plus locks, stock vortec seal to the #787 is much greater. Fwiw, afaik, many experts like the stock vortec seals.Rizzle wrote:Run beehive springs/retainers (comp 787-16 iirc), they hit the seal around .585" (how my head checked anyways) which does away with machining your guide bosses and lightens up the valvetrain in one step.
installed height was @ 1.75" for my set of stock 062's with the comp retainers.
A set of pac 1215's will get ~ 120 seat @ 1.75, though being oem heads best check your specific heads for installed/clearances.
Note - iirc, the GM beehives [only 90# seat, but stiffer rate iirc] are a little tight on the guide boss [smaller inside], compared to the comp 918s. Here's a thread in case you look at them;
viewtopic.php?f=1&t=38544
Dave
Re: Vortec valve guide boss machining
Yeah, the ls-6 springs are a little tight, they also have a higher spring rate than the aftermarket beehives, at 373lb/in vs 313lb/in for the pacs. The blue/yellow gm springs both fit with different degrees of pressure. The retainers had varying levels of fit as well.
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Re: Vortec valve guide boss machining
You will be fine machining the Vortec spring pockets and guide bosses. I run them at appx. 150 rpm.
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