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I just found a distributor of Standard Abrasives not too far form where I live, so ill be working on the heads a bit ..
Id like to know, after reading threads and diffrent types of options,
can I simply install umbrella seals, and +.50 keepers with the maching springs, or is it a must to have them machined for more lift ?
umbrellas don't really have much to do with it, but .050 offset keepers "taller", will give you .050" more distance between rocker stud (or positive seals), and the retainer.
Remember you still want the right open/closed spring force, and that offset throws that off as well I think.
Machining down those guide bosses isn't the end of the world, it might run you $80.
Vortec heads don't flow well with a lot of lift anyway, they experience port stall in the .530"ish lift area. Shoot for .500" lift or thereabouts, and more duration if you want the added power (don't think you'll need to go crazy to get gobs of power though).
i'd get the heads machined for screw-in studs, spring pockets opened up and the guides machined down. now with my combo I had all that done and for my particular keepers and retainers, along with the installed spring height I needed I only have .530 inch lift clearance for a cam, with .060 safety factor calculated in. FYI check the heads yourself after you get them back. Luckily I'm running a smaller cam than .530 barely so I'm in the clear. More duration=more power, but at a loss of driveability.
__________________ 2011 chicago world of wheels placed in super street class
Best Engine '11 Thirdgenfest
Best Modified Camaro Thirdgenfest '05, '07, '11 Second place Camaro Modified '06, '08, & '10
MFBA March 2008 Featured Calendar Vehicle
also in this one, they emphasise that guides dont have to be machinded.
Its not really that I dont want to have the heads machined, I plan on buying the valve guide cutter, and the valve seal remover, I was just implying that
Id like to complete the work myself , and doubt that I can get those tool
and perform the work properly, by myself, so I started to look for alternatives ..
Ill get the guides machined if its the only logical way to go, whicjh bring me here
I, too, would recommend the machine work, but there's a recent article on carcraft.com on comp cams beehive springs that claim to add lift without the machine work. A bit pricey for springs but probably a less expensive alternative when factoring in the purchase of a valve guide cutter, etc. (and you still need to purchase springs). Screw in studs are a must, though.
One alternative ot machining the valve guide tops for more lift is to limit the valve lift of the cam you install. Isky Cams has some great "lift limit cams" the are just right for a 350 vortec street motor. Isky Cams#201278 is 278-278-.450"/.450" 106 LSA 234@.050" At only .450" lift no machining is required. Use Manley #22410 valve spring (no machining req) Don't be mislead by the modest lift, this cam makes power. Wants a hi rise "RPM" style intake, headers, a high stall converter and high rear end gears.
normally I don't agree with the idea of adding duration but not lift... But in this case i'd have to say F-bird is on to something here.
FWIW, I remember reading a post here, which was linked to a Vortec head build up on another forum. I guess one of the engineers who helped design the Vortec head posted on there.
He had a 350 I think, with a 270* @.050 duration cam (not a typo there), and something like .480" lift. Solid flat tappet. It ran low 11's I think. He was talking about vortecs lift limits and port stall, etc, and why he used a .480 lift cam and not higher... It wasn't due to rules, he was trying to go as fast as possible on a **non ported** vortec headed car. The only rule was to run vortec heads with 0 port work done, any lift or duration was a-ok, and he ONLY ran .480" lift by choice.
He had a 350 I think, with a 270* @.050 duration cam (not a typo there), and something like .480" lift. Solid flat tappet. It ran low 11's I think. He was talking about vortecs lift limits and port stall, etc, and why he used a .480 lift cam and not higher... It wasn't due to rules, he was trying to go as fast as possible on a **non ported** vortec headed car. The only rule was to run vortec heads with 0 port work done, any lift or duration was a-ok, and he ONLY ran .480" lift by choice.
you know what link this is to? That's a lot of HP compared to the typical high 11s/low 12s buildups that I've seen.
__________________ 2011 chicago world of wheels placed in super street class
Best Engine '11 Thirdgenfest
Best Modified Camaro Thirdgenfest '05, '07, '11 Second place Camaro Modified '06, '08, & '10
MFBA March 2008 Featured Calendar Vehicle
I think he put it in a nova or something... solid flat tappet cam, like 270* at .050, .480" lift or so.... damn, I keep trying to find this and i'm coming up blank...
Could well be this excellent stickied thread on NastyZ28.com, by Dirt Reynolds. Has some quotes by one of the design engineers of the Vortec head. Been looking for this info myself, planning a 383 Vortec/HSR.
BINGO!
"Gary Penn" is who i'm thinking of. On one of those 7 pages of that thread there's a link to his own personal website with some more info. but that one post about halfway down shows his combo.
I just ordered the valve guide cutter for vortec heads (cuts guide to .530) the stud puller, and the valve seal installer
the guy was telling me you can just remove the seals by hand or with a vise-gripe ..(dont know about the hand part lol) and then install them with the tool.
crane apparently doesnt sell them anymore, thus got them from compcam, and I also found a distributor of standard abrasives, (http://www.sa-motorsports.com/diyport.shtm), so ill be ordering the deluxe porting kit, with the gasket removal kit.
oouuff lol, now I need an electric grinder, and a few bits I cant think of...
this man speaks the truth i have these exact springs and i didnt need to machine guides or anything, well i guess i had them machined for compression but they work awesome!!! i would really recommend these because you dont have to deal with getting them machined all you have to do is put the springs into the heads and presto higher lift