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Vortec Head Info

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by dyeager535, Feb 5, 2003.

  1. dyeager535

    dyeager535 1 ton status Premium Member

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    After being told that it would cost $300 in machine work and parts to run stock Vortecs with my roller cam (.452 max lift), I was to the point of selling them. I feel bad, I did offer them for sale at one point, I really thought it was worth it to just get ones already done for more lift.

    However, on a tip, I called the machine shop that had done another set of heads for me a few years back.

    Lets just say, that Z-28 springs, with the inner damper removed, have 112# of pressure installed, only *2*lbs over what Crane recommends.

    To honor what the shop asked of me, I can't give the exact cost, but it was WAY (way way way) under $300...well worth it compared to going with the "complete" already prepped Z-28/Vortec heads. /forums/images/graemlins/smile.gif

    The cost included a check of the seat pressure obviously, but also checking maximum lift 'till coil bind (.572") and checking at what lift retainer to seal interference would occur. (.550")

    As always, it's good to deal with people that know what they are doing! Hopefully anyone considering these heads can use this info to get an approximate idea of what they will be dealing with.
     
  2. Mr.Chevy4x4

    Mr.Chevy4x4 1/2 ton status

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    Dorian,

    I had the same dellima. I called Scoggin-Dickey in Lubbock the the tech there told me the stock heads were good to .460 valve lift before retainer to seal problems would occur. I was happy to learn this as my cam has .452 lift on the exhaust side. I have run the stock vortec heads with this cam with zero problems.

    Mike
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    Yeah, that retainer to seal issue had bothered me too, but then again, there's a guy running a 350 in a Monte Carlo, Vortecs, that has a cam with .480 lift, and he isn't kind to it /forums/images/graemlins/smile.gif
     
  4. Nrose07

    Nrose07 1/2 ton status

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    Well what I have found out is that no 2 pairs of Vortec (L-31) heads are the same specs on the spring seat/seal/coil bind, from the factory. I took mine to a reputable guy just to have my stocks spring swapped for my Crower units (I was lazy) and he said I didn't have enough clearance between retainers/seals, so he took a extra 45min, machined my valve bosses down and now I'm good for .610" He didn't even charge me extra, wooping $45! Anyways, probably didn't help.
     
  5. 4DiggerDan

    4DiggerDan 1/2 ton status

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    If I had built you a set of Vortech heads, with brand new Z28 springs, clearanced to .550" lift with phosphor bronze guides (with a positive metal clad stem seals installed, which are triple spring friendly.) you would have had around 4 bills into them. Thats bare bones minimum for what I would do for a head that you're going to run hard. I like to run that extra .090-.100" margin for a fudge factor in case you do something stupid. Like float a bunch of valves and bust your stem seals all to sh!t turning 7 grand (that means the cam is turning 3500 RPM) while guzzling Budweiser and Scotch. If you don't have that fudge factor, you do something stupid, then you have to go back to the machine shop and pay him MORE money to do it right the 2nd time.

    I'm curious about what spring you pulled... With a spring installed height of 1.750 (real close to factory spec for a Vortec) you should have had about 118# on the seat and 280-290 at that gross valve lift (.452") with Z28 springs. In a roller cam set up, I probably would have gone one bigger and used like an Elgin 1943X (Or pioneer 1943X) these are beefier Z28 spring (stock OEM replacement Z28's are the 943X) They run about 140 Lbs on the seat and 320-340 over the nose at .450-.475" lift. (943's are about 36 bucks a set, 1943's are about 55 bucks a set) Thats not too much spring for a roller cam... Crane always seems to be on the light end with their recomended springs and I did have some valve float problems taking their advice. When you get valve float with a roller cam, you will literally brinell the footprint of the roller into the closing ramp of the cam, making is a piece of 250 dollar junk...

    Last thing. When GM added the damper to their springs, it had to do more with the spring soaking up harmonics that a valve train ca create than it did with the pressures it delivered. I really wouldn't run those springs without dampers. You've got to remember that once you bump the key, and the thermostat opens, the average spring takes about a 8-10# "set." I've proved this time and time again to myself on stock car engines.
    I've seen a brand new set of Z's take a 20# set in just two races, but then thats more abuse than you'll ever see in a 4 digger.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    </font><blockquote><font class="small">In reply to:</font><hr />
    If I had built you a set of Vortech heads, with brand new Z28 springs, clearanced to .550" lift with phosphor bronze guides (with a positive metal clad stem seals installed, which are triple spring friendly.) you would have had around 4 bills into them. Thats bare bones minimum for what I would do for a head that you're going to run hard.

    [/ QUOTE ]

    Which is exactly why I was ready to sell them. At a $400 acquisition cost, $400 "build up" and the "special" vortec intake, I would have been BETTER off going with aftermarket heads that already had screw in studs, bigger valves, took the "old" style intake, and so on...as it is (using DD2K to guesstimate), the engine stops making any sort of useful power at about 4-4500RPM, (stock TPI being one large limiter) which is what I wanted. Large amounts of low end torque. It won't see hard use. I'm fairly hard on it at lower RPM's, but that's it.

    </font><blockquote><font class="small">In reply to:</font><hr />
    I'm curious about what spring you pulled... With a spring installed height of 1.750 (real close to factory spec for a Vortec) you should have had about 118# on the seat and 280-290 at that gross valve lift (.452") with Z28 springs.

    [/ QUOTE ]

    Unfortunately I wasn't there when the springs were installed, had someone take them down for me and watch him work. Did call him back on the phone though to confirm everything.

    </font><blockquote><font class="small">In reply to:</font><hr />
    I really wouldn't run those springs without dampers. You've got to remember that once you bump the key, and the thermostat opens, the average spring takes about a 8-10# "set." I've proved this time and time again to myself on stock car engines.
    I've seen a brand new set of Z's take a 20# set in just two races, but then thats more abuse than you'll ever see in a 4 digger.

    [/ QUOTE ]

    No choice at this point, and besides, I'm sick of messing with stupid crap on this thing. If they don't work, they don't, and I'll have learned a fairly expensive lesson: it's worthless to waste time and money on making a non-roller block roller when you can buy one for so cheap.

    This thing won't see over 5,000RPM, when I get a chip burning setup, I'm going to work on making sure that it won't go over that limit anyway. /forums/images/graemlins/smile.gif
     
  7. 4DiggerDan

    4DiggerDan 1/2 ton status

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    YOU PAID 400 BUCKS FOR A SET OF VORTEC CORES????????? You can buy brand new Enginequest castings, with .085" thicker decks, factory machined for screw in studs, and safe to use with early (NON torque to yeilds) for 500 bucks. They're a night and day comparison to OEM Vortecs. Of course I'm factory direct with Enginequest (mostly becuase I see two busted sets of 2.9/4.0L fords a week,) so I buy them cheaper than THAT. However, I'm not really in the business to sell parts, I'm a machinist. After I get a set of them freighted to me, I make like 40 bucks on the phone call. After I get them machined to my liking (even the Enginequest castings have a clearance issue, and there's a few other things that I like to straighten out.) put a set of Ferrea valves in them, the stouter Z28 spring (roller cam friendly, not flat tappet friendy without a soft spring break in) machine the guides for positive triple spring friendly stem seals with clearance for whatever cam you're running (up to .630" lift) and lovingly assemble them. I build 'em for about 950 a pair... If you want to use cheap OEM valves and the softer Z springs, it'll save you about 180 bucks. If you've got to have more clearance, bronze guides, and bigger springs, it'll cost you 400 bucks more.

    Goodson just came out with a jig last year for machining Vortecs for the earlier style intake manifold pattern. I'd already have one, except they get like 300 bucks for it. That and there's quite a few intake manifolds available right now. Most guys just plan on buying one... But I could probably charge an extra 100 bucks just to give my customers more flexibility (that and they wouldn't need a 100 dollar intake manifold)

    My biggest gripe with Vortecs is that they have no exhaust gas crossover to heat a carb. Up here its cold in the mornings 9 months out of the year... That means your 4 digger will be cold blooded until the thermostat opens up. I've been meaning to find somebody out there making a water heated base plate for common spreadbore patterns... That would help.

    Dorian, how much do you know about custom fuelie systems? Or are you pissed at me for that Chevy Big Block thread??
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    </font><blockquote><font class="small">In reply to:</font><hr />
    YOU PAID 400 BUCKS FOR A SET OF VORTEC CORES?????????

    [/ QUOTE ]

    I'm sorry I made you waste all that typing...no, I didn't pay $400 for Vortec cores....they are brand new, complete. /forums/images/graemlins/smile.gif

    </font><blockquote><font class="small">In reply to:</font><hr />
    I build 'em for about 950 a pair

    [/ QUOTE ]

    I have no doubt your heads are good, and probably have more attention paid to them than AFR's, but just to keep some continuity, I could buy AFR's for $1250 (shipped, as I recall). If I add extra for bronze guides and screw in studs (you didn't mention those) I'm even closer to $1250 on a set of cast iron heads.

    Of course, if I really wanted to go low, I could talk about the Edelbrock performer heads. I would have gone with the Performers (AL, heat/EGR crossovers, 62CC's, fairly small port heads for those that don't know) had I been able to find more data. What I did find wasn't very good...flow numbers not on par with any of the other aftermarket heads, and not much in the way of recommendations. I don't think I'd bolt a set on unless I saw a dyno test back to back with some Vortecs. They are about $8-900, and I'm not sure if they just did it or what, but they are now being touted as "redesigned". Edelbrocks Etec heads (Vortec replacements) are the same way...who really knows if they are any better than Vortecs? I don't know as there have been any objective tests done on either head yet.

    There are numerous gripes I have with the Vortecs: require rail rockers as delivered complete, one intake pattern, thin castings, weak springs, press in studs, and no way to run EGR/heat crossover except externally. The AL GM Performance Products Fast burn heads (apparently Vortecs in AL for the most part) are, I believe, in every respect better than the cast Vortecs, for less than aftermarket AL heads, except the pesky heat crossover/EGR issue. I believe they are even dual intake patterned. I'd have to check that again though, 'cause the Vortecs have the raised ports...how is that handled when the Vortecs are drilled for the earlier intake patterns??

    </font><blockquote><font class="small">In reply to:</font><hr />
    Dorian, how much do you know about custom fuelie systems? Or are you pissed at me for that Chevy Big Block thread??

    [/ QUOTE ]

    I don't hold grudges for the most part, so no, I'm not pissed. You don't learn anything if everyone agrees with you, and doesn't bring a different viewpoint or different info with them.

    As to the custom fuelie systems, I don't know a whole lot compared to some. I'm trying my darndest to keep my '8X Camaro TPI system (ok, some of it's '88, some '89, some '91) as complete/intact as possible for the truck swap. I'm going to be running Vortec heads, a Crane 204/214 .429/.452 112* LSA cam, Scoggin Dickey TPI base, SDPC external EGR setup, '88 Camaro plenum and runners, Camaro TPI fuel pump in a new TBI truck tank, and so on. Using the stock GM harness, so I'm running VSS and what not. Only thing I'm removing from the harness is AIR and EVAP, since that won't affect the computer at all (and I can't fit them to the truck).

    Doubt that counts as custom, but my philosophy on injection is that you need to mirror the factory system if you want factory driveability. (so I'm anti-Painless or RamJet in other words) Of course there are makers out there that DO mirror the factory car systems, but the above 2 don't.
     
  9. 4DiggerDan

    4DiggerDan 1/2 ton status

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    The Enginequest castings ARE facroty machined for screw in studs, although they aren't shipped with them. Yes you still have to run rail rockers, but stock ones are easy to find used, and aftermarket aren't much more than non rail types. The Enginequest castings ARE .085" thicker on the decks, so NO you don't see them crack like OEM heads.

    As far as drilling them for the early style pattern, I've never done it. I did lay a standard intake manifold gasket up to one once, and it looks feasible. The jig looks like it bolts up to the bolt holes that are already there and it has bronze lined "guides" to run the drill in to keep it from walking around (it would save time, and make the job profitable, where increasing drill size from a center drill all the way up to whatever the drill size for 3/8" stud is in 1/64th increments is NOT.) On the EQ casting there's enough meat to hold a thread (about like you'd see in TBI heads)

    On the fuelie thing, I was hoping to find somebody that had used a FAST system after Comp bought them out. I'm wanting to build myself a custom system on a single plane Edelbrock Torker II. That way, if and when all else fails, I can just use the low pressure pump out of the tank and put a plain old spreadbore 4 barrel back on top to drive it home. The problem I got with OEM systems is the inability to do just that... Your TPI craps out on the trail, you're screwed. Where I'll have my truck up and running in about 10 minutes (although poorly...) I've got all the machine work figured out, I'm just trying to figure out the computer logistics is all...

    After all, carburetors are for BONGS!!!
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    If you are starting with thicker casting, perhaps you won't run into the same problems drilling the heads like the stock ones.

    There are a lot of SBC head options out there...really gotta research them before committing to one or the other.

    </font><blockquote><font class="small">In reply to:</font><hr />
    The problem I got with OEM systems is the inability to do just that... Your TPI craps out on the trail, you're screwed. Where I'll have my truck up and running in about 10 minutes (although poorly...) I've got all the machine work figured out, I'm just trying to figure out the computer logistics is all...

    [/ QUOTE ]

    See, this is another one of those "blown out of proportion" deals. When injection first came about (electronic anyways) it was kind of a "won't keep working on trucks" issue, but now, it's obviously not. Injection is more than reliable enough for trucks.

    This is one of the reasons I say the OEM system is the way to go. The system was warrantied from the factory, likely has 100,000 miles on it (used setups obviously), yet hasn't failed.

    Think about it...how many people do you know that ACTUALLY (not just changed it because they didn't know any better) had something catastrophic like an ECM fail in ANY new car that is injected? It happens, but what percentage?

    Sure, you could have an O2 sensor go bad, TPS, whatever, but the thing will STILL get you home...it may not run right, but it will RUN with many, many things not working. I've seen I4's run on two cylinders "no problem" with two of the injectors bad. I have no doubt that 2,3, or maybe even 4 injectors could fail on a SBC or BBC before you couldn't drive it.

    I think for the most part, compared to a carbed system, the one thing you'd want to carry as spare, is the ECM, if anything. Everything else (fuel pump, wires, ignition pieces, etc.) would be required as spares for a carbed setup as well.

    There has been talk of using single plane intakes with a throttle body mounted in place of a carb, but I've not seen it done using many stock parts. Chev and Olds is fairly easy because of the common distributors that can handle timing duties with a computer, others are a bit more difficult.
     
  11. 4DiggerDan

    4DiggerDan 1/2 ton status

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    Well, I really didn't have it in my mind that I was going to use a stock injector... My plan was to start with a system that would run a naturally aspirated engine, reliably, and in the worst possible environment (a 4X4.) Then once I get the hang of that, I'd try building one that would work with a the bigger non OEM Vortec superchargers.

    IMHO GM's TPI is the only fuel infection system that has anything going for it. I really don't like their TBI, and its way too complicated to get it to work with some engine combo's. It is pretty reliable though, on a stock as gramma's tits 350. /forums/images/graemlins/shocked.gif
     

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