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Wrong Valve geometry?? Bad parts combo how do I check?

This is a discussion on Wrong Valve geometry?? Bad parts combo how do I check? within the Internal Engine forums, part of the LSx Technical Help Section category; Short story, long post! So I bought an 03 z06 with STS kit on it in 2010; Motor had blown ...

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    Wrong Valve geometry?? Bad parts combo how do I check?

    Short story, long post! So I bought an 03 z06 with STS kit on it in 2010; Motor had blown ring lands, story was that it had gone lean on the tall end of a street race. I picked it up cheap from impound yard, and was just doing what was to be a motor rebuild aka 3-6 month project. It became a frame off full vehicle rebuild, coupled with my first machinist's death and second machinists incompetence and finally my own health failures it's now going on it's third year. So normally, I'm comfortable rebuilding ls motors with stock parts. Unfortunately this isn't a stock motor anymore; I haven't turned it on yet, I was going to and then started re-researching my original bookmarks from which I picked my parts, saw so many possible issues that now I'm bit scared.

    Info on build: My Goal "stock sizes but forged was staying with the sts and stock cam as I'm in CA and smog legality matters, want to drive to events, not tow" again comfortable setting up stock ls1/ls6's done a few 5.3's as well no issues with any.

    Block: was bored for new pistons; No mill, I was trying to stay as true to a 347 as I could. Added a DFI engine girdle that was milled to fit correctly but that's on the bottom of the motor, and I'm fairly secure that the bottom end is correct.

    Rotating Assembly: Forged Crank and Rods (both stock dimensions); Wiseco Pistons, closest to stock but forged that I could find. So the block required smallest bore over possible to fit new pistons. I added a two piece timing cover. Figured down the road when I inevitably give up on the STS kit (had one on my z28 hated the thing) that I'd go head and cam. So I also have arp head / main bolts reusable stuff this time)

    Heads and valves themselves are stock but I rebuilt with Patriot Gold Dual Springs, Titanium Retainer and keepers (bought as a kit), also of course new stem seals ;

    Cam: New 2003 Ls6 cam, the old one wasn't wiped out, but since I was changing rockers, pushrods, valve springs, bearings figured new cam too.

    Vavletrain Bits: CompCams "R" lifters, CompCams hardened Stock Length Pushrods, Yella Terra 1.7 rockers, Cometec slightly thicker Head Gaskets. (figured a bit less compression is probably a good thing)

    Assembly (where and why I'm concerned),
    1. I didn't put anything under the springs, nor any shims in them. Will these Patriot springs eat into the head, are they going to be correct spring tension just out of the box for a stock z06 cam?
    1a. I haven't, nor know how to check the spring height and tension, assumed as it was sold as a "Complete Kit" from a reputable sponsor site that the parts supplier knew what I was asking for and without my original machinist around I did the work myself. So I'm uncomfortable that this combo is dangerous.

    2. I used a non stock gasket size, aftermarket rockers, push-rods, lifters. Are my pushrods the right length anymore, how do I know? Has the gasket difference and aftermarket bits made a geometry issue, and how do I check? I did follow the Yella terra instructions but it didn't feel right compared to the other 5 motors I'v rebuilt (again I'v only every used stock parts in my rebuilds previous and had a friend (machinist) around to keep tabs on me); How do I check the pre-load, what about Coil Bind? I did lots of research but all the write ups I find only discuss stock components or giant cams! What is going to be right for this setup. Again thick head gaskets, stock lengths comp pushrods, comp r lifters, a stock z06 cam (same pn that came out of original motor), original stock sodium filled valves in the heads, with Patriot Gold Dual springs, YT 1.7 rockers.

    3. There were no parts left over out of any of the kit's purchased. But sometimes "Kits" expect you to re-use something from the old valve train setup, and mine being a stock z06 (so I was told anyway) didn't have any shims on-top or bottom(technically these are locators I guess) of the springs to begin with.

    Figured before I turn this thing on is there a good way to check that my geometry is correct? And should I worry about adding locators shims under the valve springs (They were such a PITA to get on) I haven't put the cooling system back in the car, and could easily pull valve covers and check. I just don't know how to check (install height, pre-load, pushrod length, rocker adjustment). Almost every write up I'v seen just confuses me more as none of the combos match, don't know many people running stock ls6 cam with dual springs, and a slightly oversized gasket.

    Bit more info:
    I also took the original Z06 yellow springs too the local jr. college and had their tensions checked, they where way out of whack! Not even close, as well one cylinder on driver side head wasn't even the right Z06 springs to begin with they were ISKY's!!

    Motor wiped at about 100,000 miles, lands blown off two pistons (#5, #8), but valve-train wise looked good and had a dual roller timing chain and sts kit installed already. It still ran fairly well just ate oil up, the cyl walls also looked good surprised since lands were cracked.

    Any ideas, or what you would do's? I'm leaning hard on parting this car out as it's just gotten so far out of hand and I'm second guessing myself. I'd assume it's 10-20hrs from completion unless I have to start going backwards due to this.

  2. #2
    Spaz is My Mentor SMWS6TA's Avatar
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    Wow you got a lot here....

    Quote Originally Posted by albrntout View Post
    Info on build: My Goal "stock sizes but forged was staying with the sts and stock cam as I'm in CA and smog legality matters, want to drive to events, not tow" again comfortable setting up stock ls1/ls6's done a few 5.3's as well no issues with any.

    Block: was bored for new pistons; No mill, I was trying to stay as true to a 347 as I could. Added a DFI engine girdle that was milled to fit correctly but that's on the bottom of the motor, and I'm fairly secure that the bottom end is correct.

    Rotating Assembly: Forged Crank and Rods (both stock dimensions); Wiseco Pistons, closest to stock but forged that I could find. So the block required smallest bore over possible to fit new pistons. I added a two piece timing cover. Figured down the road when I inevitably give up on the STS kit (had one on my z28 hated the thing) that I'd go head and cam. So I also have arp head / main bolts reusable stuff this time)

    Heads and valves themselves are stock but I rebuilt with Patriot Gold Dual Springs, Titanium Retainer and keepers (bought as a kit), also of course new stem seals ;

    Cam: New 2003 Ls6 cam, the old one wasn't wiped out, but since I was changing rockers, pushrods, valve springs, bearings figured new cam too.

    Vavletrain Bits: CompCams "R" lifters, CompCams hardened Stock Length Pushrods, Yella Terra 1.7 rockers, Cometec slightly thicker Head Gaskets. (figured a bit less compression is probably a good thing)

    When you say bore I believe you mean hone. The LS1/LS6's didn't have much material in the sleeves to be bored out.
    You have some real good components. The cam is weak but I understand why you are want to keep it. Cams have greatly changed since the LS6 cam came out. I know you can find a better cam that can suit your needs. Several places you can go to. Martin form Tick Performance, AI (Advanced Induction) can work magic on heads and cams. You have a lot of options I'm trying to say.

    Assembly (where and why I'm concerned),
    Quote Originally Posted by albrntout View Post
    1. I didn't put anything under the springs, nor any shims in them. Will these Patriot springs eat into the head, are they going to be correct spring tension just out of the box for a stock z06 cam?

    1a. I haven't, nor know how to check the spring height and tension, assumed as it was sold as a "Complete Kit" from a reputable sponsor site that the parts supplier knew what I was asking for and without my original machinist around I did the work myself. So I'm uncomfortable that this combo is dangerous.
    1) Yes you need to have the cups, locks and retainers for the springs. Otherwise you have incorrect seating and tension which leads to valve float or something more expensive.

    1a) If it was sold as a complete kit then it should be rated for the cam. If in doubt you can always ask the place you got them fr0m again to make sure.

    Quote Originally Posted by albrntout View Post
    2. I used a non stock gasket size, aftermarket rockers, push-rods, lifters. Are my pushrods the right length anymore, how do I know? Has the gasket difference and aftermarket bits made a geometry issue, and how do I check? I did follow the Yella terra instructions but it didn't feel right compared to the other 5 motors I'v rebuilt (again I'v only every used stock parts in my rebuilds previous and had a friend (machinist) around to keep tabs on me); How do I check the pre-load, what about Coil Bind? I did lots of research but all the write ups I find only discuss stock components or giant cams! What is going to be right for this setup. Again thick head gaskets, stock lengths comp pushrods, comp r lifters, a stock z06 cam (same pn that came out of original motor), original stock sodium filled valves in the heads, with Patriot Gold Dual springs, YT 1.7 rockers.
    Chances are you have incorrect pushrod height. Why the different gasket size? Were the heads milled down? If so how much? Also with FI (force induction Turbo or SC) you may need specific type of gasket set to handle the pressure. Not all gaskets are equal. This is something I'd ask a shop that handles FI builds. May have to look around.

    Good news is that in order to check it only requires a $20 tool. Compcams sells a pushrod checker. Look for the one that states "adjustable form 6.8" to 7.8" in 0.050" increments"

    You only need to torque the rockers to 21ftlbs for stock, YT's may be different, the instructions should state how much.

    Checking preload - If they were LS7's or BTR lifters I could tell you. Seeing how these are form CompCam I'd call them and ask. they look to be used with an adjustable rocker.

    Coil bind - if your springs are rated for the cam (you got them in a cam kit) then you should be ok. If you pieced it together without researching what the cam specs needs then you may have issues.

    Quote Originally Posted by albrntout View Post
    3. There were no parts left over out of any of the kit's purchased. But sometimes "Kits" expect you to re-use something from the old valve train setup, and mine being a stock z06 (so I was told anyway) didn't have any shims on-top or bottom(technically these are locators I guess) of the springs to begin with.
    Quote Originally Posted by albrntout View Post
    Figured before I turn this thing on is there a good way to check that my geometry is correct? And should I worry about adding locators shims under the valve springs (They were such a PITA to get on) I haven't put the cooling system back in the car, and could easily pull valve covers and check. I just don't know how to check (install height, pre-load, pushrod length, rocker adjustment). Almost every write up I'v seen just confuses me more as none of the combos match, don't know many people running stock ls6 cam with dual springs, and a slightly oversized gasket.

    Quote Originally Posted by albrntout View Post
    Bit more info:
    I also took the original Z06 yellow springs too the local jr. college and had their tensions checked, they where way out of whack! Not even close, as well one cylinder on driver side head wasn't even the right Z06 springs to begin with they were ISKY's!!

    Motor wiped at about 100,000 miles, lands blown off two pistons (#5, #8), but valve-train wise looked good and had a dual roller timing chain and sts kit installed already. It still ran fairly well just ate oil up, the cyl walls also looked good surprised since lands were cracked.

    Any ideas, or what you would do's? I'm leaning hard on parting this car out as it's just gotten so far out of hand and I'm second guessing myself. I'd assume it's 10-20hrs from completion unless I have to start going backwards due to this.

    You kinda answer your question about how to check the spring tension here. Do the same thing. A good machine shop should be able to do this for you.

    Did you have a shop look at this block before you started rebuilding and adding parts back on?


    If you are that unsure then either seeking a professional to look it over or look for a new block. Short blocks are not as expensive anymore. LS6's are going to be impossible to find and expensive. GM stopped making them and those that have them want a premium for them.

    My shop is doing/charging the following for my block:

    Magnaflux the block and examine:$60
    Hot tank: $50
    Install new new cam bearings: $40 + cost of bearings
    Balance the rotating assembly (crank & pistons) $225
    Build to short block: $250 + crank & rod bearings (est $200 for the one's I want)
    Last edited by SMWS6TA; 07-30-2013 at 09:38 AM.

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    Thanks for taking time to respond. I ended unease yesterday and removed valve covers, and rockers and still couldn't tell if shim was installed. I then took the springs off a cylinder and there was a locator shim at the bottom (hooray! I'm not as incompetent as I thought, was very hard to see black shim with reflection of coils radius); As for block I did have it blueprinted by a good machinist, sadly he passed away while working on this motor. I found him dead in shop, he told me to come on a Friday, but wouldnt answer door or calls and his truck and shop lights were on for a week before we (son and I) broke down the door. He had finished the short block work, but had the heads disassembled on a work bench. He had died the Thursday he called me, the smell, and visual is something ill never forget. I don't really want to pull this un run motor out a third time, for another machinist, since none in my area seem to know ls motors, and finding a trustworthy machinist is well hard to say at the least. The second one I took heads too was a. Over priced, b. lagger, c. Generally incompetent about ls motors. I ended up re-rebuilding heads myself as he didn't even check what I asked him to check. Don't know why felt like shims were forgotten, but I'm sold that I do need to check pushrod length, since the preload seemed funny, its within spec according to the yella terra instructions, but funny is funny. Again first time using their rockers so maybe its correct, but might as well check rod length for piece of mind. The springs are overkill for the cam, no doubt they are stiffer than a stock yellow ls6 spring. I have run sts kits in the past with similar results btw (blown lands) and just don't trust them, even with a quality tuner and tune on the car. At the time figured new springs were necessary and might as well get something for the future when I decided it is time to scrap the sts kit. As for springs and cam as a kit purchase, no those were individual purchases the springs are super similar when considering lift of a stock ls6 cam, again down the road expected to go in .580ish lift so wanted .6 capable springs. Pretty sure I'll get away with that, gonna lose a bit of power for the slightly stiffer spring. It was my thought of added stress that became main point of hardened pushrods, and lifters. Trying to compensate added strength of springs. Gasket difference is pretty small and otherwise valve train is identical dimensions (or so the specs say I'm a believer in checking myself anyway cause boxes/descriptions aren't always right); Hoping the automatic adjustability in hydraulic lifters can make up the gasket difference. But hoping isn't knowing (had to know locator shims were in for example); so I'm gonna take your advice and get a pushrod tool in there ASAP. Still on fence of letting this whole project go elsewhere, it is close to done and has one of those mod lists that never stops. I unfortunately am also close to done (as in iv been given an expiration date by doctors that iv already surpassed.. I'm supposedly dead already); I put finishing proj / driving this car once on my bucket list but its kind of low on totem pole and money would be better placed towards people I'll be leaving behind. Wife and kid keep telling me to keep it as they helped build it and want it around sentimentally. That's a different story all together. Either way it ends up being her and daughters to decide they'd probably get more out of it as parts, financially and as a car it holds value in a family kind of way. Dear lord had visual of my 11yr old driving this thing in 5yrs, lol really should sell it! 16yr old girls in 650hp (conservative guess) cars... Least it has a cage and harness. Again thanks for response, ill check rod length and see. Then its radiator, ac, ic, other front of car stuff (air pump, brackets), watermeth intake plumbing and hood back on away from complete. Well sorta anyway, the re-torque after break in and more tuning I'm sure will be needed as well. Maybe ill still be around, kind of pushing my luck time wise. Just dawned on me there is physically no way I can drive it alone anyhow. Someone will have to shift for me, lol another funny thought.. But old lady has gotten pretty good at turning a wrench and following instructions. Daughter as well knows her way around garage proud of her for an 11yr old girl she gets it quick. So either way we all already got a lot out of this car. Hence does sentimental value, out weigh financial value? Dunno.. There's other bucket list items for me the money could go too. In meantime going to do whatever they want with it, which at the moment is finish the project. If it blows up financial value is lower, but think finishing project means more to them than the potential money. If it runs true so much the better.

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    Spaz is My Mentor SMWS6TA's Avatar
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    good luck

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    Well, the push rods ended up a hair off, less than < .001 aka unmeasurable with the tool I borrowed. Lifters are going to make up that difference, heck it's a surprise they were so close at least imho. It also passed the turn over by hand and watch rocker tips contact the valve stem test. They travel in a nice arc with no off edge, it's well centered at all points in the cam rotation. Think it's ready to be fired, worse case push rods are a hair off pre-load, which gets readjusted after first heat cycle anyway.

    P.S. Why readjusted even if sounds right?? YT rockers specify needing adjustment after first full heat cycle, and states "This is not optional" on an added paper slip to the original instructions lol (wonder if this had been an issue); I am shim-less, and at 22lbs torqued down so we will see. Checking my old purchase invoices turns out the gaskets used were Fel-Pro 1160's couldn't find the comtec at the time they were back ordered, so I switched out to fel-pro. So that's two things I remembered wrong "spring locators, and which head gaskets" Felpro's are listed with a crush of .053, Best I can tell an 03 stock gasket was listed as .054; So compression drop I had in my notes were do to the valve reliefs in Wiseco pistons. I should be @10.3:1 vs 10.5:1 sucks trying to remember what happened 2.5-3 years ago, glad I keep ridiculous notes and all invoices.

    Thanks again.

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