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Best valve springs?

Discussion in 'Engine & Drivetrain' started by Geotrash, Sep 28, 2020.

  1. Geotrash

    Geotrash Supporting Member

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    I'm in the fortunate position of having both of our Denali's here in Richmond, VA for a few months (normally we leave one in Colorado for when we're there every month, but with COVID we're not flying back and forth). So I'm going to take this opportunity to do some heavy-ish maintenance work to both of them since we only need one in service at any given time right now.

    One of the things I'm considering is putting in new valve springs on both, understanding that it's a weak spot on these engines. I seem to remember a thread somewhere where someone recommended a specific (non-GM) brand of valve springs that are bullet-proof, but try as I might, I can't find it. Anyone know or have a good recommendation for them?

    Denali #1 is a 2007 with the L92 and 208K miles (no AFM)
    Denali #2 is a 2012 with the L94 and 117K miles, and an AFM disabler.

    I'm also open to other ideas for things I should probably do, since both are used for cross-country drives and towing sometimes, and I like keeping my stuff tiptop. No other signs of impending trouble at the moment, thankfully, except as noted below.

    Some things I've done already:
    • H3 motor mounts on the '07
    • Gruvenparts billet heater core tee mod on both
    • All new belts and hoses on both, including new bearings on all idler pulleys.
    • New OEM fuel pump on the '07 due to high fuel pressure and related codes. Solved.
    • New alternator on the '07
    • All new fluids on both (engine oil, trans, diffs, TC, brakes and PS)
    • All new front suspension on the '07 with all Moog parts. Drives like new again.
    • Planning to replace the rear autoride shocks and airbags on the '12 with OEM. One of them is leaking fluid. Pump seems to be working fine, no air leaks noted.
    • Considering a new cam phaser assembly on the '07, given the mileage. Thoughts?
    I'm reasonably handy and comfortable doing even heavy maintenance work. I've successfully rebuilt a ZF automatic transmission from a BMW 740iL on the bench in my workshop, have done timing chain work on the same car, cylinder head work on an Acura Legend, driveline work on Land Rovers, etc.

    Thanks for your consideration, guys!

    Cheers,
    Dave
     
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  2. Chert_Detective

    Chert_Detective Supporting Member

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    I haven't heard much about valve springs failing, not saying it hasn't happened though. What is common however on those two engines are lifters. The AFM lifters as I'm sure you're already aware are notorious for failures. The 2012 will no doubt have them. The 07/08 L92s depending on when the engine was built will have them as well, but the AFM feature itself is not active.

    Check the valley cover of your 07, if it is the same as your 12 then it too has the AFM lifters. @swathdiver can double check me on that as I'm not 100% sure if they still put the AFM valley cover on the 07s. I know on my 08 it had conventional lifters and valley cover as 08s did not even have the AFM hardware like 07s.


    Full circle.. lol. Be more concerned with lifters than valvesprings.
     
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  3. wjburken

    wjburken Supporting Member

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    ‘07 Denali’s did not have the VLOM valley cover.

    I had two valve springs fail on my ‘07. Got lucky and no damage to motor.

    Had two lifters have their rollers lock up and take out the cam. 1st one resulted in a crate motor. The 2nd just a new cam and lifters.
     
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  4. Chert_Detective

    Chert_Detective Supporting Member

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    That's wild. How many miles were on it when you had the spring failure? Just a lifetime of regular driving?
     
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  5. wjburken

    wjburken Supporting Member

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    At about 120K and 135K.

    Bought it off my employer at 100K knowing it was well maintained.
     
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  6. swathdiver

    swathdiver Full Access Member

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    The very earliest L92s, those manufactured in or before April of 2005 have the AFM hardware but it was not active in the tune. The first L92s went on sale in the Yukon Denalis in December 2005 (MY2007) and the Escalades followed suit in January 2006. This was limited to just a few hundred units and we've seen just a few on here and over at Performance Trucks.

    As for valve springs, every year we get 2-3 people coming on here with 6.2s with a broken valve spring, usually on cylinder #8 but not exclusively and these are usually 2007-2008 Denalis though other years have also been represented. One wonders if this is due to metal fatigue due to age? We rarely hear of this issue with the 5.3s, their camshafts have less lift by about .018 to .037 inches.
     
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  7. iamdub

    iamdub Full Access Member

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    I can't suggest any particular valve spring other than new OEM ones. Which, I wouldn't be surprised if they all come with the "LS6/LS3" spring as standard equipment.

    Don't forget new valve seals while your're at it.
     
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  8. Mechanic421

    Mechanic421 06 Denali XL

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    Vinci performance
     
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  9. Geotrash

    Geotrash Supporting Member

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    Thanks for the replies, all.

    James, I'm relieved to know it doesn't seem that frequent in your considerable experience here.

    Chris, I believe you're correct. That said, GM just released a bulletin for newer Corvettes to fix an issue of breaking valve springs from engines manufactured this year, and valve springs seem to be more of an issue with 2015-2020 6.2s in general as well. I'm concerned that there could be a problem with valve springs manufactured by GM's suppliers in the last several years, but especially in the last several months, hence the desire to buy a different brand, as long as its reputation is sound. Could be a total waste of time, but it's an irrational peace of mind thing.

    David, I'll check out Vinci. Thanks for the tip.

    Best,
    Dave
     
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  10. Geotrash

    Geotrash Supporting Member

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    Checked out their site. Makes me want to install a new cam in the 2012 for a proper DoD delete, complete with new lifters, pushrods, springs, rockers, timing chain/sprockets and seals.
     
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