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I never noticed this on my LS2 before. Today I started up the car to take it for a drive, when I got out of the idling car to close the shop door, I heard a light clacking sound. Not just the normal LS sewing machine sound, it sounded kind of like hydraulic lifters that had been sitting for a long time and needed to pump up to take up the valve train slack. My old Chevy small block sounds like this sometimes when it has sat for a long time. And like the Chevelle, after a minute or so of idling the sound went away. Car drove and ran just great the rest of the day. Never heard this sound again even though I stopped and restarted it numerous times throughout the day. It was NOT a rod knock, I know what that sounds like. But the sound was loud enough to barely notice from inside the interior of the car and more noticeable outside the car. Oil pressure at the time and throughout the day was just fine.

If stock LS2 lifters can bleed down over time, one contributing factor of "why now when it never did it before" may be that this past Spring I installed 1.8 ratio rockers with new valve springs that are about twice as stiff as stock springs. Point being, these new springs are stronger and press more heavily on the lifters all the time it is sitting, especially on those that are holding valves open.
 

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OEM LS lifters can only take so much added spring pressure. You might want to think of upgrading.

Depending on how long it was sitting, but i've never had this happen before. My springs are 400 psi open, i think. Normally they should pump up as soon as each lifter gets oil pressure and goes through a valve cycle.

If they were totally dry, maybe it will take a while. Still shouldn't take a very long time.

They might just be worn to the point where the bleed down rate is too high.
 

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I recall that when I was opening it up to do the rocker upgrade, all the valves were closed (it had been sitting over the Winter at that point). I thought that was odd. But it always starts right up at the touch of the key and runs just fine. Not sure how that works out, how they pump up so quick. But today, the clacking only lasted maybe 30 seconds. On my old SB Chevy, it can sometimes take 3-4 minutes to quiet down, like starting it the first time after it sat over the Winter. But it doesn't do it every year so maybe it also has something to do with just exactly what the orientation of engine parts were when it stopped.

Anyway, I'll pay close attention for these sounds at the next few start ups. If it comes back or becomes more consistent I'll have to consider upgrading the lifters. Ugh. That would really begin to make the 1.8 rocker upgrade look less and less like a good idea. But they did give the engine noticeably more "edge" in throttle response, especially beginning at the midrange and above.
 

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There is a point in the crank cycle where all the valves will either be closed or in a very low lift position.

If the lifters bleed down all the way, depending on your current preload, they can lose a pretty substantial anount of lift. Like .100-.150 or so. The 1.8 rockers will make that number a little higher.

As soon as the lifters get oil pressure, they should start to fill up. That's what that check ball in them is for. As long as the bleed down rate isn't to high, you should be golden.

What type of oil do you run?
 

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Discussion Starter #5

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Overall the engine only has 46k on it, I can't imagine the lifters are worn to the point of not working right. Might be to do with the higher rate springs. Might have just been an anomaly too. I should also check the header bolts, I may have been confusing an exhaust leak tick for lifter noise. Exhaust leaks at the head can sound like all kinds of things. I'll check the header collector bolts too, I recall them being a bugger to get snugged down evenly for some reason that escapes me now.
 

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Im at 49k and I have switched to 10w40 and I live in so california but my results are good mobil1
 

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I’ve had exhaust leaks develop that fooled me into thinking I had a lifter problem.

it’s either been leak at the exhaust manifolds Near the heads and/or between headers and mids.
 

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yeah, always used the GM MLS header gaskets and i don't remember having an issue.

i've had exhaust leaks on other cars that made me think i had rod knock, lol.
 

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Discussion Starter #11
I used GM gaskets but it never hurts to check the header bolts a few times after install. I've checked them once, wouldn't hurt to check them again.
 

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Yes my name is Holden
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Good Morning Rich, Not hubert & all; I'm still here following you youngin's blazing this Ls trail, as I get closer to dis-assembly? Back in 2013 I was helping a good buddy work on his Ls-6, during a re-fresh of my upper end on The Bronze Brick. I got to receive a oil lesson from Rick Sparks (VP of the Comp Cams Conglomerate). This is no sh_t he called back twice & I had called them-him twice & tech guy twice. Total 6 calls & 4 hours And I'll mention why we hit it off so well. He was only 10 yrs younger than me, we both had L-78's. Do I need to say more? I'll try to condense this? Much of the conversation revolved around Pounds Per Square Inch - LOAD! So we got to ask yourselves where do we exceed the design parameters of Ls-2 lifters & the oiling recommendation - system from GM? When GM spec-ed M1 oil it had a bunch more ZDDP, gone in 2007. So now us Hot Rod Types come along & up the spring pressure, increase the speed the valve opens, maybe faster ramps. All leading to more wear (good god I know about this). To top this lesson off was the first lesson I learned on day one at Pershke Engineering, 1972. What does oil do? Answer, carries heat away! So can't be too thick, but High Perf engines had Lots of clearance back then, fresh & new. So can't be too thin, can you say counter-diction? Anyway once we increase the loads & increase the RPM we have to address these issues, more volume faster flow with some additional Old Load carrying ZDDP. I switched to Driven by Gibbs, Ls30 & I'm still stock. And I just spoke with Sparks again a few weeks ago (he didn't remember me right away), The Comp Corp has purchased the Driver oil Co.
Oh on a another note, I found - decided where to take my heads. Right here in Good Ole' Wisconsin, Wegner's & they have a 5 axis machine center & have Mooco experience on Ls stuff. Later Ole' Bob.
 

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Discussion Starter #13
Having high levels ZDDP shouldn't be all that important for a roller cam engine and high levels of ZDDP are bad for catalytic converters (another reason catted engines are typically roller engines). I use high ZDDP oils in my old flat tappet engines to help keep them happy. In a modern engine, just a touch of ZDDP components is typically adequate. Synthetics are best for these tight clearance engines as it begins to flow immediately at almost any temperature.
 

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Yes my name is Holden
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Hi Rich & all; High ZDDP is relative of course & my brain don't remember the parts per million that higher loads require. Rolling motion vs sliding motion means little. It was explained to me, It's Pounds Per Square Inch & the ZDDP amount needed to carry that load over time. It's hard to explain the detail that Mr Sparks went into about oil & Loading. And OX sensors are expendable & easily replaced compared to cams & lifters!
also think about push rod cups-tips, piston skirts, Lifter inner workings & rollers, Oh don't forget cam bearings not to mention rod & main bearings. I wore out a lot of cam bearings. Think Load my friends.
I'll come back to it later, but as I get ready to do my Re-Fresh this fall the OE oil pump has been asking me to do an for early retirement, wants a buy out & bench job. Bugging me as I try to go to sleep, Ole' Bob.
Ps: Rich call me after supper tonight if ya get time?
 

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Hi Rich & all; High ZDDP is relative of course & my brain don't remember the parts per million that higher loads require. Rolling motion vs sliding motion means little. It was explained to me, It's Pounds Per Square Inch & the ZDDP amount needed to carry that load over time. It's hard to explain the detail that Mr Sparks went into about oil & Loading. And OX sensors are expendable & easily replaced compared to cams & lifters!
also think about push rod cups-tips, piston skirts, Lifter inner workings & rollers, Oh don't forget cam bearings not to mention rod & main bearings. I wore out a lot of cam bearings. Think Load my friends.
I'll come back to it later, but as I get ready to do my Re-Fresh this fall the OE oil pump has been asking me to do an for early retirement, wants a buy out & bench job. Bugging me as I try to go to sleep, Ole' Bob.
Ps: Rich call me after supper tonight if ya get time?
I run mobil 1 0w40 fs for this reason. It has elevated zddp levels, but not race oil high.

I actually use it in both GTO's and sometimes my beater truck.

The way i see it, roller lifters or not, there is always the possiblity for the oil film to get sheared away somewhere under load and for there to be momentary metal on metal wear, which is what the zddp is for. Besides, being a 0w40 oil, at temp the viscosity of the oil is more than most xw30's. So a bit more protection there as well.
 

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GM recommended Mobil 0W40 in the C8, although I think it's a different blend than the European formula preferred on this forum (and what I use). Hmmmm, maybe these LS engines did need a thicker oil at operating temperature.
 

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Discussion Starter #17
Tonight I checked the headers, no loose bolts.

I started it up, no noises that shouldn't be there. Headers sound so nice.

I'll have to look into heavier oils.
 

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Yes my name is Holden
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NO,NO guys don't use heaver oil! It won't flow fast enough to carry the heat away, Ls OE oiling system. Lindenfelter (2004) recommended 15-50 M1 for my buddy's Ls-6 (2003) & his #1 exhaust roller got TOo hot & started (22,000 Mi) trying to welding it's self to the cam! That's how I meet Mr.Sparks from Comp. Do the 0-40 M1 or Driven Ls -30 or a 5-40 if some one has it available. Or 5-30 with a bit of extra ZDDP. Now if ya open up the bearing clearances (percission build) & install a High volume pump I'll be on the band wagon for heaver viscosity. Believe me I'm a Mobil 1* fan as I've been using it since 87, but I don't want it in an engine I'm going to be Hammerin' on (use above 6000). I too don't like the OE oil pressure 40-45 in my Ls-2. So I asked the tech guy at Gibbs oil about mixing weights telling him I want a 7-40 & before I tell him I been mixing for years, he says just mix the various weights to achieve what ya want. So now you guys know I'm crazzy! I've got a mixture of one Qt of M1 * Extended (5-30), 3 Qts Driven of Ls-30, one Qt of Driven HR-4 (10-30) & one Qt of Driven HR-3 or a Qt of Vr-1 (15-50). I end up with 7.5- 33.3 & it's $70! I like Not Mr hubert & others idea of 0-40 M1 with higher levels of ZDDP. The Driven also has a additive that some other oils skimp on, a film a hears during long storage.
Rich I'm So glad to your uncommon noise has departed. Internal lifter wear would make some sense.
Take care guys,Ole' Bob.
 

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No offense, but yeah i do think you're crazy. Just find one oil that has the properties you want. There's tons of info on the internet about almost every oil, on bitog and 540rat and elsewhere. You're mixing more than just weights. You're mixing additive packages and that may not be a good idea.
 

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Can’t contribute to the oil debate but next time you start after sitting for some time prime the engine by holding down the pedal to the metal. I usually let it spin over a few times, 5-10 secs, then let it start. No dry start that way
 
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