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Old 10-20-2011, 09:43:23 AM   #1
woody80z28
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tick/rattle from engine under load

The 357 I just built has a tick/rattle that you can hear under load and I can't figure it out. The best way I can think to describe it is "diesel-like" in sound. At idle and past about 2500rpm you can't hear it.

It's not spark knock, I've checked the knock sensor with a hammer and it works, and pulling timing didn't help.

I thought maybe it was from the small weld pinhole in my fabbed exhaust (which is the only leak I could find) and fixed that last night with no change in sound.

Oil pressure & level is good. 80psi cold and about 40 warm at idle according to the stock gauge.

Could it be a lifter or something mechanical? The engine has less than 150 miles on it so far. I converted the engine to an OE-roller setup and adjusted the lash a half turn past the pushrod spinning by hand (same as I have done with my other SBC).

It runs well, but just doesn't sound normal.
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11:1 forged 383 w/ AFR 195s, .575/.584 roller, 1000cfm Holley HP EFI, T56 6spd w/ SPEC 3+ clutch, Moser 8.5" w/ 4.10s, 12"f/11.6"r disc brakes w/ line lock, Hotchkis springs & sways w/ PTFB stopflex, 18s w/ 255/295 Nittos, Slide-A-Links w/ 275 Mickeys, elec fan & water pump w/ battery in trunk, 4th-gen interior w/ custom gauges
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Old 10-20-2011, 09:19:54 PM   #2
Pfrederiksen
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XE cam?

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Old 10-20-2011, 09:24:26 PM   #3
woody80z28
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Nope. Stock LT1 F-body cam.
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11:1 forged 383 w/ AFR 195s, .575/.584 roller, 1000cfm Holley HP EFI, T56 6spd w/ SPEC 3+ clutch, Moser 8.5" w/ 4.10s, 12"f/11.6"r disc brakes w/ line lock, Hotchkis springs & sways w/ PTFB stopflex, 18s w/ 255/295 Nittos, Slide-A-Links w/ 275 Mickeys, elec fan & water pump w/ battery in trunk, 4th-gen interior w/ custom gauges
My Chevy garage GEARHEAD dezign
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Old 10-21-2011, 12:40:37 AM   #4
woody80z28
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Uh oh.

Decided to check my valve lash and I could spin the pushrods by hand. So I tightened them until they stopped spinning (maybe 1/8 turn) and gave them a half turn of preload. Went back through to double check and they all could spin by hand again. So I gave them another half turn. Went to start the engine and it wouldn't fire.

So I backed them all off and adjusted them opposite of the open valve like I always do and must have missed one in a hurry. Sounded like the engine ran on 7. So I went through and did them all one by one adjusting them just a little after valve closing.

Now it sounds like I have one distinct lifter tick. Did I collapse a lifter running it with too much preload?

And - the original sound is still there.
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11:1 forged 383 w/ AFR 195s, .575/.584 roller, 1000cfm Holley HP EFI, T56 6spd w/ SPEC 3+ clutch, Moser 8.5" w/ 4.10s, 12"f/11.6"r disc brakes w/ line lock, Hotchkis springs & sways w/ PTFB stopflex, 18s w/ 255/295 Nittos, Slide-A-Links w/ 275 Mickeys, elec fan & water pump w/ battery in trunk, 4th-gen interior w/ custom gauges
My Chevy garage GEARHEAD dezign
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Old 10-21-2011, 09:26:50 AM   #5
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Adjust them with the motor warmed and running.

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Old 10-21-2011, 01:17:31 PM   #6
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I hope you fix your problem with some simple upper valve train tuning.

But I always remember a friend's 400 T/A that started running a little weak and made a tapping/clackety sound when he got on it....his turned out to be a broken cam lobe. Hope yours is simpler, but I thought I'd share it.
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Old 10-21-2011, 04:09:32 PM   #7
woody80z28
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The lifters were used out of a salvage L31 Vortec engine. Maybe I'll just pull the intake and drop in a brand new set to rule it out.
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80Z build thread
11:1 forged 383 w/ AFR 195s, .575/.584 roller, 1000cfm Holley HP EFI, T56 6spd w/ SPEC 3+ clutch, Moser 8.5" w/ 4.10s, 12"f/11.6"r disc brakes w/ line lock, Hotchkis springs & sways w/ PTFB stopflex, 18s w/ 255/295 Nittos, Slide-A-Links w/ 275 Mickeys, elec fan & water pump w/ battery in trunk, 4th-gen interior w/ custom gauges
My Chevy garage GEARHEAD dezign
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Old 10-26-2011, 11:05:29 AM   #8
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Can a collapsed and/or otherwise noisy lifter straighten itself out? The distinct lifter tick I was hearing has gone away and the engine is running great. I bought lifters, but I'm wondering if I really need to swap them in.
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80Z build thread
11:1 forged 383 w/ AFR 195s, .575/.584 roller, 1000cfm Holley HP EFI, T56 6spd w/ SPEC 3+ clutch, Moser 8.5" w/ 4.10s, 12"f/11.6"r disc brakes w/ line lock, Hotchkis springs & sways w/ PTFB stopflex, 18s w/ 255/295 Nittos, Slide-A-Links w/ 275 Mickeys, elec fan & water pump w/ battery in trunk, 4th-gen interior w/ custom gauges
My Chevy garage GEARHEAD dezign
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Old 10-26-2011, 02:03:08 PM   #9
middleagecrisis
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If the motor is running good, I'd chalk it off to the lifters being out of adjustment and run it as-is.
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Old 10-26-2011, 02:12:28 PM   #10
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This is outta left field maybe, but I've heard it in alot of mid-90s and newer 350/LT1/LS engines with a stock bottom end... are you maybe hearing some piston slap? Does it change with temperature? I've heard a few stock, untouched LS1 engines that had some wicked piston slap when cold, that would mostly (but not entirely) go away when warmed up. GM called it normal, and I've never heard of any problems that came from it. My '97 LT1 did it a very little bit too when cold (usually up to around the temp the guage would start to read), and it never caused me any problems either. It fits the 'diesel-like sound' description.. especially the LS engines lol.

What bottom end is in your motor?
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Old 10-26-2011, 03:00:42 PM   #11
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sounds like a bad lifter. I have definitely gotten the odd used, bad OEM roller lifter. They don't last forever. My lt1 cammed oem roller motor is totally silent running, you should not have tapping.
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Old 10-26-2011, 10:30:57 PM   #12
woody80z28
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I didnt think it was the difference in FT/roller lifters I was hearing, because my Beretta is full roller and quiet as well.

The engine has stock crank & rods with new hyper pistons. Hot/cold doesnt make a difference.

I'm just gonna drop my new LS7 lifters in and be done with it.
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80Z build thread
11:1 forged 383 w/ AFR 195s, .575/.584 roller, 1000cfm Holley HP EFI, T56 6spd w/ SPEC 3+ clutch, Moser 8.5" w/ 4.10s, 12"f/11.6"r disc brakes w/ line lock, Hotchkis springs & sways w/ PTFB stopflex, 18s w/ 255/295 Nittos, Slide-A-Links w/ 275 Mickeys, elec fan & water pump w/ battery in trunk, 4th-gen interior w/ custom gauges
My Chevy garage GEARHEAD dezign
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Old 10-27-2011, 11:12:37 PM   #13
gingerbreadman
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what method or formula are you using when adjusting your rockers ? are you waiting for exhaust to start rocking then adjust intake or are you doing them one cylinder at a time with a formula. reason i ask is there a chance you are messing one or more up?
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Old 10-28-2011, 12:36:17 AM   #14
BondoSpecial
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EOIC method and a half turn on those and they should be the quietest valve train ever
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Old 10-28-2011, 12:20:18 PM   #15
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Quote:
Originally Posted by Air_Adam
This is outta left field maybe, but I've heard it in alot of mid-90s and newer 350/LT1/LS engines with a stock bottom end... are you maybe hearing some piston slap? Does it change with temperature? I've heard a few stock, untouched LS1 engines that had some wicked piston slap when cold, that would mostly (but not entirely) go away when warmed up. GM called it normal, and I've never heard of any problems that came from it. My '97 LT1 did it a very little bit too when cold (usually up to around the temp the guage would start to read), and it never caused me any problems either. It fits the 'diesel-like sound' description.. especially the LS engines lol.

What bottom end is in your motor?
My 2000 model chevy truck with a 5.3 sounds like a coffee can full of marbles at first cold start of the day. Piston slap is a understatement.
My old 6.0L gmc did too, just not as bad. For the record, my 5.3 has well over 200k and aside from cold start noise is the best engine I have ever had.
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