4.8 LS with bad lifter ... HELP!!

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Dec 12, 2010 | 02:40 PM

ronniet

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4.8 LS with bad lifter ... HELP!!

I will only buy gm vans as the extended 1ton is king. Recently I was able to get a 6.0. What an awesome truck. It has 220k on it and runs like a champ. SOOO, bought an 05 with 180 on a 4.8. Runs like a softer version of the 6.0

I recently heard a loud tick upon start up. 10 seconds and it went away. I drove the truck for days without issue. On day I cam home for an hour. upon refire, tick tock, its back and wont leave. I tried to run a Q of desil in it so a few to no avail. Popped the v cover to find a mere 1/4" valve lash...lol

I hear I have to pull the head to get at it. At this point, would I not just pull them both, go thru them and replace ALL the lifters?? Anybody had this happen??

Thanks for the help.

Ronnie

Dec 12, 2010 | 11:57 PM

Damian

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#1- You don't check "lash" on a stock valvetrain in these engines like you do an older 350. Once they're set to zero lash (no rocker wiggle), they're to be TQ'd to 22 ft lbs while the lifter is on the base circle of the camshaft.

#2-What does your oil pressure look like? A good sign of a failing lifter(s) is fluctuating oil pressure.

#3-Yes, the cylinder heads have to be removed to replace lifters.

Dec 13, 2010 | 01:17 AM

BennyB

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replace them all man

Dec 13, 2010 | 09:19 AM

ronniet

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I'm figuring pull both heads, go thru em (complete w bowl job) and do all lifters. If 1 is bad, how far gone are the rest!!?

Any other cool basic mods that can be made to these ls motors??

Dec 13, 2010 | 09:36 AM

Damian

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If the lifters failed, be sure to peak down and look at your camshaft. Spin the motor over by hand and make sure the lobes are in good shape.

Dec 13, 2010 | 07:58 PM

ronniet

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dont get me started!! lol... mild cam, bowl job..... maybe It can rumble like my stock 6.0! We love that van! She kinda cams a tad. Complete with that tinny rumble by the motor at idle..