Just hashing this out with a buddy today actually...
The popular setting seems to be 1/2 turn. But we're starting to feel that it should be 1 turn, or possibly 1-1/2 turns due to the finer pitch on the rocker studs of the 2.8 vs the 350 (etc).
If memory serves, the 1/2 turn on the SBC's got you about .050" of precompression on the lifter. This was supposed to center the piston of the lifter in its bore. Someone care to measure the stud on a 2.8 and see how many turns it'd take to get the same?
I set mine to about 1/2 turn (trying to prevent high revving pump up of the lifter) but now I've got a really noisy valve train. If I get bored this week I think I'll reset 'em to 1 turn.
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01:09 AM
GTDude Member
Posts: 9056 From: Keysville, Virginia, USA Registered: Nov 2001
LOL.......I've been setting mine to 3/4 of a turn for years.......just split the diff! I'm sure you know they must be tightened in the correct sequence.
Phil
------------------ GTDude OVER 25 years GM experience
[This message has been edited by GTDude (edited 08-06-2002).]
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07:13 AM
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
Originally posted by watts: Just hashing this out with a buddy today actually...
The popular setting seems to be 1/2 turn. But we're starting to feel that it should be 1 turn, or possibly 1-1/2 turns due to the finer pitch on the rocker studs of the 2.8 vs the 350 (etc).
If memory serves, the 1/2 turn on the SBC's got you about .050" of precompression on the lifter. This was supposed to center the piston of the lifter in its bore. Someone care to measure the stud on a 2.8 and see how many turns it'd take to get the same?
I set mine to about 1/2 turn (trying to prevent high revving pump up of the lifter) but now I've got a really noisy valve train. If I get bored this week I think I'll reset 'em to 1 turn.
Well, I searched around for the answer also - after doing the 1-1/2 turns, which seemed to be to much. Someone mentionted the best answer - using a feeler gauge and just measure the lifter lash. When I replaced my cam/lifters/rockers I put in the "Magnum Roller Tipped Rockers", lashed with 1/2 turn, and now it sounds like a sewing machine. Lotsa clicking-ticking. Gonna take the covers off soon and give them another 1/2 turn. But, I have heard these roller rockers are just noisy and shouldnt worry about it, but I dont believe that. 1/2 turn doesnt seem to be enough
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08:25 AM
watts Member
Posts: 3256 From: Coaldale, AB, Canada Registered: Aug 2001
Originally posted by watts: "welcome to sewing 101"
I've got the same rockers in mine. Lemme know if going 1 turn kills the "Singer effect"!
you went 1/2 turn also? I've heard the rollers are noisy, but its worrying me. Had them in for a week now. Anyone else with roller tips? are they supposed to be so clickity? They're not as loud tickin as a loose rocker, more like a shicka shicka shicka than a tick tick tick
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03:19 PM
Gary W Member
Posts: 1092 From: Cape Coral, FL Registered: Oct 2001
I installed them as per the instructions that came with them and they are quiet on my engine. You wouldn't know the car has roller rocker arms unless you pull a valve cover. The only time I've been able to hear the rockers is if I put a mechanics stethoscope to a valve cover - then you can hear a chatter.
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08:45 AM
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
Originally posted by lateFormula: I also have Magnum's (1.52:1 ratio).
I installed them as per the instructions that came with them and they are quiet on my engine. You wouldn't know the car has roller rocker arms unless you pull a valve cover. The only time I've been able to hear the rockers is if I put a mechanics stethoscope to a valve cover - then you can hear a chatter.
that settles it for me - I'm pulling the valve covers and giving my rocker adjusters another 1/2 turn
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10:09 AM
Synthesis Member
Posts: 12207 From: Jordan, MN Registered: Feb 2002
I have Sealed Power hydraulics, and went 3/4 of a turn, and you can hear the lifters as they leave the cam and then reimpact the cam after the lobe... I pulled one bank and went back to a turn and a half before they finally quieted down... I suspect with the finer thread pitch, a turn and a half might be a hair too much, but is closer to proper setting than 1/2 or even 3/4 of a turn.. Now, to pull the other bank and retighten em.
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11:41 AM
Aug 8th, 2002
Pyrthian Member
Posts: 29569 From: Detroit, MI Registered: Jul 2002
Originally posted by Pyrthian: that settles it for me - I'm pulling the valve covers and giving my rocker adjusters another 1/2 turn
took a stethescope, and took a fine listen. 1-3-5 was perfectly normal, 2-4-6 was noisy, exspecially #4. Took off the valve cover (without removeing any plenum - what ***** ). gave #4 exhaust 1/4 turn. laid cover on - started it - still a noisy. anyways, did this back & forth for a bit turn out #2 intake +1/2 turn, #2 ex +1/4 turn, #4 intake +1/2 turn, #4 ex. +3/4, #6 ex. +1/4 turn. kinda puzzles me that 1-3-5 was pefectly fine, and 2-4-6 needed all that tweakin' (espcailly #4) - anyways - no sewing machine sound no more.
