loose rocker arms after fresh rebuild?
08-22-2013, 11:50 AM
#1
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loose rocker arms after fresh rebuild? Started hearing an off beat tick that sounded like someone was tapping a screwdriver on the inside of the valve cover. Havent heard this noise untill yesterday, the engine and trans has about 2k miles on a fresh rebuild. Just thinking logically, with steel arp bolts holding the rockers down to aluminum 5.3 heads, and the expansion/contraction of the new engine break in process... could it be a possibility that they have come loose some? I took the valve cover off of the drivers side head (where the noise was coming from) and nothing was broke. I did notice that 6 of the 8 valves were "loose" and could slide them back and forth, when it should technically be the other way around. I tried searching but could not find a definite answer if this was a possibility... below is a video i uploaded to youtube. Thanks in advance.
08-22-2013, 04:43 PM
#4
You need to do a process of elimination. If the rocker bolts are still tight start taking the rockers off and check the trunnions in your rockers and check to make sure you don't have any bent pushrods. What type of cam, springs, and pushrods are you using? If your rockers and pushrods check good then take a dial indicator and start checking lobeliftat the pushrod tip. If lobe lift is good you probably have some collapsed lifters. "Pushrods may be too long!" You either have the right preload or you don't depending on your lifters .
08-22-2013, 08:20 PM
#7
Your engine builder is an azz if he installed push rods that were too long. That may be your issue. If they are too long, your lifters may be clacking.
Properly torqued fasteners should not come lose. I have about 3500 miles on my new engine and they all looked good after checking 2500 miles later. I marked them for movement indication are they were exact.
Properly torqued fasteners should not come lose. I have about 3500 miles on my new engine and they all looked good after checking 2500 miles later. I marked them for movement indication are they were exact.
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08-22-2013, 11:19 PM
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Yeah, I double checked all the rocker bolts on the drivers side and they were all torqued. I will have to start digging further this weekend. I have 228r cam, comp cam springs and 7.4 pushrods. Thanks for everyone's input, will keep you informed.
08-23-2013, 06:16 AM
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yea if the pushrods were to long it could have beat the hell outta the lifter and they just finally had enough...its weird that it never made noise befor...either way if he told me he did that id be throwing them threw his front window
that's why I never take that kind of stuff to a shop they just don't have the attention to detail to your "baby" to them its a paycheck...plus I have the worst luck finding yahoos lol. good luck keep us updated.
that's why I never take that kind of stuff to a shop they just don't have the attention to detail to your "baby" to them its a paycheck...plus I have the worst luck finding yahoos lol. good luck keep us updated.
08-23-2013, 08:32 AM
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He will get his... im hoping to have to just replace pushrods, lifters, and springs. Could the longer pushrods cause the springs to lose their properties? Such as spring rate?
Last edited by Fast98Z28; 08-23-2013 at 10:01 AM.
08-23-2013, 12:34 PM
#11
what spring are you using and what cam? shorter answer its possible if the cam was close to the max rated lift of the spring and if the pushrods were way too long and bottoming out the lifter...I would think the car would have trouble idling if that were the case though.
08-23-2013, 02:35 PM
#13
assuming those 918s and that 228R is under .600, around .588. You should be good... Do you know if the deck was resurfaced and/or heads milled any? GM MLS gaskets? Those 7.4 should have been close to what you needed if there was no milling involved. Honestly would start the car for 30 secs~1 minute...then shut it down and pull the intake/exhaust rockers off of #1 or #2 cylinder, turn the motor over by hand until your on the heel of the cam/valve fully closed and reinstall PR, rocker. Run it down finger tight to 0 lash, play will suddenly be gone from the rocker. Then torque to 22lbs and count the turns, should be anywhere from 1 turn to 1 1/4, some will say 1 1/2, 1 3/4 turns on LS7 lifters. I personally don't like that much preload. With stock rockers the PR longer/shorter is the only way to adjust preload.
08-23-2013, 03:24 PM
#15
FWIW...With my 228R cam, heads milled .020", GM stock gasket (thick)...I'm using a 7.375" PR.
Depending on thick your head gasket (Assuming thin being a cometic) is and assuming you have not milled the heads...With that info already I would think your pushrods are too long.
Depending on thick your head gasket (Assuming thin being a cometic) is and assuming you have not milled the heads...With that info already I would think your pushrods are too long.
08-23-2013, 03:58 PM
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Im hoping that is all it comes down to. If i do find out my PR's are too long, should i replace the springs also? 5.3 heads would not make a difference in PR length would they? Unless they were milled obviously. I will be working on this tomorrow morning and will find out. I wish i would have known what i know now when the engine was being assembled.
