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Rocker Arm Problem |
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Javelin360 
AMC Nut 
Joined: May/23/2011 Location: Nevada Status: Offline Points: 304 |
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 Posted: Oct/03/2018 at 6:09pm |
60 on start up as engine warms up it drops to 40 at idle.
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69 AMX 401/727
74 Javelin 360/727 09 Mustang Supercharged 4.6 14 Wrangler Sport 4X4 18 GMC Sierra |
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Javelin360
AMC Nut
Joined: May/23/2011 Location: Nevada Status: Offline Points: 304 |
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Posted: Oct/06/2018 at 2:15pm |
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I spent a bit of time this morning determining the differences between the rocker arms and taking some measurements.
The lifter rods are 7.8 inches long. The valve spring height is 1.8 inches. I know the push rods are the correct length. Can anyone verify that 1.8 inches is the correct height? Pictures of the rockers up close. The area that appears to be a shadow is the older rocker arm. It is considerably lower than the newer rocker.   |
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69 AMX 401/727
74 Javelin 360/727 09 Mustang Supercharged 4.6 14 Wrangler Sport 4X4 18 GMC Sierra |
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304-dude
AMC Addicted
Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082 |
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Posted: Oct/06/2018 at 2:29pm |
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Donna, but the old rocker arm seems a bit more taller on the sides (wall height) at the push rod half, up to the stud. Maybe having some reason as to your issues. Like explained in an earlier reply, not all stampings are perfect.
Actually the sides are not taller... After looking harder, the depth of the push rod end is a wee deeper, thus the taller wall height. If what I see is right, that would explain why the new rocker has some looser fitment again the push rod. Edited by 304-dude - Oct/06/2018 at 2:32pm |
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71 Javelin SST body
390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker |
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Javelin360
AMC Nut
Joined: May/23/2011 Location: Nevada Status: Offline Points: 304 |
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Posted: Oct/06/2018 at 2:37pm |
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Yes there is a definite difference in the rockers. What I'm not sure of is if the problem is because the new rockers are incorrect or if the valves and the old rockers are the problem. I have ordered 4 sets of Melling rockers that should be here by the 15th. If they are also loose I'm guessing that the problem is the valves and old rockers.
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69 AMX 401/727
74 Javelin 360/727 09 Mustang Supercharged 4.6 14 Wrangler Sport 4X4 18 GMC Sierra |
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Boris Badanov
AMC Addicted
Joined: Dec/14/2013 Location: NH USA Status: Offline Points: 4209 |
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Posted: Oct/06/2018 at 2:47pm |
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In my AMC experience stock rockers are excellent. Aftermarket rockers SUCK. If you can not find a set of NOS rockers it is best you convert to aftermarket rollers rather than mess with the aftermarket stamped steel junk.
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Gremlin Dreams
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Javelin360
AMC Nut
Joined: May/23/2011 Location: Nevada Status: Offline Points: 304 |
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Posted: Oct/12/2018 at 9:57pm |
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Looks as if it is going to be a valve/Rocker problem. I received some OEM rockers today and installed them. The looseness is still present.
 As it is now I've got enough OEM rockers to replace them all and get some longer push rods. I've got a buddy coming over tomorrow to help me determine the length I will need.
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69 AMX 401/727
74 Javelin 360/727 09 Mustang Supercharged 4.6 14 Wrangler Sport 4X4 18 GMC Sierra |
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Javelin360
AMC Nut
Joined: May/23/2011 Location: Nevada Status: Offline Points: 304 |
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Posted: Oct/13/2018 at 5:28pm |
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Looks to be that there is about .040 difference between the height of the ball socket areas of the old and new rockers. Ordered some push-rods that are 7.900 inches. If that isn't quite enough I can remove another .025 from the bottom of the pivots on my surface grinder. Hopefully this gets things up and running decently. Some time in the future I'm going to have to yank these heads and get them reworked.
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69 AMX 401/727
74 Javelin 360/727 09 Mustang Supercharged 4.6 14 Wrangler Sport 4X4 18 GMC Sierra |
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Javelin360
AMC Nut
Joined: May/23/2011 Location: Nevada Status: Offline Points: 304 |
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Posted: Oct/27/2018 at 5:19pm |
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Spent two hours today with a hot rod buddy dinking with this motor. He feels the the valve train is functioning correctly and there is something else wrong. Looks as if I'm pulling this motor after I attend the SNAMC show next week and start tearing it down with him to figure out what is wrong. The upside is I will know what has been done internally after we are finished.
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69 AMX 401/727
74 Javelin 360/727 09 Mustang Supercharged 4.6 14 Wrangler Sport 4X4 18 GMC Sierra |
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Boris Badanov wrote: