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Too much play in the rockers?

Old Aug 29, 2018 | 11:23 PM
  #1  
linksvu's Avatar
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From: Littleton
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0l
Default Too much play in the rockers?

I am replacing a blown head gasket on my '98 4.0l and was hand-testing the rockers... how much is too much play? almost half of them would shift very slightly from side-to-side, but none of them would move up and down. Most of the push rods would spin freely too.

I'm just not familiar enough to know if they should be solid as a rock or if a little side movement is normal/acceptable.

What are your thoughts on how much movement good rockers should have?

(I tried to upload a short video of them but the site wouldn't let me.)
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Old Aug 30, 2018 | 06:38 PM
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Any thoughts on how much play is normal on these rocker arms?
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Old Aug 30, 2018 | 06:43 PM
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Garrett S.'s Avatar
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Year: 1996
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That sounds normal to me. I have had many engines apart and the rockers that are not currently under load always wiggle a little.
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Old Aug 30, 2018 | 06:48 PM
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From: Calgary, AB
Year: 1998
Model: Grand Cherokee (ZJ)
Engine: 5.2
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Originally Posted by linksvu
I am replacing a blown head gasket on my '98 4.0l and was hand-testing the rockers... how much is too much play? almost half of them would shift very slightly from side-to-side, but none of them would move up and down. Most of the push rods would spin freely too.

I'm just not familiar enough to know if they should be solid as a rock or if a little side movement is normal/acceptable.

What are your thoughts on how much movement good rockers should have?

(I tried to upload a short video of them but the site wouldn't let me.)
Rockers have a torque spec. I think its like 21ft/lbs
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Old Sep 1, 2018 | 04:09 AM
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From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
Model: Grand Cherokee (WJ)
Engine: 4.0L
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Any valve that's on a cam lobe that's off it's base circle should be tight enough so that you can't move the rocker...unless the lifter has bled down. You're talking about side-to-side movement, right? It should be about 1/2 of them if the engine was recently shut down.
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Old Sep 3, 2018 | 10:28 PM
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Originally Posted by dave1123
Any valve that's on a cam lobe that's off it's base circle should be tight enough so that you can't move the rocker...unless the lifter has bled down. You're talking about side-to-side movement, right? It should be about 1/2 of them if the engine was recently shut down.
Correct; the movement was side-to-side and it had been shut down for some time. What I'm reading in these replies is this play sounds normal. Which is good. I was hoping not to replace the rockers since I may be re-rings in the cylinders... saving some costs since the head was not replaced but machined and cleaned.
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Old Sep 4, 2018 | 04:32 AM
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From: Manlius, east of Syracuse, NY
Year: 2000 XJ Sport & WJ Laredo
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When you bolt down the pivots during reassembly, It's best to do them on closed valves, one cylinder at a time. If you crank them down compressing the valve spring, they tend to go offcenter so when it fires up, the rockers won't be centered on the valve stems.
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Old Sep 4, 2018 | 06:40 AM
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From: syracuse ny
Year: 1997
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Engine: 4.0, new lifters valve job with new springs and exhaust valves, preload set with shims
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If you are doing the head gasket you would be crazy not to replace the lifters at the same time. I guarantee they are shot as you will see.
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