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Pivot's stuck to bridges? "wear" mark on push rods
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
Hi, had to pull the head on my 87 to remove a broken header stud (back one, snapped off at an angle 1/4" IN the head by one of the previous owners) and now that I'm putting it back together I'm noticing a few things I'm not sure about.
I'm putting my rockers back on and I'm noticing the pivots are stuck to the bridges on all of the rockers but one (bent bridge on the one that isn't stuck on). Is this an issue? I'm trying not to replace the pushrods/lifters/rockers etc as there didn't appear to be anything wrong with them before I had to take the head off.
I've also noticed a small mark on all the push rods about 1.5" from the "top" that goes all the way around each of them, is this also normal? None of them are bent, none of the oil tubes were clogged, valve train wasn't especially noisy before i took the top part of the motor off.
I didn't pull the lifters and there was some crud down there but nothing I'd call alarming and I was able to get most of it with the shop vac. Head was in decent condition according to the machine shop that planed it for me and no cracks or worry spots, valve train checked out ok too.
This isn't my first tear down and rebuild but it is my first 4.0 so I'm not sure what's "Normal".
This was supposed to be a quick header gasket replacement but it's gone FAR beyond that at this point.
Last edited by eagle11401; Sep 14, 2015 at 09:58 PM.
Reason: Spelling fix
Pretty much normal. You should be able to separate the bridges from the rockers though. Twisted bridges are usually due to the bolts being over torqued and or tightened without that particular cylinder on TDC.
Those are paint marks put on at the factory. Why(?) I don't know except they go towards the rocker. Why(?) I don't know.
If the pivots are stuck to the rockers replace the entire set, bridges and all. Make sure the passage in the push rods aren't plugged.
Wait...you say the pivots are stuck to the bridges? They should be. During a brain fart I thought you said the pivots are stuck to the rockers. If the pivots and rockers are excessively grooved (can catch our fingernail on the grooves) replace them.
Sorry for the confusion, the pivots are stuck to the bridges, the bottom of the pivots and the rockers look to be in good shape and nothing looks excessively worn (167k on engine). The one bent bridge I was able to form back into shape and everything looks lined up pretty good now that I've put everything back on finger tight. I'll torque it down to 21ft/lbs next time I can get out there.
The pivots on the bridge for Cylinder 1 were loose but that is probably due to the bridge being bent. The rest were stuck to the bridges.
The pushrod holes are clean, none were clogged up and I cleaned everything down with brake cleaner to inspect it while it was out (did not remove the lifters though, just cleaned the crud out of the valley with a shop vac).
I've coated everything in fresh mobil 1 10w-30 conventional so I don't have a dry start on the valve train.
I plan to run the oil for about 1k then change it and the filter again just to be safe.
Last edited by eagle11401; Sep 16, 2015 at 11:49 AM.
Reason: Pics added
One more thing to note, the grooves on the rocker and the pivots, they are NOT uniform direction between the cylinders. I found this odd. The grooves on the pivots match each rocker but each cylinder was different in orientation.
For example Cylinders 1, 2 and 6: /\ \/ was the pattern
For Cylinders 3, 4, and 5 it was: /\ /\ for the grove directions on the rockers/pivots.
(view is from looking at the rocker in it's "position" from the passenger side of the truck)
Is there a reason they're different? I figured it may have something to do with the way oil is designed to circulate in the valve train??? That may be why some puddle or splash oil more than others???
Anyone know?
Last edited by eagle11401; Sep 16, 2015 at 11:46 AM.
Reason: Pics added
As I said earlier, the pivots should be attached to the bridges. The ones that are not attached are not normal, but no biggy, they're not going anywhere when installed.
The grooves in the pivots can be any which way.
Button the thing up.
Cheers
Originally Posted by eagle11401
One more thing to note, the grooves on the rocker and the pivots, they are NOT uniform direction between the cylinders. I found this odd. The grooves on the pivots match each rocker but each cylinder was different in orientation.
For example Cylinders 1, 2 and 6: /\ \/ was the pattern
For Cylinders 3, 4, and 5 it was: /\ /\ for the grove directions on the rockers/pivots.
(view is from looking at the rocker in it's "position" from the passenger side of the truck)
Is there a reason they're different? I figured it may have something to do with the way oil is designed to circulate in the valve train??? That may be why some puddle or splash oil more than others???