97 XJ...running rough...bend push rod

[wishihad1]

hey everybody,

Well Ive got a friend that bought a very clean 97 a few months ago. The previous owner pretty much gave it away because he couldn't get it running right. It had a rough idle, along with a very bad stutter at 45-50 mph if you held the throttle constant. Well we started going through it and the previous owner had did quite a bit of work himself. new plugs, wires, cap, TPS, 02 sensors, etc.

A few weeks ago we did replace the head gasket, which it needed badly after seeing the original one.

While replacing the head gasket we noticed that the number 1 cylinder rockers were really rusted..like I took a wire wheel to them to knock the rust off it was so bad. I didn't really understand how they could rust being covered in oil, but we cleaned it up and put it back together. Well today he goes and pulls the valve cover to check out those rockers, and he sees the one of the push rods on the #1 cylinder has bent, and a small part of the bottom has chipped off.

so...Were thinking this jeep has been running on only 5 cylinders since he got it, and the #1 cylinders push rods haven't been working. hence the reason that the lifters were so rusted.

Would pulling it back apart and replacing that lifter, and a new push rod fix anything, or are we off track here?

 

[ktwalker01]

I don't know if this is good advice or not, but I would imagine inspecting the cam would be a good idea.

 

[old_man]

If the lifter does not come out easy, beware of putting a new lifter in without honing the bore, then flushing the engine oil. The cam may also be eaten up. Pull the pan and do a good visual inspection. When you put it back together I would put a dial indicator on the rockers and verify the lift is the same as the other cylinders. If not it will need at a minimum a new cam and a full set of lifters.

 

[CharlesS]

A couple years ago during the Moab Fall Fling we had a guy drive in complaining of his engine missing....
After all the usual checks by the resident Jeep guru I mentioned about the popping at the exhaust pipe and thought it could be caused by a bad valve.
More testing and then disassembly of the valve train resulted in a bad lifter and pushrod along with a worn cam lobe.
The guy didn't have the money for a new cam so we installed a new headgasket, lifter and pushrod. As far as I know the Jeep owner is still driving the vehicle that way.... and it is working fine.

 

[wishihad1]

I think were gonna try to pull the head again, and replace the lifter. Its pretty much going to be a last ditch effort as we have litterally tried everything under the sun to get this miss to go away. And we atleast know this problem needs to be fixed

 

[souske]

Its worth a shot, good luck!

 

[jeepguy72987]

A lot of times when you replace a lifter it destroys the cam lobe. they must make the aftermarket lifters out of harder metals than the cam. has happened to me on 3 jeeps now. yes i do the proper break in and lube the shit out of everything when putting it back together.