so i have XJ

with about 220k miles. its been ridden hard but well maintained.
about a year ago i developed a slight knocking noise when i first start the car. as soon as i rev it up it would get louder then go away permanently as soon as it hits high rpms and not repeat until the motor gets cold and sits again. literally one rev to 4k RPM and the noise would stop and be completely gone at the next 4k rev.

the noise got worse. to the point it has never gone away.
when i first start my truck in the morning to go to work it it does not tick. as soon as i put it into gear and start on the accelerator it starts ticking. the ticking sounded exactly like a rod knock. as i drove to work the engine warmed and the noise got noticeably quieter, but not going away completely.

so i got sick of the noise so i took the motor out, took it all apart.
*rod and main bearings perfect
*replaced oil pump <- old one had perfect pressure
*replaced timing chain. old one was very loose.
*had a valve job done on the head. i had 3 leaky exhaust valvs one badly leaking.
*all push rods were straight and clean. no blockage in them.
*rockers seemed fine.
*all new lifters
*cylinders and pistons looked perfect, no ridge buildup or anything. i was amazed
*new sparks
*new water pump
*new alternator <-- old one bearings starting to go

put the motor back together all new gaskets and stuff. everything torqued down to specs. cleaned all the grease and grime off the block. motor looks bran spanking new..

started it up and it ran like ****, but im sure it was just cleaning its self out and the computer had to re align all the variables and sensors and such...
after 5 mins it ran perfect. i drove the car about 2 days with no noise at all. i was sure i had fixed the noise problem. well its back and as loud as ever.

what did i miss?

could the cam shaft have a flat on a lobe ? if so how do i check for that?
and what would cause that??

worn valve spring? wouldn't the place that did my valve job check the springs??? i hope that assumption was not a mistake

the pistons wristpins seemed perfect. i could no find vertical play at all.

cant be lifters , their all new!!

am i going insane? is this noise just me day dreaming from remembering the horrors of removing the top two bell housing bolts and somehow manifesting in a knocking sound???

my best theory i can think of to explain the possible cause problem. my original oil pulp was not putting out enough psi to a lifter. i am assuming that this also lubricates the cam shaft. Maby a oil galley running to that particular lifter was or is blocked or restricted somehow. insufficient lubrication of the cam lobe wore a flat spot from hitting the lifter...

im still hitting myself from not checking the cam


on a bright side, i have noticeable more horsepower after the valve job. and probably better aligned timing with the new chain, not to mention new sparks....

if im off base here someone please tell me. im desperate to figure this out.
i love this truck and really want to keep it running. if i have to ill go get a low miles junkyard block and call it a day.. or two

i can post a Video of the exact noise when running while cold if anyone wants to hear it.

 

Year? Trans type? Brand of oil filter used?

 

Im sorry
Its a 2000 sport.
As for transmission i am not sure. Its a 4 speed. Borg- warner
Using fram oil filter. 10 w 30 oil

 

Ditch the Fram for a Wix or Napa Gold. Worth a try.

 

maybe you answered your own question...hit yourself again.lol

 

With valve cover off check the oil flow though the pushrods? Could be a worn cam bearing maybe?

Get a mechanics steath a scope and see if you can isolate the noise.

 

You can check lobe lift with a magnetic dial indicator. Attach it to the head with the valve cover off then measure the movement of the rockers while manually turning over the engine. Check them all and this will tell you the health of your cam and if you have a flat lobe. I have the exact same issue on my 99. I will be installing a stage 1 cam kit from 505 performance.

 

Ok. Sounds good... is there an easy way to fix a restricted oil jacket? I really do not want to remove the engine again. Also can i put that performance cam in my motor with everything else stock? Ill keep this thread updated if i can find the time to do this cam soon. Thx for the advice everyone.

 

According to 505performance, the stage one cam is the only one that you can run without replacing the valve springs. I am going to replace mine anyway but since you have already rebuilt your cyl. head, you should be good.

 

You said this was a 4-speed, but is it an Automatic? If it is maybe it could be a cracked flexplate, or loose bolts in the flex plate. I suppose a flywheel could cause the same trouble, but their usually a lot thicker.

 

Its an automatic. I checked the fly wheel. No aparent signs of cracking.
the knock sounds like its coming from the block. Near the cam. Doent they make a lifter extractor tool? I was told i can change the cam without removing the head if i lift all the lifters up at once. And im strongly considering the performance cam.

 

Take a torque converter bolt off and see if the hole is wollered out any

 

To remove the lifters you can use a tool that looks like a retractable radio antenna with a magnet on the end. You'll need to install new lifters with the new cam. But from what I've read any cam above the stock grind would require new rockers and springs. I can't say for sure about 505's cam, someone else said it works with stock parts. Might want to check into that before you purchase.

And if you're keeping your stock parts (push rods/rockers/springs) be sure to keep them in order and replace them into the exact same place they came out of.

 

505 has a stag one kit that comes with everything you need including the lifters and pushrods. That is why I am going that route.

 

ok. i have the valve cover off. i put some cardbord to prevent spillage..

pushrod flow video

engine knock sound (cold engine)

is that the proper oil flow out of the pushrods with a warm engine??