I have a '94 22re with a stage 1 Toyota cam. I installed new rockers and adjusters when I installed the cam about 5,000 miles ago.Today all of a sudden there was a loud tappet noise. (like a rocker was out of adjustment) I shut it off for a min. and then started back up. It was fine for 20 min. and then it did it again.I pulled the cover off and can't find anything wrong.I did notice on the exhuast rockers on #2 and #3 cyl.that you could actually slide over on the rocker shaft and have the adjuster screw "drop" off the valve stem.No other rockers are capable of doing that. I noticed that the springs next to these two rockers are not as compressed as the others on the shafts.On the intake rocker shaft they have spacers on #2 and#3 but not on the exhust side.I think that is my problem.Should I put spacers on the exhust side? Have you ever heard of this happening before?

 

The spacers are suppose to be on the intake side and not on the exhaust side. Other than maybe an adjustor screw bad I dont know without seeing it. Does it have a miss in the engine when this happens ? possible valve sticking

 

There is a miss for sure. At the same time I replaced the cam ,I also replaced the cyl head and had a valve job done.If it was a sticky valve I would have thought it would not "fix" itself.It seems to be fine and then all of a sudden it gets loud for a few miles and then it stops making noise.I pulled the rocker shafts apart when I replaced the rockers. I believe I put the shafts back together exactly as I took them apart.Are all the springs the same on the rocker shafts ? (Both intake and exhuast ) I would think that the rockers wihout the spacers would have longer springs to compensate for the lack of spacers(to achive the same tension as the ones with spacers)Thanks for your help

 

Did you use toyota factory rockers?

You need to examine the cam carefully and look for wear marks. If the rocker is loose, it's because of one of two reasons: Either the adjuster has backed off for some reason, or the rocker shoe which rides on the cam has failed.

 

I used only factory parts.The cam lobes are in perfect shape.No scaring at all.Like I said,it will run quietly for days or weeks and then all of a sudden it will sound like the clearence went to a half inch !!! Then I will drive along (trying to get back home) and it will get quiet again.Judging by the speed it has to be in the valve train.( not in the lower end)The adjuster tips still have the hard face intact (no pits or scaring) just like the cam lobes. It sounds like the rocker moves over off of the valve stem( the shoe would still be on the lobe of the cam) and hits on the spring retainer .I know it does not make much sense,but that is all I can figure.I looked for any signs of wear on the retainers or rockers and I don't see any marks or wear.Do you know if Toyota uses all the same springs on the rocker shafts or two different ones on #2 and #3 exhust.(The engine has 160,000 miles on it.Could they have lost tension ?)They do not seem to have as much tension on the rockers as the others do. It seems to have happened when I shifted at 5000+ rpm. I know that is alot but redline is around 6000.I don't know what would make a rocker"jump" off the valve stem.I have never heard of that before.Thanks again for your time.

 

There are spacers between the rockers that prevent them from sliding like that; were they all put in or replaced??

 

Sounds like your timing chain tensioner is crapping out. Sounds like it is coming from the rockers but it is the chain.

 

Mine is having similar symptoms, it stumbles and acts up and if I pull over and let it idle, the idle is rough . If I shut her off for a couple minutes and then start her back up it runs fine until the next episode, days, weeks later. I can smell the smell of fresh oil in the cab also when this happens. With 175,000 miles on the engine, I have no clue if the valves have ever been adjusted, and the plenum has carbon and crud built up inside when I took the EGR off yesterday.