geordi wrote:
Ok... If the injectors are out, and you are hitting a single place where the feel of turning the motor is different - STOP RIGHT NOW and by all means, DO NOT attempt to start the motor!
Something else is going on. Did they replace EVERY rocker? Are you SURE? It isn't that hard to take the cam pulleys back off, and pull the top valve cover. Yeah, the job will suck, but you need to be SURE.
With the valve cover off, you can inspect / replace all the rockers easily. At the same time, you can inspect the valve stems to ensure they are all at the same level, THEN give the crankshaft a few spins clockwise. Before turning it, make a mark on the crank pulley when you know that the #1 cylinder is 90 ATDC - This is the correct position when the bolt holes are vertical and horizontal. Which stroke (intake or exhaust) won't matter because the cams are off the rockers and the valves are all closed.
If you feel ANY funny business at this point... Something else has happened, and the bottom end needs to be inspected. I hope it isn't, but you need to pull this thing apart again to find out what it is trying to tell you.
Thanks for the response.
The rockers have all been replaced by me so I know that has been done.
Just as a little background the car was booked into a dealership for an unrelated suspension recall and a coupe of days before going in the misfire occurred and so I asked the dealer to investigate. After much confusion and their suggestion to REMOVE THE ENGINE of all things Jeep Technical advised them to check the rockers so the valve cover was removed at a dealership and the rockers were discovered to be damaged. They wanted the equivalent of about $5000.00 for the work required ( the day before they wanted $4000.00 to remove the engine and investigate).
The potential cost and my lack of confidence in the dealer resulted in the vehicle being recovered to my home in a dismantled state. I obtained a set of rockers and replaced them, put the cover back on and the rest is history.
When I received the vehicle back the crank was aligned so I simply put the pin through the flywheel and the first time I turned it over was after the installation of the top end. I wish I turned it over before so I would know if it was unrelated to what I have done or not.
There is no sound to indicate anything is being contacted such as valve and piston crown (which the timing pins would verify too). As I wrote previously, as part of the tightening of the cam sprockets and then finding the pin holes once more they were turned many times without a sound or anything noticeably wrong.
I must admit that I didn't pay any particular attention to the valve stems when the cover was off but why would they be at a different level unless the collets had somehow unseated or they had been badly bent? There was nothing too apparent. Each rocker seated nicely on top of each valve. I put a little grease on each one to hold the rocker in place a little more.
Now if there is indeed a bottom end problem or piston to bore problem then at least it wasn't caused by my workmanship and is another fault possibly linked with the rocker failure.
I am a few hours away from starting anyway as I have to connect and bleed the fuel system and install the air intake together with various harness connectors.
I must admit I am loathed to remove the cover again. The revolution of the crank takes no more effort but it feels irregular through my ratchet at the same spot on each turn.
What do you think to the rocker failure to begin with? The cause may have damaged rings or journals too perhaps.
Once more, any input is appreciated.
The mystery continues.