knocking/tapping...cant figure it out!!!

[stoffdog01]

ok, i have a 90 laser RSt. It is an awesome car, and ran really well when it ran I recently did a complete motor rebuild in the summer (0.020 over sized bore, crank 0.010, all new bearing and everything) and was very happy with the way it turned out. I bought the complete rebuild kit from slowboy, and used all the parts it came with. I have experience with turbo cars, just not much with the mitsu...needless to say, this was my first mitsu turbo build. As of now the car is set up for stock boost. the upgrades i have done as walboro 255 pump, afpr, 2.5 in full exhaust (no cat), and a few other things. The car ran great for the frist 800+ miles i put on it. A few weeks ago i was driving home from work and it seemed that the car retarted the timing and didnt want to idle. I pulled over to the side of the road to see if everything was ok. When i popped the hood, i heard a ticking sound and immediatly i thought liter tick...no problem, and easy fix. later that week i bought the 3g lifters and put those bad boys in hoping to solve my lifter ticking problem. I let the car sit over night, and tired it the next day after work. When i first started the car the ticking continued, but after a few mins the ticking went away. Now heres the strange part, the ticking went away, but a single "knock" developed. I let the car run for while hoping the knock would go away like the tick did.....no, still here. I have owned another car that had a bad rod bearing...the sound of the laser sounded so much like it. I pulled the pan to see what damamge was done to the bearings...or course there was no signs of major damage. The bearings had a few shiny spots on them, but nothing major ( I have seen what a spun bearing looks like...not pretty)..i figured it was just normal break-in wear. Just to be sure i order new 0.010 over sized bearing and installed them. After I installed them and put the car all back together, again i was dissappointed that the same problem was there . I have been reading the forums a lot lately and i cant decide what to do next. I have tried running the car and pulling off one spark plug at a time and nothing seems to be leading me to a better idea of what the hell is going on. The sound is like a knock, but not as servere as a rod knock. It sound like it is top end...somewhere around the number 3 piston. Its requency increases as the rpms increase and has no variation...it is present when hot and on a cold start up. Does anyone have an idea of what this could be? I am running out of patience and ideas..there is no reason that engine should be haveing problems this soon

Let me know if you have any ideas or similar problems...i need all the help i can get.

thanks for the space, and sorry for such a long post, Tim

 

[TNT02SS]

Just rebuilt 4g63 had upper eng knock found cam gears bolts loose. Retorque to 72ftlbs knock noise gone.

 

[luvmygst]

Did you take the balance shaft's out?

 

[4G63GS]

hey my 90 laser had crank walk due to the machine shop balancing the crank wrong. bought .10 reman crankj with bearing from slowboy. started it up had to set cam. idles perfectly on 750 no odd noises. smooth as a whistle. But oil pressure is not there its under l it worked before but no doesn't and when engine is reved it stumbles and knocks. i have no balance shafts did the elimination and did it right. oil pump gear was turning like it was in 90 weight though thats also new. read in book might be low grade fuel or timing is off and is tapping valves. firing at the wrong times.