I just rebiult my 1995 SOHC for the secind time! After I rebiult it the first time a fuel pressure issue was causing the car to run lean and high combustion temperature eventually caused oil to burn making oil carbon which was then cycled through the engine it took only 2000 miles for this to happen. I then tore it down planning on a second rebuild but first I had to get the block bored .040 over and the crack turned .010 over. After the motor was in the car all rebiult for the second time and I went to start it up my oil pressure was completely stopping at 11 PSI no matter what I reved the car to. I only ran it for about 2 minutes then realized the problem wasn't going to fix itself. Upon tear down I expected to see a spun bearing but only found what seems to be a small crack in the thrust bearing in the corner but I know this corner isn't riding on the crank it just somehow cracked. the engine looks great no spun bearings, cylinder walls look fine, brand new pistons also look fine, no grooves in the crank i haven't torn apart the oil pump yet i bought that used from a junkyard but i've already ordered a rebiuld kit with the gears since it seems that this is the only thing it can be, oh and the black was hot tanked before the first and second rebuilds.

 

holy bejesus, you had your CRACK turned? OUCH!!!

Why on earth would you put in a junkyard OIL PUMP as is with no rebuild?

With only 11 PSI oil pressure, I'd take a close look at the top end if you ran it for 2 min like that..... Would also be sure the oil control rings are not already oil baked with varnish....

and what the hell is oil carbon? Running lean tends to burn valves....again, check the top end carefully

 

Yeah I kind of ran out of money after I bought all new internals for it, I tore the oil pump apart and it looks find not so bad, but i put the rebiuld kit in it anyway, I'm getting ready to take the cam out just to make sure nothing happened there since there anrn't any cam bearings it just slides into the head. Really though I still haven't found anything that seems like it should have caused this, oil carbon its like erg I wish I knew how to explain it almost like black soot?

 

the only way oil gets into the cylinders to burn is if the oil control rings on the pistons or valve related seals are letting it pass into the combustion chamber. This should not happen 2000 miles after a proper rebuild.

Did you replace the valve guide seals? Valve guide seals are a killer on these engines and will pass oil......

 

Just tore the head apart everything seems okay, cam looks fine and the rollers almost seem like they were getting a little bit of oil, I just had a head job dowe on it beforethe first rebiuld valve giude seals, valves, and springs, they were all shot. The oil wasn't really like pouring into the cylinders it was just burning the coating off the cylinder wall and as it continually got replaced mroe and more oil carbon would biuld up.