I've got this engine I am swapping over to a civic hatch and its finally time to diagnose what went wrong when I rebuilt it years ago). To try and make a long story short, I rebuilt this engine for a 91 teg after having a machine shop do some work (valve job, hone, clean, etc). After getting it all back together and starting it up, it never sounded right. Its always sounded like it was misfiring slightly, but not enough to actually feel any hesitation when driving. Compression was showing around 135 psi after the rebuild, but I chalked it up to a weak gauge. Engine never smoked or hesitated, just sounded noisy in the engine bay... almost like a diesel, but not that bad. It does have headers. When trying to break in the engine, I couldn't get my hands on straight 30 weight oil, so I used some Castrol non synthetic.

The engine basically sat for the last couple of years and I'm now the middle of the swap I decided to tear it all down and have a peak inside, and I see a lot of sticky oily residue inside the intake manifold and baked on nastiness inside the cylinders. No obvious signs of wear to anything... rings and cylinder walls look ok (as far as the untrained eye can tell). The cylinder walls do look a bit untouched, but I only put like 5k miles on it, so maybe thats normal?

Its back at the machine shop now where I've asked them to pressure test the head and check the cylinder walls, but it could take weeks as they are backlogged a bit.

My question is... does this sound like the rings never seated properly? Something else perhaps?

 

The rings should have seated far before 5k miles. That weird oil in the intake manifold could be blow by from the valve cover vent, that goes back into the intake manifold. How do the spark plugs look? Are the injectors stock or aftermarket / do you think they need a cleaning? Are you able to post some pictures of whats stuck onto the cylinders?

 

Could you determine what kind of that oil in intake manifold.