chain constantly rattling and other quirks

[Touchdown038]

First of all let's start with a little bit of background info.

So a couple of years ago I changed out the timing chain and guides on my 89 240sx. The startup rattle disappeared for a while, but about a year or so later it came back with a vengeance. I've just been putting up with it, thinking that it isn't doing much damage.

Fast forward to today.

While I was driving home from work today I noticed that the rattling had begun almost constantly, whenever I keep the engine speed the same or decelerate (rattles big time during slow engine deceleration) and even during idle now. Anybody have a clue what's wrong?

Also, when I remove the oil cap it seems there is a LOT of pressure built up, in fact, I bet it would die if I left it off long enough. Is this normal?

Either way, I am putting a rebuilt engine into my car shortly, but not for a couple of weeks, and I would like to get this fixed for the time being.

[s13sr20chris]

lots of pressure in crankcase? you gots worn rings. i would drive it into the ground if you have a fresh one waiting.