Bad Engine Problems: Grinding...

[Thoughtful_One]

The car is a 1992 with a KA24DE, all stock. At idle, I have the infamous chain rattle, and the rattle is very frequent.

When revving in neutral, all is fine until 2800 RPM. Pass this point, there is a secondary sound they is louder than the engine itself. It sounds like dragging a motorcycle chain across a piece of plywood, and it's intensity increases as the RPM increases.

The oil level is good, but I'm not sure about the pressure. The oil itself seems VERY thin (I used 10W 40 when I changed the oil three weeks ago). The coolant in the radiator looks fine, no discoloration, or film indicating headgasket issues.

The motor itself *really* lacks power. The idle is pretty solid at 800 RPM. At WOT, the car seems to bog. When I pulled codes awhile ago, code 11 came up, indicating Cam. pos. sensor. When I looked in the FSM, it said a whole host of things could cause that to happen.

What is causing this incredibly loud grinding? I don't want to just remove the guides because they are not causing the grinding. I really need help.

[rogoman]

If you have chain rattle, then the mystery noise is most likely the chain assembly; If it is, fix it ASAP or else if the chain skips several teeth, several valves can get bent.

Is the noise coming from the front of the motor or elsewhere? If it's not in the front, then it may be rod bearing knock.

Check the oil pressure.

[StuntingShaggy]

That's definitely your cam chain problem.

Change your tensioners and possibly your chain, then retime it and you should be in a lot better of a position.

[Thoughtful_One]

***One thing that I wanted to mention is that when I changed the valve cover gasket one month ago, the upper chain was tight, there was hardly any slack in it. The tensioner was also able to move back and forth.

Could the tensioner be maxed out because the chain is stretched too much? I think I'm starting to like engines with timing belts now...

[rogoman]

The chains don't stretch very much; it's the guides that go. For the upper chain, you can remove the top guide if there's one; you can also remove the guide that's on the driver's side.

If the chain tensioners are causing the problem, then the motor may have very low oil pressure.