View single post by Greg Fletcher
 Posted: 10-16-2008 04:13 pm
PM Quote Reply Full Topic
Greg Fletcher



Joined: 03-11-2005
Location: Lake Nacimiento, California USA
Posts: 430
Status: 
Offline
 A "scary rattle" is something to be very concerned about. I would classify this under Mystery Noise and assume the worst. If the compression is up to par, then we can assume the valves and rings are sealing, but that's about all. If you can't get a proper reading, then you have nothing to go on. First, be sure your throttle sticking problem is fixed, that's rather dangerous.

If this were my car, I'd start by ruling out for certain any external source for the noise, such as pulleys or the alternator or whatever. You'd be surprised how one thing can sound like another with everything whirling around down there.

Checking the valve clearances on each side as a matter of course before you remove the cam towers would be in order. If the noise is really coming from the valve train area, I would expect to find a broken part, such as a spring or even a valve guide. I've never seen this happen, but you never know. A broken ring in one of the cylinders can make some scary noise also.

I once had a machine screw unknowingly get sucked into a carb on a Rover P6 where it ended up getting pounded in the combustion chamber. It made an interesting indentation in the piston and head and made a horrible racket that sounded like it was a valve problem. Almost like ball bearings in a blender. I just popped it out with a cold chisel and put everything back together and it was fine.