Ok, so I let my truck idle for about 20 minutes and the knock never appeared so I wasn't able to isolate the knock by cutting out spark to specific cylinders. But I did hook up the timing light and the flashes seem to go faster than I remember the knocks to be. The last time I heard them, they were at about the frequency of the clicks on the stopwatch at the start of tv show "60 Minutes". I think the knock must only appear after actual driving. It definitely sounds like it is coming from the lower part of the engine.

 

ok, I just took it out for a spin and the amazing thing is that it doesn't make this noise until it has been driven for about 5-10 minutes. Before that it runs so perfectly and makes no odd sounds. So this time I came home and it was making the clicking sounds again. I got my wire out and started grounding out sparkplug wires. When I got to the second one back from the front of the engine on the passenger side (not sure which cylinder number that is technically) it made a noticeably different softer clicking noise - almost non-existant, then when I let the cylinder fire again the louder knock came back. I am thinking based on the fact that it doesn't make the noise until 5-10 minutes of driving that I might be leaning more towards a slipped sleeve - like someone already mentioned on this thread earlier. Also, on my last oil change (the other day, and for that matter on past oil changes) I didn't notice any metal filings in the used oil that came out. It was very thin this last time (almost like water) but it wasn't low on oil. So my new question is, can you drill and tap the block/sleeve on that cylinder without pulling the engine out of the car? Could I get by with pinning the sleeve by just taking the oil pan off and working from the side and bottom of the engine? I really don't want to pull the top apart on this thing.

 

You can as long as you can do it correctly. Here's a .pdf on what's involved; https://www.google.com/url?sa=t&rct=...Tp8FvqurVfS2Qw

 

Ok, so been driving it a bit and the knocking sound does not make noise at startup. But once the engine is warm it is very noticeable. It seems to be loudest when going up hills (where the engine is under heavier load). When I pull a particular spark plug wire, the sound seems to get a little quieter.


I'm probably going to drain the oil and pull the oil pan and have a look around.


A couple questions:


1. can you take the oil pan off without having to lift the engine off its mounts or detach other things under the car?


2. what is everyone's best guess - think it is rod knock or slipped sleeve?

 

Raise vehicle by the frame, let front axle stay on the ground, unbolt and drop pan, disconnect pick-up tube, pull pan over front axle. While you have pick-up tube off check screen.

 

did you ever figure out what this was??

 

Sorry guys I was thinking I had already posted the solution to this one already.

Sadly, that vehicle is long gone. I sold it several years ago to a guy and then not too long ago I saw an ad on craigslist with it pictured, but the guy was selling parts off of it. Apparently it must have gone to the crusher. I really miss that truck too!

Proudly, I still have this little trophy hanging from the garage wall:



It was an exhaust leak out of the head gasket. You can see the part around the cylinder where there is a completely open gap (right next to the drywall screw on my wall). that thing had deteriorated to the point where exhaust was just shooting out the side of the engine... Obviously I did both head gaskets at the same time but the other side was fine. This was the passenger side one.