@Mitch150, Thanks for the response, I was also curious about the exhaust manifolds. I had that issue with an older 400M engine I had in a '79 bronco. Not too long ago I checked them out when I was trying to fix the phaser tick noises... I ended up replacing all of the timing components and that took care of the ticking noise, (at least down to where I could hear the injectors again). So I think the manifolds are okay.

@F150Torqued, I really like the idea of thicker "hot" oil. Someone on this site did a great write up about their results when using various viscosities of oil... maybe it was you! Anyhow great write up and I'll probably end up with a thicker oil. However I also want to find out why the oil is bleeding down in the first place and the leading cause as far as I have found out is the tensioners. So I think some new ratchet type tensioners are in my near future... just trying to figure out what else I should replace while I'm in there. I would really like to figure out and fix the floating miss too!

Thanks again everyone.

 

@rocket_man


Do you have an after market Oil Pressure gauge? I would be interested in how long the "knock" persists and how that relates to gauge pressure building to normal. Also, does it ONLY "knock" on a cold soak start - and not warm start?


Some thoughts: I believe Leak down on "the pressure side", as you suggest in the OP, is most likely not the culprit. Reasoning - I believe all engines drain LOTS, if not all, oil back down to the pan during a full cold soak. There are many-many points in the pressure side where air can enter, or "leak" into the oil passageways, and gravity will take care of the rest. An example is in 24 lash adjusters that have a "weep hole" in the very top of them. Cam bearings and the phasers are just not air tight. Phasers and tensioners are intended to oil the chains with what leaks out and gets slung around.


The gearator oil pump moves enough volume to fill and push all the air out of the pressure side of the system VERY VERY quickly. BUT, the oil pump is not positive displacement and therefore, ff it looses "prime", it would take some time to get going. It would be moving nothing but a bunch of bubbles into the pressure side.


The oil pump is above oil surface level. But the pickup tube / screen is "below" the oil surface in the pan. Therefore as long as no air can get in - between the pump and oil level surface - it would never loose prime. But THAT makes me suspect the 'o' ring on or the connection between the pickup tube and the oil pump.


Even the "relief valve" is on the pressure side. Junk in the valve would require air to enter there - WHILE the pressure of oil higher than that, ie: in the head, crankshaft, oil filter - etc is "above" that level. No air should be sucked in through the pressure relief.


Any of that make any sense?

 

F150Torqued,
Yes I have added a mechanical oil gauge plumbed into a "t" fitting on the oil filter adapter. The first gauge I used didn't have the resolution I wanted, so I replaced it with one that has finer markings on it, which works great.

The noise is definitely longer upon a cold start, verses a warm start. Some months back, I can't remember it even being there and now it's happening more and more regular, so something is getting worse.

I'd say that on a cold start, sitting at least 24 hrs, the noise is about 3-4 seconds long, maybe slightly longer. On a warm start, truck sitting for a couple of hours, the noise is maybe 1-2 seconds. On a warm start where the engine has been sitting for just minutes, I don't recognize any noise.

My personal suspect is either the tensioners, or the oil pump screen O ring. But I'm also very suspicious of the lifters and/or camshafts, (since these don't have any cam bearings). Maybe even another broken timing chain guide and the noise is the tensioners pumping up to "take out the slack" so to speak?

The odd thing is after I start the engine, if I bleed out all of the air out of the oil gauge line, the gauge seems to pulse, or flutter. This makes me wonder if the floating miss me and others have, is somehow related to this low oil at startup condition.... don't know, but it makes me curious. I just can't see a gear type pump having a discharge pressure that pulses.

Thanks again for the information.