Thanks 52 Merc and 52 USCG Panel, you cleared things up. I drained the oil, and put it back a quart at a time, each time measuring the witness left on the dip stick. 3 quarts puts me at the FULL mark. 5 quarts puts me an inch (ish) higher. With the tube (that I don't have), I'd be right at the FULL at 5 quarts.

bmoran4, thanks for the lead on the tube, but it turns out that it is no longer available. I guess I'll either have to troll swap meets, of fashion one out of tubing.

The scary part for me is that this truck has been running on 2, maybe three quarts of oil tops for years I'm guessing. The oil pressure has been ok, about a third of the way up the scale on the factory gauge. When I filled it blindly (5 quarts), the pressure rose to half scale, or 30 psi, according to the same gauge. I suspect that having a full reservoir made for improved oil delivery. That coupled with, I'm guessing, sludge buildup in the oil passages in the head are the cause of the blue smoke that I now see; I'm thinking that more oil is getting to the top faster, and can't drain fast enough, so it is leaking past the valve bushings into the cylinders. I plan to run some SeaFoam through it, change the oil again, and hopefully this will solve the smoke problem. At least I know for certain that it isn't being overfilled.

Thank you all so much for your time and helpful suggestions.

See you on the forum.

Bob

 

The traditional wisdom I've always gone by is that it is better to be a little low on oil than overfilled. I can see why it would have run fine on 2-3 quarts at about 15-20 psi in the past if it wasn't pushed hard, that said, you may be looking at more wear on your drive train as a consequence. What I don't get is why when you fill it to 5 quarts, which should be correct regardless of your dipstick issues and slightly dented oil pan, you get a bunch of blue smoke. Particularly when your oil pressure is at 30 psi, which is in the normal range (20-30 psi). Your idea that residual sludge in the head is causing the smoke seems reasonable. If the Seafoam doesn't work, I guess the nest step is to perhaps pull it to inspect the oil passages in the head and top of the block?

 

I was (reluctantly) preparing to at least remove the top valve cover, then thought of SeaFoam. I figured it couldn't hurt to try, the stuffs been around forever.

Fingers crossed.

Thanks

 

It's definitely worthwhile, regardless of the Seafoam treatment. Valve cover gaskets are cheap, and you'll definitely get a better idea of whether you need to pull the head.

 

Without a dip stick tube, the stick is just flopping around and isn't even sealing. Here's the tube you need. My old catalog says this is the right part not only for N tractors, but for 226, 254, 215 and 223 6 cylinders from 48-55, which is the coverage of my catalog.
https://fixthatford.com/oil-indicator-tube-9n7020.html

 

Is there an echo in here?