56willys, one thing about a rod knock, it doesn't go away. You can quiet it down for a short period of time but a true "rod knock" is a bearing spinning if its loud, or getting ready if its quiet. Knocking sounds from an old worn engine usually occur when they are cold and quiet as they warm up. Like gm said, the rod bearings and rod ends get out of shape and clearance becomes excessive. there can be a bit of "clanking" around and oil pressure drops off as clearance picks up.
You can drop the pan and check the bearings. However I would bump the idle up to about 700 - 800. That should give it some idle oil pressure. A lot of times a piece of carbon can get stuck in the combustion chamber and make a knocking sound, then go away. A good drive will fix that. If the knocking is most prevalent when its cold and seems to improve when it gets warm, it might be getting a bit worn. If it has good oil pressure, compression, the oil stays in the motor and the plugs aren't fouling with oil, rebuilding it is not necessary just yet. It is however a great experience! It is a solid lifter engine so a valve with too much clearance will "tic" loudly. As the engine warms the clearance will tighten up and the sound might change. I would experiment a little with the knocking sound and let us know how its doing. Be gentle with it till you know for sure. If it is knocking from wear and you put it under a good load, that is where the trouble will occur. If it is going to spin a bearing it will do it then. A spinning engine bearing is very loud. You wont wonder if it is something serious. You will know. There will be metal in the oil.
Now you got me thinking. You said a chunk of carbon in the cylinder could make noise. I just put some seafoam in the gas the day before it started knocking. So maybe it is just carbon getting broken up.
I will definitely raise the idle up. And adjust the valves. Any tips for adjusting the valves? I've never tried lashing valves before. How much gap should there be?
Jacob, do you have the Willys Service Manual? Just in case, here is a link. Let me know if anything needs clarification. I don't think you will have any trouble. You set the lash on a cold engine. The lash on the F134 is .018" on the intake valve and .016" on the exhaust. The lash is set by loosening a lock nut and making an adjustment on the adjuster stud, then re-tightening the lock nut while holding the adjustment stud.
Well, yesterday I pulled the side valve cover and oil pan off. Didn't find anything wrong. It all looks super clean like its had a rebuild recently. There's some gunk In the bottom of the pan but nothing gunked up in the block or oil pickup. All the rod bearings feel tight. Some normal front to back.But no up and down play. And definitely nothing lose enough to knock. And cam lobes look good. Now I'm thinking its got to be carbon. At least I have the assurance that's its not something serious and there won't be a window in the block when I run it.
No i don't have the manual. I do have a circa 1970ish truck repair book that covers jeeps. Although it wasn't clear on valve lash.
Stick to the manual I gave you the link for. I think that is the best one out there. There are some areas that require clarification, but that's what the internet is for!
It sounds like all is good and you need to take it out for a ride. If you can, get yourself a printed manual. Mine is nicely full of greasy fingerprints, well used. I find it easier to use a printed manual rather than the computer screen.
New tires on the Willys. I found these at Spring Carlisle. 30/9.5/15 Bfgoodrich all terrain Ko2. Were alredy mounted/balenced on the wagon wheels. Practically brandnew, just a couple hundred miles. Still have the vent spews mostly intact. Definitly an improvement for looks and performance. The old tires were completely different front - back. And the rear tread was basiclly useless.
Nice looking shoes! Good thing you took the different tires front to rear off. In 4 wheel drive, if the rolling radius is different, it can and will raise trouble with your drive train.
Those are my go-to tires for anything with 4X4. They work great on and off road no matter what the terrain. I put a set on our 2A, and they made a world of difference in the drivability of the Heep. That was a great score.