Is there a source for patterns to make or outright purchase the oil nozzle height gauge, oil pan target gauge and oil trough gauge? I have done some searching but still don’t understand how the tubing inside the oil pan is disconnected prior to removing the oil pan on a 1947 second series 3100 panel truck.
I recently unstuck the engine after a five year soak. When I drained out the oil, about a half gallon oil water came out first. I believe that this engine has 56,000 miles according to the odometer and grandsons of the original owner. They said he stopped driving it in 1958 when it started to develop a knock. I did fill the block with water with the oil pan plug out and it’s not flowing out anywhere so I assume it got in through the valve cover vents. I’m hoping the wear isn’t too bad and it’s possible to remove some shims to correct the tolerances. Probably just wishful thinking but I’m hoping that it won’t need a full rebuild….
"The oil that is metered to the rocker arms" is from the low pressure side of the oil distributor valve and the same low pressure oil supplies the oil pan trough tubes.
Oil flow rate at the nozzles will be dependent entirely on the volume of oil the pump pumps at any given RPM, less the amount that flows past the main and camshaft bearings and the amount metered to the rocker arms.
We can only guess what proportion of the total goes to the nozzles, but given that the bearing clearances are very very small, and the six nozzles holes are quite large (between 7/64 and 1/8 inch I think), it is likely that by FAR the biggest part goes to the nozzles.
Total pump capacity was rated as 7.16 gallons per minute at 4000 RPM with hot oil. So at idle total flow is likely around 1 gallon per minute. And on the highway around 5 gallons per minute (assuming 2800 RPM).
So from there, your guess is as good as mine, but I'd guess in the vicinity of a little over 3/4 gallon per minute for all six nozzles together at idle. And about 4 gallons per minute on the highway.
So... Adjust your water flow until you are putting 1/2 QUART per minute in a container from one nozzle and you will see what it looks like when idling... And adjust until you are putting 2/3 of a GALLON in a container from one nozzle and you should see what it looks like on the highway.
I have never seen where they increased the size of the nozzel. The oil supply for the nozzels come from th low presure side of the oiling system and is probally about 2 pounds at idle, just enough to fill the trough.
I am not sure what your container fill time data will tell you. You have already observed that the replacement nozzle is not flowing as much as the other 5. No matter what your data shows there will not be much flow at idle when the pump is only capable of producing 2 psi with hot oil. Remember that pressure is the result of resistance to flow.
My best guess is that there is some type of blockage in that pipe. It could be excess solder from the repair joint or it could be a piece of very reluctant sludge/goo. It seems like some of that crud will not dissolve with any cleaner and air pressure will not dislodge it. So it needs a more direct mechanical cleaning.
I used this trick on my ‘37 to make sure the tube that goes through the head and feeds oil to the rocker arms was clean. I squirted a small amount of brake cleaner into it multiple times over a couple of days. I could see that fluid would drip through but seemed like it was still partially clogged.
So I pushed a length of “safety wire” through it. I made sure the the wire had many small offsets and bends in it. I would pull and push it back and forth in the tube. That loosened some of the crud stuck to the inside diameter. The brake cleaner flowed better but I still thought it should be more . So I chucked the upper end of the wire in my drill and slowly rotated the wire while working it back and forth. Boy did that really clean things!
It's true that the rocker arm oil came off the low pressure side up to and including 1939.
For 1940 and after, the rocker arm oil came off the HIGH pressure side. But... it ran past a bleed off hole which ran back to the low pressure side of the oil distributor valve... and then through a metered orifice... and then into the line up to the rocker arms.
This change was made when the change to the newer style oil distributor valve with the sheet metal cover was made, and I suspect this was done to make lubrication more reliable and less likely to plug in the line up the rocker arms.
It was done to get more cold oil to the rocker arms sooner to reduce valve noise during warm up.
On the low pressure 235 engines the rocker arm oiling was from oil taken from the rear cam bearing (which came from the rear main bearing) and piped to the head casting and (restricted) to the rocker arms. Dippper oil still from the low side of the distributor valve. If the oil would have been taken from the high pressure side all the flow would go to the point of least resistance which would be the oil supply pipe for the dippers - which did not require high oil pressure.
Most of my info sources are from the USA. You point out that the low pressure 235's oiled the rocker arms from the rear camshaft bearing. The blocks on Canadian 216's from about 1951 up were more akin to 235's in that they had the short push rod cover etc. So did the late Canadian 216's also oil the rocker arms from the rear camshaft bearing?
Yes, because the parts list does not list the oil line that went through the block and other oiling parts used for that form of rock arm oiliing but does list the short oil line like the 235 used from rear cam bearing to the bottom center of the head like the 235 had.
I completely agree that the trajectory of the oil stream is critical. At higher speeds the dippers need to get oil from the steam from the nozzles. The action of the dippers in the troughs is so great due to speed that it almost leaves a channel or groove in the oil.
As always Gene is correct about the rocker arm oiling for the 235’s. That change to taking oil from the rear cam bearing was often a point of trouble. The oil had to pass around the rear rocker arm stand bolt. That small passage often would plug (sort of like the oil flow to the timing gears on a 216). Even with a bypass oil filter the lack of detergent oil allowed the sludge to form.
You can find a fantastic old film showing actual high speed camera footage of the "pressure stream" system in action here:
Go directly to the 7:57 mark to see the main action.
This film is from 1937. From 1940 up (I think) the oil pump capacity was increased and at some point the nozzle diameters were slightly reduced (as per my post above) so the advancing stream of oil in Kevin's 1947 would actually reach much further out by the time the dipper comes around and hits it. The distance the stream reaches out between scoops should remain about the same regardless of RPM's because the volume changes in direct proportion to the RPM as no oil is being bypassed unless the pressure is above the 60 or more psi setting of the bypass in the pump itself. (which rarely happens, and never with hot oil)
Thanks for the update. Sounds like you are making progress. It is hard to imagine how something like those valve adjustments got done. Things like have taught me to never be surprised at what I find on an old vehicle.
I agree that you need to gauge to confirm the dipper height. If I remember correctly the dippers on my car are fairly square. The idea is that you want them to just scoop the surface of the oil in the troughs. If they go too deep the bottom end of the rod displaces all of the oil out of the through. Plus it is adds drag on the rod throws of the crank.
If you look calculate the dimensional differences of the gauge you should find that the dipper only goes about 1/4” below the top edges of the trough.
