Oil Filter Stud Metering Hole Question

[DRaymond]

1948 FCUB restoration and engine rebuild.

Am I correct in assuming that the metering hole in the side of the stud above the threads should allow oil to pass through it to the drilled out hole in the threaded end of the bolt (to return oil to the pan after being filtered).

I ran a small wire into the metering hole and could not see it when looking into the hole at the threaded end of the bolt. I also tried using my air gun to blow air through the metering hole and no air passed into the bolt hole chamber. I even tried using a #60 drill bit to hand twist into the metering hole to no avail.

I sure would appreciate any discussion, suggestions or education on this return oil feature.

[Eugene]

Am I correct in assuming that the metering hole in the side of the stud above the threads should allow oil to pass through it to the drilled out hole in the threaded end of the bolt (to return oil to the pan after being filtered).

Your assumption is correct.

[DRaymond]

Does the metering hole just penetrate the oil filler stud bolt cavity at a right angle? If so it mine appears to be blocked tight. Can it be opened by drilling it out? If so does anyone know what the metering hole diameter should be?.

[Eugene]

There has to be a method for the oil passing through the filter to reach the oil pan.

I would do a couple of primitive measurements.

Stick a drill bit up/on the larger hole in the bottom of the stud. See if the hole is deeper than the hole on the side of the stud. Same thing with the hole on the side of the stud - - - compare to the thickness off the stud. This will tell you which hole needs to be lengthened.

I would use the same diameter drill bit as the hole in the side of the stud. Reason, the oil filter has a small but some built in resistance to the oil flow.

[DRaymond]

Well I checked out the location of the blocked metering hole. It was located so that it would enter into the oil filter stud bolt's center hole cavity. The metering hole had a very solid blockage-no light,air or liquid could get through it. The metering hole looked to be the diameter of a #60 drill bit so I drilled the obstruction out with a #60 bit. The bit broke off just as it broke through into the hole in the bolt. I used the remaining piece of the bit to drive out the broken bit tip and to clean out the hole. I Cleaned up the bolt. The metering hole flows free now. I recommend that you have a couple of #60 bits handy if you need to tackle this job

I do not know how oil would get filtered if the metering hole were plugged. Just makes sense to check that the metering hole is clear at every oil change. It sure would not take a very large debris particle to plug it up.

Thanks to all for the feedback.

[John *.?-!.* cub owner]

The size of that hole is critical. too small or plugged, and oil does not go through filter. Too big and oil pressure will be low.