Moparts Tech Archive

Big Block

BB oil pickup measurements - Moroso myth facts

In this picture is a stock 3/8 NPT pickup from a stock pan, a 1/2 NPT pickup (P4529567)for a hemi pan (P4529884), and the Moroso 1/2 NPT pickup (24800) for their deep pan (20760).

The stock 3/8 NPT pickup measured 0.693" OD, 0.41" ID at thread, and 0.49" ID remainder. This matches schedule 40 (std wall thickness)steel pipe (spec: 0.675" OD, 0.493" ID). The hemi 1/2 NPT pickup measured 0.840" OD, 0.57" ID at thread, about 0.61" ID remainder. It was hard for me to measure the main pipe diameter since it was larger than the ID at the thread. This matches schedule 40 (std wall thickness) steel pipe (spec: 0.840" OD, 0.622" ID.) Both Mopar pickups apprear to have rolled threads (not cut) which necks down the ID a little at the thread. I cut the 3/8 stock pickup to verify the ID away from the threaded area.

Below is the Moroso pickup details:

The Moroso pickup uses standard 3/4", 0.065" wall tubing (0.620" ID), welded to a custom boss with the 1/2" NPT threads (cut, no necking down). It might apprear to neck down, but that is only the outside, the inside is the same all the way!

If anyone has the Moroso 3/8 NPT pickup for this pan, it would be interesting to get these same measurements.

It would not surprise me if the Moroso pickup with the 3/8 NPT uses the same tube as my 1/2 NPT pickup. If that is true, they really have their act together. This is much better than than the stock pickup.

Everyone concerned should check the size of the rest of the passage from the pickup to the oil pump. I have seen blocks with those passages only 9/16" instead of 5/8".

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O.K., I just got back in from the garage. Well, I can't cut open my pick-up because I'm using it, but.... The O.D. of the pick-up tube is .750", exactly the same tube as the 1/2" pick-up tube. I will assume the i.d. is identicle too. My measurement of the threaded end i.d. came to about 11.3mm or roughly .448". So, the difference between the two Morosso pick-ups seems to be the threaded end. Wanna upgrade your system?? Skip the $45 1/2" pick-up tube, cut off the end of your 3/8" piece and weld on a piece of 1/2" NPT pipe to the end of it. Because there is so much wall thickness in the end, I might just pass a bigger drill bit through the end of the existing one and open it up a bit. A little cheap insurance??

Where else but here can you get this kind of tech.???

Thanks for measuring the Moroso 3/8 NPT pickup. That seems like a good idea they have. Put a big (ID) tube to reduce losses and weld the 3/8 NPT on the end to fit the block. That way only a short distance has the smaller ID. Most of the benefit without drilling and tapping the block.

The minor diameter of a 3/8 NPT thread is around 0.58". So with 0.448" ID, that leaves a wall thickness of 0.066". I wouldn't drill that out any thinner than a standard pipe (0.493" ID).

I always drill and tap the block because it is easy and I do it myself so it doesn't cost anything once I bought the drills and tap ($45 tap, $20 drills). The big drill bits (45/64") are expensive in high quality made in the USA stuff.

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