Right Angle Oil Filter Adapter Concerns...

This is a comparison of the right-angle oil filter adapter that is available through Mopar Performance and the

stock piece found on 340 and many 273 engines. I bought a new adapter before I found my Barracuda. I was

going to use it on my Valiant when I got around to using headers. Since my Barracuda came with a 72 model

340, it also had an iron adapter. Just for fun, I took them apart to see what the differences were...

First is the fitting that the filter attaches to. The new one is on the left. Note that the threads that go in to

the adapter are different... no swapping here. Also note how these parts are attached to the adapter: the

new one has a 3/8" square hole to use a common ratchet. The old one has a large hex to be tightened with a

standard wrench. Although the square hole has slightly more opening area, it also has a greater head loss

(resistance to flow) than the round hole has.

The new adapter has a much cleaner transition to the filter area (lower opening above)...

...than the old piece does (upper opening, barely visible above).

Here, the new main adapter bolt is shown on the left. It's difficult to see, but the new one has four round holes to pass

oil through, where the old bolt has two long slots. On the end, the new bolt, still on the left, has a smaller passage through

the center than the old bolt has. This is another restriction, and no amount of additional holes in the shank of the new bolt

will increase the flow beyond what the outlet hole can pass. See the quick calculations below (*).

Finally, here is the plug end of the adapter. The required plug was NOT included in the kit. I had to fund the

required plug locally. Final recommendations: if all else fails, use the main bolt from the older adapter with the

reproduction housing. If you already have the original adapter, don't replace it, just do some minor porting work

to it and live with the extra pound of weight.

*Calculations:

new bolt inlet = 0.314" dia, area = 0.0774 in^2 x 4 = 0.3097 in^2

new bolt outlet = 0.441" dia, area = 0.1527 in^2

old bolt inlet = 0.175 W x 0.719L

Then, 0.719 - 0.175 = 0.544" x 0.175" rectangular opening = 0.0952 in^2 + 0.175" dia hole, area = 0.0241 in^2

for a net area of 0.1193 in^2 x 2 = 0.2385 in^2

old bolt outlet = 0.600" dia, area = 0.2827 in^2

Last updated 01-10-00