[Formulas]

Those sizes lust4speed posted are nominal external tubing dimensions not internal -10 is fairly close to the major block passages which I would consider minimal sizing for external plumbing

Also it's a good idea to bump up oil pump pressure when going with a cooler up in front of the radiator to negate pressure loss at the end of the galleries

Even with a totally stock system there will be a pressure drop from the filter housing and distributor port, just the way it is in transmission of fluids or electricity

[Formula jg]

I was never happy with my fitting connections into the block adapter so now would be a good time to change them out.
I’d like to see how some of you have plumbed your block adapters, pic would be greatly appreciated.

[Formulas]

Made my adapter from a rough block of 6061 or 7075 on my drill press took a long time but worth it -10 fittings and 1/2 pipe from memory on the pipe part

Couple raw blocks for illustration

.

[Schurkey]

Thousands of years ago, Chevrolet was suggesting MINIMUM 1/2" plumbing for external oil filters. Larger would be better.

[72LuxuryLeMansLa.]

Originally Posted by lust4speed

Nobuddy is correct, there is only about 12" of passage (8" horizontal and 4" up) between the oil filter adapter oil pressure outlet and the block outlet by the distributor. The B-body 90° filter adapter has the oil pressure outlet after the filter cartridge while the angled A-body adapter has it on the feed side before going through the filter. Even with the A-body design, as long as the filter bypass is working correctly there should be less than 5 PSI loss through the filter.

Gauges are notoriously inaccurate and I would bet that the pressure difference you are seeing is probably a difference in gauge readings.

I used to repair and calibrate gauges for helicopters. On bladder type gauges such as oil pressure, there was no real attempt to calibrate the entire sweep. We got the operating zone through the red line accurate and the low end only if possible. This was in a F.A.A. regulated shop for gravity defying equipment, imagine how loose tolerances are on these old cars.

[Formula jg]

I’m ready to increase to AN12, hopefully I have everything needed for this install (first time AN fittings user).

[grandam1979]

I used this from Butler runs lines straight out to stay away from header for $40 it’s a nice piece.

[Schurkey]

Originally Posted by Formula jg

I’m ready to increase to AN12, hopefully I have everything needed for this install (first time AN fittings user).

1. "AN" is an obsolete spec. for military and aerospace plumbing. Nobody sells genuine AN hardware any more. What you're buying isn't aerospace-grade, it's industrial-grade, it is NOT "AN". If we had a functioning Federal Trade Commission, vendors advertising "AN" would be fined and slapped-down.

2. The tubular elbows are probably OK, but the forged elbows are going to be restrictive.

[Formula jg]

Ok, so they are faux AN12 fittings and the forged elbows are more restrictive than tubular elbows. Now regardless of those facts I still consider this to be an upgrade with a major increase and improvement to oil volume and flow over my current arrangement.

[Formula jg]

I cracked the aluminum adapter that threads into original oil filter housing (grrrrrrr!) and have had no luck searching for a similar one so I can configure the fitings as I had them.
Is the thread size (where the original filter would typically thread on to) 13/16”-18?

[Formulas]

Those adapters are total crap they crack and also never seal well at the big O'ring plus you can't use 2 elbows,

Those -12 fittings are necked down internally to accommodate that pipe thread size I bet

I tried that style system 35 years ago realized I was wasting my time and built my own, you are now paying for your education

[Formula jg]

Do you know where I can get this same style adapter?

Also, can someone confirm the thread size of OEM oil filter housing 13/16”-16 or 3/4”-16?

[tc]

https://www.fram.com/media/1075/fram...sell-sheet.pdf
that is for the ph25 right? 13/16-16

[Formula jg]

Thank you.

Looks like Perma Cool still has these available at Summit.

https://www.summitracing.com/parts/prm-114

[Formula jg]

FYI- Although the adapter was cracked I installed it with the new 3/4” id. (nominal) lines and fittings and fired it up for a minute just to see the oil pressure difference.

Previously with 3/8” lines, cold start, 12-14 psi drop between OEM filter housing and distributor.
Now with 3/4” lines, cold start, 4-5 psi drop between same 2 locations.

Wish I would have done this years ago.

[steve25]

That same spin on filter line adapter can still be had and even a bolt on one to replace the stock one from Trans dapt which is now part of the Headman performance group.

[Formula jg]

This roll pin partially came out when I was tightening the fitting and I bent it trying to tap it back. I’m not sure what it’s purpose is or how to get it back in the hole now that its bent. Someone please school me on this.

[johnta1]

I would say it's what keeps the swivel head from coming off the fitting.
(letting the fitting swivel instead of being solid)

Finding the correct size of the pin may be a problem.

Who's fitting is it?
Maybe talk to their tech?

[lust4speed]

Yes, if that pin comes out the fitting will separate and pressurized oil will go everywhere - and that would be just the beginning of the fiasco. That pin was meant to be pressed in permanently (deadheaded in place) and it working out is a manufacturing defect. The complete fitting needs to be replaced because of the future failure potential.

[Formula jg]

Thank you guys for explaining this mystery to me.