1 hour ago, Yarb said:

https://www.amazon.com/WIX-Filters-Complete-Line-Filter/dp/B000CSEUPG

This filter worked perfectly for me. Changed over to Wix when the Fram was no longer clear. Give it a shot.

That's allegedly too fine (20 microns) for a pre-pump filter. My pump was much louder with the Fram version installed than without.

Don't overlook that the pressure drop is affected by the area of the filter media. Not just the pore size. So, a larger diameter filter will be less noisy.

It would be interesting to try one of the big 280Z EFI filters as a pre-filter. There's a reason there so big. Lots of surface area in the pleated media.

Also, if you're filtering to save the pump don't over-filter. The clearance inside the vane-type roller pumps is pretty big. Certainly greater than 20 microns.

Edited 12 hours ago12 hr by Zed Head
+ -

They're cheap too. Main problem is the 8 mm (5/16") nipples.

https://www.rockauto.com/en/catalog/nissan,1978,280z,2.8l+l6,1209260,fuel+&+air,fuel+filter,6200

Weird how complex the whole fuel filter market is. Few details and what looks like poor conversion skills. 10 mm = 3/8"...not.

Here's a couple from the local store, one with paper media, one with bronze. One about 4" long, the other undefined. One special order, the other available.

https://www.oreillyauto.com/detail/c/spectre-performance/spectre-performance-fuel-filter/spt0/5965?q=Spectre+Performance+Fuel+Filter+-+5965&pos=0

https://www.oreillyauto.com/detail/c/trans-dapt/performance/filtration/fuel-filters--universal-/383bc52af696/trans-dapt-3-8-inch-inlet-3-8-inch-outlet-fuel-filter/tdp0/9177?pos=3

Are you running the Bosch factory pump? It worked perfectly on my 78 280. You could have a tank problem with the strainer. There was a good reason why they went with the 3/8 input to the pump and 5/16 output.

8 hours ago, Yarb said:

Are you running the Bosch factory pump? It worked perfectly on my 78 280. You could have a tank problem with the strainer. There was a good reason why they went with the 3/8 input to the pump and 5/16 output.

I installed a new factory fuel pump a few years ago and have maybe an hour run time on it total since then. I just did a full restoration of the tank and removed the strainer, which was clogged with rust when I took it out. This is why I want to install a pre-filter before the pump. Without that, there is nothing to protect the pump from ingesting debris that might end up in the fuel tank. The filter I linked is pretty large and has a replaceable filter element. It strains to 100 microns, which is commonly accepted as a good compromise between protecting the pump from damage while not being so fine as to clog and restrict flow enough to cause cavitation in the pump itself. If you want more detail, read back through this thread. That's why I resurrected it.