Oil Filter Return

HD Rider

Senior Member
For those of us who had the oil filter return to a banjo bolt in the distributor I have a solution to the rotten return line.

Down at the distributor I used an 8mm banjo to male -4 JIC adaptor.
At the bottom of the filter a 1/8 MNPT to male -4 JIC 90*
I used 3/16 hose but 1/4 works as well with a 90* Female -4 JIC hose end and a straight female -4 JIC hose end at the filter.

It may not earn extra points in judging but it is clean and functional. There is not room to route the hose as origionally done through the hole in the filter mount.
 

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Last edited:
For those of us who had the oil filter return to a banjo bolt in the distributor I have a solution to the rotten return line.

Down at the distributor I used an 8mm banjo to male -4 JIC adaptor.
At the bottom of the filter a 1/8 MNPT to male -4 JIC 90*
I used 3/16 hose but 1/4 works as well with a 90* Female -4 JIC hose end and a straight female -4 JIC hose end at the filter.

It may not earn extra points in judging but it is clean and functional. There is not room to route the hose as origionally done through the hole in the filter mount.
Tasty solution!
Where did you get the hollow bolt at distributor? Is that a brake line bolt?

Also: my '40 firetruck has the oil canister at the rear of head. Do I need to move it to the front to get the gravity drop.
 
I used the original bolt. I could not find an original style return hose so I had to come up with something that would work as a replacement.
 
All Right! I found the bolt at Third Gen.

Where can I find 90 degree Female -4 JIC hose end and the straight hose end?

My Oil filter has a Brake line fitting. Can I go from -4 hose to a brake line fitting?

Thanks!
 
You can get the hose, fittings, and ends at any hydraulic supply, farm implement dealer, or large truck service center.
Yow do not have to relocate your filter from the back of the head. Most of those setups returned oil to a fitting in the oil pan or the base of the dipstick.
 
The only thing that I can think of that might cause an issue in the amount of oil that is now going onto the front area of the crank. Will it "flood" the front main seal? Heck if I know - I'm just wondering out loud here . . .
 
My engine will drip out of the stock front triangular pan breather - like every other pre-49 flathead I've ever owned or built (stock pan and breathing system).

As long as you're using this type of oil pan (up to 1948) and have not modified the engine for a PCV system (where you block off the pan vent), you'll probably be leaking oil out the front breather. I've never seen one that doesn't . . . especially if you run the engines as hard as I do. LOL
 
I tapped a 1/8 NPT in near the top of the timing cover - lubricates the timing gears.

This really isn't needed as the front cam bearing will pass pressurized oil onto the timing gears. But more oil surely won't hurt the gears - especially the aluminum cam gears that many of us run.
 
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