Looks like this modification isn't too hard to do. This mod is basically intended for high-revving engines that need more sustained oil pressure and volume on the front gear bearing from what I understand. I think the other idea behind it is to help eliminate some of the pressure drop points that the oil would normally have to take from the oil filter stand area (rear iron housing) through to the lateral oil galley leading to the gear/bearing, namely the upper tubular dowel run, the lovely banjo fitting, and the vertical galley in the front iron housing. By running a line from the oil filter stand straight to the side of the front iron, all of this can be bypassed and theoretically a 'better' source of oil will hit the bearing when needed.



I performed the modification on my own personal engine a couple weeks back and it wasn't all that hard to do. What I used, contrary to Lynn Hanover's advice, was a -6AN line instead of a -10AN line. Here's what I did:



- Used an existing Racing Beat oil pressure/temperature adaptor block (rests below the oil filter stand) -> had this block machined and tapped for 3/8"NPT by our good buddy Scalliwag on the outlet oil galley. The RB block's oil pressure and temperature (machined) outlets are on the *unfiltered* side so I couldn't in good conscience use this for the source of the loop line.

- Ran a series of 3/8"NPT brass fittings off the newly machined galley and then ran a 3/8"NPT to -6AN adaptor (about $4) for the source.

- Made a -6AN ss-braided hose with about 16 to 18" of length coming up from the filter stand block, winding its way down to the other end being a -6AN 90 degree fitting

- Drilled the factory plug out of the front iron housing (the galley is machined all the way to the end but plugged by the factory) and tapped it for 1/4" NPT. Threadded in a 1/4" to -6AN adaptor fitting. My front iron oil galley was not plugged with a threadded plug although a friend of mine has told me that several of the engine he's torn down all had threadded, allen-head plugs in them? Can any of you guys verify this?



Here's a few pictures. Sorry for the size!



















No major changes to oil pressure were noticed except quicker rate of oil pickup and higher oil pressures at idle, even with crankshaft re-jetting. I did do alot of modifications to the oil pickup and front iron oil galleys so I'm leaning towards the better pressure readings coming from those chamfering modifications.



Comments? Criticism?



B

 

That is a beautiful engine.

 

hmmm. Would have to think about this before commenting as I've never studied the oil flow patterns in a 13B. Job for tonight me thinks.



Shame that I can't fit that mod on my car at the moment, as the dry sump pump gets in the way of the plugged galleries.

 

Had a long stare at various engines this evening and think I know what this means now. Couple of questions though.



1. You said it bypasses the banjo fitting. I can't work that one out. The only bajo I am aware of it the oil return line into the bottom of the rear iron. you still have to go through that to get filtered oil



2. Will a -6 hose flow any more oil than the dowelled gallery? Doesn't seem as if it would



3. On the top of your front iron there is a bolt of somesort (just next to the M of mazda on the first picture. I've got that one 1 of my 13Bs I just noticed. Does that enter the oil gallery and if so, wouldn't that have been a better place to put the oil feed (asking cos it could simplify the plumbing on my Dry sump setup.)



Learned a few things today so thank you.



Bill

 

Finally did it! Looks good Brian.

 

i had a look at a couple of housings and the threaded allen plug goes to the water jacket.

 

I have this done on my FD, I still have my A/C and P/S in the car. Anyone else done it with A/C and P/S in their car also?

 

ok it looks good and i want to do it but where are the two front oil cooler lines going to go now.

 

they are still in the same place, you can see them in the pictures too.

 

Nice mod.

Anybody have any miles on this setup? And do you block the original oil galley?