beatnu

ive just been recommended to put a 3 window stationary gear bearing on just the rear gear just wondering what you guys think on this ive all ready got my oil pressure sitting on 95 by spaceing out the pressure control valve and regulator but need to replace my rear gear bearing hence the ? oh and one more thing i was checking my oil jets in the eshaft to make shaw it was all clean and desided to look at a couple of old shafts i had luying round the 2 that i had a look at had no springs or ***** in them any idea on why? and can anyone tell me whats involved in cross drilling the eshaft thanks guys honestly your help is aesome

beatnu

bump

Lynn E. Hanover

On older engines the front oil pressure relief is set at 144 pounds. It is in the front cover and is there to protect the "O" ring junction, and the oil radiator from overpressure in a cold start. It needs to stay at 140 pounds to do that.



The rear oil pressure relief in the bottom of the rear iron is the one you play with. That 95 pounds is plenty. We run just 100 pounds for all out road racing.



Lots of folks think that you will get better rotor cooling by spraying in more oil from the crank. The oil sprayed into the rotors gets badly foamed, and becomes a poor coolant, as air acts like an insulator. Those folks remove the springs and ***** so as to allow more oil flow into the rotors. Probably doesn't hurt anything, but it reduces the idle oil pressure to 5 pounds. That is also no problem, for the huge oversized bearings, but it looks tacky to have so little oil pressure and that light blinking.



But then you jack up the oil pressure to 100 pounds or more, and those stock oil jet holes start looking pretty big. So you install a Weber air jet or main jet in the 200 size (Racing Beat) or I use a 180 main jet for 100 PSI oil pressure. Works great.

Never a failure. The ***** and springs are there to speed up rotor heating (by not spraying oil into them at idle) in a street car to get emissions working quickly, and to have some oil pressure showing at idle, from the undersized stock oil pump.



All of the modern engines now have windowed rear bearings. The later stationary gears have a groove behind the bearing shell to feed the windows. So go ahead and use the newer stuff. The front bearing is more likelyto fail, and if you plan on really hard use, like all day pylon racing, then an extra oil line to the front statioary gear bearing would be a good idea.





Lynn E. Hanover

beatnu

ok sory you got me a bit lost on it .on the bottom off the front cover series 3 rx7 there is a spring and piston they call a pressure relief valve the spring free lengh is ment to be 73mm you say not to alter this?

what sort of oil pump do you run other than stock? 13b ?



i had a engineer cut a 1.5 ml groove in behind the new 3 window bearing on my stock statoinary gear is this good? i also have a later model 9 window 13b front gear i could get machined down to suite 12a or i could perform the same mod as the rear one?



as for the oil jets i dont quite get if you thought it was good or bad sory ?



how do you do this ?

{an extra oil line to the front statioary gear bearing would be a good idea. }

Lynn E. Hanover

The front pressure relief should already be set at 140 pounds or more. So no need to change that.



I use (or have used) Weaver Brothers, (OK if you can get one cheap) Peterson (The newer square ones are no good. the older round ones are just fine). And now Moroso. All are three stage dry sump pumps. All set to deliver about 100 to 110 PSI.



The front gear and bearing need only have a hardened gear and lots of oil to survive very hard use.

It would be possible to window the bearing but to what end? When you jack up the oil pressure this improves oil flow to all bearings. The problem is not lubrication, it is cooling the bearing surface. So the excess oil flow moves the heated oil off of the bearing interface, so the low melting temp of the antimony does not ruin your day. So for racing you need lots of cool oil moving fast, and that means big pumps and high pressure.



The front bearing is at a disadvantage, in that the path from oil entering the block to the front bearing is long and has way too many 90 degree turns. Also the very start in the upper dowel gallery has to pass through the dowels where you can see threads (used to pull the dowels) and that makes for lots of drag.



So, in all out racing an additional oil line is installed at the point where oil from an external source enters the engine. Usually a block that replaces the filter stand. The external hose more than doubles the cross section of oil gallery to the front bearing.



The lateral gallery to the front bearing is drilled out, and tapped for a dash 10 tube to boss fitting, to attach the hose to.



In all out racing the crank is modified with leading scoops on the main bearing oil holes, and trailing tear-drops on the rotor bearing oil holes. The springs and ***** are removed and a Weber air correction or main jet is installed, to limit oil flow to the oil spray jets. Because, when you jack the oil pressure up from stock (about 72 pounds) to 100 to 110 pounds too much oil sprays into the rotors. In racing the oil pumps are huge and the idle is usually set up pretty high, so low oil pressure at idle is just not a problem.





Lynn E. Hanover