3rd member talk (ring&pinion setup etc.)

[gon]

I can see an easy way to put more oil in the differential (use half a U turn that has the same tread as the plug, and install it in the diff, making sure it points up. That way it will fill until “the half U” get to his top, how much depends on the size of “the half U”

My problem is that I think it is not a good idea to do that, and the pinion sealer will start to let go some oil.

[Ivan141]

I didnt think this one up myself.. a well respected ring and pinion manufacturer (richmond gear) recommends doing this for racing applications in their installation instruction video (which I have).

[adomz]

hey guys, really good writeups there!!

thumbsup!!

adam

will need all that soon i think!

[NoHachi]

Some helpful links and info:

Quote:20.1.2 Splash Lubrication
Splash lubrication is used with an enclosed system. The rotating gears splash lubricant onto the gear system and bearings. It needs at least 3 m/s tangential speed to be effective. However, splash lubrication has several problems, two of them being oil level and temperature limitation.
1. Oil level.
There will be excessive agitation loss if the oil level is too high. On the other hand, there will not be effective lubrication or ability to cool the gears if the level is too low. Table 20-2 shows guide lines for proper oil level. Also, the oil level during operation must be monitored, as contrasted with the static level, in that the oil level will drop when the gears are in motion. This problem may be countered by raising the static level of lubricant or installing an oil pan.
2. Temperature limitation.
The temperature of a gear system may rise because of friction loss due to gears, bearings and lubricant agitation. Rising temperature may cause one or more of the following problems:
- Lower viscosity of lubricant.
-Accelerated degradation of lubricant.
-Deformation of housing, gears and shafts.
- Decreased backlash.
New high-performance lubricants can withstand up to 80 to 90ºC. This temperature can be regarded as the limit. If the lubricants temperature is expected to exceed this limit, cooling fins should be added to the gear box, or a cooling fan incorporated into the system.

Quote:Worm gear lubrication
Worm drives are inefficient because the gears experience sliding rather than rolling contacts, leading to operating temperatures much higher than other gear types. Spur gears normally operate at 28°C higher than ambient temperatures while worm gear temperatures typically rise 50°C over ambient. This temperature difference is required to aid in dispersing the friction heat generated.

Due to the sideway sliding motion in worm gears, it is difficult to maintain a hydrodynamic oil wedge. This results in gears operating under boundary lubrication conditions. Also, high operating temperatures that approach 88°C and higher usually require oils with an ISO VG of 460 and higher. They also require good thermal and oxidative stability. The types of oils used to lubricate worm gears are compounded mineral oils, EP mineral gear oils and synthetics.

http://www.roymech.co.uk/Useful_Tables/D...ation.html
http://www.qtcgears.com/Q410/QTC/Q410P441.htm
http://www.machinerylubrication.com/arti...icleid=707
http://www.khkgears.co.jp/english/teach/KHK342_1.html

Judging from this info..both factors may be influencing ring gear failure, but temperature failure is most likely.
Also see the remark in one of the links about shockloads. Ordinary gear oild cannot handle the extreme stress from shockloads. In these cases synthetic fluid MUST be used..Now I am sure synthetics come at their own cost, but I'm too busy to find out now.

[gon]

great link's

I thought that an LSD oil could handle something like 120º, but from what I read it's more like 90

[wouter86]

[quote="Ivan141"]

-Increasing capacitiy the other way, there is this build-up thread of an N2 spec ae86 coupe where the rear axle housing is modified to allow more oil in it. A sort of protrusion is welded on the rear of the axle for that purpose. I have also heard a similar story from a guy that used to race a KP60 starlet
quote]

My brother has the ae86 bible with all the part numbers and stuff and I too saw that the rear axle was modified this way.There was a description written in english and said something about the oil being pumped into the diff via a copper tube that was aimed right where the ring and pinion connected.I can look it up if u are interested, don't know if a cooler was also involved, probably yes.

[NoHachi]

Quote:20.1.3 Forced-Circulation Lubrication
Forced-circulation lubrication applies lubricant to the contact portion of the teeth by means of an oil pump. There are drop, spray and oil mist methods of application.
1. Drop method:
An oil pump is used to suck-up the lubricant and then directly drop it on the contact portion of the gears via a delivery pipe.
2. Spray method:
An oil pump is used to spray the lubricant directly on the contact area of the gears.
3. Oil mist method:
Lubricant is mixed with compressed air to form an oil mist that is sprayed against the contact region of the gears. It is especially suitable for high-speed gearing.
Oil tank, pump, filter, piping and other devices are needed in the forced-lubrication system. Therefore, it is used only for special high-speed or large gear box applications. By filtering and cooling the circulating lubricant, the right viscosity and cleanliness can be maintained. This is considered to be the best way to lubricate gears.

Sounds like the above to me. Needed above 12m/s tangential speed.

[Ivan141]

On that subject, you can clearly see the oil pickup and oil return where the ring and pinion meet on the N2 car.
http://kaipower.web.fc2.com/story/ae86/v...ol.11.html

Cant say I like the way that the protrusion looks, maybe it is done this way due to clearance issues. My guess is that it acts like an oilpan so the pickup always has enough oil to keep the gears lubricated. The website mentions a 400cc increase in oil capacity.
Couldnt really see how the oil is routed outside of the axle.
Also note all the funky modifications to the 5-links.. panhard is relocated%reinforced...but that's all a bit off-topic.

[NoHachi]

The protrusion is made that way for a very good reason. Its the only way you can add volume to the housing, without changing the oil level. Going lower then the housing reduces already tight ground clearance. Anything above the oil filler cap doesn't get filled anyway. So you see the space you are left to work with.

To high an oil level will cause the gears to act too much like a whisk, beating the oil to a foam state. Foamed oil has very poor lubrication properties. Thats the reason that you ideally don't want to raise oil level in a car that won't be spending much of its time under high G cornering loads.

[firehawk]

Hmm, maybe using an external reservoir (possibly combined with the oil cooler) would be a good solution for increasing the oil capacity without making large protrusions such as the one on the Kai Power AE86. The reservoir could be pressurized so that an electric oil pump would suck from the bottom of the diff housing, fill the reservoir and cooler, and then return the oil back. The return path could be done through a pair of oil squirters, similar to those used to cool the pistons on smallport 4A-GE - putting these on top of the diff housing would ensure a constant lubrication on the gears with cooled oil. A relief valve would probably be needed in addition to the squirters to keep a constant pressure on the squirters as having them as the only return path would probably create too much pressure in the system.

This would require drilling four holes to the diff housing (intake, two squirters and relief valve) and making threads for them. The relief valve and squirters can be connected with copper tube, so that only two steel braided hoses would leave from the diff housing to the pump, reservoir and cooler which would be mounted to the body of the car. The power for the pump could be taken either from the fuel pump, or by adding a separate fuse and a switch to the dashboard/center console.