bjhines Posted April 19, 2006 Share Posted April 19, 2006 Here are a few pics of the cooled oil return I have drilled into the top of the differential housing.... It will allow oil to run forward around the pinion shaft through the top channel and out to the sump along the bottom channel... some of the oil will be dumped over the inner ledge and onto the rear pinion bearing... not the gear itself... I mocked this up on a broken R200 housing and tested 2 GPM flow in several locations.... this location will dump 75% of the oil down the top channel... and about 25% of the oil will run down the inner face of the housing around the pinion rear bearing... there is significant clearance between the inside of the housing and the back side of the pinion gear... this should not pour a lot of oil onto the fast spinning gear... therefore minimizing oil foaming, expansion, and cavitation of the pump... this flow pattern also works well with the normal flow pattern from the ring gear slinging oil onto this ledge... the top and bottom channels will freely allow quite a bit of gear oil to flow through them... I am trying to draw heat from the entire housing... by drawing it out of the drain bung on the rear cover.. and returning oil back to the top/front of the main housing... the cooled oil will pick up heat form the entire length of the differential housing... as well as providing extra lubrication to both the front and rear pinion bearings... The hole is tapped for 3/8-18 NPT... my cooler lines are AN-8, I have a setrab 9 row half width oil cooler with ducting.... Quote Link to comment Share on other sites More sharing options...
s3079893 Posted April 19, 2006 Share Posted April 19, 2006 are you going to mount the oil all the way up front where the radiator is and then pump the oil there and back? Is this for a racing car? Quote Link to comment Share on other sites More sharing options...
260DET Posted April 19, 2006 Share Posted April 19, 2006 I believe the Euro versions of the 300ZXTT had diff oil coolers from the factory, be interesting to see how they did it. Yours looks good but I'm no expert on the subject, usually the cooler itself is mounted not far from the diff. Quote Link to comment Share on other sites More sharing options...
BlackBeaut Posted April 19, 2006 Share Posted April 19, 2006 My S13 200SX short nose R200 has a hole in pretty much the same place that the oil cooler return line was hooked up to. I've just stuck a bolt in to the hole as I'm not ready to be messing with oil coolers yet. I've got the large finned rear cover which will hopefully keep things quiet for the time being. Cheers, Rob Quote Link to comment Share on other sites More sharing options...
bjhines Posted April 19, 2006 Author Share Posted April 19, 2006 With a midly modified L24... I am getting my open R180s soo hot that they sizzle when you spit on them.... I had to add a catch tank to the vent so that it would not dribble gear oil out and onto the exhaust.... I have been told by several people who race S30s in various classes that they hold up fine to this kind of heat.... but I am putting a 350HP V-8 in this car... and this is a Nismo CLSD unit.... I am very concerned about heat damage over time.... I do not expect to work on this rear end every season.. I would like it to last at least 8-10 seasons of abuse.... that is roughly 80-100 events... Quote Link to comment Share on other sites More sharing options...
mark Posted April 19, 2006 Share Posted April 19, 2006 JB, what kind of pump are you using? Quote Link to comment Share on other sites More sharing options...
HS30-H Posted April 19, 2006 Share Posted April 19, 2006 Nothing much new under the sun is there? Photo ( taken in late 1972 ) shows an R200 from a Nissan 'Works' 240Z rally car: Quote Link to comment Share on other sites More sharing options...
bjhines Posted April 19, 2006 Author Share Posted April 19, 2006 HS30H..... If you only knew how much time I spent looking for a picture like that.... The funny thing is... I have a schematic/diagram of the system written in Japanese... It seems to show the return in a similar location.. but dumping oil onto the ring gear and pinion... I brought this up with a highly respected BMW team Mechanic in Florida... He told me NOT to return oil directly onto the gears... He said that it would foam the gear oil and cause a great deal of expansion, parasitic drag, and could cause more localized heat due to shearing the excess oil out of the gears... so I did my own research using an junker R-200... I managed to find a location that would get most of the flow down the upper channel... with a small amount of over flow going down to the rear pinion bearing... It stays off the gears... and the force of the oil being slung off the ring gear is likely to force all of the returned oil down the top channel.... It is funny to me that NOW THAT I SEE A PICTURE... that is EXACTLY what Nismo did in their race cars... At least it confirms my solution is correct... I wonder what they did for the oil pickup.. and if they added any slingers or traps inside.... Where did the works cars mount the heat exchanger... how big was it... and what was their flow rate.... did they use an external resivior... and where did they vent the system...?????? I have my own ideas... but it would be nice to see what they had done... Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 19, 2006 Share Posted April 19, 2006 looking good! I am curious like mark what type of pump you decided on. Also where will you mount the cooler? At the rear of the fender well im guessing? I am thinking about doing something of this nature because I am using a smooth rear cover. However it seems like there was a post a while back regarding diffy coolers and everyone got into a bit of a argument weather or not it was worth it. Looks like a great idea to me! Especially with the availiblity and price of oil coolors and pumps. Quote Link to comment Share on other sites More sharing options...
bjhines Posted April 19, 2006 Author Share Posted April 19, 2006 Tilton pump with Buena seals...$179 Setrab narrow 7 row cooler... it is compact but it has a huge surface area and tiny volume... flow is good too.. It will go just behind the mustache bar.... with an air scoop with debris trap... I am still trying to decide of I should use the finned cover... I think I will jsut go with an external resivoir. Quote Link to comment Share on other sites More sharing options...
Synlubes Posted April 19, 2006 Share Posted April 19, 2006 I am still trying to decide of I should use the finned cover... I think I will jsut go with an external resivoir. The finned rear cover will get you the added bonus of extra volume without having to mess with an external oil tank. Also look at using a synthetic gear lube. This will also be a benefit for cooling. Very nice work! Quote Link to comment Share on other sites More sharing options...
331CI 280z Posted April 19, 2006 Share Posted April 19, 2006 The finned cover will also dissapate heat, and is threaded for an oil cooler, so no fab work would be necessary. Quote Link to comment Share on other sites More sharing options...
HS30-H Posted April 19, 2006 Share Posted April 19, 2006 The funny thing is... I have a schematic/diagram of the system written in Japanese... It seems to show the return in a similar location.. but dumping oil onto the ring gear and pinion... Maybe that was a later system for ( essentially ) road cars, as opposed to serious race cars? The later R200 long case diff carrier castings had a boss that could be drilled for a cooler return. It is funny to me that NOW THAT I SEE A PICTURE... that is EXACTLY what Nismo did in their race cars... At least it confirms my solution is correct... I wonder what they did for the oil pickup.. and if they added any slingers or traps inside.... Where did the works cars mount the heat exchanger... how big was it... and what was their flow rate.... did they use an external resivior... and where did they vent the system...?????? I have my own ideas... but it would be nice to see what they had done... First of all' date=' remember that this was was a [i']long[/i] time before the formation of 'NISMO'. It was Nissan's 'Works' competition department that built and developed the Works circuit race and rally cars, and 'Nissan Sport Service' that developed and sold the parts in the 'Sports Option' race parts lists. Here is a scan from one of the Sports Option catalogues, showing the diff cooler kit that they sold over the counter in Japan. You will see that it simply consisted of a pump ( which was designed to be fitted inside one of the tool bins on the inside of the car ), a small oil cooler, a relay and a switch. Extra oil capacity contained in the pump lines and oil cooler was deemed to be sufficient to make an oil tank / reservoir redundant: However, the true Works race and rally cars often used a more complex system that included a heat-exchanger. This heat exchanger was housed on the inside of the body at the rear - right around the fuel filler area, and consisted of a pair of fuel pumps, a small fuel tank also acting as a swirl pot, and the heat exchanger. The diff oil pump - housed in the tool bin - pumped hot diff oil up to the heat exchanger, where it was cooled by the fuel passing through on its way from the tank to the swirl pot and carbs or injection system. Apparently it was a pretty effective solution. In fact, on a couple of rallies in the early 70s the Works mechanics disabled the diff coolers, as it was decided that the weather was cold enough for them not to be needed. The diffs on three out of four team cars promptly failed due to overheating ( the Loctite holding the crownwheel bolts melted ). I'm afraid I don't have any hard data for the heat exchanger systems, but I do have a brand new and unused cooler pump on the shelf in one of my garages. I will see if I can get any capacity / flow rate information from it. The rear covers on the Works cars had extra oil baffles inside, and the pickup for the pump was a long tube that went down through the rear cover from the top at an angle. I have a Works schematic drawing of this somewhere. I'll see if I can find it. Alan T. Quote Link to comment Share on other sites More sharing options...
bjhines Posted April 19, 2006 Author Share Posted April 19, 2006 331ci 280Z..... Well... It certainly is not easy to bolt on a finned cover... I think it may be easier AND cheaper to add a tank... HS30H... THANKYOU!!! for the fantastic information.... the schematic mentioned a heat exchanger... but I thought it was tied into the water system somehow... I had no idea they were using FUEL... what a brilliant idea... Quote Link to comment Share on other sites More sharing options...
Sparks280zt Posted April 19, 2006 Share Posted April 19, 2006 does AZC not sell the mustache bar now that allows you to use the finned cover in an s30? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted April 20, 2006 Share Posted April 20, 2006 It's also really easy to make a new link there that allows room. Hell I did it as one of my very first fabrication projects, and mine even adjusts the rear toe. John- why you would want to put heat into your fuel (which will cause you to LOSE HP) to cool a diff that's only running a 20 or 30 minute session is beyond me. But you're doing nice work, so kudos on that. Quote Link to comment Share on other sites More sharing options...
bjhines Posted April 20, 2006 Author Share Posted April 20, 2006 JM.. I totally agree... I would not want to heat the fuel.... and I like your rear toe adjuster.. nice work... I just happen to have some tanks and coolers on my shelves from previous projects... I would have to find a finned cover and spend the time making the rear bracket.... I may have located a finned cover today... someone is checking for me.... If you guys know of a cheap ready source... please let me in on it... Quote Link to comment Share on other sites More sharing options...
frank280zx Posted April 20, 2006 Share Posted April 20, 2006 I believe the Euro versions of the 300ZXTT had diff oil coolers from the factory, be interesting to see how they did it. Yours looks good but I'm no expert on the subject, usually the cooler itself is mounted not far from the diff.' even s130 have oil coolers on a 3.3 gearing, the 300tt's had gearboxcooling aswel ( on the BW ) that im installing in my car aswel Quote Link to comment Share on other sites More sharing options...
frank280zx Posted April 20, 2006 Share Posted April 20, 2006 Maybe that was a later system for ( essentially ) road cars' date=' as opposed to serious race cars? The later R200 long case diff carrier castings had a boss that could be drilled for a cooler return. First of all, remember that this was was a [i']long[/i] time before the formation of 'NISMO'. It was Nissan's 'Works' competition department that built and developed the Works circuit race and rally cars, and 'Nissan Sport Service' that developed and sold the parts in the 'Sports Option' race parts lists. Here is a scan from one of the Sports Option catalogues, showing the diff cooler kit that they sold over the counter in Japan. You will see that it simply consisted of a pump ( which was designed to be fitted inside one of the tool bins on the inside of the car ), a small oil cooler, a relay and a switch. Extra oil capacity contained in the pump lines and oil cooler was deemed to be sufficient to make an oil tank / reservoir redundant: However, the true Works race and rally cars often used a more complex system that included a heat-exchanger. This heat exchanger was housed on the inside of the body at the rear - right around the fuel filler area, and consisted of a pair of fuel pumps, a small fuel tank also acting as a swirl pot, and the heat exchanger. The diff oil pump - housed in the tool bin - pumped hot diff oil up to the heat exchanger, where it was cooled by the fuel passing through on its way from the tank to the swirl pot and carbs or injection system. Apparently it was a pretty effective solution. In fact, on a couple of rallies in the early 70s the Works mechanics disabled the diff coolers, as it was decided that the weather was cold enough for them not to be needed. The diffs on three out of four team cars promptly failed due to overheating ( the Loctite holding the crownwheel bolts melted ). I'm afraid I don't have any hard data for the heat exchanger systems, but I do have a brand new and unused cooler pump on the shelf in one of my garages. I will see if I can get any capacity / flow rate information from it. The rear covers on the Works cars had extra oil baffles inside, and the pickup for the pump was a long tube that went down through the rear cover from the top at an angle. I have a Works schematic drawing of this somewhere. I'll see if I can find it. Alan T. Hi Alan dont the UK models of the 300TT have de Gearbox cooler and oilcooler ? I know the UK did not get the stock Turbo ZX . that in holland has a cooled diff from the factory .. and it looks exactly like what you have there ! and they do have the longer tube in the cover. Needles to say that i have 10 of these pumps, so i think i can try a flow rate by testing say 4 letting them run for a set time, and measure the pumped liqiud. BTW intresting 4.3 diffs where Guus just installed his 4.6 in shop ( he needs to get more oil though) Now all he needs is some power and handling to back up that diff Quote Link to comment Share on other sites More sharing options...
331CI 280z Posted April 20, 2006 Share Posted April 20, 2006 I believe that Courtesy Nissan is no longer selling the finned differential covers. I ordered and got mine from them several months ago, but it looks like they are discontinued on their website. I have 2 Nismo covers. One on the car, and one new in the box. I was going to keep the one in the box for another project, but if I get the right price for it, it's gone. In my opinion, the fab work necessary for the finned cover is much less intensive then the work involved in tapping the differential itself. Quote Link to comment Share on other sites More sharing options...
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