You Are Stupid
Nice talk, that will get you in the door, turn off the audience and youll never get you point across. Yeah Yeah Yeah.
Well here is the message. I took the rear apart from yesterdays posting and took photos for you all. THe results were most amazing to me and I feel better informed about the issue at hand.
THis rear was not flogged at the track too much as I understand it and still the failure is complete though hidden. THe rear failure was that of the ring and pinion, not the spider gears or the pin in the rear. THe cause is still the same in my modest opinion, and I have a solutition for ya.
THe photos are in one of my albums, please feel free to browse the others for you entertainment. I have posted the link below.
You will have to look around and see the photos, technical stuff and not a primer on the rear end construction. But the images will show you how it works and how it looks inside. Further the wear or gaulling of the parts will show you how the wear and tear damage the internal parts of the rear end.
Recap: When I got the rear it looked ok at first. When I tried to twirl the spider gears it became apparent that the spiders were causing the pin to rotate in the case, this is not acceptable. THe PIN is anchored in the rear end case by a "roll pin" thru the case. The case has a photo of a dental tool sitting in the holes that this roll pin is set into, for your understanding. The roll pin is a hardened strip of steel rolled to form a cyclinder that expands and grips the pin and rear to provide retention of the spider pin in the case. Its a roll of metal strip forming a rolled up magazine shape with a hole in the middle and thus not solid. THe driving forces this particular rear saw, were sufficient to break the pin and allow the 3/4" diameter spider pin to rotate in the case.
I took apart the rear to expose the spider gears and the two side axle gears. Please see the shot of gears laid on the table and note the two pieces of the roll pin on the 9 oclock position. THe bigger gears turn your axles and the smaller ones are driven or rotated by the spider PIN. This pin is photographed to show you the tearing of the surface on this pin known as gaulling.
Gaulling Definition of Galling is caused by metal to metal contact and motion. THe forces causes the metal contacts to rub, melt and stick to one another leaving a rough surface, shreaded metal results. THis is due to poor lubrication and excessive stress allowing the metals to wear metal to metal. THis is a Taaaa Daaaa moment. The lube is the issue in addition to stresses exceeding the limits of the rear gears strength.
I have set a flashlight to illuminate the interior passages of the spider gears to show their chewed up surface which matches the metal missing from the PIN. THe engine turns the transmission, which thru gearing increases the torque 3 to 5 times and then turns the rear which increases the torque another 3 times. I have 300+ foot pounds of torque, not counting the shock from gear changes. 300 x 4 x 3 is 3600 foot pounds of force twisting the differential and all that is supported by the 6" long PIN, or 7200 pounds of force, yikes.
THe rear has little chance of surviving that long and if one wheel spins, the speed of the gears on the PIN really heat up the surface weaking the oil films strength.
THe spider gears look ok to me, the pin and interior of the spiders show lots of damage due to gaulling. THe axle gears show little distress in this particular rear and look sound. We need better lubrication to start with.
EXAMPLE: My son did not note the difference between the main engine bearings and put the thrust #3 bearing upside down using federal mogule bearings. Typically I use clevite which have both bearings the same. Anyway the oil passage of this bearing was closed off and the lower half bearing was covering the oil port, thus no oil fed the thrust bearing from day one. Well the car was run on the drag strip, converted to autocrossing and run for a year without incident. I had cause to tear into the car for other reasons and found the error much to my suprise.
THE FREAKING CRANKSHAFT had NO marks or distress though the bearing looked roughened. THe crank was not damaged because I had tried and run synthetic oil in the car and the 8 quart deep sump / scraper oil pan. NO damage because of synthetic oil, what an eye opener.
Back to the crossfire rear. I did the phantom grip differential over a year ago and went to synthetic oil. THis probably explains the lack of problems I have had with my car even though I drive the heck out of it autocrossing in two clubs here in Northern Va.
SOOOOOOOOO if you want your car to last, I can tell you that if you dont get synthetic oil in your differential soon .............................. _ _ _ _ _ _ _ _ _ _ _ _. See the Title.
Your W
DY
Crossfire rear dissection and eval. - CrossfireForum.org Gallery
Last edited by waldig; Jul 27, 2010 at 08:42 PM.