i received my obx diff from sparktec today and took it apart to inspect it to see what work will need to be done befor the install. i am doing this for information if someone decides to take this route so you will know what you need to do, and dont appreciate scorn being heaped on me for trying this unit..it cost me $400 usd delivered to canada so idont expect it to be of equal quality of some name brand diffs. 100's are being used every day with only a few failures..i know the risks and accept them.
on first impressions the diff looked pretty good. that casting was smooth with no inclusions visible.
![Image]()
![Image]()
![Image]()
![Image]()
i started stripping it down to get measurements for the bellville washers and bolts that i will be changing.. the original bolts were marked 12.9 but i will be changing them and thread locking things to be safe. all the bolts were the same length and none were stripped. the bellville washers, 7 of them stacked
()()()( will also be changed. i contacted richard bryant to get the washers and bolts and as this is the first svt diff he is supplying parts for he is giving me a $15 discount on the bolts/washers as i got to do some measuring for him.
he sent me this email on the subject of these diffs.
John,
It is a good design done with fairly low quality manufacturing.
Like you mentioned things are rough and should be deburred, the washers are junk, the bolts are sometimes overtorqued.
Other things like making sure that axle splines are tapered so you can get your c-clips out. Make sure the center sun gears aren't backwards (c-clip taper is on the correct side).
Make sure the axle fits and isn't too tight after the bearings are pressed on (they sometimes compress the holes a little).
Make sure the sun gears are machined squarely (problem with a run of neon differentials).
Check the runout on the differential (mainly a problem with one run of honda differentials where they are a little off center and wobble taking out bearings).
If it all checks out then you will be fine. Remember this design is MUCH stronger than a normal open differential. Even with poorer quality materials it won't have problems like spitting out diff pins.
If you have good mechanical ability and can check things out then it is worth the time to deal with them compared to a quaife.
-Rich
![Image]()
![Image]()
on further examination the cases will need some deburing and cleaning up on the inside as there are some sharp edges and the oil holes will need cleaning out as there is some swarf from machining. also the axle splines are not tapered as he mentioned so i will be fixing that with a lathe. on the whole the unit looks very sturdy and seems to be made of a pretty tough steel as i tried to mark it with a file and it didnt scuff it. not very scientific i know but its only an obx diff.
![Image]()
![Image]()
i will update this post as i complete the deburring and reassembly and instalation into the getrag tranny.
on first impressions the diff looked pretty good. that casting was smooth with no inclusions visible.
i started stripping it down to get measurements for the bellville washers and bolts that i will be changing.. the original bolts were marked 12.9 but i will be changing them and thread locking things to be safe. all the bolts were the same length and none were stripped. the bellville washers, 7 of them stacked
()()()( will also be changed. i contacted richard bryant to get the washers and bolts and as this is the first svt diff he is supplying parts for he is giving me a $15 discount on the bolts/washers as i got to do some measuring for him.
he sent me this email on the subject of these diffs.
John,
It is a good design done with fairly low quality manufacturing.
Like you mentioned things are rough and should be deburred, the washers are junk, the bolts are sometimes overtorqued.
Other things like making sure that axle splines are tapered so you can get your c-clips out. Make sure the center sun gears aren't backwards (c-clip taper is on the correct side).
Make sure the axle fits and isn't too tight after the bearings are pressed on (they sometimes compress the holes a little).
Make sure the sun gears are machined squarely (problem with a run of neon differentials).
Check the runout on the differential (mainly a problem with one run of honda differentials where they are a little off center and wobble taking out bearings).
If it all checks out then you will be fine. Remember this design is MUCH stronger than a normal open differential. Even with poorer quality materials it won't have problems like spitting out diff pins.
If you have good mechanical ability and can check things out then it is worth the time to deal with them compared to a quaife.
-Rich
on further examination the cases will need some deburing and cleaning up on the inside as there are some sharp edges and the oil holes will need cleaning out as there is some swarf from machining. also the axle splines are not tapered as he mentioned so i will be fixing that with a lathe. on the whole the unit looks very sturdy and seems to be made of a pretty tough steel as i tried to mark it with a file and it didnt scuff it. not very scientific i know but its only an obx diff.
i will update this post as i complete the deburring and reassembly and instalation into the getrag tranny.
]
