KMS Differential Questions

[1795]

John,

No, we did not install the differential cooler at this time as the majority of the races are sprint races of 30 minutes or less. If we ever consider doing a race that lasts longer than an hour, i.e., 12 hour or 24 hours of Sebring we will need to install a cooler. At this time have not seen any diff oil showing signs of excessive heat. We are running a 3.54 Dana currently. If for some reason we went with a higher gear ratio and were spinning the gears faster we might consider it as well.

Jim

[CompClassics]

Morris,

All and all the Superformance designed catch can is a poorly designed bandaid for an incorrectly installed differential breather location. It’s as if they were trying to create an Accusump without the pressure behind it to keep the oil in the differential with the catch can and placement. Once the lubricating oil leaves the differential the damage is done. If everything is working correctly the only thing in the vent hose and catch can will be vapors, nothing more.

[patrickt]

Originally Posted by 1795

JWe are running a 3.54 Dana currently.

Uhhhh no, it's a 3.538461538461538

[1795]

Originally Posted by patrickt

Uhhhh no, it's a 3.538461538461538

Patrick,

They must love you in court. How can someone as obsessive as you have chosen beige for a car? Don't know what this site would be like without you.

Jim

[Morris]

Originally Posted by CompClassics

Morris,
Once the lubricating oil leaves the differential the damage is done. If everything is working correctly the only thing in the vent hose and catch can will be vapors, nothing more.

I agree 100%....

[Riverside racer]

Originally Posted by ALF

I'm following this thread and now I'm unsteady.

Should I close this breather line or is it OK

What thread and size is that breather hole Alf? Ross

[CompClassics]

The AN fitting size is a -6 male to the hose, I believe the differential case is tapped for a ? NPT thread. I will be getting my clients differential and damaged parts back from the rebuilder today. I’ll post the pipe thread size when I have it in hand.

Alf your breather is in the correct spot according to Kirkham’s recommendations.

The Kirkham differentials are shipped with this AN fitting already in place.

[E5USMC]

I’ll have to get under mine and see if I can feel the top of my diff to see what I have on top of mine.... a fitting or a plug. Not sure how much room there is to work or if I’ll need to drop the diff to get my lines installed to KMCs recommended location.

Granted.... my catch can is dry as a bone as is the area around it so no fluid is overflowing from there but even if the can is somewhat filling during a drive I’m still missing fluid from the diff. What a pain!!!!

[CompClassics]

Picked up the differential today. I’ll post photos later.

Riverside racer,

The pinion vent is tapped 1/2” x 14 NPT

[Morris]

Originally Posted by CompClassics

Picked up the differential today. I’ll post photos later.

Riverside racer,

The pinion vent is tapped 1/2” x 14 NPT

That’s so you can use a -8 AN hose to run cooled oil back on the Pinion Bearing....like I said .....that is a return line to the rear end from the cooler.....

Vent lines are -6 AN and use 1/4” NPT.......on the transmission and rear end....

[patrickt]

Speaking of Powr-Lok break in (which no one was, but who's counting), Jaguar released an interesting service bulletin back in the early 1960's specifically advising not to do the recommended differential oil change at 500 miles if you had a Powr-Lok (which they had always prescribed up until then). Now, if you've gone to the trouble of having your Jag rear diff rebuilt by super-pros then, by all means, follow their directions for break in and not a 50 year old service bulletin. I don't think they even had climbing gear lube back then much less friction mods specified by today's rebuilders. Regardless, here it is should anyone ever ask you about it, which they won't.

[CompClassics]

Originally Posted by Morris

That’s so you can use a -8 AN hose to run cooled oil back on the Pinion Bearing....like I said .....that is a return line to the rear end from the cooler.....

Vent lines are -6 AN and use 1/4” NPT.......on the transmission and rear end....

Morris,

I agree with you about it being the return line for the differential cooler, that is the way I have my car plumbed. I also changed out the differential cover on my car very early on when the Kirkhams mistakingly putting jeep covers with the higher oil capacity that were leaking everywhere to a proper Jaguar cover.
Because of the lack of an oil deflector on the billet aluminum cover that Kirkham supplied with this differential it seems to be the most feasible spot for a differential breather in this circumstance.

When I picked up the differential from the rebuilders they had reinstalled all of the differential mounts except the pinion support mount, they felt that someone had compromised the mounting breaker holes and that they might pull through, why would someone have done this on a purpose built part?

[CompClassics]

Looks like another part that the manufacturer is not going to back. I will say this my beef is not with Kirkham on this issue as I firmly believe what I was told by David and others that have PM’d me on this subject.

[cobrakiwi]

Man seeing this bracket reminds me of a lot of shoddy workmanship I have had to deal with,

I know you should not have to, but not that big of a deal to fix it, do a little welding and drill the holes where they should be.

While the welder is out weld the baffle on the diff cover.

[CompClassics]

cobrakiwi,

I remember your plight well, it is far better to make these deficiencies public if the manufacturer is not willing to have respect for the person that has bought their product.
I am going to reroute the breather per Kirkham’s instructions and block off the other port.
As per the transmission mount, that can be corrected too, as many of the issues with this chassis already have been. This car was not a case of you get what you pay for.

[Morris]

John

When you install the rear end into the chassis....the front mount lower section holes do not line up with the holes in the chassis....so what you have to do .....is with this bracket loose on the rear end (just start the bolts on the front of the rear end bracket) ....then you have movement in the lower section and you can wiggle the bracket until you get the lower bolts started in there threaded holes.....then you can start tightening the bolts on top around the rear end....then go back down to the lower bolts and tighten them up in the chassis bracket......

My guess is that someone wanted more play to line up the lower chassis bolts....ie; elongated the holes to make it fit.....

McMaster Carr has some extra thick washers that could probably be used to clamp the bracket properly......or use some hat type washers and grind the hat down to the thickness of the bracket.....

Great that you caught this issue now and not later....it’s a wonder the diff didn’t move around....and make some noise....

[CompClassics]

Morris,

I fully agree with your assembly procedure, this was a simple case of an amateur hour move. These are simply issues that the purchaser shouldn’t have to be responsible for or expect for such an expensive “roller”.

[David Kirkham]

Originally Posted by Riverside racer

What thread and size is that breather hole Alf? Ross

The threads in the differential case are 1/2 NPT. The fitting to the hose is a dash 6.

David

[David Kirkham]

Originally Posted by CompClassics

Morris,

I agree with you about it being the return line for the differential cooler, that is the way I have my car plumbed. I also changed out the differential cover on my car very early on when the Kirkhams mistakingly putting jeep covers with the higher oil capacity that were leaking everywhere to a proper Jaguar cover.

Actually it wasn't a mistake. The differential covers with the hole in the Cobra location (lower) have not been available for a long time now. The jeep covers are also much thicker so they tend to hold the back of the differential case together better than the original covers which were quite thin (they are only something like 1/16" thick). We ultimately decided to billet the covers for a variety of reasons, the most important being we were able to put the fill hole in the right location.

Originally Posted by CompClassics

Because of the lack of an oil deflector on the billet aluminum cover that Kirkham supplied with this differential it seems to be the most feasible spot for a differential breather in this circumstance.

If anyone can figure out how the billet in the deflector I'd LOVE to hear!!!

Originally Posted by CompClassics

When I picked up the differential from the rebuilders they had reinstalled all of the differential mounts except the pinion support mount, they felt that someone had compromised the mounting breaker holes and that they might pull through, why would someone have done this on a purpose built part?

I'm really surprised at the size of those holes???

David

[David Kirkham]

Morris,

That is some really clean work--as always. Thanks for sharing the pics--I may need to "borrow" some of your ideas!!!

David