MG Sports Cars

Steve,
I did not find the speedometer, fuel gauge or tach problems to be much more than nuisance items on the to be fixed list. A GPS devise and or a smart phone worked well for me. I trust my gps for accurate speed, I do not trust most speedometers even in new cars they are often off enough to get a ticket.
Now the vibration was disconcerting and in my opinion a much higher priority. Once near the TX/ AR state line I pulled over to tighten the fancy nut on the "star wars" air breather, it was nearly off and ready to smash the windscreen before skipping down the side of the interstate at 70 mph./ Also carbonated beverages must be opened with great care after being transported in this fine machine.
If you decide to shuttle Roadmaster to FC in Durham, and need any help like a ride home, just let me know.

If the diff comes out the axles should be balanced. It could help. (But don't forget to loctite the hub splines on reassembly. They could be difficult to disassemble. Balance should be OK, the shafts turn at 1/3-1/4 driveshaft speed.) We do not know the gear ratio so Steve, if you put it back on your lift could you mark the driveshaft and tires and see about what we have? We will not turn down any diff in good working order Max. But it would not hurt to know what we are starting from. The engine doesn't care much, but that could move the vibration out of the cruising range possibly.

What was the issue with the cam? Is it still an issue? Seemed to me the mileage was up and it was running well. We don't need more power.

I believe the engine and pinion angles are both at 3 degrees but it would not hurt to check. The driveshaft is balanced I believe, at least Mike Malonious paid for it and the shop is a reputable one. There should be some offset, I think the pinion is probably higher than the tailshaft. But zero offset should not cause vibration. Stock lower brackets are available I think with different angles for the pinion if we have to change that. With everything settling in there could be some changes.

Good job Steve, on the wheel vibration btw.

I found a neat capacitive fuel gage used on experimental planes:
[www.aircraftspruce.com]

Surprisingly affordable, though not inexpensive. May not be something we want here tho.

So Max, would Flying Circus like to have the car back up there now that it runs and is driveable? I have no doubt Bill would go along with that.

Jim

Max,

I think I added a couple of spare relays to the tool kit when the car was here, but I'm not sure.

If the "ignition" relay fails, none of the "key-on" circuits will work. If they are working, the relay is good.
I sent you a package of Jag IRS info a few minutes ago. That should help you find replacement differential internals if needed.

Dan

Jim,
When I had the diff open before, I checked the tooth count. It is a 3.54. I think it should have a 2.88, but I don't have one, so whatever we can get.
I don't think it will fail soon. It could be loud for years.
Should I pull the dash or forget it?
PJ, thanks for the offer. I may take you up on it. Let's see what Max wants to do. We could put in a new diff at Max's or here.
Steve

I don't hear anybody donating good working gages Steve. I guess it is your call.

Jim

Hey Guys:

I remember Steve saying he counted a 3.54 (even though rumour was it was a 3.7...). I also agree that a 2.88 would be better, but according to the info Dan sent me I'm only going to find a "recommended" one in an 89-95 HE XJS. (Dunno if we got one of those out in the Field of Screams...) Failing that, at least the 3.31 would be a mild improvement...

I'll print out the info pages and pick Toby's brain sometime during Lunch. :)

AS for the car coming HERE--- ooh, no. WE are absolutely slammed to the fences and there is no room for even one more vehicle, let alone one that would distract from work hours. I wouldn't dare broach that subject at the moment... :-(

I would suggest the car "winters" at Steve's and points further south (and get the driveshaft checked for balance, measure the installed angles, check the u-joints, check the halfshafts, etc. to find this vibration!)

IF THE VIBRATION (driveshaft!) has been really bad-- THIS can be ruining the outer pinion bearing and making the axle noisy! (Though, was it noisy from the get-go?). I would be loathe to go through all the effort of doing a diff swap just to put it into a bad situation...


Perhaps springtime (that's March 1st down here for all you Northerners... nyah nyah!) we can see about sneaking it up for a weekend worksession like before. (Maybe get the newest AARP member-- Floyd!-- to come over. ;-) )

Also, it would be great to figure out HOW to calibrate the speedo-- but IF our goal is to drop the ratio, then we'd still have to calibrate it yet again!


RE: Gauges. Did anyone notice if the tach reading got WORSE with the MSD? You can't run a Lucas tach with an MSD. I wonder if we need to look at a set of Stacks or something.... (RAcetech?) I like the look of the SW-- but the suckers don't work!

Cheers,

M

I will NEVER join that liberal organization, AARP!

As for the rear gears, Yes, there were always noisy. They howled, roared, & whined all the way home from Charleston, WV.

I agree with double checking the driveshaft/u-joints. I remember Jim B having a go at a home rebalance. Maybe his remedy departed the driveshaft?

Well, no, we were going to do that when Mike volunteered to take the driveshaft to Dayton Clutch and U-joint Service so we had them shorten it 1/2" or so and balance it. Doesn't hurt to check it when it is out but it should be right.

Perhaps running it on the lift (with wheels both off and on) will reveal the vibrating component.

Did the tach get worse with the MSD? Maybe, but it has never worked right. Personally I doubt it ever will and I feel the same way about the fuel gage. Personally I think it's time to punt those SW gages over the wall. But we need something to replace them with.

331 gears will work fine. 288's will too. Or anything between.

I really can hardly believe we are at the point of NVH reduction on this project. What that means is that the build is a complete success and now we are fine tuning it. Well done! It is finally becoming the car that everyone will want to drive and that has been a long time in coming. Eventually we will figure out how to lighten the pedal pressure and otherwise "tame the beast" to the point that there is really nothing left to do but show it off and I think we are most of the way there.

You guys are Good.

Jim

Had the car on the lift. I had forgotten to grease the rear end, many fittings. While lining up the left half shaft fitting I heard it clicking.
The inner joint had rust streaks coming from it. I greased everything. The suspect joint would not take grease to my satisfaction ( only seeps from one cap) .
Went to Car Quest, they have the joints. Now:
1. Replace just the one joint.
2. Replace both on that shaft.
3. Replace all 4 in both shafts.
4. Wait to do any of them until we get a new diff and do it all at once.
The joints from CQ are Spicer and cost me under $20 apiece.

The car is still very driveable, it just shakes at high speed.

Steve

Okay, maybe it's not the driveshaft. What about a worn tailshaft bushing?

Noise, vibration, harshness - yeah, I had to look it up. The glass fitting properly against the seals would go a looong way towards helping the noise. Of course, the wind noise also helps drown out the rear gear noise. ;)

Don't recall any harshness. One down, only two to go!

I mentioned way back when I had the car in March that I feel that the Stars Wars air cleaner is subjected to too much wind force at Interstate speeds. It needs to be braced or swapped for something else during Interstate trips. We don't want to see that thing imbedded in the windshield of the car that is following us!

Steve,

You posted that while I was slowly pecking away. I like option #4 provided that the car doesn't wind up being handed of to someone without the skill/facilities to do the job before we locate another diff.



Edited 1 time(s). Last edit at 11/29/2012 11:23AM by MGBV8.

Probably all four should be replaced, however I'd just do the one side unless the diff is being replaced as the other side will need to be unbolted eventually anyway.

So Max, you still there? It sounds like the sooner Steve can get a diff from you the better, provided that that was your offer.

And I wouldn't put it off Steve.You will recall that is part of the upper suspension link.

Jim

I will touch base with Max.

Steve

I'm here!

I will not be producing a diff in the next week, so don't wait on Me.

Personally, because of the future diff work and because I do u-joints as LITTLE as possible (all that broaching/interference fit just renders the flanges useless over time), I would vote for change the ONE that is bad and see if that improves it (vibration-wise).

I never heard back-- was the Toe Out issue ever resolved in the rear? I thought maybe someone cut the trailing arm and rethreaded, but not sure.... That would n't cause a vibration, but would make it squirrely and speed and cause tire "cupping"-- which THEN might be causing roadnoise/vibration.

$.02

M

PS: I'll try to get a "Diff" ball rolling, but busy time here. We close for a week at xmas and try to get as many cars out the door as possible. Extracurriculars have to take a back seat... :-p

Max,
the toe problem was taken care of.
I will plan to replace the one joint and then see what happens.
should be next week when I get to it.

Steve

Steve, you may change your mind.
The axle spline where it goes through the hub has been loctited in place. It is a spline about 2-3" long and you are not likely to get it apart with just a BFH.
This is in accordance with Jaguar tech bulletins which require the loctite to prevent stub shafts from shearing off. I do not think you can change the u-joint without removing the stub shaft from the upright.

The good news is, at about 300 degrees F. the loctite softens to the point where it offers little resistance and the spline and hub is a slip fit. The synthetic lube in the hub will easily tolerate that temperature I believe so the trick is to position a small heater to warm the upright slowly and evenly until the hub will slip off the spline. That may take half the day so schedule accordingly.

This is why I say you may change your mind about doing them both while you have it apart.

Jim

Jim,
thanx for the infor.
I was just planning to change the inner joint now and wait for the new diff to do the rest.

Steve

Maybe you can drop the inner end and change the joint without pulling the shaft.

Jim

Update:

Talked with Toby-- I'll take the spec sheets from Dan into the shop and we'll see what we have for parts cars that might provide a suitable donor differential. No guarantees, but I think the odds are good. :-)

However, I think the 2.88 is a longshot-- we only have one XJS parts car, and it's a 6 cyl. :-(

M

Guys,
In regards to the half shaft u-joints, as you can well imagine, some are better than others. I did quite a bit of research on them, both on the Jag-lovers web site and different drive shaft shops and this is what I came up with. Driveshaft Specialist of Texas seemed to be very knowledgable about their business and they highly recommended the Spicer #5-1410x for this application. It's a cold forged, solid cross, non-greasable u-joint, virtually indestructable. Shop around, good prices are available.
[www.driveshaftspecialist.com]





Edited 1 time(s). Last edit at 12/01/2012 12:02PM by TR6-6SPD.

Ken,
I can get those u-joints for about $22.
If that is what the group wants to use.
I prefer a greaseable joint.

Steve