As stated by all on this post, the rear end ratio is indeed 2:88.
Since I would rather do some extra work than spend money, I opted to convert the 91 700r4 speedo from electrical to mechanical.

I have purchased a lockup kit, drive and driven gears, TV cable and filter and gasket set from Jegs, all of which came in today.

The lock up kit came with the 4th gear pressure switch, internal harness, external harness, a vacuum switch and an additional harness to use on my brake cancel switch(the one for cruise control disable).
I am keeping the original pressure switch and harness for when I switch over to TBI.

After doing an internet search, I found it more feasible to go with the XJS transducer from SunCoast Conversions. This should be here sometime tomorrow or Saturday.

Funny thing, I went to the dealer to order the appropriate gearset for the speedo and after explaining what I needed, I was met with a blank stare and "I would need year, make, model and VIN to help you". I just thanked them very much, bid them a good day and left.

 

Spare yourself the grief ,...these small specialty items have to be sourced on the internet and often you get the blank stare from counter people at the parts store.

They have no comprehension of what you are doing ...this engine swapping stuff is a bit of an art and not everybody can get their mind around it.

I get a lot of blank looks when I try to answer any questions that are asked about the swap. Internet and this board and knowledge are the answers
Bow tie transmission has the parts you need and JTR sells the VSS you will eventually need when you go TBI.

Pay attention to which hole you use for the retaining clip that holds the drive gear on the shaft best..

 

I installed the '91 700r4 yesterday and I have run in to a couple of issues.
First, let me say that I am using the cross member plate from Johns cars and with the TH350, I had no clearance issues.
Using the same installation method, the 700r4 is touching the tunnel just above midway of the transmission pan. I need to lower it about 1/2 inch.
Also, I purchased a speed transducer from Suncoast conversions and there is not enough room to install it unless I pry the shift cable downwards. Even so, there is only about a 1/4 inch of room there. If I lower the transmission I will have to either pry it down even more or push it up as far as it would go, install the transducer and let the cable rest on it.
Seems as if I would have to purchase a 90 degree adapter like Alyn did to make it work with no clearance issues. The 90 degree adapter I have will not work as it has a male end that is too small for the xjs transducer.
My options are to use additional spacers to lower the cross member plate or purchase a new one from Suncoast or JTR. I will examine more closely tomorrow to determine what my options are.
Also, my driveshaft is 1 inch too short. When I pull the driveshaft back, to the differential, I have about 3 inches of the yoke in the tail shaft. New driveshaft? or use a slightly longer yoke which I have but will need to be cut to 6.50 inches. The yoke from the TH350 is 5 inches from center to tip.
I will take some pics and post them tomorrow.

 

Use a large hammer on the tunnel to obtain the needed clearance... 90 degree adapter was needed on all my Jags... there is very limited room to put on the speedo cable and tighten the round "nuts"... I used slip ring pliers to tighten for the length of the handles...

That is why I like the JTR trans mount best... no large plate covering up that area on the trans...mine has my custom exhaust "U" cutouts that are not part of their design. Allows the pipes to be up higher for more clearance.

My '72 XJ with John's stuff, LT1/700R, did not have need any spacers on the trans mount...

Driveshaft shop can add back the needed amount of length.. they will just cut it off and start over and then balance...

 

Sanchez,.. If you eventually go TBI or any other computer controlled injection system, you will need a VSS unit,.. that also runs off of the trans speedo output - and it will not,... also fit in that small space....between the trans and the tunnel,,, I used a 20 inch cable,..

So - trans / angle drive / 20 inch cable / VSS / Jag transducer plugged into electrical connection for the speedo...all in that order on my car.


Whose motor mounts are you using ? Different ones put the engine in different places relative to the car. The engine / trans mounts are a matched set and the drive line inclination has been calculated buy each manufacturer. If you are using say JTR motor mounts and a Johns Cars trans mount ,...you may have clearance issues and drive shaft vibration if the phasing is off. Not a matched set.

 

Roger:


That modified JTR mount is slick. Nicely nestled pipes there.


I've not been down and under for a while in my car. Oh, the other day, an oil and filter change. Yahoo, filter came off the right way, no fight required.


I don't think my pipes are inset in the transmission mount. Mine is Johnscars sourced. The muffler guy had no issues with picking up at the same level of the Sun Coast down pies and plumbing back to the
Jaguar mufflers. Cats are just aft of the transmission, and the "H" a bit further aft. Slick, if needed, I undo four exhaust joints and drop the entire unit down.


My transmission is a 4L60E, a close relative of the 700. No issues with clearance for the Electrics. It fits nicely in the tunnel. Sans moth eaten bear rug, though!!!


Sanchez: Not sure why you want to mess with going to a mechanical
speedo? Especialy as EFI is in your future???


OT: Lamp buckets here. Quaint, but in great shape, thanks.... I responded PM.


Carl.

 

UPDATE: Thank you Roger. After I posted last night. I looked through some photos I had taken of the rotted donor car I had purchased for the GM powertrain and conversion kit.
There were 4 spacers that were placed between the cross member and the mounting points. This morning going through the parts I removed from that car I found the spacers and installed them and no more clearance issues. The spacers were 1 inch thick and by putting them on, the driveshaft fits with about 3/4 inch slip on the output shaft. I purchased 2 Spicer 1310 u-joints which I will install tomorrow.
@Carl: I am not going for a mechanical speedo. The XJS transducer I purchased from SunCoast Conversions for my speedo to work is big, and with the selector cable running on the same side, the electrical wires from the transducer are bent tight. To resolve this issue I will have to go the way Alyn did his: trans / angle drive / 20 inch cable / VSS / Jag transducer plugged into electrical connection for the speedo, (something to that effect)or I will see if Suncoast has a 90 degree drive that would fit on the trans and transducer.

 

UPDATE:
Took the car on a 40 mile round trip today.
The 700r4 transmission is working great except I have no kickdown (passing)gear. I believe I have to do some additional adjustment on my TV cable.
I have the lockup powered through the cruise control brake cancel switch.
It goes into overdrive at around 45-50 mph.
I installed new speed gears for the speedometer and installed the transducer I purchased from SunCoast Conversions.
At 2000 RPM I am cruising at 82 mph.
I decided to take the car a little faster for a short spell and at 95 mph the speedometer started to fluctuate then dropped to zero. No more speed reading.(Maybe it was a sign that I should not drive the car that fast. I normally don't, but that was for testing purposes only)
I believe the transducer or the electrical connections between the transducer and speedometer somehow failed. I will check on that when the car cools down.
Temperature stayed at around 75 degrees C, but I am running it without the thermostat. I will be installing it over the weekend.
Oil pressure at a steady 55 psi when hot.
So far so good.
Once I get the little items sorted out, I will be starting the TBI conversion.

 

Excellent!
Obviously you got the locking torque converter working! That's on my list for the coming Winter.
(';')

 

Yes, the lockup kit I used was a TCI product. It also came with a vacuum switch to connect to ported vacuum on the carb to signal lockup based on engine vacuum and 4th gear oil pressure. I opted to not use it and instead use my CC brake cancel switch to unlock the converter. Really very easy to do.
I will lift the car tomorrow and check the transducer and wiring.
Is there a fuse feeding the transducer circuit? Inline or otherwise?

 

Have you confirmed your speed is equal to a portable GPS speed? Hard to make the speedo really correct.

 

Curious as to why the speedo quit... maybe angle drive too tight and heated up/seized ....??? Otherwise glad to see progress is being made and car is coming along...

 

@ Roger: I had a friend drive my Volvo and I followed him. I was reading a couple of MPH higher than him. At 50 mph on the Volvo, the Jag was reading 53 mph; at 80 mph on the Volvo, the Jag was reading 82 mph @ 2000 RPM.So, the speed is off somewhere between 2 and 3 MPH. As per Suncoast and Alyn's calculations, for the 2:88 rear, the speed gears were 17/38. I am running stock size tires.
@Alyn: I was not able to get the proper size angle drive, so I made a slight indentation on the tunnel where the speed transducer is installed, so I have about 1/2 inch of space between the tunnel and the transducer. When I was installing the transducer, I thought that the fit of the transducer drive to the driven gear was a little sloppy. I am hoping that it didn't round out the square hole on the driven gear.
Tomorrow, I will diagnose and post results.

 

At least your error in the speed and speedo is in the direction that will help cut down tickets... 2-3% is as close as you can expect -- good work.

Speedo angle adapters are not precise fitting and they become looser with use... my only problem is getting the two end rings tight due to the lack of
physical access. But, I have never used a electric Jag speedometer.. only their mechanical ones.

 

UPDATE:
I removed the transducer this morning and discovered that the stem of the driven gear sheared off. See attached pictures. This speed gear was installed in the original bullet and as per the TCI bulletin was the proper bullet for this size gear.
I spoke to Jegs and they are stumped except to say it was probably a manufacturers defect. They are replacing the driven gear.

 

I purchased a Tach interface unit from Sun Coast and I installed it.
When I first start the car the jaguar tach reads correctly. However, I am getting erroneous readings after driving the car.
When I first start the car, after warm up, the tach reads 800 RPM in Park. In drive, AC on, it drops to around 700 RPM. I drive the car and when I get to a stop light the Tach is reading 1300 RPM even though I am idling way below that. I do not have a sticking accelerator pedal.
Prior to this happening, the tach reads about 1900 RPM at 80 mph in overdrive.
When the tach starts to show a higher than actual RPM at idle, I get up to 80 mph and its reading 2400 RPM. Any thoughts?

 

Around here, we have these Radar trailers that the cops post from time to time in areas where we get too antsy. They display the speed limit and "your speed". I see my error there. I have the fix and one day, I'll get to it...


My tach was "fixed" as a part of my purchase of the Johnscar kit.
It functions durn near perfect.


And, yes, I did the TC lockup via the CC switch. It did the job just fine. But, in a recent "adventure" I followed the Jaguar-specialties schematic to reverse the brake light switch logic and do the TC function.


So, if ever, I choose to enable CC, it is there.


Ain't it fun????


Carl

 

Can anyone tell me if this is the correct shifter?
David said it came off an xjs with the 400 tranny and is not certain whether it will work on the 700R4.
I don't want to purchase something that would not work.

 

Having used an XJS V12 shifter in my car (do not remember what year car it came out of ) ,..all I can say is,.. the chrome shifter arm (once the little oval shifter halves are removed,) looks the same as the standard Jag XJ6 shifter assemblies - has an eye hole ot the top. the detent part is matched to the GM 400 shifter arm positions.

The one in the picture looks a bit rough.. I got mine from David and it was a nice one - but if I remember correctly I also switched the actual arm for the one that was in my XJ6 (direct replacement) as it was even nicer with no pits in the chrome and same configuration.

 

Sanchez:


I tried to open those pictures to get a closer look. No luck, black screen!!!


It is a bit grimy, but a bath can fix that!!


I can see the back up light switch on the side. That seems correct.
The cable location seems correct as does the lever and housing.


What I can not see is the front. As I "recall" two micro switches should live there. One for cc interrupt and one for start interrupt.


The "correct" XJS tower should closely resemble the S3 unit.


XJS unit has the reverse lamp switch and the GM spaced detents.


As to tach verification? Do you have an old tech running unit?
with a means of measuring dwell and rpm? It should count the - pulses just fine and convert them to rpm.


Or, some on line research for those speed and distance formulae.


Good work, it runs and drives!!! A huge milestone. Only refinements to do....


Kudos....


Carl