89 XJS v12 (Marelli) 5 speed swap

Not yet, I’ve had a few other priorities. This weekend, fingers crossed.

Today I fixed my mistake of not taping the fittings on the throw out bearing, and put the transmission back in working at a fairly leisurely pace. The transmission slid into place easier than it ever has before, this being about the fifth time, with the test fits and so on, so I take that as a good sign.

We bled the throwout bearing, no problem, and then I decided to raise up the pedal stop a bit, the plan being to lower it as needed to get the release point where I want.

It’s a good thing I did, because lo and behold there’s a wiring harness where I did not know there is one. Namely, directly under the clutch pedal.

My drill job resulted in one wire severed and two nicked. I got off really easy, it could’ve been way worse. It’s on me for not being more careful about checking before drilling . Anyway, repaired that mistake, got the carpet layed and the clutch stop set.

I found a pack of 32 of these nifty little dense foam rubber furniture pads, self stick, which will make a perfect clutch pedal stop pad. And I have 31 extras.

1 Like

Next the exhaust went back in, which is pretty easy with my one piece exhaust system. Furniture dolly courtesy of Harbor freight.

Plenty of room around the trans and exhaust, the only cats on the car are behind the transmission under the big heat shield.

1 Like

To put the trans in with the bell housing in the car, you have to get it high and level. This meant I had to remove the shifter, which is easy, four bolts.

Figuring out the shifter stick, as short as it needs to be, was an evening adventure on the Internet in itself. I cobbled this set up together so I could get it in gear while I’m setting up the clutch release point. There’s nothing wrong with it, except that it’s ugly. The top piece was part of a separate shifter I bought a couple of years ago, when the plan was to rebuild my own T5. I had to find a threaded bushing to mate the top piece to the shifter knob that I had, then I just drilled an aluminum bar to screw everything together.

I am going to drive it with this shifter for a while, which will eventually be invisible because everything will be covered by a black gaiter. This is kind of the least of my worries at the moment, but after driving it for a while, I’ll know if I want the shift stick to be any longer or shorter, and I’ll know if I want to put any kind of a bend or angle in it to adjust the position. Once I’m comfortable with all that, I’ll build a one piece stick that bolts to the transmission at one end and has the proper threads for a little different looking knob on top.

Tomorrow I’ll work on getting the console back in the car. Step one will be to stuff the gaps between the transmission and the tunnel with pieces of foam, similar to what we do on XJS radiators. I’ll route the reverse wires, then this rubber accordion boot will go over everything to seal out heat and noise. This will be completely covered by the console and the ski slope, to be topped off with the aforementioned gaiter. I’m probably going to have to weld up some of the holes in the ski slope and re-cut them, and I’ll convert the ashtrays to cupholders at the same time. That’s a bit of a project in itself, so I may have to drive around topless a.k.a. no ski slope for a bit…

2 Likes

OK, as planned, today we started out by insulating with some foam around the top of the gearbox, and installing the gigantic rubber accordion boot that I got from Summit. If the chrome ring on the boat looks a little wavy, it’s because it is. There are some compound curves that I need to force it to conform to. Hex sheet metal screws are the ticket here, you’ll never get enough torque on a Phillips.

The reverse light wires are routed through, and I was able to reuse the factory female spade connectors, sealed them up with some heat shrink.

Now we move on the console installation. I was excited about this, because it meant the car will no longer look like it had been disemboweled, but I also had a bit of trepidation, because I could just see this thing being a pain in the arse to make fit right.

With a little fiddling, it dropped right in. The console is only held in by four screws. Two above the radio/HVAC, which are behind the black face plate, and one on either side at the back end.

Now for the Kenwood “digital media unit “. That’s a fancy way of saying it doesn’t have a CD player, which means it’s a bit shallower. It doesn’t need to be shallower, we all know you can fit a normal size deck im an XJS, but I have no use for a CD player. Also, it took me quite a while to find a deck that didn’t have Alexa built-in.

Some people are intimidated by car stereo work, there’s no reason to be. Just work through the wires one at a time, and when it’s time to connect, start with the longest first then work your way back to the shortest and slide the deck in.

Every time I have the deck out of this car, which isn’t that often, but every time I gripe about the stupid nuts that go around the HVAC control shaft, and hold the black face plate in place.

Today I decided to quit complaining and do some thing about it, and took a few minutes to build this nifty tool. It might look like the slot is too short, but it actually works really good when you brace it against the shaft.

Deck is in and looks good!

1 Like

Now we do a bit of wire routing and clean up, mounting relays near where they used to be, some of them were bolted to the PRNDL, I just use the screws for the rubber boot.
Thanks to @A.J_Simpson suggestion, I removed the rear seat ducts, which gives me all kinds of room to just lay wires in place.

I flipped and reused the mounting tab for the radio relay.

1 Like

I did a test fit of the ski slope, and determined that I only need about a half inch clearance to get full shifter travel.

I broke out the air saw, and was very careful, and made a beautiful cut. I took this picture to show how much clearance was required compared to the previous hole.

About this time I realized that I had clearanced to the top of the slot and not the bottom. Nice. I did the other end so they match. As previously mentioned, this will be welded up and re-cut in the future.

Now we go ahead with ski slope install, it will come back out for a makeover at some point, but I decided I wanted it in for now. Yes, you do have to pry on it just a bit to get it to drop down past the metal bow at the back of the console.

The ski slope is held in by two tabs that slide into slots under the hvac face plate, these little ears on the side, and one screw at the top center in back. This ear is actually wrong, tab on the ski slope is underneath the speed nut, needs to be on top.

Making progress! Yesterday I did fill the trans with 2.5 quarts of mobile one synthetic ATF, as recommended by Tremec. So I can remove the tag from my steering wheel.

Ski slope is in and buttoned up, looks good.

3 Likes

Next I did an oil change, since it was up in the air and time for one. I managed to do that without making a big mess.

I got the car down on the ground again, and almost had a disaster, it rolled off the blocks. It rolled about 6 feet out of the driveway before I dug in my heels and got it stopped. It was just sitting on a couple of 2 x 6 blocks at each corner, that I use so I can get the jacks in and out. So no harm done. But the lesson here is that I need to adjust my parking brake, which I never use but will now. Now that I don’t have an auto trans, I really want a good parking brake.

Time for the moment of truth, I jump in, run through my checklist one more time, turn the key, nothing. Zip. Nada. OK, think think think. Got it. I did not jumper the neutral safety switch. Off comes the ski slope, I pull out the appropriate harness, which fortunately I labeled, and make a quick jumper and install it in the neutral safety switch wires.

Fingers crossed, try again, it fires up. Excellent. This is a fresh Bywater ECU, and while I was sure it would be fine, it sure is nice when expectations are met.

Now I try to put it in gear with the engine idling. It goes hard into the forward gears, and grinds going into reverse. Time to lower the clutch stop. I lower it by probably 3/8 of an inch.

Repeat the test, and it goes easily into all gears.

Time for a test drive, which I will write a whole lot about later. The short answer is, it’s phenomenal. I am super pleased. Shifter location seems good, clutch release point perfect, ECU works perfectly, no stalling when the clutch is pushed in and the engine is allowed to drop to idle.

“I can move under my own power again!”


(yes the bonnet is cracked to let the hot out. SOP for me after a drive.)

9 Likes

Super nice, great job!

1 Like

Well done @BobPhx!!!
Impressive job.

1 Like

Superb !
Well done and well documented. Be justifiably proud. Bob.

1 Like

Great job, and thank you for the thorough documentation. It will be interesting reading your impressions as you drive it more. Looks like my '88, Signal Red.

1 Like

Great job Bob. Congratulations. Can’t wait to hear your impressions on driving your conversion. I have a 5-speed donor car coming for my 86 xjs.

1 Like

Nice job on the conversion.
I noticed your gauge cluster replacing the trip computer. Was that a pre-made setup, or did you fabricate the mounting yourself? If premade, where did you get it?

1 Like

Thanks! I fabricated the gauge panel. It’s just an aluminum plate with 3 small (1.5", I think??) mechanical gauges from Autozone. There is a bit of detail at the bottom of this page:
https://goflyrc.com/projects/XJS/xjs.htm

Thanks! I didn’t connect that page to you before now.
Jon

Here is a quick cost breakdown, based on memory. Feel free to call out anything I missed.

Item Cost
Transmission $1,950
Clutch $180
Bellhousing $600
Throwout Bearing $130
Bleed kit $30
Transmission Input Bearing Retainer $130
Clutch Master Cylinder $150
Driveshaft $600
Flywheel $400
ECU Modification $500
Used 3.54 Diff $400
Pedal box $400
Misc: Pilot bush, shift boots, trans mount, clutch line, -3AN adapters, misc nuts/bolts, fluids, shipping, etc. $750
Total $6,220
3 Likes

A couple more questions: Apparently Autopro was bought out by Bosch, but the gauges appear to be just rebranded. Individual 1.5 in gauges aren’t available, only in three gauge sets. Other than Bosch, only Autometer ($$$$) and Equus appear to make 1.5" gauges. I can buy two sets of Bosch gauges for the price of 1.5 Autometer individual gauges. Equus doesn’t appear to make mechanical gauges.

Did you have any issue running the temp gauge capillary tubes? How long were they? Where did you run them thru the firewall?

It appears from your website that you are measuring temperature on one side at the front of the engine, and the other at the rear. Do you see a large temp variation as a result?

Thanks!

Jon

Hi Jon-
I bought two of the 3 packs to get two temp gauges. I looked at Equus as well and found them pricey. I personally like mechanical gauges, but modern electrics are just fine too. The problem is finding a 270d sweep, which I wanted. If you can find a 1.5" 270d sweep electric that would be cool (maybe Equus is the only option there…)

Yes I am measuring temp at two points. I do not see any variations more than an occasional 3-4 degrees, which is probably within the gauge margin of error. Most of the time they track spot on. I do not have any mods to my cooling system except for the dual electric fans. The stock temp gauge is still hooked up too.

Running the tubes was a PITA on the drivers (left) side. I believe I cut a new hole up high above the accelerator pedal somewhere… I don’t recall exactly. The tube was just long enough. The passenger side was easier, it goes thru the existing boot where the AC vac lines and other stuff comes thru.

I was initially concerned that these were “low quality” gauges and wouldn’t last or be reliable. But they have been just fine for several years now.

@gregma has a similar setup, he may have thoughts as well.

Regards
Bob