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I figured I'd chart the progress of my '86 XJS V12 project, which (after the TH400 failed) is getting a Getrag 290 that I picked up from AutoReserve Jaguar, to be installed with the conversion components that SimplyPerformance makes. I'm really impressed by how light the Getrag 290 is. Given how pleased I was with how the car drove with the TH400, I'm really looking forward to getting the manual into the car. Not having a 1950s torque converter eating a third of the power and exceptionally tall gears holding the V12 back will be really nice. After that, it'll be time to liven things up by dragging the engine through AJ6 Engineering's catalog and getting some nice tires.
I'm looking forward to updates. I'd like to do the same, but with a Tremic T5 gearbox as I'm in the US on my 75 XJ12C
I'm in the US as well, I decided to go with the Getrag as it seems to be the most straightforward of the manual swaps. It's definitely not going to be the cheapest, but it'll be the most like if it came out of the factory with a manual. I'll try to keep the thread updated, things are relatively quiet as I'm just buying parts right now. I'll post pictures of stuff as I get it in. My current plan is to pre-assemble as much as possible so I need as little time on the lift as possible. I also may wind up deciding to do it on jackstands when the weather warms up.
I'm in the US as well, I decided to go with the Getrag as it seems to be the most straightforward of the manual swaps
Ahh. Interesting thing is that I keep hearing that the NV 3500 used in the GM light trucks of the 90's is a G290. I expect that the bell housing would be different though. The kits here appear to be around $7k for a Tremec which is way too much (IMO) spend when you can you buy lots and lots of MT cars that are fun to drive for that kind of spend and a 6 speed in my mind would be overkill. My car came with a 700R4 already installed so I'm hoping that the adaptor plate which adapts a GM trans to a Jaguar enigne could be used on a GM T5 from a 80's V8 Camaro.
Ahh. Interesting thing is that I keep hearing that the NV 3500 used in the GM light trucks of the 90's is a G290. I expect that the bell housing would be different though. The kits here appear to be around $7k for a Tremec which is way too much (IMO) spend when you can you buy lots and lots of MT cars that are fun to drive for that kind of spend and a 6 speed in my mind would be overkill. My car came with a 700R4 already installed so I'm hoping that the adaptor plate which adapts a GM trans to a Jaguar enigne could be used on a GM T5 from a 80's V8 Camaro.
The Getrag 290 has a cast-in bellhousing, so you need a Jaguar specific transmission. If you can find one, I think it’s a great option, but it’s a big if and the shipping can be painful if it’s coming from overseas. I know someone made a T5 kit, it was mentioned in Experience in a Book, but I can’t remember who. Another option would be to dig up the gearbox from an old E Type S3, since that would in theory bolt right on. I dunno how common or easy those are.
I think you’ll probably need a custom bellhousing done, but I don’t know who does that sort of thing. A lot of why drew me to the Getrag conversion is that it’s very well understood, SimplyPerformance has done upwards of 200 of them and has almost all the custom parts on hand. I know I’m going to also need to modify the shifter and pedal box since the shift lever is about an inch too long and it’s $375 for a RHD pedal box from the UK and $1000 for a LHD one from Florida.
With the big V12 and 2.88 rear end I’ll take as many gears as possible, although the five speed will do fine especially with overdrive 5th for highway cruising. It’s never really going to be a lap record machine because I’m leaving it very mostly stock aside from the manual/intake/exhaust, but the reported 20+ highway MPG with a 5.3L V12 and a 24 gallon gas tank is really appealing. Plus, it’ll be really nice to not have a torque converter eating 1/3 of my engine output and then failing if you go above 5500rpm.
Last, on price, I’m going to probably wind up about $6-7k in parts before the swap is done, so I don’t think the other options are necessarily any cheaper. I really hope it works out for you though, these V12s really deserve a good manual.
Last edited by Iceboatguy; 12-30-2021 at 03:34 PM.
The kit that i'm familar with is from the driven man as I bought the XJ12C from him back in 2010 or so. At the time, they offered a 5 or 6 speed kit but in looking at their site now, they only offer 6 speed. If it's a turn key kit with a brand new transmission, it may be worth the money at around $7k
Things are kinda quiet as I'm waiting for some parts to ship from Britain, but I got around to buying a proper floor jack and stands, and fixed a couple minor issues I was having. There were four exhaust leaks that are now patched, and I had to pull the fuel pump and epoxy a hole on the bottom. That will need to be replaced before I put the car back on the road properly, but they're not exactly rare or expensive. I may also do all the fuel lines in the trunk, they don't look original but they also don't exactly look new. I also discovered that the transmission does go into gear while cold, so I'm thinking I might be able to get it to actually go into gear by flushing the fluid which'd save my back some work when I move it to a different area around my building to do the transmission swap. My plan for this weekend is to track down whatever's keeping the windshield wipers from working -- I'm hoping it's just a blown fuse, since I never actually have checked the fuses yet.
Well, I've got the adapter plate and pedal box, and the clutch and clutch master cylinder are on their way. I've only got the flywheel, propshaft, and some small parts left to order, then it'll be time to get it put together. Interestingly, it looks like I should be able to get away with not modifying the clutch pedal, since it more or less fits in the foot well without being bent over. I'm going to reuse the brake pedal shaft from the automatic pedal box.
I've got the clutch kit, clutch master cylinder, and pedal box. The flywheel is in transit, and then there's one more batch of small parts before it can go in.
That's a RHD pedal cluster, and won't work in a LHD car without straightening the clutch pedal lever, and bending it to the right some. I used the brake pedal out of the automatic cluster, and cut off the original pedal pad and used the removable pedal from the RHD cluster. To straighten the clutch pedal lever, it has to be heated with a torch, and reheated it an oven to temper it. I had a local welding company do it, and it took a few tries to get it right.I just did the whole Simply Performance conversion with the Getrag 290, so ask if you have questions. Most of it is pretty straight forward.
Thanks for the tip! I’ve got a local blacksmith that I’m trying to work with to get the gear shift lever shortened and the clutch pedal bent. I have to ask, do you know what it gets hung up on in the footwell? When I was crawling around in there holding things in place to see how it would line up, it didn’t seem like there was much of anything to hit, but both you and Ben from SimplyPerformance have stated it’s a necessary modification. I’m planning to reuse the LHD brake pedal as you did.
I’ll definitely let you know if I have any questions, I’m hoping and praying that the swap goes smoothly once I get the rest of the parts.
Once you remove the old pedal cluster, it will become obvious. The space the fit the pedals thru is very small, and the stock RHD cluster would have the pedals way over to the left, against the left kick panel. If I had it to do over again, I would buy one of the ebay cluster kits for LHD, or there are some suppliers that make them. It would be less hassle. It was hard to get things right si that the brake and clutch pedal levers woulld fit thru the hole provided., and right now, the clutch pedal and brake pedal are too close together, so I'm going to have to do more work on the cluster.
Well, the last batch of parts should be here tomorrow. I kinda wish I had a go pro or something to make a time-lapse of the swap, but such is life. I'm really looking forward to getting it done and having the car back on the road.
One thing to be aware of. When I put in the 290, I had to drop the back of the engine much farther than I did to get the TH400 out. The shape of the top of the 290 bellhousing wouldn't clear the body until I did. I ended up taking off the exhaust downpipes because they starting hitting the suspension crossmember. I also had to remove the engine fan because it would hit the shroud otherwise.
The Getrag 290 has a cast-in bellhousing, so you need a Jaguar specific transmission. If you can find one, I think it’s a great option, but it’s a big if and the shipping can be painful if it’s coming from overseas. I know someone made a T5 kit, it was mentioned in Experience in a Book, but I can’t remember who. Another option would be to dig up the gearbox from an old E Type S3, since that would in theory bolt right on. I dunno how common or easy those are.
I think you’ll probably need a custom bellhousing done, but I don’t know who does that sort of thing. A lot of why drew me to the Getrag conversion is that it’s very well understood, SimplyPerformance has done upwards of 200 of them and has almost all the custom parts on hand. I know I’m going to also need to modify the shifter and pedal box since the shift lever is about an inch too long and it’s $375 for a RHD pedal box from the UK and $1000 for a LHD one from Florida.
With the big V12 and 2.88 rear end I’ll take as many gears as possible, although the five speed will do fine especially with overdrive 5th for highway cruising. It’s never really going to be a lap record machine because I’m leaving it very mostly stock aside from the manual/intake/exhaust, but the reported 20+ highway MPG with a 5.3L V12 and a 24 gallon gas tank is really appealing. Plus, it’ll be really nice to not have a torque converter eating 1/3 of my engine output and then failing if you go above 5500rpm.
Last, on price, I’m going to probably wind up about $6-7k in parts before the swap is done, so I don’t think the other options are necessarily any cheaper. I really hope it works out for you though, these V12s really deserve a good manual.
Making this took me a morning. It adapts a V12 to a Chevy manual transmission bell housing. A drill press and a way to cut aluminum are the only required tools. Oh and a piece of cardboard to transfer the holes location. The post 1977 Jaguar bell housing uses the same locating pins location as the Chevy bell housing does. So no need to worry about the critical alignment. How thick a plate you start with is determined by which transmission is used. For street use I recommend buying
a Trimec 6 speed transmission. New it sells for slightly less than $3000. You can buy similar used transmissions for around $1500 But few of them are as strong. Designed to handle 800 hp & 8000 rpm. It’s plenty strong enough for our Jaguars.
Plus it’s compact and much much lighter than the Turbo 400 it replaces.
My application is for racing and I use a Seinz dog ring 5 speed. The gears are designed to pull out quickly so you can change ratios in the pits. The whole process is about 1/2 hour compared to the same job taking 6-8 hours on a street transmission. ( (If you can find the alternate ratios)
swapping to the Trimec with all new parts is still going to be in that $4000 range.
With any manual transmission swap pull the whole rear end assembly from a 93 and later car. It will have a 3.54 ratio and save wear and tear on the clutch. ( plus allow smoky burn outs if you’re that sort) with 5th & 6th gear both overdrive your top speed will still be still be over 150 mph. And fuel mileage in the 20 mpg range.
Ahh. Interesting thing is that I keep hearing that the NV 3500 used in the GM light trucks of the 90's is a G290. I expect that the bell housing would be different though. The kits here appear to be around $7k for a Tremec which is way too much (IMO) spend when you can you buy lots and lots of MT cars that are fun to drive for that kind of spend and a 6 speed in my mind would be overkill. My car came with a 700R4 already installed so I'm hoping that the adaptor plate which adapts a GM trans to a Jaguar enigne could be used on a GM T5 from a 80's V8 Camaro.
it will just make a copy of the adaptor I took a picture of above
The Getrag 290 has a cast-in bellhousing, so you need a Jaguar specific transmission. If you can find one, I think it’s a great option, but it’s a big if and the shipping can be painful if it’s coming from overseas. I know someone made a T5 kit, it was mentioned in Experience in a Book, but I can’t remember who. Another option would be to dig up the gearbox from an old E Type S3, since that would in theory bolt right on. I dunno how common or easy those are.
I think you’ll probably need a custom bellhousing done, but I don’t know who does that sort of thing. A lot of why drew me to the Getrag conversion is that it’s very well understood, SimplyPerformance has done upwards of 200 of them and has almost all the custom parts on hand. I know I’m going to also need to modify the shifter and pedal box since the shift lever is about an inch too long and it’s $375 for a RHD pedal box from the UK and $1000 for a LHD one from Florida.
With the big V12 and 2.88 rear end I’ll take as many gears as possible, although the five speed will do fine especially with overdrive 5th for highway cruising. It’s never really going to be a lap record machine because I’m leaving it very mostly stock aside from the manual/intake/exhaust, but the reported 20+ highway MPG with a 5.3L V12 and a 24 gallon gas tank is really appealing. Plus, it’ll be really nice to not have a torque converter eating 1/3 of my engine output and then failing if you go above 5500rpm.
Last, on price, I’m going to probably wind up about $6-7k in parts before the swap is done, so I don’t think the other options are necessarily any cheaper. I really hope it works out for you though, these V12s really deserve a good manual.
On the exhaust do not waste money on headers. Most aren’t really headers they are simply too short. proper headers require you to cram 27 feet of tubing in that compartment and if you manage that. You gain 20 horsepower. Yep, just 20. Back to back dyno numbers. Go on U tube to Camp Chaos by Robert Knodt. Look for how I wasted my summer.
Much better gains come from regrinding your camshafts. Depending on which profiles you select there is a strong 100 horsepower to achieve.
Don’t worry about rough idle. I had a set of racing billets in mine and it still sat there smoothly idling at 600 rpm. Swapping cams is simple, straightforward, and much easier than a typical V8. You don’t need to take the timing cover off water pump off or vibration damper. Valve covers only. Jaguar even gives you a bracket to slide the timing chains on when cams are removed.
The limit is based on what The ECU can manage. AJ6 can readjust your unit to handle the cam change. But you might look into aftermarket ECU’s like Megasquirt that really opens up possibilities.
Want to more than double your power? There is room for a pair of turbo’s. Use a T3/T4 combo on each side they only cost about $130 each. Add the rest like pop off valves etc. and suddenly you’re making 5-600 horsepower.
Actually hooking everything up is simple. And affordable. Plus it’s self learning. That means once everything is properly connected it will start.
The difficult thing is you will need some dyno time with someone familiar with tuning. To get everything running properly.
I bought the whole kit from Simply Performance, and it was right at $6000 US, shipped, at the end of 2021. That included everything you need including the tranny, adapter, flywheel, clutch, master and slave cylinders, new trans tunnel cover, ski slope, pedal cluster, driveshaft, etc, basically everything you need except for a shift, knob, a few bolts, and fluids. The trans, pedal cluster, ski slope, and rubber shifter boot (under the leather boot) were used. Everything else was new. Support from Ben at Simply Performance has been great. Everything fit, and it works great. You have to make a mod to the bellhousing on the trans to provide access to the upper starter bolt. And if you don't use a geared starter without a snout, you need to mod the bellhousing for that clearance. I used the geared starter. The pedal cluster is for a RHD car, and required mods for use in a LHD. If i had it to do over, I'd delete that, and get a modded LHD cluster from a US vendor. I drove it briefly with the 2.88 rear end, and it's acceptable, but with the 3.54, it's quite quick. Absolutely transforms the car.On their advice, I did not have the ECU modded. Works fine without it, no stalling. In summary, I'm very satisfied. I think the 290 solution is as good as any, and I consider the price reasonable and the after sale support is great.Jon
12-29-2021, 03:34 PM
'86 XJS V12 Getrag 290 swap
