Just thought i would start my official build thread since its getting so far along.

my V12 makes a better coffee table than a motor.

anywho for those that dont know heres the specs so far.

Engine: L67 3.8L supercharged (240bhp, 280# ft/tq stock. weighs in at about 350lbs less than the V12)
Mods: 3.4" modular pulley system, pacesetter camaro headers with 1.5" primaries. Camaro Flexplate, Camaro oil pan (for rack and pinion clearance) Camaro oil screen.

Transmission: 700R4 w/ 60* V6 bellhouse pattern.

a little background on the car. its a 1985 XJS, formerly V12. IRS, LSD, and 2.88 gears. the PO installed some cheap *** cragar knock offs, a killer set of 2.25" true duals, some bargan bucket racing seats, and a sick *** Nardi torino brass woodrimmed steering wheel. the interior was originally champagne and it has since been died to a two tone champagne on black. after i got it, i modified the bumper struts to make the rear bumper fit more flush with the car. i ditched all the black rubber bumper trim, and then cut and polished the original rear bumper. i removed the front alltogether. still waiting on a member on JF to get back to me about my missing chin spoiler.
























Got some paint on the thing. hit the block, heads, and pulleys with black. the LIM, Timing cover, and water pump are gonna be sandblasted and clearcoated when i port the LIM for the intercooler and install the new cam. The blower and rocker arm covers are gonna get sprayed red when i pull the blower off for case and inlet porting.









here i was afraid i had some clearance issues. the whole purpose of switching to a camaro flexplate was to increase the surface area of the splines on the TC so that the TC didnt have to come so far forward.

apparently this clearance is normal? im installing an 1/8" spacer just in case.












Heading off the to scrap yard now to pick up some 3" by 3/8" bar along with some 1 3/4" DOM pipe for the transmission crossover and motor mounts.

 

Just typed a long post and got kicked off the net and lost it all! Grrrrrr..
Anyway, I don't believe many had any more of a problem with the Jap engine as a SBC. I'll be the 1st to admit I came verrrry close to doing the same thing. My engine was toast with coolant coming out every orifice and no compression in any of the cylinders!

I think the main issue was that we all suspected your mechanicals of the V12 were good, and it was an electrical gremlin that just had to be chased down.

Doesn't matter, that is neither here, nor there now, so lets move on. I for one am interested to see how your project turns out! I just wish I had the money to pick up all your spare parts!

 

Good luck man, keep posting up progress reports and pictures! How much power you looking to make out of this?

 

power levels are a guess. in the W body world, power is restricted by the FWD exhaust, because even FWD headers are more restrictive than a basic RWD camaro type exhaust manifold. that being said, the front doesnt flow nearly as well as the back bank on a FWD setup, and a lot of Knock occurs in the #1 front facing cylinder because of flow issues. so power is limited to what kind of setup you can get away with, without getting a bunch of KR and cracking the #1 piston crown.

so to make a long story short, since ive got RWD headers paired with a proper supercharger pulley, im already ahead of the game by about 30-40 horse.

the cam im looking at, along with a fullsize intercooler, a ported throttle body, Heads, and a Gen V m90 would put any FWD L67 in the 400WHP range.

im gonna take this engine as far as my budget will allow me. and since the fastest supercharged 3.8 in the world (10.8 1/4 mile) was built on a pizza delivery budget, im shooting for ~400WHP. ive seen turbo builds climb upwards into the 800WHP range, but im sticking with the blower.

 

I hope I am not too late and you have not hit that 800 HP mark yet. For the time being and since you have your motor out, I suggest changing supercharger oil. I know on my XKR it was real bitch to do, without pulling some stuff around it.

 

changing the supercharger oil is easy on the M90. it only requires removing the filler screw on the snout (which im sure you can see in picture number 7) sucking the oil out with a syringe, and filling it with new oil.

 

It would be cool to find good Typhoon / Cyclone motor and put that in XJS, but I am sure these are not cheap, are they?

 

if you could even find one. i picked up this L67 for $300 and the tranny for $200.

 

I might stop by and check out your XJS when i go up to Columbus Joint and Clutch to get the driveshaft fabbed up.

 

cant forget the most important picture in the whole thread!

 

Nah, I am really interested in seeing how this works. Sounds like a super combo - light on the displacement with a roots-style supercharger will give you the torque you need to get the heavy car moving. The roots supercharger torque is so much fun!!

The only thing that looks suspect is the fitment of those headers. I don't know about your XJS engine compartment, but the one on my XJS gets deceivingly narrow as you get closer to the firewall. That and the steering shaft is perfectly placed to interfere with anything exhaust related. I hope those headers fit though!

Regarding the flexplate/converter spacing - I wouldn't be too worried. It's not unusual to have to shim aftermarket converters in the LS world - this shouldn't make a difference either. Even my stock 4L80E converted need small shims. As long as you have enough thread on the other side, you should be fine.

Keep the updates coming!

-Dave

 

You do that my friend!
BTW, what are your plans with that V12, coffee table, I presume?

 

im a little concerned with the fitment of the headers as well. passenger side should be fine but that damn drivers side sticks out too far.


and if i can get a head puller ill turn the V12 into a table.

 

UPDATE*
Well the camaro oil pan wont clear the rack and pinion, the throttle wont clear the firewall, and the camaro headers wont clear the fenders. ive got my work cut out (no pun intended) for me.

 

Well good luck. The Buick V6 you are using is a 90 degree design and the Jaguar V12 is 60 degree. So the engine is narrow like a 60 degree engine.

You have your work cut out for you. Still convinced this is less work than fixing the fuel injection on your original engine?

 

i wouldve fixed the fuel injection had i known what or if anything was wrong with it. for all any of us knew, it couldve been just about anything.

and in the end ill have a 3500lb XJS with lots of room for some serious and inexpensive mods and an overdrive gear. plus i can literally walk down to the junkyard and pick up a V6 T5 for next to nothing.

 

Yea, looking at that oil pan, I'm not surprised. You'll see that the oil pan and intake manifold inlet has a give-take relationship: the further forward you move the engine, the deeper your sump has to be, but the more room you'll have for the intake manifold inlet. Moving the engine forward will also give you more header clearance.

Speaking of which, it might be easier to ditch the headers in favor of exhaust manifolds. There are probable a lot of stock designs between the FWD cars and the Camaro. Though they'll be a compromise on flow, they'll allow you to get the job done and they'll be cast iron which wears really well. You could also port them a little bit.

 

ive ported exhaust manifolds a bit. headers make a notable difference on NA engine, but they are night and day on a FI engine. so im gonna do what i can to keep them

also, if i can modify the oil pan enough to slip the engine down another 4 or 5 inches, the headers should clear the fender wells.

 

Finding a running, wrecked XJS would've cost you $500 I'll shut up about that now, you've already waded in pretty deep (but not so far you can't go back to shore)!!

Seriously, I admire you guys who have the skill and testicular fortitude to do drivetrain swaps (especially without the assistance of a proven kit)!! Thanks for keeping us posted, and for all the huge pics to look at. I have no idea what I'm looking at, but it's fun to watch!!

Sorry I can't offer anything more than moral support from Houston.

Good luck man, and keep the updates flowing

 

On second look at those pics, man the V6 is TINY. I am really curious how the transplant will affect the character of the XJS. Unfortunately M90's was never running correctly with the V12, so we'll need to recruit a local to take it for a spin and write up a nice comparison