I've acquired a jag IRS and am fitting it to a 29 A tudor. Due to the rim offset and tire size, I need to widen it by at least 2.5". I think my best bet is to cut and lengthen the arms and drive shafts. Seen a lot of reference to shortening but none to lengthening. ANY SUGGETIONS? do's or don'ts? I'm planning on using the top mount of the pumpkin and doing a solid mount. If I mount the top mount parallel to the ground, that puts the pinion flange at a 5.5 degree up angle. This seems too radical to match with the engine/trans at 5.5 degrees. Is there any downside to making that angle less? Anti squat issues? rear toe in loss? Last thing, I don't see any reason to use the link rods that connect from the outer arm to the ch***is if I'm doing a solid mount.
Couple questions..........what model/year is the Jag rear end? What wheels are you planning to use on it? If you have an earlier E type or S sedan, consider acquiring a later XJ6/12 or XJS rear end or lower control arms/axles shafts. They are several inches wider. I think the Mark X sedan is in between. Your engine trans downward angle seems excessive at 5.5 degrees. And, I can understand why you think that looks odd on the pinion. The fact is, that would be correct for the pinion in order to keep the u-joint angles compatible. HOWEVER, I would recommend you seriously consider changing the engine/trans angle to a lesser amount....commonly found to be around 3 degrees. The actual most common determining factor on carbureted engines is the carb mounting pad. That should be level when the ch***is is at ride height. That's where I would start......place the ch***is at the ride height angle and measure the carb pad. If it's not level, level it by changing the mounts of the engine and/or trans. As for the links, most experienced Jag guys say if the rear und is mounted solid, the links aren't needed. Only if the cage is rubber mounted as in the OEM install are the links required.
I ran a sedan jag rear in my 29 model A. Terry's Jaguar is a good source for parts. Try google if you need some. I personally would hunt for the wider real and save a ton of time, probably headache and even money. Mine was mounted to the stock model a rear cross member with a spacer on top of the cage that was welded to the rear cross member. Also to change the angle of the rear shocks, I had 3 holes cut and sleeved in the cross member to change the angle as needed.
How wide do you need to go? I have both inboard and outboard brake versions 56" and 61-1/2" hub to hub, 3.54 posi. Has your unit been narrowed or is it an early E Type at 53" hub to hub?
i beleive Snow White tells you to set the crossmember at a slight angle to set the pinion angle. i think i've also seen where someone did the mount pad so it had a camfer to set pinion angle. i've done multiple jag ifs swaps and am doing irs to match the ifs in my neighbors 52 f1 but we haven't started the rear yet. i have 2 spare xjs rears sitng here if you need anything. i've had them for sale for a while and am probably gonna part them out soon...
I run an 87 Jag xjs(12 cylinder car) under my 39 Ford truck with hot rod flatmotor; bought all parts from Snow White in Cali and have driven truck many miles and have nothing but praise for Snow White. The kit was excellently crafted and fit exactly as was intended.
Thanks for all the info. I'm not sure which model I have. Maybe the following will help ID it; Width from outer axle flange to outer axle flange = 65 1/2" Inboard brakes with e-brakes As for the angle - I'm still unsure if I can alter the pinion angle without making a mess of the fulcrum angle and toe. Snow White suggests that they can modify the fulcrum mounts to allow for flatter angle. The engine will be EFI so the angle won't disturb the fuel delivery but 5.5 degrees still seems excessive for eng / trans mounting.
Your rear end measures 65 1/2 now & you want to add 5" that's 70 1/2 " that is crazy wide !!! normally 56" is wide enough for a model A . What wheels are you running ??
That seems extra wide to me too double check your measurements. I would chose different wheels before modifying the rear end. Jim Ford
That still is plenty wide for a Model A, you might even need to narrow it. What wheels are you running? What width and offset? Jim
wheels have 2.375" back spacing Tires are the Firestone dirt tracker 890-16 The body is 54.5" and tire inside sidewall to inside sidewall is 52.5" So with camber rise I need another 2.5 to 3" in width.
something ain't addin up or i'm looking at something wrong. 61.5" wheel mount surface to wheel mount surface minus 5"(i rounded your 2.375" up to 2.5" and doubled to account for backspace value of both wheels) of overall backspace reduction should equal 56.5" even if you add in another 1" of sidewall bowout(which is quite alot) on each side that still should give you 54.5" inside sidewall to inside sidewall. i don't see having more than an inch of sidewall bow/bulge so i'd have to ask are you sure about the back space amd or width of wms to wms.....
4 1/8" from the rim mounting surface to the sidewall widest section That tire is on a 6 " wide rim - within spec
perplexing....seen the jag set up on a good bunch over the years and never really heard of a problem with width. and those seem like fairy standard offset wheels one might expect. hmmm.......
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