motor swap xj for xs

[erldrums]

evening chaps!
well just got in from trying the new motor[82 82 xj] in the old xs after the sad demise of old lump.
swaped the vacuum advance over ,no probs. swapped the alternator over , no probs[ once i'd got the old rotor off!..a tip i just learnt... apparently the rear wheel axle is the right thread for the inside of the rotor,, screw it in , with large heavy object on it ,.. use like slide hammer to shock old rotor off!!]
Well got to say it goes like stink!,,no backfiring or popping , idles nice, revs right through to the red line ,just one odd noise..kind of 'knocking at 3 grand in all gears..??..pulls hard through it.. no power drop.. could be clutch..hmmm..gears...valves??? well will have to investigate.. timed it up as per xs [found true top dead, attached little pionter strobed it up , idles lovely revs beaut...was the timing /cams significantly different for the 82 xj's?
any input greatly recieved... ken mentioned someone else had done this swap.. any ideas
well gonna sit down with a newcastle brown ale , and ponder!!
erl

[Geezer]

The alternator rotor could be slipping on the crank. If so, you want to fix this ASAP becase it will quickly chew up the end of the crank.

When changing the alternator rotor, I usually clean both mating surfaces with electrical contact cleaner then tighten the bolt with an air wrench.

Geezer

[TopCatGr58]

Hey Geezer,and other carb gurus,

Isn't 3k around the transition phase of the carbs into the mains from pilots?? And if he kept his OEM 80 carbs on the new XJ engine, aren't there some YICS ports that he might need to cap off to have it work with the older carbs and ignition system!??

Just rambling/reaching for ideas??
T.C.

[Geezer]

Originally posted by TopCatGr58
Hey Geezer,and other carb gurus,

Isn't 3k around the transition phase of the carbs into the mains from pilots?? And if he kept his OEM 80 carbs on the new XJ engine, aren't there some YICS ports that he might need to cap off to have it work with the older carbs and ignition system!??

Just rambling/reaching for ideas??
T.C.

The YICS ports are inside the head and would only need to be blocked off during carb sycronizing. I'm not say that the carbs may not have a problem but the YICS has nothing to do with it.

Geezer

[erldrums]

well ,..checked the rotor...thanks...nope .it's ok ....carbs were syched from old motor 2 weeks ago ...they're pretty close.. not perfect ...different breathing etc,... but close enough i think..
sounds much more 'mechanical'..for want of a better.. and i hope cheaper , term
will have to go out again[dam!] and suss it...ideas are great though!