[xk-engine] Distributor drive dog misalignment

Guys,
I am ready to fire up the xk140 motor that I put into my
xk120 over the last week. I did give it a crank and the
engine spit back thru the starting carb (I have the
anti-blowback valve but haven’t put it in yet. I immediately
went to double check the timing. With the flywheel at TDC
and the cam lobes for #6 pointing outwards (e.g. exhaust
stroke is next), the distributor drive dog slot is slanted
at about 75 degrees away from ‘‘horizontal’’ (horia = parallel
with the block). Furthermore, the offset of the drive dog is
toward the engine, which would put the #6 plug wire at the
11 O’clock position when you’re standing on the off-side,
facing across to the near-side and looking down at the
distributor cap.

Now, this motor was fully rebuilt by a very reputable shop
(different and shop than the one that rebuilt my zero
compression smoker motor). The engine has never been
installed or run yet.

Per the manual, this is wrong. Is there anything wrong with
doing the obvious bodge (move the plug wires around) to
compensate for the incorrect dist drive gear position?

John Feng
P.S. Are there really any shops that can rebuild an XK motor
right on the first try?–
John
Boston, MA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

//please trim quoted text to context only

In reply to a message from John sent Sat 23 Aug 2014:

No, there is nothing wrong with doing the obvious, shifting
the wires around, as long as you get the firing order right
of course.
To fix it right you would have to take off the oil pan and
front timing cover because the lower end of that shaft has a
nut so you can’t just pull it up and put it back the right way.
I don’t know if this is true on 140, but on my 120 the dog
is only a little bit off center, so it is possible for a ham
fisted yokel to cram the distributor in 180 degrees off and
force it down.
Yes, there is a shop that can build an XK engine right, it’s
your own garage. Nobody can be paid to care about your
engine more than you do.–
XK120 FHC, Mark V saloon, XJ12L Series II, S-Type 3.0
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

//please trim quoted text to context only

In reply to a message from Rob Reilly sent Sun 24 Aug 2014:

I '‘think’ you are saying, from your check of where the dist
shaft slot/dog fits that the internal lower dog is installed
incorrectly,…so as Rob says you can re assign the plug
wires to cap,. If…it is only the distrib that was
installed wrong…180 out it would seem the alignment would
be further out…but that is if the case…then just the dizzy
R and R, reversing it would do the job.
Firing order firing order 6-2-4-1-5-3, #1 cyl at firewall,
#6 toward radiator-front. Engine and crank damper rotate
counter clockwise from positon of driver in seat facing
forward, which is the ONLY orientation for rotation and
right and left. Distributor rotor rotates counter clockwise
as viewed in place from above, Turning distributor body
clockwise advances timing. SB 124 corrects degrees per
flywheel tooth to 2 �. (actual is 2.73) 132 teeth on
flywheel, 360 degrees. Distributor 40199E most common to
late xk120 and 140. Many distributors exist, and will work,
,most differ in the springs for mech and vac advance units.
Timing ranges mostly from 5 deg early xk, to 7 deg late,and
10 deg xk140. Pt gap .014-.016, with 016 most commonly
used, plugs NGK BP5ES mid-hot for older, BP6ES colder. Plug
gap .022-.025. .022 for longer higher rev use. .025 most
commonly set. When flywheel is set with proper timing mark,
the distributor rotor should point approx. to #6 sparkplug
wire connection as on cap. Distrib is correctly installed
when the vac unit is on left.
#6 is front-radiator end.
Early XK120 timed at 5deg BTDC, later XK120 at 7deg, XK140
times at 10 deg BTDC, one tooth is 2.73 deg. Rotation of the
flyweel is counterclock (as from driver facing front).
Rotation of rotor is counter clock…viewed in place from
above.

By the way, the Jaguar Service Manual states that with
regard to right and left, the viewpoint is from the driver
position facing forward. This should always be the
reference for right or left, and clockwise or counter clock
wise. You have only one right arm, the car has only one
right side. If everyone would do this a lot of confusion
and error would be eliminated.
If the distributor has been removed and you are to re-
install, To be sure the distributor dog in the drive gear is
correctly positioned and fitted and not 180 out, which is
quite easy to get wrong. The distributor base half can be
out of whack with the upper half. Always note this and mark
well on removal-dis-assembly.
The distributor Vacuum advance unit will be toward left, and
rearward. Cap clips will be Inner clip toward engine-
slightly forward, say 1 o�clock, and outer clip toward right
fender, a bit rearward, say 7 o�clock as you are at right
fender side facing the engine.
Nick–
The original message included these comments:

the wires around, as long as you get the firing order right
of course.


Nick53XK120S
Spokane WA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

//please trim quoted text to context only

In reply to a message from Nick53XK120S sent Sun 24 Aug 2014:

Thanks guys.
I moved the plug wires around the cap by 2 positions to
correct for the position of the drive dog. Fired right up
after cranking a few seconds. I’m sure the shop that did the
work felt this was an unimportant detail given how easy the
fix is. Could be a PITA for any shop that thinks the car has
the normal plug wire positions so I marked all the wires
adjacent to the cap with silver permanent marker (dunno if
that’ll last very long).

Or, the shop thought these XK motors was like BMW M30’s
where the dist drive is via a gear so you just pull the dist
out, rotate the rotor to the desired position minus the
twist of the drive gear and shove it in. Of course, this
shop has been rebuilding XK engines since the mid 1960’s …

John–
John
Boston, MA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

//please trim quoted text to context only

In reply to a message from John sent Sun 24 Aug 2014:

if you are keeping this car the marked numbers just need to
last a little longer than you do.
good to hear it is fixed and runs. Soundslike ‘‘Junior’’ might
have been assigned to install the distrib drive.
Nick–
Nick53XK120S
Spokane WA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

//please trim quoted text to context only