E-Type engine feels lumpy!

Not long got my E-Type (1969 4.2) back from a year in a Body-shop and I finally got to ride the beast earlier today. Aside from a few other minor niggles the main problem I've encountered is the engine being lumpy with erratic tick-over and sounds like it's mis-firing and not running on all cylinders. Before it entered the Body-shop it ran fine. I'm no expert regarding these problems and I was wondering if anybody out there could shed some light as to what I could do to alleviate it.

DID THEY PAINT IT,HAVE YOU CHECKED THE AIR FILTERS FOR CLOGGING? JUST A THOUGHT LOL! I'M TRYING TO FIND THE DISTRIBUTER FIRING ORDER AND THE CYLINDER NUMBERS FROM FRONT TO BACK FOR A FRIENDS CAR.. I HOPE YOU FIND WHAT IS GOING ON, YOU PROBABLY HAVE YOURS FIXED ALREADY LOL. WAS THERE A WIRE OR HOSE KNOCKED OFF ...

I AM WORKING ON A 1972 JAG E TYPE WITH A V-12 MOTOR... GETTING IT RUNNING FOR A FRIEND,REPLACED PLUGS ,CAP, ROTOR.. WHEN HE BOUGHT THE CAR SOME OF THE PLUG WIRES WERE CUT... CAN SOMEONE PLEASE HELP ME WITH THE DISRIBUTOR CAP FIRING ORDER AND THE ORDER OF CYLINDERS FRONT TO BACK ON THIS BABY/ AND WE PUT A NEW BATTERY IN IT, AND THE ALTERNATOR STARTED SMOKING , I PULLED THE CABLE RIGHT BACK OFF,AND OF COURSE I HOOKED THE CABLES UP RIGHT LOL, UNLESS THIS IS A POSITIVE GROUND SYSTEM... THE ONE THAT APPEARS TO BE THE GROUND CABLE IS ATTACHED TO THE FIREWALL,IS THAT A SUFFICIENT GROUND,BECAUSE THERE IS ANOTHER CABLE THAT IS UNHOOKED,NOT SURE IF IT GOES TO THE SOLENOID OR IF ITS IS A GROUND, I HAVE TO PUT IT ON THE LIFT AND FOLLOW IT... THANK YOU SO MUCH, ANYBODY PLEASE..

Re: E-Type engine feels lumpy

If the problem is not something obvious such as a loose plug wire, fouled distributor rotor, bad spark plug, or sticking carb float, then the camshaft timing sprocket may have slipped.

In late 1969 and early 1970, Jaguar fitted a "new and improved" timing sprocket adjusting plate to the XK engine, referred to as "cruciform", which had four projections with fewer teeth to grip the inside of the sprocket rather than the previous adjusting plate’s 360° of teeth. But the “cruciform" adjuster plate was found to occasionally slip and cause timing problems (at the best) or the valves would hit the piston crowns (at the worst).

Remove the cam covers, unbolt the adjusting plates from the sprockets, slide forward, and examine the backside of the sprocket adjusting plates to determine whether they are “cruciform” and which may have rounded off the gripping teeth.

Replace the “cruciform” adjusting plate with a 360° toothed adjusting plate (part # C30767) if you can find them. Otherwise, replace with the “new” camshaft sprockets with slotted bolt holes for making the timing adjustments (part # NBB2549AA used on 3.6 and 4.0L AJ6 engines from 1988 on) which are also becoming more scarce.

The “new” sprocket also uses a different flanged head bolt (part # JZS100082) measuring 3/8” x 24 fine thread x 5/8” length which grips the sprocket face in a way that a regular cap head bolt will not. These bolts are also getting difficult to find, but an alternate can be ordered from Fastenal (part # 0148165) which will be ¾” long. Grind off the extra 1/8” to so that it will not protrude from the back of the sprocket and grind against the cam bearing cap.

Bill Unger
1969 E-type FHC, 1997 XK8 FHC, 2007 XKR FHC