Good morning Jaguar enthusiasts!

I am a proud owner of a 1976 XJ6 Series II.

However, I have had the problem for a long time that the engine does not really run smoothly when idling. The engine starts well, runs quite well while driving. When parking, the engine continues to run for ~ 0.5 sec.

I have already checked the following things:

Intake bridge checked for leaks (with smoke leak detector)

Ignition cable new

Ignition coil new

Ignition distributor 123 new

Ignition distributor cap including distributor rotor new

new and checked spark plugs (not oily and not sooty)

AED completely overhauled and adjusted (distance from the upper edge of the square screw to the sealing edge of the housing approx. 8.5 mm)

both carburetors (HIF7) were cleaned and got a service kit CSK 82 (Gaskets and Seals, main jet and needle valve and seat float bowl), then carburettor adjusted according to manual, damper oil checked (15w40), idling 830 rpm

Compression checked:

Cylinder - bar
1 - 12
2 - 12
3 - 11.6
4 - 12.1
5 - 11.3
6 - 11.7

Ignition (measured on the 6th cylinder, without vacuum): 11 degrees before TDC

Valve clearance measured (the WHB says 0.012-0.0014 for intake and exhaust):

Cylinder - Intake - Exhaust

1-0.0115-0.012
2-0.012-0.015
3-0.0121-0.014
4-0.012-0.014
5-0.0126-0.016
6-0.011-0.012

The values ​​for intake (1 and 6) and exhaust (2 and 5) differ slightly. Is that still within the tolerance range?

Does anyone have another idea? Meanwhile I am desperate...

Thanks!
André

P.S.: Kindly excuse my bad English:-)

 

Andre:

The English is fine.

The post presents the issue well and the measures taken to resolve it.

I see an ignition timing issue as to the after run. and possibly the uneven idle. Note, many say that these engines are not known for smooth idling... erratic dwell may be a cause.

The mark on the crank dampener might not be accurate. The elastomeric bond of the inner and outer may have slipped Not uncommon.. The pointer on the engine may be off a bit. Your line of sight to the strobe may be off.

Check these out. And/or just back the initial aka static timing off about two or three degrees. Drive. Objective. As much static advance as the engine will allow and not rattle... We in USA called it "power timing"...

Others will have more for you.

Carl

 

Adding to Carl's:

Carbies are in need of a good clean, ASSUMING you have the SU HS8 carbies, and NOT the Stromberg units.

Carby balance is possibly way off, it takes time, lots of time, to get them right.

Timing, very suspect.

Connect the vac tube, as the engine would normally be operated, and tune by ear, you will soon "hear" that sweet spot when moving the distributor SLOWLY as you get the timing where YOUR engine is happy. I reckon that 11 without vac is too advanced.

Tappets, good enough for me.

English is fine, I can read it, and it is said we Aussies talk odd, HA>

 

I had similar problems a few years ago.
Timing and overhaul of the HS8's.