Dear members,

I am the owner of an xj6 serie 2 from 1975 3.4 litre . I have a problem with the timing of my engine. I checked the marker if 0 degrees is top death center. The timing for my engine is 4 degrees before tdc. But when I want to adjust the timing, the car will run much better when the ignition is about 16 degrees before tdc. Is there something I do wrong? I checked the ignition with the vacuum unplugged, measured from cilinder 6 . Hopefully someone could give me some help.

Harry

 

I think you're in the wrong forum.

 

why ? its a jaguar xj6

 

This forum is for the 2003-2009 model years XJ's.
The timing was often advanced on the older cars to make them run better.
They require the better quality, higher octane, gasoline when you advance it.
It's needed to keep the fuel from pre igniting, or firing too early

 

There have been 8 iterations of the XJ model name since 1968. This forum is for the cars made of aluminium from 2003-2009 which are totally different to all previous models in every respect. I am very surprised you don't know this, so assume you are new to Jaguars. The correct forum for your car is in the section titled "Jaguar Models (Classics)" and forum "XJ6 & XJ12 Series I, II, and III" Your car is a Series 2, but the Series 1, 2 and 3 are the same basic car with detail differences. The Series 3 cars have a slightly different body shell as the car was restyled in 1979.

 

A man's got to know his limitations.

P.S. I assume or hope that "top death center" was a typo.

Last XK engine I worked on was a Mark10 an appropriately long time ago (basically the same as a Series 2 XJ6 engine) but the 4degrees sounds much more likely than 16degrees from memory. I trust the timing chain is set correctly, if disturbed.

"Jaguar XJ" on Wikipedia might help you out a bit with the 50+ years of different models. And "Jaguar XK Engine", which was replaced around 1987 on the XJ6(XJ40). Despite all that, XK is a lovely engine.

"Dirty Harry" appears to have the same problem since 2019. Amazing!