Hi all,

What are the proper spark plugs for the XK 2.8L engine?
I've seen NGK - BP7ES / Champion - N7YC, but I've been running on old BP6ES.
For the 4.2L the BP5ES seems to be the recommended type.
Should I go hotter or colder?

I'm changing spark plugs due to poor acceleration, probably not the cause but might as well replace them just to be sure.

Thanks in advance.

 

I don't know. But, read the ones in the car. I'll not tackle a tutorial on plug reading here unless asked.


As to poor acceleration? To guess or diagnose, there, you need to be more specific. 2.8 in a big car ain't gonna snap your neck.


Carl

 

True, not really a fast car but nonetheless I've seen better riding days.
The car went slower on acceleration after replacing condenser and contacts, have no idea why, but I'm about to replace spark plugs and wires as well.

Air filter/fuel filters are ok.

 

There is your clue. Back to the days of points and condensors. I surely do not miss them at all. That is where I would retrace my steps. Set the gap again. Feeler guage if you must. Dwell meter if in your kit. Then the static timing. A strobe lamp is best.


And are the advance functions working, vacuum and centrifugal. If not, that is why the car got lazy!!!!


Carl

 

I'm no expert on this matter but will try and investigate.

Thanks!

 

+1 . . . and amen to how fickle those dizzy innards can be. Spent months totally re-building 2.4L in my avatar into a 3.0L E-Type headed fire breather . . . and spent best part of a full week and several flat batteries trying in vain to start it. That was in '68, so coming up for 50yrs ago . . . but I have never forgotten the lesson learned.

Fuel was fine; timing was spot on; had spark at points . . . although spark at plugs looked somewhat yellow/orange rather than a bright blue "crack" . . . and that should have been the clue. Despite being a brand new replacement, as was most of the dizzy innards, that condenser (capacitor) was only good for one occasional spark. For the quick succession required for starting and running, it simply broke down and failed. A second, also new one, produced an immediate start and full-blooded response.

These days, with so many derivatives of those distributors, another to watch is the proliferation of what appear to be almost Jaguar-universal rotor arms. Be warned. Unless you check very carefully, some "look alike" rotor arms are NOT compatible.

Best wishes you nail your issue,

Ken