If you’ve been cranking an engine and it won’t fire, it’s easy enough to pull a plug to see if it’s damp (with gas). If it’s completely dry, then gas isn’t getting though and so it needs investigation. Standard procedure, I’d say for trying to start any engine.
However, this one ought to have at least tried ti fire with the quick-start and the fact that it protested would seem to point to incorrect ignition timing.
Always time an XK engine at TDC on no6
Rotor arm pointing at roughly 4’ o’clock.
And at 10degrees ( BTDC) on crank damper.
That’s assuming it was built right in the first place! Slots in cams in centre of front cam bearing- visible with oil filler cap off.
If the rotor arm is at 10 o clock then that is no6
Firing order: 153624
Sounds like somehow you’re 180
Out on the timing? But if you’ve not touched the distributor or plugs leads and it ran before carb removal I’m stumped! Previously suggested checks ref carb rebuild are spot on.
Suck, squeeze, light and bang.if you have all this in the RIGHT order It’s got to start.
Perhaps you meant #1?
Hi Clive,
In my earlier post to Geoff I said that my rotor was at 7 o’clock - stupid - I meant to say 4 o’clock
Peter
OK, now I’m confused. Are PittsfordJag and pdundas1 the same person? My computer says PittsfordJag’s last post was 11 years ago.
Peter. You really should follow a logical sequence of checking timing, then compression and finally fuel. If you are not 100% comfortable with how the timing works follow the shop manual exactly. Check to ensure that when #6 is at tdc on the compression stroke that the harmonic damper is set correctly and has not slipped. Pointer should be right on the timing mark. Once you have confirmed timing 100% then go on to compression and finally fuel.
Edit: changed #1to#6
Call it # 6 or # 1 doesn’t make a bit of difference. I always thought it rather strange that Jaguar chose to call the front cylinder # 6 rather then #1 and yet did the ignition timing and cam timing off of that cylinder. I once heard why they numbered the cylinders that way but for the life of me can’t remember why, which no doubt I’ll remember the instant I push the send button!
Hi Scott,
Same person, different computer. As you say, old man forgot old membership! I’m having to relearn at my age. I’ve just found some of my notes from 35 years ago when I completely rebuild this engine.
I have to thank all of you who have responded for helping me to get back to what I knew all those years ago.
Peter
I encountered a very oddball problem when attempting the first start of my engine after a long hiatus. Static timing mark was set correctly, distributor rotor pointing to number one position, wires were on the correct plugs, spark jump at the plugs, fuel to the combustion chambers. No fire.
Turned out that the moveable advance plate inside the distributor was stuck in a considerably advanced position. Corrosion between the static plate and the moving plate.
Hi Eric,
I think I have some of this corrosion in my brain right now.
Peter
What I heard (which could be BS) was that it was ostensibly being developed as an aircraft engine which would have been mounted in the opposite direction (flywheel/prop forward) putting #1 at the front).
I was told many years ago that the original design for the XK engine was based on an aircraft engine, where #1 was at the propeller end at the output of the engine.
Peter
Erica,
The car has been laid up for about a year. I needed something to do for the winter, so I decided to rebuild the HD8 Carbs. In cold NY winter it made sense to do this in a warm basement. Then with Covid and self isolation, it well a blessing.
In June I was ready to install them and replaced the old gasoline. I also rebuilt the distributor, points, rotor an cap.
Peter
Okay so then your ignition is speculative. First things first.
If all good then we move onto carbs. But having once had my ignition 180 out, I can say your your symptoms sound very similar. It tries to start, then violently stops with a cough. Things get flooded because gas is flowing but not igniting.
Edit: actually before moving to carbs I’d ask you to in order try substituting back in your old rotor and condenser. I’ve had DOA brand new examples of both.
Sorry, yes your right, no1 which is at the back senior moment!
Geoff
Thank you for these wise words. At least I have determined that the timing mark on the harmonic damper is consistent with the cam lobe position and notch seen through the oil hole in the cam cover. I’m therefore sure of the Valve Timing (Page B63 in the Service Manuel)
However, it is still possible that the Ignition Timing is wrong!
Peter
I’ve heard that as well. But it runs counter to the oft told story of the meetings during fire watch during WWII in the factory where the engine was conceived by Bill Heynes, William Lyons, Claude Baily and Wally Hassan. Lyons wanted the engine for the post war saloons he was wanting to build.
Hence why I said ‘it was ostensibly being developed as an aircraft engine’ – in the version I heard that was the cover story as they were still supposed to be doing war production.
The part I’m skeptical of is Jaguar saying they were designing an aircraft engine to disguise the fact they were designing a car engine.
You may be close though.
I found this on the UK etype site.
I had read an explanation for the 1 near the gearbox and the 6 near the radiator. Jaguar employed engineers from the RAF and they put the number 1 like on a plane, considering the gearbox as the propeller. I don’t know if it’s a legend but it could be an explanation.
I think that the XK engine would be way too heavy for an aircraft engine and a straight six is not the best configuration for that either.