Well, did it just for a few seconds (the tach jumping, didn't appear to stumble) when I first started it up yesterday to go to work, didn't do it the rest of the day through probably a half dozen short trips. At the end of the work day I cleaned the battery ground strap and added a 4 gauge cable between the the bell housing and chassis. Didn't act up on the way home or on the couple trips I took in it last night. On the way to work this morning, however, the tach started going crazy and it gave one little stumble while sitting at a red light for 15 or 20 seconds, then it was gone and did not show up again. I don't know, it seems to be happening less frequently but it's still there. I guess at this point I'll just keep an eye on it and start looking for a distributor as it's the only thing in the ignition system that hasn't been addressed. I still say it's the strangest distributor failure I've ever seen if that's what it turns out to be. You just wouldn't expect that part to cause such an intermittent issue. Usually once they start dropping out, it's either running consistently poor or not at all.

 

Refresh my memory. Does this problem occur *only* at idle?

Cheers
DD

 

The stumbling is only at idle but the tach can start acting up at any time, really. Seems to be more frequently at idle, though. If you're underway and it starts up it doesn't affect engine performance or running. At idle only sometimes does it stumble, much of the time it's just the tach bouncing all over the place.

 

OK, the idea I had wouldn't apply then.

I'll mull it over in hopes of an idea that you already haven't thought of.

Cheers
DD

 

Well, it's been doing it pretty good, mostly when first started and for the first few minutes of driving. This weekend I'm going to take the distributor out, clean all the contact points thoroughly and make sure the gap on the contact is adjusted correctly, then re-install and make sure it's good and timed and go from there. Hopefully, at the very least, it will change something about the condition that will allow me to pinpoint the distributor as the cause.

For those who've removed them before, anything special I need to know when removing/installing the dizzy? I'm assuming putting the engine at TDC and marking the alignment of the distributor are good first steps but is there any risk of anything jumping on you while doing it that I should know about?

 

Finally got around to installing the distributor today and that was the problem. Also noticed the car idles a whole lot smoother with the new dizzy, too. Even when the old one was doing it's job it wasn't exactly doing it well, lol. Now I can finally set the in P idle below 1k rpms without the car attempting to dance in the streets when in D at a stop light. Just need to get the timing dialed in and re-tweek the idle now, very pleased after all that that it's figured out and fixed. Fwiw getting the old dizzy out required a slide hammer, too. Needed a pry bar just to even turn it once the clamp was loose, gotta love working on old cars.

Quick thanks to david boger for the NOS Lucas distributor at a solid, fair price. You're the man. And thanks to everyone else who tossed out some ideas trying to help get it figured out, strangest distributor failure I've ever witnessed and it's certainly not my first, lol. Now I'll probably try to track down a new pickup for the old dizzy to have it as a backup spare.

 

Mine sounds just like this. Is this normal? Or does it indicate the tappet sleeves are clanking around with the cam lobes?

 

That sounds a bit heavy IMHO. I'd pull the cam covers for a look-see. Start with the exhaust side

Cheers
DD

 

Look at my pictures from earlier in this thread, it will be plainly obvious once you have the cam covers off (which is quick and easy). I was lucky enough that no valve damage appears to have happened and my noise went away instantly with the installation of the stakedown kit. That said the valvetrains on these engines aren't exactly quiet to begin with so some amount of noise should be expected but there's a discernable difference between the normal vavletrain noise (likely exacerbated by valves which are unlikely to be adjusted correctly unless you've done it yourself) and the noise made by a loose tappet.

 

I guess now that I know what is under the valve cover, I can just feel around in there with my finger to see if there is already a stakedown kit installed. At 131k miles, I would be surprised if it didn't already have this done.

If there was damage to the valves, wouldn't I be seeing a lot of blue smoke everywhere? The car doesn't smoke at all!

 

http://youtu.be/cAs1clg4L_c

This is a video I just took of my engine. The ticking is pretty bad--but I'm not sure if that's normal injector noise or not? I will need to use a stethoscope to figure out where the ticking is coming from.

 

Too loud for injectors, IMHO

Cheers
DD

 

Sounds like the tappet guides to me. Mine didn't have the stakedowns, either, no reason to assume they're there, the probably aren't. It's just a few bolts and a hose or two to get the exhaust cam cover up, refer to the pictures I put earlier in this thread and you will see it.

 

Thanks. I'll probably tackle this job myself, now that I've seen how simple it is. I'm not driving the car much now, so I'll probably wait a little bit to do it once the weather is warmer.

 

Pauls Jaguar sells the down pipe and the center pipe without the cats. They are a great bunch of people to deal with. I removed my air pump and all the hoses that go with it and I have seen no problems. How involved is it to add the plates that you installed? I am just scared to drill into my head.