Gents,
My distributor pinch bolt does not seem to hold the distributor properly. The pinch bolt has a 7/16th hex bolt head which I can tighten using a small ratchet wrench but the distributor slips during driving and spoils the timing setting. It‘s a 123 electronic distributor.
I would like to remove the distributor to investigate.
The workshop manual advises to slacken the pinch bolt and pull out the distributor. There is no mention of first setting a specific motor/timing position.
The Haynes book advises to leave the pinch bolt and remove the distributor together with the pinch bolt/clamp plate assembly but removing the bolt fixing the clamp plate to the block. Also it advises to first set up the motor/timing for TDC for the front (#6) sparkplugs.
Has anyone had this problem? Which advice is correct? Does the workshop method work? It would be easier to remove the pinch bolt/clamp plate assembly when the distributor is out of the way.
Looking forward to hearing your experiences,
Dave

 

The most common problem here is the overtightening of the pinch bolt where it distorts the steal clamp on the distributor itself.
When this happens, it doesn't clamp properly it the distributor is allowed to move.

Timing:
Put #1 (at the back of the engine) on compression _ note where the rotor is pointing _ use that as a reference to re-install the distributor.
I like to remove the distributor with the clamp, that entails the removal of the bolt in the block that holds the clamp in place.
You will need a timing light to get things correct after static timing.

When you pull the distributor, I'm betting the clamp is distorted.
Sometimes they can be cracked too if someone was really reefing on it.
It just takes a slight "snugging up".

Mark the position of the clamp where it goes onto the distributor with a sharpie _ makes things a little easier to get the timing correct.
Note that the distributor rotor turns counter clock wise.
Firing order is 153624.

You could use #6 to time the engine, just make a note where the rotor is pointing; 180 degrees away from the engine block is where it's probably at.
Odd why the book says to use #6.

Many manuals assume that if you're in there working on the ignition, that the mechanic knows how to time an engine.
They just give specs. and leave the rest for the mechanic.
A rooky mistake is to get the ignition timing 180 degrees out; instead of getting the spark on compression, it gets it on exhaust.
The distributor turns half the speed of the crank because it's a four cycle engine.

Just because the piston is at the top, doesn't mean it's on compression.

 

I would follow the genuine Jaguar Service Manual & ignore the Haynes Manual.

 

IME, if the distributor is removed on an engine with correct timing and the distributor shaft OR body is not replaced in the exact location in which it was before removal, the timing will be lost. NOT removing the clamp from the distributor body (as they are usually bolted to it in only one orientation) may eliminate the possibility of disturbing the rotation of the body relative to the block, but it won't ensure that the distributor shaft will be inserted into the previously correct position WRT to the teeth on the distributor shaft and the corresponding teeth on the camshaft.

i've recently had success with a removal and reinsertion of a distributor on a 1950's vintage british sports car. i was careful to note where the rotor was in relation to the distributor body, and where the distributor body was in relation to the block when it was removed. and then again upon re-insertion. i was also careful to not disturb the position of the camshaft while the distributor was out of the block (not difficult).

fortunately, if the rotor's position WRT the distributor body, is lost, there are a fixed number of teeth on a distributor's drive gear (ten, in my case), leaving a fixed number of possibilities for error as long as the body of the distributor WRT the block, upon re-insertion, is retained.

please correct me if i'm wrong (which i often am!).

 

Jaguar distributors (Lucas 22D6) have a drive dog that is offset & can only be assembled one way. However if you remove the centre screw on the cam in the distributor drive shaft you can reassemble 180 degrees out. I can't speak for a 123 electronic distributor.

 

ah yes, forgot about that engineering innovation! ...simplified things a bit, didn't it? my '61 MGA, BITD, had one of those, IIRC.

so...let me think... if it's true that removing the clamp with the distributor body retains the body's orientation with the block and the dog retains the orientation of the shaft with the cam, then if the clamp is removed with the distributor body the timing, whatever it may have been, will be retained in all circumstances. is that righ?

i'm trying to get this straight in my head because i'm currently looking at the distributor on my table that has been removed from my 50's british car and will soon be replacing it for good with a new 123ignition distributor. i'm also contemplating the purchase of a 123ignition distributor for my mk2 once i get the car back from the engine rebuilder.

 

Refresh page for extra pic inserted.

 

Do you have a blow up diagram of a 123ignition distributor? If it has a solid shaft that can't be split like the Lucas 22D6 you are home & away. It can only be inserted one way & you do the rest with the plug leads to get the correct firing order from the rotor position or whatever they use & set the base timing. Then you dial in the curve you prefer on the road.

 

the 123ignition distributor pics for jaguars with XK engines show a drive dog, supplied and installed, on the end of the distributor's drive shaft.

it looks as though, they are set-up by establishing a base reference point (similar to traditional static timing but without the need for the wires and bulb) by aligning the crank pulley's notch with the 0 degree timing mark on the timing cover and then turning the distributor body clockwise or counterclockwise (dependent on one's engine's rotation) until a built-in LED light on the top-side of the distributor, near the rotor, lights up. ...that's it after connecting up two wires to the coil, of course. there are 16 different advance maps built-in and selectable via a small dial on the side of the body, and for a premium price, they now offer a bluetooth custom programmable mapping facility with your phone and free app. two custom (you create them) advance maps can be available and switchable, while running, with fancy dials that show RPM, etc., on your phone while driving along.

in addition to eliminating points, condenser, weights, springs, etc., the maps are entirely digital in all cases. one feature and one that cannot be duplicated by a non-digital mapping is the ability to discern very minute differences between the strengths (due to timing differences, i suppose) of the various cylinder's power strokes and compensate for them by altering the timing, thus smoothing out engine vibration. sounds a bit far-fetched, but theoretically possible, i guess. not sure i believe it. *headscratch*

 

That's very clever. I guess it could calculate acceleration of the dizzy drive on the downstroke following the spark and advance the spark to maximise it. The difficulties that come to mind are first noise in the drive to the distributor and second the risk of advancing the ignition far enough to cause knock. I accept that, for old engines running on decent fuels, advance is not so often knock limited, but it can be, especially after some mild modifications for better performance. And how does it integrate throttle movement into it all? Although I respect the cleverness of 123, there's a point where it's better (and simpler, safer and easier) to chuck the distributor and use signal from the crank with a remote processor.
​​​​​

 

If memory serves me, the light on the 123 system is there just to set the static timing when #1 is at TDC on compression or a few degrees before TDC.
I think the instructions say to use a timing light as one would normally would to get things correct.

Huey, even if the clamp is removed with the distributor, it won't allow the exact position when it's installed, I think the whole on the clamp where it bolts onto the block is elongated, so there is always room for error.
It will get you close enough though where the car will run and the timing light will get it where it's supposed to be.
You can also use the thumb adjustment on the vacuum advance to refine the timing further still.
There's an "R" and an "A" with arrows on the thumb screw to get things right. (retard and advance).

The last time I changed points, I just pulled the distributor out and retimed it, I find that so much easier then working down into that hole with all those small parts.

 

i assume sanity checks are built into the software (in fact there is an overrev function that can be set on the programmable models, IIRC) to catch an errant typo when programming and may well be implemented at runtime too for the dynamic whistles and bells stuff. ...just an educated guess.

BTW, i just got off the phone with the the primary U.S. 123distributor...ahhhh...distributor. Ed's his name and what a pleasant fellow! i didn't buy the unit from him i bought it from Limora imports, being the cheap SOB that i am, yet he was willing to do some machining on it, although he didn't know me from Adam, had a part (sold at cost) that i needed for it, and fielded a couple of phone calls (one to his equally pleasant and accommodating wife) and didn't charge for any labor. extraordinary!

after paying the bill i sent back an email requesting that he charge me for labor as i thought it only right. ...we'll see what happens. i'm hoping he's not as much of a smartass as i am, and think it humorous to charge some exorbitant amount just to see how sincere i am. as that might be something i would do. haha. we'll see...

 

Back again…
First thanks for your inputs. The problem was that the clamp plate was not sitting properly on the appropriate flange on the distributor housing. Tightening the pinch bolt was distorting the clamp plate but not tightening onto the distributor. I may have disturbed things when I replaced my brake servo…
Here are my experiences
​​​​​​- I first manually rotated the engine to the correct standard timing position (5degree BTDC for my engine with the distributor rotor tip pointing to the connector for the cable to the front sparkplug)
- I could not remove the distributor by only loosening the pinch bolt. It worked by loosening the bolt fixing the clamp plate to the block and then using the clamp plate to lever up the distributor
- The distributor is a tight fit due to the rubber o-ring on the distributor shaft
- For remounting, I first mounted the clamp plate loosely then pushed in the distributor using an old cap then tightened the bolt fixing the clamp plate to the block
- Use of the built in LED worked well to roughly set the timing well enough to run the engine and fine tune the timing using a strobe lamp by rotating the distributor and finally tightening the pinch bolt
- My distributor is marked „Jaguar XK 15-09-10“ (from 2010). Curve „0“ was set on the internal micro-switch. Contact with the manufacturer revealed none of the curves is optimal since they all start advancing the timing at a much higher rpm than the original mechanical distributor. They recommend to use Curve „0“ and set the timing at 8deg BTDC. I have done this but have the feeling that the engine is not running as well as it did with 5deg BTDC. I will try to optimize.
Hope this helps,
Dave

 

If your pinch plate damages the somewhat fragile pinch ring on the distributor body (I'm talking Lucas) you are in trouble. Do you have the correct distributor for your engine from 123Distributor. People like Orlando have had great success on the S Type Register. He is currently using curve 6.

Sorry he posted an update namely.

"Just to update this thread, for the benefit of any future readers, as my engine has a CR of 9:1, I was recommended to try Curve 0 on the 123 distributor, which is the one with the least aggressive advance curve. I have done this and set the static timing to 10 degrees BTDC, per the 123 manual.

This seems to deliver a perfectly acceptable level of performance throughout the rev band that S-type owners are likely to use and, crucially, without any pinking"

97 RON Gas/Petrol. US pumps show AKI. an average of RON + MON. ~ 3.8 litre, DG 250 transmission.

 

Refresh page for update.

 

Excellent advice, as always!

 

There’s no damage to my distributor. Its body looks like it’s machined from stainless steel and very solid. Apparently it was a recommended unit back around 2010 but obviously the new generation with a programmable timing curve is better. The blue tooth version also serves as a useful immobilizer.
As you can read, I received basically the same advice from 123ignition as Orlando and also have not experienced any pinking at higher revs. My engine is also 9:1 compression ratio.

 

Excellent!