Ignition Timing 1961 3.4 MKII (pos earth)

(Timothy M Fox) #1

On previous posts I asked about the refitting of my distributor which had just been returned to me after it had been rebuilt. The car didn’t run at all well - very roughly - so after reviewing all the connections and the timing I found nothing obviously wrong, I walked away from it for several months. Last weekend I found sufficient motivation to revisit the car and, after recharging the battery, I rechecked the firing order, set the timing using the static method described in the Service Manual (7 deg BTC - paper air cleaner 8:1 compression). However, I was told to set it using number one cylinder (rear of motor) not number 6 (front of motor) as in the Manual. Would this matter? The car sounds as though it’s labouring to turn over and then when it starts still runs very roughly and won’t accelerate without coughing and spluttering. I have mixture adjustment on both carburettors so I know they are working properly. I’ve cleaned and replaced all the fuel filters and have good fuel pressure, especially with the new SU pump. I’ve just given up again so all suggestions will be greatly appreciated.
Tim:weary:

(Ian) #2

You need to time it up on number 6 , front piston , easy way is to take number 6 plug out and place a big screwdriver or the like down the plug hole , slowly turn the engine , when the screwdriver stops moving up , your at tdc ,
I think 7 deg btc is a bit too much for a 3.4 , I would try around 2 btdc
Once your on that , just turn the distributer till the test bulb comes on ,
Not forgetting the rotation of the rota arm is anti clockwise
.Check the leads too , if you was trying to time it up at number one , you may have the leads in the wring position !

(Timothy M Fox) #3

Hi Ian, Thank you very much for that. The firing order is definitely correct. Your idea to achieve TDC on the number 6 is a great idea. The Service manual does suggest 6 deg for a paper filtered 8:1 compression car.

Back to the car I’ll go.

Tim

(Ian) #4

:+1: it’s MK1’s that are 2 :face_with_hand_over_mouth:

(Timothy M Fox) #5

What would be the effect on the motor if you set the timing using number one and not number six cylinder. Would the timing be far too advanced or retarded (like the car’s owner!:weary:)?
Tim :fox_face:

(Ian) #6

Just need to read the Manual , 1 step at a time , understand what your doing , take your time , drink Tea :smile:

(Mike Eck) #7

You can time using either cylinder 1 or 6 since they are both at the same place at the same time.

(David Jauch) #8

As long as the cylinder that is fired (…that the rotor points to!) is on the compression stroke it won’t make a difference.
And if it tries to ‘kick back’ against the starter you could try to simply retard the distributor a very small amount. Setting static timing is easier and more definitive.

(Timothy M Fox) #9

I’ll go through it step by step again soon in one final attempt. Hearing what you have all said I fear that the problem isn’t firing order or static timing. I’ll have to pull the distributor out and take it with the cap, coil and leads to another distributor specialist for analysis. It’s just so frustrating after having had it restored. I simply expected to drop it back in and have it run as sweetly as it did prior to the rebuild. It did need to be rebuilt as the internal wiring was bad with insulating virtually gone on some of the wires.
Cheers,
Tim

(Roger McWilliams) #10

Is the battery up to snuff? If the car is “labouring to turn over” it sounds like your battery is about expired if that result occurred after charging. Low voltage on the 12 volt side of the coil can give poor running with low spark. So can clogged or stuck carb parts.

On a rebuilt distributor, car should run okay with vacuum detached and plugged as long as static timing is set correctly. On rebuilds, sometimes the rebuild shop does not know what advance curve to supply and the mechanical advance springs may need changing even on a good rebuild. If condenser is bad, spark will be low also.

(Timothy M Fox) #11

Hi Roger,

The battery is brand new and fully charged. It has a new condenser and coil, as well as cap, red rotor and points too. I’m going to pull everything out and take it to another highly recommended repairer in Melbourne. Sadly I can’t drive the car there at present. If that doesn’t fix it I’ll have the car transported to the repairer on a flat bed tow truck.

I’ll be drinking lots of tea as Ian has suggested.:wink:

Thanks to all,

Tim

(Timothy M Fox) #12

Hello again,

The answer! As I couldn’t get the car to run after doing everything methodically, and drinking lots of tea Ian :wink:, I took the distributor to another repairer recommended by a trusted member of the Jag Club. The repairer took one look at it and said, “The drive gear on the bottom has been put on 180deg out!” I nearly uttered a profanity but resisted. Well in short I now know a lot more about distributors and ignition timing than I ever did before. Wisdom through trial - LOL! I will fit the distributor today then hopefully go for a nice smooth drive in the car. Finally, the repairer said never to replace the old Lucas condensers with the new ones with the orange leads as they fail with monotonous regularity. Keep the original Lucas one unless you are certain it has failed, and if it has find an original.
Cheers,
Tim :fox_face:

(Ian) #13

Sounds like you fell into the trap of thinking , it can’t be the distributor as it has been done !
Thought I see something in the manual about it .
Talking about condensers , I had a friend who had a old mini , that was playing up !
Cut a long story short , the first thing he replaced was the condenser , still had the same problem , after replacing most of the other ignition components , he put a old condenser from his tool box in , problem solved , the new condencer was faulty !!
Moral of the story , don’t think there is one , just kick yourself for missing it in the first place :smile:

(Timothy M Fox) #14

Well… no joy! The damned car still wouldn’t start.:weary: I went through everything step by step. I have fuel, I have spark. I set the timing using the static timing method to 7 deg BTDC. Please don’t be too tough on me but is it possible that I could have set the timing on number 6, as per the Service Manual, but on the exhaust / inlet stroke instead of the compression stroke?

Ian, would mind posting the whole of the article online please.

Cheers,
Tim

(Ian) #15


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(Paul M. Novak) #16

Tim,
I skimmed through this thread so please excuse me if you have heard this suggestion before. It is possible that your cylinder head was removed, the engine rotated, and the cylinder head was reinstalled at #1 TDC on the wrong stroke. This means the the spark is happening on the exhaust stroke instead of the compression stroke. If this is what is wrong all you need to do is connect the spark plug leads at the distributor 180 degrees out from their normal correct position to get the engine to run. I know about this because it happened to me.
I purchased a nicely running but crash damaged 1987 XJ6 as a parts car to use the 4.2 L engine in one of my Jaguars. In preparation to remove the engine I changed the spark plugs and leads. Then the engine wouldn’t start. It had fuel, spark, and compression and all I did was change the plugs and leads (in the correct order) yet it wouldn’t start. I had read on Jag-Lovers about this happening before to others so I swapped the leads at the distributor 180 out and the engine jumped to life at the first turn of the key. Needless to say I removed the distributor and reinstalled it correctly to prevent that from happening to me or others in the future.
If I were you I would swap the spark plug leads at the distributor 180 degrees out and see if that helps. This will only take a few minutes to do and is worth a try. Maybe it will work for you.

Paul

(Clive Jervis) #17

Hi Tim,

Much as it is frustrating, you will have a eureka moment!

Rememer you need three elements: air, fuel, ignition. Though it does look like ignition, bear the others in mind.

Start with low tension side: are points set correctly, with clean contacts? Use voltmeter to check correct 12 an 0 volts as appropriate. Are earth connections good, e.g strap between body and engine block. Is condenser good? Check all connections on low tension circuit.

On to HT side. Is coil good, are HT leads good, have you triple checked leads are in correct order, and then checked again? Is rotor arm OK, distributor cap in good condition, with good brush that contacts rotor arm? Are your spark plugs clean and correctly gapped? Do you get a nice spark at each plug. Start with testing spark from coil HT lead.

If you think your timing may be out 180 degrees, then try rotating it 180 degrees! If you can get it running at all, have dizzy loose so you can rotate it to see effect.

Bear in mind as well that timing marks can be off, deteriorated damper rubber, or wrong damper. So checking TDC corresponds to 0 degrees as marked may be wise.

If by now you are exhausted, take alcohol and leave car well alone for 24 hours. Then think about fuel and air :wink: systems.

Good luck, when you find the issue you will kick yourself, or a supplier.

Clive

(Timothy M Fox) #18

Hi Paul,

Thanks for that reflection. You won’t be surprised to learn that I have already tried that with no success, sadly. What you say about the rebuilding of the engine might be true and explain why the distributor drive was on 180 deg out from factory. Sadly I think I’ll have to have the car towed to the ignition specialist here in Melbourne and have them sort it out. It will be nice to know what they find. Naturally personal vanity plays a part in the dilemma as I would have liked to have worked it out by myself.

Amusingly, a very good friend of mine with a MKII had ignition failure yesterday, and given all that I have learnt so far with my own car, I was able to very quickly help him find that the coil had failed on his car. In went the original 1960’s coil and off it went. It was nice to help someone else as he was planning a trip on Sunday and it looked as though it was not going ahead but now it can. I’m going back to my car today and give it a very stern talking too - LOL!:wink:

I think I’ll buy a compression gauge today rather than pull off the cam covers. That way I can determine which is the compression stroke. Last roll of the timing dice.

Cheers,

Tim

(Timothy M Fox) #19

Is it possible to fit the dog drive on the distributor shaft 180 deg out or can it only go on one way?
Cheers,
Tim

(Timothy M Fox) #20

Hi Clive,

Points & condenser new old stock - all checked and adjusted; HT leads Hypalon - new; Champion screw-on plug caps - new; low tension lead new and checked; Remax coil - new and checked; Remax distributor cap - new; red rotor from Distributor Doctor - new; Champion plugs - N12YC gaps done.

12 and 0 volts checked.

Earthing points checked and okay.

Firing order checked many times, and then again.

Spark at each plug & from coil lead to earth.

Static timing with light okay = power.

I’m now worried about the dog drive being 180 deg out on the distributor shaft.

Now just fed up!

I’m sending ALL back to my distributor specialist.

Tim