Project Rusty Triumphs in Scotland - To gas or not to gas(less MIG) - 09/11/24

[MorrisItalSLX]

It might be possible to just glue the rotor arm to the shaft?

Also, that fresh paint job looks very BLU.

[dave j]

Don't all rotor arms have play in them like that? I wouldn't go welding it until its definately confirmed as an issue as it could ruin a perfectly fine dizzy

[captain_70s]

The whole shaft should have a degree of movement in it for the ignition advance, but it should snap back under spring tension. As it does.

The arm itself should be unable to spin independently of the shaft though, as that'll just throw the timing out at random as the arm rotates back and forth as the engine tachs up or down.

I doubt adhesive would last due to how hot the dizzy gets, I imagine it'd work for a few miles though.

New arm and cap ordered, so I'll try that first to make sure it's not just 2 duff rotor arms.

[Talbot]

At about 0:37 in your video above, when revving the engine up, that is unmistakably a single-cylinder misfire, meaning it absolutely has to be ignition rather than fuelling, and if I were a betting man, it's somewhere from the rotor to the spark plug, (IE components specific to one cylinder only) most likely the rotor arm not aligning with the pick-up in the cap, as you've identified.

The shaft on the distributor doesn't look worn.  Usually the first thing that happens is that the rotor becomes loose on the shaft, which yours isn't.  What's more likely is that the rotor arm isn't the right one for the car, and its D-flat is too small, meaning it can move about on the shaft.

I'd look to see if you can get a better quality/better fitting rotor arm.  Also whip all your spark plugs out and check them.  How new are the HT leads?  Do they all fit with a good "snap" onto the plugs?

[captain_70s]

Leads are about 2 years old, still click onto the plugs fine, the plugs are all good, light brown deposits.

Main oddity is that the 2 rotor arms I have are identical and have done at least 10,000 miles between them with no prior problems.

This running issue only appeared when the car left the workshop after being repaired. Hence my assuming it was a gummed up carb from sitting and only running in a dusty garage. It's not something you can really miss as it rendered the car essentially undrivable. 

[big_al_granvia]

this gunk is good to 130 degrees Celsius  https://www.halfords.com/motoring/paints-and-body-repair/adhesives/evo-stik-serious-glue-33g-174543.html

[SiC]

Tried a timing gun on each lead to see which cylinder it's misfiring on? (Or if all)

Surely when the engine is running, the rotor arm probably won't be moving that much on the shaft? The rotor arm isn't that heavy with a lot of mass. Especially as it looked like it had a fair amount of friction holding it.

Also, does it matter if it does move? The Rotor Arm doesn't define ignition timing, unless wildly out that it isn't in roughly the right place to create a circuit. Hard to tell from the video how much play is there as the rest of the shaft is moving against the weights + springs.

Have you tried bending the spring out inside the rotor arm to make a stiffer fit? Is the wiper on the top of the cap making good contact?

[Zelandeth]

I had issues with my Skoda 135 Rapid where the rotor arm refused to fit properly - it was absolutely fine until you went north of 4000rpm at which point it would ride up the shaft and knock the timing about 45 degrees out.  Usually mid overtake.

I wound up wrapping a bunch of that self adhesive aluminium foil around the distributor shaft to make it a tighter fit.  Took a couple of tries but did work.

[Talbot]

2 hours ago, SiC said:

Also, does it matter if it does move? The Rotor Arm doesn't define ignition timing,

Usually the width of the end on the rotor and the "contacts" for each cylinder is enough to allow for the ignition advance mechanism to do it's thing while maintaining the proximity of the arm and contact.  The fact that the point of ignition changes as the ignition advance changes is a good thing, as it distributes the electrical pitting/burning over the whole rotor rather than always being the same point.

However, the ignition advance curve might be upwards of 30 degrees.  That means the rotor arm and contact have to be close enough to each other over a 30 degree arc of the rotor arm.

Start adding in another 20 degrees of movement, and I can well believe that the rotor arm is far enough away from the contact to get a reliable "connection".

To confirm this, I'd fit the rotor arm exactly in line (flat on the shaft in line with the flat on the rotor arm) and see how well it runs.  Also, see if it moves in service.  It could well be that the last 10k miles have been achieved with the arm in the right location, and friction has meant it's not moved.  As it's since been "twiddled with" it could have been at an extreme of travel, hence beginning to not transfer spark when needed to, as it's simply too far away from the correct contact in the cap.

If the plugs are all good and the HT leads in fine fettle, the only remaining area is the distributor.  Nothing else (other than something deeply mechanical) affects one cylinder only.

[SiC]

Usually the width of the end on the rotor and the "contacts" for each cylinder is enough to allow for the ignition advance mechanism to do it's thing while maintaining the proximity of the arm and contact.  The fact that the point of ignition changes as the ignition advance changes is a good thing, as it distributes the electrical pitting/burning over the whole rotor rather than always being the same point.

Yes I know that and you cut out the bit in my quote where I mention providing it's not wildly out. Hard to judge on that video on how much movement is going on there without the rest of the mechanism slack in there. 

[GingerNuttz]

Megajolt time. 

[Talbot]

There looks to be at least an extra 20 degrees of movement there, which could easily be enough to push the rotor out of range.

It sounds a lot like it was too far in the retarded position, meaning that when the engine is idling with a big dollop of vacuum advance, it would run on 4.  As soon as you step on the accelerator, kill the vacuum and retard the ignition further, it splutters.

Then as the engine speeds up and you get some dynamic advance happening, it runs on more cylinders again.

[captain_70s]

There is an easy 20 degrees of play on top of whatever the mechanical advance is (around 30 maxed out at 4k IIRC). Vac advance is irrelevant really as it's disconnected!

As I said a few posts ago with the slop taken out and the rotor arm firmly locked in place with a bit of card (whether dead straight or not) it ran considerably better and started first turn of the key whereas before it was kicking back. The floaty rpm return and lack of idle the car developed I'm 90% was me knocking something in the throttle linkage which is mega sensitive to being bent/knocked out of adjustment.

[jaypee]

6 hours ago, GingerNuttz said:

Megajolt time. 

Aye, he'll need that for the turbo..... 😋

[bezzabsa]

On 2/9/2021 at 12:21 AM, captain_70s said:

Accurate.

Celebratory snow:

Never eat Yellow snow!!!!! and that s a LOT of yellow snow :O

[Jikovron]

The mechanical advance doesn't change the rotor arm to cap spark position as the rotor and ignition trigger are floating but fixed reference to each other, the vacuum advance does have a small effect on the rotor arm to cap position but it's a small range of movement.

[bezzabsa]

21 hours ago, captain_70s said:

First sunny day for a while so went to try and diagnose the Acclaim's running issue.

Naturally the battery had gone flat again so I had to bump start the car down a hill to drive it round to the flat while it ran like arse. Once it was parked it stalled and the battery wouldn't restart it, so I swapped it's battery for a spare I had upstairs. Annoyingly this had Japanese standard terminals and one of the adaptor rings was missing, so ingenuity was applied.

I replaced the ignition control module, which did nothing.

I tried revving the car up and covering the intakes to try and suck any shite out, this also did nothing.

When trying to restart after stalling it kept backfiring through the carb and kicking and then immediately stopping dead like it was out of time. Checked the dizzy and that was tight and hadn't spun loose, so unscrewed the cap to have a look inside and found the issue.

The rotor arm had a good centimetre plus of slop on the shaft. The shaft itself was tight and the advance mech all seemed alright but the arm was loose as buggery. So I whipped out the spare from the boot that was known working when removed and... That was exactly the same. Somehow my dizzy shaft has worn in such a way the rotor arms won't hold true. I wedged a bit of thin carboard between the flat of the shaft and the rotor arm to test the theory and was rewarded with a car that would rev smoothly but not idle and was taching down far too slow.

It's hard to say if the lack of idle and slow return after revving is connected to the dizzy issue, I suspect I've just disturbed something in the throttle linkage while fucking about.

Gonna' try TIGing the dizzy shaft and file it down, 'cause I can only find one place that lists the dizzy as in stock and it's £150.

 

OMG I didn't know Ewan Mcgregor was on Autoshite!!!!!!!

[Dick Cheeseburger]

12 minutes ago, bezzabsa said:

OMG I didn't know Ewan Mcgregor was on Autoshite!!!!!!!

Now you've said it, I can hear what you mean. Maybe some celeb* voice-over work could help pay for future rust preventative fluids? 

[bezzabsa]

48 minutes ago, Dick Longbridge said:

Now you've said it, I can hear what you mean. Maybe some celeb* voice-over work could help pay for future rust preventative fluids? 

first few seconds had me like......Really!!! Is it??

PMSL

Hmmmm not a Triumph...but tis shite!!! 

[Talbot]

23 hours ago, Jikovron said:

The mechanical advance doesn't change the rotor arm to cap spark position as the rotor and ignition trigger are floating but fixed reference to each other, the vacuum advance does have a small effect on the rotor arm to cap position but it's a small range of movement.

Both the mechanical and the vacuum advance units will change the relationship between the rotor arm and the cap positions.  It's very clear to see in the Captain's video above that the ignition trigger ring is fixed to the same shaft as the rotor arm, so anything that moves the relationship of the trigger ring to the engine timing will also move the rotor arm.

The fact that the Vacuum advance is disconnected does throw my theory above out somewhat though, as the misfire sounds quite regular as the engine is revved up, despite the fact that the ignition timing will be changing as the engine speed increases.

It's definitely ignition related though.  Fuelling misfire sounds very different to that.

[GeorgeB]

41 minutes ago, Talbot said:

Both the mechanical and the vacuum advance units will change the relationship between the rotor arm and the cap positions.  It's very clear to see in the Captain's video above that the ignition trigger ring is fixed to the same shaft as the rotor arm, so anything that moves the relationship of the trigger ring to the engine timing will also move the rotor arm.

The fact that the Vacuum advance is disconnected does throw my theory above out somewhat though, as the misfire sounds quite regular as the engine is revved up, despite the fact that the ignition timing will be changing as the engine speed increases.

It's definitely ignition related though.  Fuelling misfire sounds very different to that.

The vacuum advance will move the plate that the pick up for the trigger is mounted to. It won't move the rotor arm.

[Jikovron]

15 minutes ago, GeorgeB said:

The vacuum advance will move the plate that the pick up for the trigger is mounted to. It won't move the rotor arm.

WHS ^^, the when the trigger tooth passes the pickup the rotor arm is always at the same position when it sparks however due to mechanical advance the engine is put further behind , when the vac advance pulls the pickup plate advanced the reference that the trigger/rotor arm sees has moved around the dissy body and thusly the cap .

[Talbot]

9 hours ago, GeorgeB said:

The vacuum advance will move the plate that the pick up for the trigger is mounted to. It won't move the rotor arm.

You're right.  My description above was poor... when the ignition is advanced by the vacuum advance, the rotor arm relationship to the engine position won't change, but the spark timing does, meaning the relationship between the spark timing and the rotor arm does change.  If the spark was already on the limit of being able to jump from rotor arm to cap pick-up, some vacuum advance could make the difference between it getting to the plug or not getting to the plug.

... but as the vac advance is disconnected on this car, makes no difference from a diagnostic point of view.

[captain_70s]

More fun times.

Rotor arm replaced and marked, car currently running alright but with a slight misfire on one cylinder at idle. The mega floaty idle and dying was a vac hose that'd gotten pulled off with me lifting the airbox away from the carbs. Really the carbs need a full service, may throw a new coil at it as well.

Then I rehung some of the doors and adjusted the hinges so things line up/close as well as they're ever going to. 

Then I set about refitting some interior plastics and noticed a wet bit of carpet in the rear footwell.

Ah, that's quite a lot of water, and explains the tendency for the car to steam up to fuck. Well, it'd be easier to see where it's getting in if the carpet was out...

And while the interior is out I should probably assault it with the VAX...

The carpet is a bit faded!

Currently the car just has the driver's seat and seatbelt back in to make the water ingress easier to spot. I then came down with food poisoning and have spent the last several hours in bed being unable to eat or drink, so progress has slowed somewhat...

[vulgalour]

Ah, you are playing the song of my people.  My thoughts are with you at this difficult time.

[captain_70s]

Drove to work and back in it today.

Can't use the handbrake because the only way to disengage it on the passenger side is to lie down under the car and smack the lever with a rubber mallet. The indicators don't always engage 'cause I think the stalk contacts are jammed up with grinding dust and the exhaust rattles almost unbearably at lower rpms and on the overrun.

I also thought it smelt a bit petrolly of late so I checked the new fuel hoses up front, all good. Noticed it again when I got home and had a look underneath.

That'd certainly explain it. Looks like it's leaking out of the filler neck hose. That'll give me something to do before work tomorrow I suppose...

At least managed to park next to a car that wasn't ridiculously vast by comparison. Hard to do these days.

(The trail of liquid behind the Acclaim is actually water which seems to be leaking out of the rear valance or the boot or something. Another thing to hunt for...)

[Jikovron]

Old car niggles man, they're like a war of attrition but bit by bit they shall be knocked off the list. 

[captain_70s]

A 1980 Dolly 1300, 60k on the clock, original paint (polished through in places), been laid up for the last 1.5 years. Also not mine. Sad.

A fella on the TDC forum was asking for advice as his car wouldn't start, he's in Glasgow and I have form for fucking about with Triumph OHVs that are reluctant to start so I offered assistance. 

Whipped out a plug and confirmed we had spark, then attached my hand pumped fuel primer thing and dragged some petrol up to the pump. With enough cranking the pump eventually managed to get some fuel up to the carb, the dashpot was empty so I topped it up with 20w50 to stop the piston getting stuck, and she fired up no bother.

The fuel had drained back to the tank/evaporated out of the float bowl and the mechanical pump takes an age to drag fuel up from the tank if it's pumping air. In my experience the battery will usually die before fuel arrives at the carb. Once started she ran a bit lumpy for a bit and wouldn't idle off choke at all. So I booted the throttle a couple of times and once a load of crap had been ejected from the exhaust a nice smooth idle came into being.

The fella who owns it can't actually drive, being partially sighted and having had a stroke, so his wife drives him around in it. Doing 100-200 miles a year around Glasgow I imagine it was pretty clogged up!

Driving the Acclaim in the pissing rain also aided in finding leaks. Rear passenger side is water getting in where the brake line passes through the rear bulkhead, easy to seal. Rear driver's side is now bone dry having previously been a lake, but I'd spotted a twisted door rubber and fixed it so that may well have been the cause of that. There also seems to be a bit coming down the front bulkhead, so that'll be the windscreen seal. Not exactly a surprise as it's rough as buggery.

[captain_70s]

A return to daily duties for this thing as the Saab's ignition switch seems to be getting increasingly unreliable and I nearly ended up stuck at Rutherglen Tesco with a flat battery earlier in the week.

Naturally it had to end in tears and I came out to the car at the end of my shift tonight to find the windscreen had cracked. How? No idea. No signs of rust around the screen, not been particularly cold/hot, probably a fucking pothole given the roads around here look like they've been fucking carpet bombed.

So, windscreens are apparently a pig to remove and usually break in the attempt, so second hand ones are mega rare. Pilkington will make one, but it takes 8 weeks and costs over £300. Also the one place that had Acclaim/mk2 Civic windscreen seals in stock, a place in Australia, now doesn't have any left.

 

[vulgalour]

On the positive side, at least the crack is now edge to edge so unlikely to spread across the screen.