Wandering Timing Magical Mystery!
Wandering Timing Magical Mystery!
..here's a funny one for you. I can't understand this at all.
My ignition timing wanders. Over 3000 - 6000 odd miles, it creeps from 8 btdc to the point it wont start at around 12 - 14 degrees btdc!
Everything is tight.
New distributor.
New auxiliary shaft.
It was doing this before the new parts too. It's really weird as I can't see how this can happen. Has anyone ever had or heard of anything like this?
My ignition timing wanders. Over 3000 - 6000 odd miles, it creeps from 8 btdc to the point it wont start at around 12 - 14 degrees btdc!
Everything is tight.
New distributor.
New auxiliary shaft.
It was doing this before the new parts too. It's really weird as I can't see how this can happen. Has anyone ever had or heard of anything like this?
I'm the one who leaves all those shoes in the carriageway.
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Re: Wandering Timing Magical Mystery!
Yeah, that is unusual
Just to check..Are you timing it and checking it with the vacuum advance removed? It will move under vacuum as normal so would give different readings when checked.
If it’s changing and the distributor body is tight (and it’s drive gear is correct) then thinking about everything that might jiggle the timing all I can think is either, the cam belt is stretching over time changing the timing (don’t see how but that would move the timing) one of the cam toothed pulleys is moving independent of the actual cam belt (again, they shouldn’t but…) or that the internal plate that allows vacuum advance/retard to move is loose in some way so it’s flopping about and changing the timing?
Other than that I don’t see how the timing can move? And since it was doing it before new parts it makes it even more of a magical mystery to be sure!
Just to check..Are you timing it and checking it with the vacuum advance removed? It will move under vacuum as normal so would give different readings when checked.
If it’s changing and the distributor body is tight (and it’s drive gear is correct) then thinking about everything that might jiggle the timing all I can think is either, the cam belt is stretching over time changing the timing (don’t see how but that would move the timing) one of the cam toothed pulleys is moving independent of the actual cam belt (again, they shouldn’t but…) or that the internal plate that allows vacuum advance/retard to move is loose in some way so it’s flopping about and changing the timing?
Other than that I don’t see how the timing can move? And since it was doing it before new parts it makes it even more of a magical mystery to be sure!
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Re: Wandering Timing Magical Mystery!
As with the previous reply, I'm also thinking of something odd with the timing belt Tom. Is that new also? If not it may be worth changing it as they're cheap enough.
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Re: Wandering Timing Magical Mystery!
End float on th aux shaft ? If it was able to move in and out it would alter spark timing . Im assuming cam timing is constant. 6 deg aint much ....enough to cause starting issues , specially if there is a bit more compression than usual . Its just about gotta be somewhere around the aux shaft or dizzy drive gears .
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Re: Wandering Timing Magical Mystery!
Points and condenser or leccy ignition?Major_Tom wrote: ↑Sat Jan 15, 2022 12:48 pm ..here's a funny one for you. I can't understand this at all.
My ignition timing wanders. Over 3000 - 6000 odd miles, it creeps from 8 btdc to the point it wont start at around 12 - 14 degrees btdc!
Everything is tight.
New distributor.
New auxiliary shaft.
It was doing this before the new parts too. It's really weird as I can't see how this can happen. Has anyone ever had or heard of anything like this?
If an honest man is wrong and after demonstrating that he is wrong he either stops being wrong or stops being honest
Re: Wandering Timing Magical Mystery!
How tight is the belt tensioner?
I had one once where the numpty before me had levered the tensioner as tight as they could, rather than letting it settle into a natural position.
It held the belt tight against the top pulley for too long and gradually would lift the belt out of the tooth and into the next one.
Given my assumption that you still have your tendency to utilise the full rev range ( ) it may be that the belt is slipping?
I had one once where the numpty before me had levered the tensioner as tight as they could, rather than letting it settle into a natural position.
It held the belt tight against the top pulley for too long and gradually would lift the belt out of the tooth and into the next one.
Given my assumption that you still have your tendency to utilise the full rev range ( ) it may be that the belt is slipping?
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Re: Wandering Timing Magical Mystery!
Check the dizzy end float too, they are not supposed to have much but ive seen them with 2mm or so
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Re: Wandering Timing Magical Mystery!
I have a book here called "Pinto , the worst engine ever made" ,this sort of thing is probly just one of the reasons .
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Re: Wandering Timing Magical Mystery!
Thanks gents, will report back when I can!
I'm the one who leaves all those shoes in the carriageway.
Re: Wandering Timing Magical Mystery!
If you remove the belt cover (if you have one?) then slowly turn the bottom pulley using a suitable socket you may be able to see the belt riding up the top of the cam sprocket then falling back again. That's how I found mine.
That was on a GT4, wonder if there's any of those left now?
Re: Wandering Timing Magical Mystery!
I am thinking of a respray and adding the side decals from the GT4 actually, they look so fantastically 80s, I love it.Bug wrote: ↑Mon Jan 17, 2022 5:04 pmIf you remove the belt cover (if you have one?) then slowly turn the bottom pulley using a suitable socket you may be able to see the belt riding up the top of the cam sprocket then falling back again. That's how I found mine.
That was on a GT4, wonder if there's any of those left now?
I'm the one who leaves all those shoes in the carriageway.
Re: Wandering Timing Magical Mystery!
Don't forget the bonnet ones too.Major_Tom wrote: ↑Tue Jan 18, 2022 11:12 amI am thinking of a respray and adding the side decals from the GT4 actually, they look so fantastically 80s, I love it.Bug wrote: ↑Mon Jan 17, 2022 5:04 pmIf you remove the belt cover (if you have one?) then slowly turn the bottom pulley using a suitable socket you may be able to see the belt riding up the top of the cam sprocket then falling back again. That's how I found mine.
That was on a GT4, wonder if there's any of those left now?
Re: Wandering Timing Magical Mystery!
Wandering timing seems to have been intermittent sticking of distributor weights. Sorted now thanks for the suggestions gents.
I'm the one who leaves all those shoes in the carriageway.
Re: Wandering Timing Magical Mystery!
Tom, are you having some kind of clear out? Answering all the replies you were given from years back??
Re: Wandering Timing Magical Mystery!
Getting my affairs in order Martin!
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Re: Wandering Timing Magical Mystery!
Hey Tom,
Happy you got this sorted. Do you put a drop of oil on the felt pad under the Rotor arm every now n then? I have done this on all my cars as this lubricates the mech advance bits n bobs / cam bearing....
Basically when checking the engine oil on the Dip Sick, whip off the Dissy cover and rotor arm and put the bottom of the dip stick on the pad.... Job done...
I am always surprised by the number of people who do not seem to know about this, but it is mentioned in every Haynes manual I've ever read for Routine maintenance = 6 Months - 6000miles..... I hope this helps if this is a persistent issue?
Cheers for now,
John...
P.S. Don't do this if your engine oil is dirty / burnt!!!! Just use a bit of fresh off the bottom of a screw driver....
Happy you got this sorted. Do you put a drop of oil on the felt pad under the Rotor arm every now n then? I have done this on all my cars as this lubricates the mech advance bits n bobs / cam bearing....
Basically when checking the engine oil on the Dip Sick, whip off the Dissy cover and rotor arm and put the bottom of the dip stick on the pad.... Job done...
I am always surprised by the number of people who do not seem to know about this, but it is mentioned in every Haynes manual I've ever read for Routine maintenance = 6 Months - 6000miles..... I hope this helps if this is a persistent issue?
Cheers for now,
John...
P.S. Don't do this if your engine oil is dirty / burnt!!!! Just use a bit of fresh off the bottom of a screw driver....
Re: Wandering Timing Magical Mystery!
Cheers mate, yes I think that was the issue I do lubricate the dizzy, about once a year, but I guess it was not regularly enough. It's a rally distributor too, I think it gives less advance at higher revs, so perhaps spring tension is not as great and the need to lubricate more frequentTaff50ish wrote: ↑Thu Jun 30, 2022 2:06 pm Hey Tom,
Happy you got this sorted. Do you put a drop of oil on the felt pad under the Rotor arm every now n then? I have done this on all my cars as this lubricates the mech advance bits n bobs / cam bearing....
Basically when checking the engine oil on the Dip Sick, whip off the Dissy cover and rotor arm and put the bottom of the dip stick on the pad.... Job done...
I am always surprised by the number of people who do not seem to know about this, but it is mentioned in every Haynes manual I've ever read for Routine maintenance = 6 Months - 6000miles..... I hope this helps if this is a persistent issue?
Cheers for now,
John...
P.S. Don't do this if your engine oil is dirty / burnt!!!! Just use a bit of fresh off the bottom of a screw driver....
I'm the one who leaves all those shoes in the carriageway.
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Re: Wandering Timing Magical Mystery!
Yep , gotta admit I had a bit of a moment when the cause was revealed .
Sometimes I talk to myself ... and we both have a good laugh