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  1. #51
    FEP Super Member erratic50's Avatar
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    Well - it would be unusual for a timing set to shell out before the rest of the motor then but it's possible.

  2. #52
    FEP Super Member 84StangSVT's Avatar
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    Quote Originally Posted by Walking-Tall View Post
    Sounds like balancer ring or jumped (or incorrectly installed) chain... though, plug wires clocked wrong or one off around the distributor cap would put things out some... just something to double check, no judgement, lol
    I'm obviously not really well versed in this, just a guy trying to learn.

    I did verify that the plug wires were installed correctly. One of the first things I checked.

    If the timing chain was installed incorrectly or had jumped a tooth, wouldn't that make the thing damn near impossible to time? I would think that even being a tooth off would make the piston to valve timing so far off that it would never run good. Would there be any tell tale signs of this besides running like crap?

    I really question the accuracy of the balancer. It looks to be original to the car and if so, it's got 33 years and 250,000+ miles on her. I have a new one I'm going to try and install this afternoon.

    I'm really thinking that this issue has been present for the couple years I have had this car, but has never been as noticeable as now. I think the carb that was on it was running so rich, that it offset the issue and hid it fairly well. Now that the EFI is trying to trim the A/F ratio, it has caused it to show the issue and in a very pronounced fashion.

    I'm not done trying to get to the bottom of this issue but I'm encouraged that it appears to be headed the right direction finally. The car ran amazing yesterday for the first time this year and honestly since I have had it.
    Brock
    1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
    1984 Mustang GT Hatchback 5.0 V-8/5 Speed

    I'm an FEP Supporter and proud of it. Are you?

  3. #53
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    I would bet the balancer ring has slipped .
    If it is running right now , i would not waiste time or money checking the timing chain .
    clowns to the left of me , Jokers to the right

  4. #54

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    A slipped balancer wouldn't explain the mechanical advance only moving 12 degrees. That sounds more like a malfunctioning timing light or the ignition module is retarding the timing even without a signal on the start wire.

  5. #55

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    Quote Originally Posted by 84StangSVT View Post
    I'm obviously not really well versed in this, just a guy trying to learn.

    I did verify that the plug wires were installed correctly. One of the first things I checked.

    If the timing chain was installed incorrectly or had jumped a tooth, wouldn't that make the thing damn near impossible to time? I would think that even being a tooth off would make the piston to valve timing so far off that it would never run good. Would there be any tell tale signs of this besides running like crap?

    I really question the accuracy of the balancer. It looks to be original to the car and if so, it's got 33 years and 250,000+ miles on her. I have a new one I'm going to try and install this afternoon.

    I'm really thinking that this issue has been present for the couple years I have had this car, but has never been as noticeable as now. I think the carb that was on it was running so rich, that it offset the issue and hid it fairly well. Now that the EFI is trying to trim the A/F ratio, it has caused it to show the issue and in a very pronounced fashion.

    I'm not done trying to get to the bottom of this issue but I'm encouraged that it appears to be headed the right direction finally. The car ran amazing yesterday for the first time this year and honestly since I have had it.
    Ditto, I've caught myself more times than I'll ever admit, overlooking this 'er that, finding it back tracking... and I thought I was the only one who gets the brain buster issues, lol

    You mentioning it being roughly 20 degrees off kilter rung the plug wire bell for me for something to check.

    Yep, I trust you, Brock, not the chain/gears or the last guy that installed it, or the balancer's integrity. I think our friend there "mrriggs" is onto something, and I'm going to add to that the fact that TWO different distributors resulted in the same amount of limited mechanical advance... something else is up... ignition module?...
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  6. #56
    FEP Super Member 84StangSVT's Avatar
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    Let me add some more intrigue.

    Pulled the plugs and had the wife rotate the motor each way while I was looking in #1 hole. I had her mark the balancer when I saw TDC both directions. It ends up at 8 btdc when marked on the balancer. The distributor rotor is just shy of the pin for #1 on the cap. The timing chain feels fairly tight as there is little movement of the wrench needed to take up any slack.

    None of this makes any sense to me as understandably, I would have to use 8 degrees as zero, but even then if I timed for 10 degrees, it would put my initial at 18 degrees, not where I have it now.

    I can't imagine that the rotational force when the motor is running would twist the balancer that far off and then have it return back to position when stopped.

    I have tried 2 other modules and they produce the same results.

    I'm beginning to wonder if my lower end new Bosch timing light isn't jacked up.

    What do you guys think?
    Brock
    1984 Mustang LX Convertible 3.8L V-6/Auto (SOLD)
    1984 Mustang GT Hatchback 5.0 V-8/5 Speed

    I'm an FEP Supporter and proud of it. Are you?

  7. #57

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    It only reading 20-something fully advanced (initial + mechanical) before now makes more sense, because your perceived 10 was only 2 BTDC. Your visually and physically found and marked 8-degrees BTDC @ #1 TDC is a fair bit to be off. Checking how you checked eliminates the chain and gears, and 8-degrees down there translates to 4-degrees with the rotor, as you saw... and the balancer (or the pointer) remains suspect... and as to "road setting" the initial, and seeing 30 afterward with the light, there's no law that says that your combination doesn't like and want that 18-20+ initial (actual) degrees BTDC...
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  8. #58
    FEP Super Member erratic50's Avatar
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    When it comes to timing lights, simple can be better. I've seen several degrees of delay out of an inductive pickup based light surprisingly. At the time I chalked it up to poor quality, but reality is any time the wires are sizeably larger than the pickup it can cause poor readings. i don't know the source of decline in accuracy when it comes to latency but I suspect it also comes from other factors like processing latency inside some of the more complex lights, etc.

    Is simpler better? You decide. For me, I usually have a target in mind like 13.5 degrees because that's what my car has always liked, but how it runs varies at that setting based upon the light I've used. I like how my car runs better at 13.5 as observed from my elcheapo Autozone light rather than the same reading from my Snapon light. (which is not the same timing setting)

    No idea which one is even accurate!

    If I were in your predicament I would set the timing with the advance removed based upon where it just starts to speed up at idle then back just a little bit. If there is a hint of pinging drop it a little more, or try again with the advance hooked up. Or mark where you are first and split the difference, etc.

    You know the dizzy is new so it should be pretty accurate compared to "correct" advance curves, but I suspect this does vary based upon application. Why wouldn't it? I know my car ran marginally better before I put a reman dizzy in my car, but my original one was totally shot so no choice. Every time I've been around a car that runs harder than others like it it's seemed to boils down to timing, but there is definitely an acceptable range that works.
    Last edited by erratic50; 08-22-2017 at 04:02 AM.

  9. #59
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    I cant remember when i used a timing light last.
    I always use a vacumn gauge to set timing .
    clowns to the left of me , Jokers to the right

  10. #60

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    You ever figure out what was causing this? My car is doing the same thing now.

    Wouldn't rev above 4k with my foot to the floor. Put a timing light on it and the advance was going backwards to TDC! Tried swapping the orange and purple wires which only made it worse. Mechanical advance is working but something is electronically retarding it. I suspect it's a malfunctioning ignition module but in your case that didn't help.

    I had a junk distributor with a "21" slot so I stuck that in there to get 40 degrees of mechanical advance. Even with that much mechanical advance, the timing only goes up about 10 degrees when I rev it.

  11. #61

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    Today I tried two timing lights, two modules, and two pickups. No difference.

    The springs in the 21-slot distributor were super heavy so I don't think it was ever advancing 40 degrees. I swapped in the guts of an E5ZE distributor; lighter springs and "15" slot. Right now it is set to 16 degrees at idle (vacuum advance disconnected), it drops to 10 degrees off idle, starts advancing again at 2500 rpm, reaches a max of 22 degrees. I tried setting the initial advance higher but then the starter had trouble cranking over the engine.

    Put a new timing chain in last fall. When it was apart, I realized that the previous owner installed the steel gear E5ZE distributor in the flat tappet motor. I put it back together with a cast gear distributor. There was visual wear on the camshaft cog from being meshed with the steel gear for years. I'm beginning to think that that is the cause of my timing issues. EVERYTHING else has been checked and replaced.

  12. #62
    FEP Super Member erratic50's Avatar
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    Quote Originally Posted by mrriggs View Post
    Today I tried two timing lights, two modules, and two pickups. No difference.

    The springs in the 21-slot distributor were super heavy so I don't think it was ever advancing 40 degrees. I swapped in the guts of an E5ZE distributor; lighter springs and "15" slot. Right now it is set to 16 degrees at idle (vacuum advance disconnected), it drops to 10 degrees off idle, starts advancing again at 2500 rpm, reaches a max of 22 degrees. I tried setting the initial advance higher but then the starter had trouble cranking over the engine.

    Put a new timing chain in last fall. When it was apart, I realized that the previous owner installed the steel gear E5ZE distributor in the flat tappet motor. I put it back together with a cast gear distributor. There was visual wear on the camshaft cog from being meshed with the steel gear for years. I'm beginning to think that that is the cause of my timing issues. EVERYTHING else has been checked and replaced.
    Hmms. so unless I'm missing something, a worn gear should make your base timing retard which you could correct with more advance at the dizzy.
    -- James

    Favorite thing I’ve said that’s been requoted: “"40 year old beercan on wheels with too much motor"

    My four eyed foxes:
    "Trigger" - 86 Mustang GT - Black with red interior. 5.0 T5 built as Z. Original motor ~1/2 million miles. 18 yr daily, 10 a toy
    "Silver" - 85 Mustang Saleen 1985-006? (Lol) Rare 1E silver GT / charcoal interior. The car is a little bit of a mystery. Current project bought as a roller, tons of Saleen / Racecraft pedigree

    Also in the stable - my son’s car. 1986 Mustang GT Convertible. Black/Black/Black conversion. 93 leather. VM1 ECU. T5Z

    past foxes -
    1989 Mustang LX Sport 5.0 AOD white/tan black top. Once I ran this one down I caught a wife.
    Wife also had a 1987 Thunderbird Turbo Coupe in the 90's.

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  13. #63

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    Quote Originally Posted by erratic50 View Post
    Hmms. so unless I'm missing something, a worn gear should make your base timing retard which you could correct with more advance at the dizzy.
    Yeah, I'd assume that the gear would be constantly loaded in one direction due to the drag from the oil pump. An engine's motion is far from linear so maybe the oil pump drag and loose gear fit is preventing the distributor gear from following the constant acceleration/deceleration of the cam?

  14. #64
    FEP Super Member erratic50's Avatar
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    Quote Originally Posted by mrriggs View Post
    Yeah, I'd assume that the gear would be constantly loaded in one direction due to the drag from the oil pump. An engine's motion is far from linear so maybe the oil pump drag and loose gear fit is preventing the distributor gear from following the constant acceleration/deceleration of the cam?
    Would show erratic timing that gets more predictable with thicker oil. So as it warms up the timing gets more and more all over the place if there is not enough drag by the pump to keep it near constant.

    One hole makes power every 90 degrees. The rest of the holes drag against it. Two full engine rotations for one cam rotation. So accelerating cam every 45 degrees.

    i would think there would be enough drag there to keep it engaged all the time.
    -- James

    Favorite thing I’ve said that’s been requoted: “"40 year old beercan on wheels with too much motor"

    My four eyed foxes:
    "Trigger" - 86 Mustang GT - Black with red interior. 5.0 T5 built as Z. Original motor ~1/2 million miles. 18 yr daily, 10 a toy
    "Silver" - 85 Mustang Saleen 1985-006? (Lol) Rare 1E silver GT / charcoal interior. The car is a little bit of a mystery. Current project bought as a roller, tons of Saleen / Racecraft pedigree

    Also in the stable - my son’s car. 1986 Mustang GT Convertible. Black/Black/Black conversion. 93 leather. VM1 ECU. T5Z

    past foxes -
    1989 Mustang LX Sport 5.0 AOD white/tan black top. Once I ran this one down I caught a wife.
    Wife also had a 1987 Thunderbird Turbo Coupe in the 90's.

    I'm a four eyed pride supporter, are you? Become one today!
    http://vb.foureyedpride.com/payments.php

  15. #65

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    The only time I have seen such behavior, upon increasing rpm from idle, ignition advance actually retarding first, and then advancing later, was when the mechanical/centrifugal ignition advance springs' tension was very slack, not enough... because, stiffening the advance springs, by bending the tabs outward, eliminated that retarding first thing...
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  16. #66

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    Did something I should have started with; check the input and output signals of the ignition with a scope.




    That one test eliminates ALL electrical components. The timing discrepancy has to be mechanical. The error in timing equates to roughly 1mS. There is not a 1mS delay between the signal from the pickup to the spark at the plug. In fact, zooming in shows less than 50uS which is actually quite good for an inductive ignition. (ignore the downward pip of the yellow line where it meets the rising purple line, just noise from unshielded leads)




    To eliminate the springs from the list of possibilities I swapped in two heavy springs and bent the tabs as far out as they would go. The timing still went backwards with increased rpm but no longer came up with more rpm.

    Its got a tight NOS OEM double-roller timing chain so I'm confident that it's good from the crank to the cam. And today's tests indicate that everything is good from the distributor shaft to the spark plug. The odds of having two timing lights with identical malfunctions is pretty slim. Besides, the performance of the engine matches what I'm seeing with the light. It was the poor performance that led me to check it with the light, and as the timing light reading improved, so did the performance.

    What else could it be besides the cam/distributor gear fit?
    Last edited by mrriggs; 07-05-2018 at 09:28 PM.

  17. #67

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    Pretty sure you're right on. The scope pattern is what I was about to suggest to divorce electrical/mechanical faults. Assuming the chain is taught (check for failed rollers/rivets), the only other possibilities are cam thrust control, cam chattering in the bearings (both highly unlikely), cam sprocket moving relative to the cam, and cam to distributor drive gear fit.
    Jim DeAngelis
    Cornucopia of Useless Knowledge
    Connoisseur of Dearborn Ferrous Oxide
    '83 GT hatch, currently under the knife
    '79 Capri 2.3L n/a, Medium Copper metallic, survivor
    (bought from MRausch82)

  18. #68

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    Searching for an answer to how the timing can move so much if constantly loaded by the oil pump turned up this;

    Distributor spark scatter is not generated from the downward thrust but is more so the byproduct of the oil pump's internal gerotor mechanism loading/unloading as it pumps oil and slightly twists the hexagonal driveshaft (which is connected to the bottom of the distributor).
    From here; https://www.fordforums.com/f641/dist...oughts-156816/

  19. #69

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    torsional vibration generated by the oil pump and its drive shaft... hadn't thought of that! I always replace the shaft with a hardened unit when I rebuild. Maybe that suppresses the vibration?
    Jim DeAngelis
    Cornucopia of Useless Knowledge
    Connoisseur of Dearborn Ferrous Oxide
    '83 GT hatch, currently under the knife
    '79 Capri 2.3L n/a, Medium Copper metallic, survivor
    (bought from MRausch82)

  20. #70

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    hmmm.... maybe check distributor shaft thrust collar clearance, too? Excess clearance would cause vertical travel, resulting in torsional oscillation and a change in advance.
    Jim DeAngelis
    Cornucopia of Useless Knowledge
    Connoisseur of Dearborn Ferrous Oxide
    '83 GT hatch, currently under the knife
    '79 Capri 2.3L n/a, Medium Copper metallic, survivor
    (bought from MRausch82)

  21. #71

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    ... so we're talking about excessive distributor shaft end play?... essentially a "floating" distributor gear at idle, that's pulled down with initial rpm increase, causing counterclockwise rotor rotation due to slight distributor helical gear rotation, which, counterclockwise, retards distributor timing, which doubles at the crankshaft, the degrees of timing retard read by the timing light? ... I find it hard to believe, with any engine rpm... or any amount of slow idle rpm would not have the distributor gear pulled downward (even just brief starter cranking will pull down a distributor that isn't meshing with the oil pump drive shaft)... but I guess that might be what's happening for you? Shut off, how much up-and-down distributor shaft play is there?...
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  22. #72

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    Checked the end play with the distributor in the engine, 0.008". That is definitely not my issue.

    Couldn't measure the rotational play but it is very small, also not my issue.

    Back to the scope. The yellow traces above are actually the output of a signal amplifier I built to hook a TFI module to the Duraspark distributor. The signal from the distributor also appeared to coincide with the spark output but it didn't have the characteristic VRS shape. The input impedance of the amplifier was too low and dragging down the VRS voltage. On a whim, I unplugged the purple wire and put a 10k resistor in series. THAT FIXED IT! So, yes, the ignition was firing in time with the signal, but the signal itself wasn't in time with the distributor.

    What's really odd is that this problem started with the Duraspark module. I didn't have another Duraspark module (or 4-pin HEI) on hand to replace it so I built the amplifier to use a TFI module. It seems kind of far fetched that I built an amplifier with the exact fault as a malfunctioning Duraspark box. I'm more confused than ever, but at least the car is running well now.

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