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  1. #1

    Default Need help with my 5.0

    Hey I have an 83 capri with a full 86 drivetrain swap (came like this)
    I have always had a slight stumble/pop at idle and recently I upgraded to a mini starter so the headers off, also took the time to install a wide band, anyways I started the car sounded fine still the slight stumble at idle but revved up and such okay, I decided to re set all of my factory rockers thought maybe something was too loose. Now a couple of days later I've got what sounds like an exhaust leak but it seems to be coming out of the right side header, still pulls pretty steady vacuum so i don't suspect a valve sealing issue but off idle to about 1500 rpm engine seems to stumble. Not sure what to think, timing is 14 degrees btdc, plugs are new and wide band says about 12.5 ratio at idle. Let me know what you think. I have videos but not sure how to post them


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  2. #2
    FEP Power Member Ourobos's Avatar
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    Pulled left header to install starter.. Now sounds like exhaust leak from left header.. Seems to answer itself?
    1986 CHP SSP Coupe

  3. #3

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    12.5:1 @ idle... "... but revved up and such okay...". Yes, admitting more air to mix with the gallons of gas coming from the injectors like fire hoses?... No black tail pipes or smoke behind it? Fouled spark plugs? Can I stop you if I said I've heard this story before? (lol) ... I'd like to know how folks are adjusting or resetting factory rocker arms, being that they are bolt-down, non-adjustable, set and forget... Anyway, 12.5:1 is more like a safe wide open throttle air:fuel ratio... you running 70-80+ psi fuel pressure or something? Jammed shut fuel pressure regulator? It must be rich misfiring ("stumble", "pop", etc) off the hook... which surprises me you're not seeing any lean numbers also...
    Mike
    1986 Mustang convertible 3.8L ---> BUILD THREAD
    1983 Mercury Cougar 3.8L LS
    1986 Ford Thunderbird 5.0L ELAN
    1966 Ford Fairlane sedan 200-6
    1966 Ford Fairlane GT (390ci 4spd)
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang Fastback
    1974 Pontiac Luxury LeMans

  4. #4

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    Quote Originally Posted by Ourobos View Post
    Pulled left header to install starter.. Now sounds like exhaust leak from left header.. Seems to answer itself?
    Seems like it but the puff sound is coming directly out of the header, I have no exhaust on at the moment


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  5. #5

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    Quote Originally Posted by Walking-Tall View Post
    12.5:1 @ idle... "... but revved up and such okay...". Yes, admitting more air to mix with the gallons of gas coming from the injectors like fire hoses?... No black tail pipes or smoke behind it? Fouled spark plugs? Can I stop you if I said I've heard this story before? (lol) ... I'd like to know how folks are adjusting or resetting factory rocker arms, being that they are bolt-down, non-adjustable, set and forget... Anyway, 12.5:1 is more like a safe wide open throttle air:fuel ratio... you running 70-80+ psi fuel pressure or something? Jammed shut fuel pressure regulator? It must be rich misfiring ("stumble", "pop", etc) off the hook... which surprises me you're not seeing any lean numbers also...
    It's a carburator, I didn't set the idle with the wide band, they are not super accurate at idle, it was set with vacuum gauge


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  6. #6

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    Quote Originally Posted by Ourobos View Post
    Pulled left header to install starter.. Now sounds like exhaust leak from left header.. Seems to answer itself?
    I know it seems like a very obvious problem, that's what it seems like it should be but you don't hear it from up top it comes right out of the header collector, I have videos but not sure how to upload them


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  7. #7

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    Quote Originally Posted by Capri5o View Post
    It's a carburator, I didn't set the idle with the wide band, they are not super accurate at idle, it was set with vacuum gauge


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    And for the rocker arms I'm not sure how the previous owner did them so i loosened them all and re set them all to the torque spec with the valve fully closed


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  8. #8

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    Quote Originally Posted by Walking-Tall View Post
    12.5:1 @ idle... "... but revved up and such okay...". Yes, admitting more air to mix with the gallons of gas coming from the injectors like fire hoses?... No black tail pipes or smoke behind it? Fouled spark plugs? Can I stop you if I said I've heard this story before? (lol) ... I'd like to know how folks are adjusting or resetting factory rocker arms, being that they are bolt-down, non-adjustable, set and forget... Anyway, 12.5:1 is more like a safe wide open throttle air:fuel ratio... you running 70-80+ psi fuel pressure or something? Jammed shut fuel pressure regulator? It must be rich misfiring ("stumble", "pop", etc) off the hook... which surprises me you're not seeing any lean numbers also...
    And it still pulls 17.5 inches of vacuum at idle pretty steadily so I don't suspect the valves it sounds like a burnt valve or something but you would 100% see that on a gauge


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  9. #9

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    Couldn’t hurt to pull the plugs and check the compression.

    Stumbles can be timing. I’d pull the advance and set it “by ear” as sometimes the marks have moved or are inaccurate.

    Turn the advance until the motor just starts to speed up then back a hair. Reconnect the advance. If it kicks back against the starter it’s advanced too far. If it sounds a little pissed off when you rev it, it’s about right.

  10. #10

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    Quote Originally Posted by erratic50 View Post
    Couldnít hurt to pull the plugs and check the compression.

    Stumbles can be timing. Iíd pull the advance and set it ďby earĒ as sometimes the marks have moved or are inaccurate.

    Turn the advance until the motor just starts to speed up then back a hair. Reconnect the advance. If it kicks back against the starter itís advanced too far. If it sounds a little pissed off when you rev it, itís about right.
    Yeh I've double check tdc made 100% sure the balancer is dead on, sounds pretty angry when revved up just seems to be an idle thing, il check compression again


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  11. #11

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    For what it’s worth, I’ve never been able to get away with 14. 13.5 on premium is the absolute max and any more slows down acceleration and gets me into cooling challenges.

    E6SE heads are high swirl and do not tolerate as much timing advance.

  12. #12

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    Quote Originally Posted by Capri5o View Post
    It's a carburator, I didn't set the idle with the wide band, they are not super accurate at idle, it was set with vacuum gauge


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    "full 86 drivetrain swap (came like this)" fooled me at first... okay, so thankfully, no EFI, lol. I wish some folks would be more specific and add some more detail when having issues and asking for help over the internet. I hope you're talking about wide bands being nothing but an oxygen-sensing tool, because that is all they are, and can be fooled even with rich misfire and indicate a false lean condition... and they're as accurate as their makers, at idle or anywhere else, sensing the oxygen in the exhaust, and that's all they do... because you're talking to somebody who knows a carburetor can be dialed in to be deadly and super accurate... and 12.5:1 @ idle doesn't cut it in my book. 13+ at idle should be a breeze.

    Besides the point for right now, but what's the carburetor? More on that later maybe...

    The point: Reading the other comments so far... the previous owner "did" the rockers, did they?... ask the previous owner if any cylinder head work was done. You might not like hearing what I have to say/suggest next, that quite likely might be the problem, but don't kill the messenger that's just honestly trying to help you, lol... I've witnessed what you're describing once before, so it's pretty specific and is ringing bells here. The noise you're hearing sounds exactly like what valves, specifically and most likely exhaust valves, "hanging open" sounds like, maybe probably not until, or more so when the engine is warmed up (?), from valves (or new valves?) in (new?) guides that were not honed for proper valve stem clearance. You won't see exhaust valves hanging open on a vacuum gauge, but you'll hear them out the exhaust... a popping or huffing or puffing sound out the exhaust. Better pull the valve covers off again, and see if you can catch any of them with what seems excessive rocker arm to valve stem tip clearance, "hanging open"... and/or if this is the case, and it sounds like it, and not too much damage has happened already to valve heads etc, remove the cylinder heads and disassemble, keep accurate track of which valve goes back with which seat, like with a length of wood to stand against the wall/bench with numbered holes to stick the valves into while you continue to work, and then check and then hone or have the guides honed for correct valve stem clearances. Or have this done or parts repaired/replaced somewhere where they know what they're doing... and then everything might be much different and you'll be happily motoring down the road. Good luck with it.
    Last edited by Walking-Tall; 03-21-2018 at 05:53 AM.
    Mike
    1986 Mustang convertible 3.8L ---> BUILD THREAD
    1983 Mercury Cougar 3.8L LS
    1986 Ford Thunderbird 5.0L ELAN
    1966 Ford Fairlane sedan 200-6
    1966 Ford Fairlane GT (390ci 4spd)
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang Fastback
    1974 Pontiac Luxury LeMans

  13. #13

    Default

    Quote Originally Posted by Walking-Tall View Post
    "full 86 drivetrain swap (came like this)" fooled me at first... okay, so thankfully, no EFI, lol. I wish some folks would be more specific and add some more detail when having issues and asking for help over the internet. I hope you're talking about wide bands being nothing but an oxygen-sensing tool, because that is all they are, and can be fooled even with rich misfire and indicate a false lean condition... and they're as accurate as their makers, at idle or anywhere else, sensing the oxygen in the exhaust, and that's all they do... because you're talking to somebody who knows a carburetor can be dialed in to be deadly and super accurate... and 12.5:1 @ idle doesn't cut it in my book. 13+ at idle should be a breeze.

    Besides the point for right now, but what's the carburetor? More on that later maybe...

    The point: Reading the other comments so far... the previous owner "did" the rockers, did they?... ask the previous owner if any cylinder head work was done. You might not like hearing what I have to say/suggest next, that quite likely might be the problem, but don't kill the messenger that's just honestly trying to help you, lol... I've witnessed what you're describing once before, so it's pretty specific and is ringing bells here. The noise you're hearing sounds exactly like what valves, specifically and most likely exhaust valves, "hanging open" sounds like, maybe probably not until, or more so when the engine is warmed up (?), from valves (or new valves?) in (new?) guides that were not honed for proper valve stem clearance. You won't see exhaust valves hanging open on a vacuum gauge, but you'll hear them out the exhaust... a popping or huffing or puffing sound out the exhaust. Better pull the valve covers off again, and see if you can catch any of them with what seems excessive rocker arm to valve stem tip clearance, "hanging open"... and/or if this is the case, and it sounds like it, and not too much damage has happened already to valve heads etc, remove the cylinder heads and disassemble, keep accurate track of which valve goes back with which seat, like with a length of wood to stand against the wall/bench with numbered holes to stick the valves into while you continue to work, and then check and then hone or have the guides honed for correct valve stem clearances. Or have this done or parts repaired/replaced somewhere where they know what they're doing... and then everything might be much different and you'll be happily motoring down the road. Good luck with it.
    Yeh I'm not sure if heads were ever touched on this motor, the strange thing Is it only started after I loosened all the rocker bolts and inspected everything, and then put them back on, I did it exactly to procedure so I don't know how that would cause a valve to hang open a bit all of a sudden. I'm going to tighten my header bolts as I haven't yet since it's been started see how that goes


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  14. #14

    Default

    Quote Originally Posted by Walking-Tall View Post
    "full 86 drivetrain swap (came like this)" fooled me at first... okay, so thankfully, no EFI, lol. I wish some folks would be more specific and add some more detail when having issues and asking for help over the internet. I hope you're talking about wide bands being nothing but an oxygen-sensing tool, because that is all they are, and can be fooled even with rich misfire and indicate a false lean condition... and they're as accurate as their makers, at idle or anywhere else, sensing the oxygen in the exhaust, and that's all they do... because you're talking to somebody who knows a carburetor can be dialed in to be deadly and super accurate... and 12.5:1 @ idle doesn't cut it in my book. 13+ at idle should be a breeze.

    Besides the point for right now, but what's the carburetor? More on that later maybe...

    The point: Reading the other comments so far... the previous owner "did" the rockers, did they?... ask the previous owner if any cylinder head work was done. You might not like hearing what I have to say/suggest next, that quite likely might be the problem, but don't kill the messenger that's just honestly trying to help you, lol... I've witnessed what you're describing once before, so it's pretty specific and is ringing bells here. The noise you're hearing sounds exactly like what valves, specifically and most likely exhaust valves, "hanging open" sounds like, maybe probably not until, or more so when the engine is warmed up (?), from valves (or new valves?) in (new?) guides that were not honed for proper valve stem clearance. You won't see exhaust valves hanging open on a vacuum gauge, but you'll hear them out the exhaust... a popping or huffing or puffing sound out the exhaust. Better pull the valve covers off again, and see if you can catch any of them with what seems excessive rocker arm to valve stem tip clearance, "hanging open"... and/or if this is the case, and it sounds like it, and not too much damage has happened already to valve heads etc, remove the cylinder heads and disassemble, keep accurate track of which valve goes back with which seat, like with a length of wood to stand against the wall/bench with numbered holes to stick the valves into while you continue to work, and then check and then hone or have the guides honed for correct valve stem clearances. Or have this done or parts repaired/replaced somewhere where they know what they're doing... and then everything might be much different and you'll be happily motoring down the road. Good luck with it.
    Just did compression test compression is good across the board so must be fuel or ignition problem


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  15. #15

    Default

    A bent valve would do it.

  16. #16

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    Quote Originally Posted by Capri5o View Post
    Just did compression test compression is good across the board so must be fuel or ignition problem


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    Compression is good across the board, at ___ psi... ? What did the spark plugs when out look like? The engine temperature at the time of the compression test was ___... ? Funny noises out the exhaust... what was your word for it?... puff sound... greatly retarded ignition timing might not even run the engine, but if so, would backfire pretty loudly obviously out the exhaust... fuel... I can't think of an instance there'd be cause of that making huffing/puffing exhaust leak sounding sounds out the exhaust... I'd warm the engine up real good, pull the valve covers and spark plugs, rotate the crankshaft to #1 TDC compression stroke (indicated by the balancer/pointer, and the distributor rotor pointing at #1 plug wire terminal), mark the balancer or crank pulley at TDC, put another mark 180-degrees from that, and marks halfway between both those at the 90-degree spots, so you've essentially (because your balancer's TDC mark won't be straight up) got marks at 12 (TDC), 3, 6, & 9 o'clock (the cylinders fire every 90-degrees), then while still at 12 o'clock, #1 TDC compression, check #1 cylinder's (front passenger side) rockers/valves for any slack between rocker and valve stem tip, and if none, just for good measure, loosen and re-torque those two rockers bolts to their torque spec, then rotate the crankshaft clockwise 90-degrees to your 3 o'clock position and check the next cylinder in the firing order (the firing order of the camshaft, and therefore the ignition plug wire routing, is known and has been checked/verified, yes?)... continuing the same for each cylinder in the firing order, rotating the crankshaft 90-degrees between each cylinder checking/setting with your 12 & 3 & 6 & 9 o'clock marks, until all 8 cylinders have been checked/set. I still think you might find something amiss with an exhaust valve or more... hopefully not, but worth checking and fixing if so... valve stem clearance problems don't just go away, they get worse and engines go BANG.

    Welcome to the site, by the way. Love Capris... had 'an '80 Turbo RS years ago that I put a 302 in.
    Last edited by Walking-Tall; 03-22-2018 at 10:19 AM.
    Mike
    1986 Mustang convertible 3.8L ---> BUILD THREAD
    1983 Mercury Cougar 3.8L LS
    1986 Ford Thunderbird 5.0L ELAN
    1966 Ford Fairlane sedan 200-6
    1966 Ford Fairlane GT (390ci 4spd)
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang Fastback
    1974 Pontiac Luxury LeMans

  17. #17

    Default

    Quote Originally Posted by Walking-Tall View Post
    Compression is good across the board, at ___ psi... ? What did the spark plugs when out look like? The engine temperature at the time of the compression test was ___... ? Funny noises out the exhaust... what was your word for it?... puff sound... greatly retarded ignition timing might not even run the engine, but if so, would backfire pretty loudly obviously out the exhaust... fuel... I can't think of an instance there'd be cause of that making huffing/puffing exhaust leak sounding sounds out the exhaust... I'd warm the engine up real good, pull the valve covers and spark plugs, rotate the crankshaft to #1 TDC compression stroke (indicated by the balancer/pointer, and the distributor rotor pointing at #1 plug wire terminal), mark the balancer or crank pulley at TDC, put another mark 180-degrees from that, and marks halfway between both those at the 90-degree spots, so you've essentially (because your balancer's TDC mark won't be straight up) got marks at 12 (TDC), 3, 6, & 9 o'clock (the cylinders fire every 90-degrees), then while still at 12 o'clock, #1 TDC compression, check #1 cylinder's (front passenger side) rockers/valves for any slack between rocker and valve stem tip, and if none, just for good measure, loosen and re-torque those two rockers bolts to their torque spec, then rotate the crankshaft clockwise 90-degrees to your 3 o'clock position and check the next cylinder in the firing order (the firing order of the camshaft, and therefore the ignition plug wire routing, is known and has been checked/verified, yes?)... continuing the same for each cylinder in the firing order, rotating the crankshaft 90-degrees between each cylinder checking/setting with your 12 & 3 & 6 & 9 o'clock marks, until all 8 cylinders have been checked/set. I still think you might find something amiss with an exhaust valve or more... hopefully not, but worth checking and fixing if so... valve stem clearance problems don't just go away, they get worse and engines go BANG.

    Welcome to the site, by the way. Love Capris... had 'an '80 Turbo RS years ago that I put a 302 in.
    I've done as you've said for setting rockers, they all give a half turn or less before reaching specified torque so don't suspect anything bent rocker or pushrod wise, the car made 140 psi give or take 3 psi on all cylinders with the engine pretty much cold it had been ran several hours ago and was -5 Celsius outside

    I started it again today after putting my carb spacer back on and it seemed to be a lot less prevalent, even gone, I will take a closer look at the carb it is brand new but you never know


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  18. #18

    Default

    Quote Originally Posted by Capri5o View Post
    I've done as you've said for setting rockers, they all give a half turn or less before reaching specified torque so don't suspect anything bent rocker or pushrod wise, the car made 140 psi give or take 3 psi on all cylinders with the engine pretty much cold it had been ran several hours ago and was -5 Celsius outside

    I started it again today after putting my carb spacer back on and it seemed to be a lot less prevalent, even gone, I will take a closer look at the carb it is brand new but you never know


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    I just need this motor to last about a month this summer until I can get my aluminum headed supercharger motor in.. sick of this stupid flattop motor lol


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