On the road... sort of

[electrorc]

Hey everyone, I'm back

Good news first:
The Mustang is fully street legal, and I've been driving it around a little bit. I'm enjoying it for the most part, but really wish I could get all the issues ironed out. I also don't have overheating issues anymore--she stays right around 1/2 or a bit under on the gauge now. The oil pan leak is fixed as well, courtesy of a new generic gasket. I'm also now a college grad.

The bad (I'll just list things first):

• It's still idling really rough. It's shaking and what not. Rev it to 1500 or so and it will smooth out a bit, but you can normally still feel some vibration through the gas pedal.
• It seems to have some sort of clatter or something up in the valvetrain. I'm not really sure how to describe it, but it just seemed noisy and seemed to be coming from around there. It almost seems to be worse at the back of the engine.
• I think it's missing a little. The exhaust feels very uneven if you put your hand out past it and it kind of pops.
• It hesitates or stumbles when you hit the gas while driving. When you first get on it, it won't do much of anything, but then if you just hold your foot there for a second longer it'll go.
• I just found this one today after driving it around. I happened to look underneath and saw something drip. The bottom of the transmission had a lot of oil on it, and then I also found there was some oil at the front of the bellhousing, just behind the block plate. It didn't seem like anything was running down from the fill plug on the transmission.

What I've done or tried:

• Compression check: The last one I did, after retorquing the head bolts, gave me 162, 165, 170, 162, 165, 160. So it's not perfect, but it shouldn't be causing me issues from what I understand. This was done with the engine at operating temperature, all plugs out, throttle held wide open.
• Plugs: Replaced spark plugs, went back to an Autolite 46 (was using 45s). I've gapped them at both 0.038 and 0.034. Doesn't seem to make much difference.
• Other ignition components: New Motorcraft points, BWD Select cap and rotor. Plug wires and coil are still what the PO installed, but I do have a Flame-Thrower coil on its way.
• Timing: I've tried timing pretty much all over the place, and nothing helped the idle. I'm not sure exactly where I am now. I had verified my balancer didn't slip back in March, but then I checked again a few days ago and it seemed wrong. So I made a new mark and set it to 12 BTDC or so there, but that resulted in pinging while driving. So I've just backed it down from there. I guess I messed up when checking my balancer this time.
• Carb: I rebuilt it in March. Leaks a little at the main gasket, but I don't think that'd affect anything. I've also tried adjusting the idle mixture, but it doesn't seem to affect anything with the idle roughness either. Accelerator pump seems fine--nice jet of fuel when you move the throttle linkage. Just a regular Autolite 1100 still, manual choke, I think it's a '63 model but would need to double check.
• Vacuum leaks: I've sprayed carb cleaner around the carb mount and that whole area, but I never noticed a change.
• Mounts: Engine and transmission mounts are all fully torqued to spec and new.
• Oil pressure: Mechanical gauge never drops below about 40-45 psi while running. It also seems to have plenty up on the head when you pull the valve cover.

Any suggestions on anything? Thanks!!

 

[bubba22349]

Congrats on being a college grad.
Have you checked the carbs Float level? Too high or also be a bad float. The oil dripping off the bottom of the transmission and at the front of the bell housing could be a leaking valve cover gasket or the front seal of trans you did not mention a color of the oil.

 

[electrorc]

Thanks!
I have the carb set so that the fuel level is a little lower than stock, from when I was trying to get it to stop leaking. So maybe I should try raising the bowl level again? Float didn't have any bubbles when I put it in water.

The oil on the bottom of the trans was just a light translucent brown, typical oil color. It did seem a little thicker, and definitely smelled closer to gear oil. What was dripping from the front bottom of the bellhousing was blacker, and I couldn't tell on the consistency.

This morning I went out and checked on the level in my trans, and as soon as I got the fill plug out, it came out pretty quickly. Apparently I managed to overfill it.

I decided to try driving it again, and it behaved other than the rough idle and some stumbling. No leaks that I immediately saw after driving.
When I was coming home from something, it totally changed behavior though. It started jerking really bad when I tried to accelerate. At one point I saw that the RPMs were bouncing around a lot too, within like a 500 rpm range (2000-2500 IIRC). It was like I was getting on and off the gas, but I was holding it steady. After a little bit of driving like that, I discovered that if I got on it more, it smoothed out a lot. But if I accelerated lightly, it would jerk.

 

[rbohm]

8) i suspect that you still have a carb issue. it is possible that the carb is just worn out and is ready for replacement. i have rebuilt a few of them with mixed results, but getting a reman from some place like oreillys made the difference.

as for your ignition system, i suggest upgrading to an electronic ignition and dump the points.

your compression readings are excellent so you have no issues there.

 

[bubba22349]

When I was coming home from something, it totally changed behavior though. It started jerking really bad when I tried to accelerate. At one point I saw that the RPMs were bouncing around a lot too, within like a 500 rpm range (2000-2500 IIRC). It was like I was getting on and off the gas, but I was holding it steady. After a little bit of driving like that, I discovered that if I got on it more, it smoothed out a lot. But if I accelerated lightly, it would jerk.

One other thing you can check is the wiring, IE from ignition switch to coil and distributor to coil, power into ignition switch too. I have had numerous times on a number of different cars were the original old wires can be brittle and broken inside under the insulation and cause intermittent problems it can difficult to find them but sometimes you can feel it when you move the wire around. If the insulation hard from heat is cracked and or missing in some areas is a good time to replace those key wires. Also if the ignition switch is worn out too would be good idea to replace

 

[69.5Mav]

Glad to see you back. I was wondering how your project was going.
Congratulations on Graduation?
How was Graduation?
What degree did you get?

Try to check one thing at a time and eliminate them or fix them. Keep written records.

It sounds like Carburetion to me.
Is it rich while idling? Can you smell gas in the exhaust?
Please check the plugs. If it's rich they'll be dark to black, if lean they'll be white.

The ignition could be contributing to you symptoms. Connect a timing light to the coil and watch it for even firing when you are getting misses.

It sounds like the engine is mechanically sound.

What sounds like a clatter could be lifter/rocker noise but don't rule out an exhaust leak, more people then would care to admit it have been fooled by an exhaust leak sounding like tappet noise including me.

Good luck and keep the info coming

 

[electrorc]

8) i suspect that you still have a carb issue. it is possible that the carb is just worn out and is ready for replacement. i have rebuilt a few of them with mixed results, but getting a reman from some place like oreillys made the difference.

as for your ignition system, i suggest upgrading to an electronic ignition and dump the points.

your compression readings are excellent so you have no issues there.

Alright, good news on the compression. I'm glad I didn't mess up another head gasket install

As far as the carb goes, I was wondering about that. I did try to get a reman back in March, but they ended up getting me one without the SCV and I didn't have time to get a new distributor or for them to get the correct carb. Mainly though, I figure if I'm spending $200+ on a reman, I may as well go ahead and put on a H/W 5200 using an adapter.

Ignition upgrades are planned; I just haven't decided what I want for sure. I've been pondering a bunch of setups, especially since I found a couple of DS2 modules in the shed last week.

One other thing you can check is the wiring, IE from ignition switch to coil and distributor to coil, power into ignition switch too. I have had numerous times on a number of different cars were the original old wires can be brittle and broken inside under the insulation and cause intermittent problems it can difficult to find them but sometimes you can feel it move the wire around. If the insulation hard from heat is cracked and or missing in some areas is a good time to replace those key wires. Also if the ignition switch is worn out too would be good idea to replace

Good point. I'll have to give it a better check sometime. I know it's not in the best shape, but it doesn't seem too terrible. I was also figuring since I didn't have any issues like this before, it should still be pretty much okay.

Glad to see you back. I was wondering how your project was going.
Congratulations on Graduation?
How was Graduation?
What degree did you get?

Try to check one thing at a time and eliminate them or fix them. Keep written records.

It sounds like Carburetion to me.
Is it rich while idling? Can you smell gas in the exhaust?
Please check the plugs. If it's rich they'll be dark to black, if lean they'll be white.

The ignition could be contributing to you symptoms. Connect a timing light to the coil and watch it for even firing when you are getting misses.

It sounds like the engine is mechanically sound.

What sounds like a clatter could be lifter/rocker noise but don't rule out an exhaust leak, more people then would care to admit it have been fooled by an exhaust leak sounding like tappet noise including me.

Good luck and keep the info coming

Thanks! Graduation was pretty decent. Not the most exciting of things, but still interesting. I have a Bachelor's in Aerospace and Mechanical Engineering.

I don't smell any gas in the exhaust--just smells like typical exhaust I guess.
I'll pull the plugs again. I know the 45s were getting a fair bit of carbon build up, but last I looked at the 46s they looked pretty decent. Not really dark, not completely white.

I did the timing light on the coil and all the individual plug wires. As far as I could tell everything was fine.

True on the exhaust leaks. I know I have leaks where the muffler attaches (both ends), so that might even be why it sounds like the exhaust is uneven. I tightened the clamps but it didn't help, so I'll work on that more. I also retorqued the manifold bolts that I could easily get to.

I also got the Flame-Thrower coil swapped in today. It seems a little bit smoother on the whole, but still shakes at idle.

 

[69.5Mav]

but still shakes at idle

I'm a bit bummed right now after being laid off for the 8th time in a 30+ year career in Electrical engineering and aerospace. I now advise people to steer clear of engineering and become a banker. They get bailouts and bonuses not lay offs.

Enough of my troubles on to yours.

Try this. Get special pliers made to remove spark plug wires while the engine is running. At idle with a fully warmed up engine remove and replace each one while noting its effect on idle. The engine might die a lot but if you stick with it you should find at least one that has no effect. If you do then find out why. This is how I found two bent push rods on my sons 302 maverick. This could also tie into to the clatter you heard at the back of the engine.

If not then I might try opening and closing the choke to see if it makes any difference.

If you close the choke some and the idle smoothes out you are to lean.

If closing the choke some causes the idle to worsen then you are to rich.

Good luck

 

[electrorc]

I'm a bit bummed right now after being laid off for the 8th time in a 30+ year career in Electrical engineering and aerospace. I now advise people to steer clear of engineering and become a banker. They get bailouts and bonuses not lay offs.

Enough of my troubles on to yours.

Try this. Get special pliers made to remove spark plug wires while the engine is running. At idle with a fully warmed up engine remove and replace each one while noting its effect on idle. The engine might die a lot but if you stick with it you should find at least one that has no effect. If you do then find out why. This is how I found two bent push rods on my sons 302 maverick. This could also tie into to the clatter you heard at the back of the engine.

If not then I might try opening and closing the choke to see if it makes any difference.

If you close the choke some and the idle smoothes out you are to lean.

If closing the choke some causes the idle to worsen then you are to rich.

Good luck

Ah dang, sorry to hear the lay off :/

When I pull the wires, each one results in about the same change--a small drop in engine rpm and not a whole lot more than that.

With my carb setup, I can't do the choke thing unless I modify the linkage. Closing it also revs the engine a bit higher, and I'm pretty sure the increased smoothness just comes from the higher revs.

These are what my plugs looked like this morning:
Plugs 1, 3, 6
Plugs 2, 4, 5
So they're mostly white but with a little bit of brown. I think this indicates it's pretty close to correct? Plug 6 is a little browner than the others.

I adjusted the float last night. I dropped it back to around the stock spec, such that there is more fuel in the bowl. This seemed to help. I took it for a drive after that and the stumbling seemed a lot better and it was a lot smoother overall. About halfway through the drive it started to be jerky again though. Not as bad as it was a couple days ago, but a little bit. I'm guessing something must be getting too hot. My dash lights also gave out around that time, so I got to guess my speed most of the way back home lol. That was just a fuse, so an easy fix.

Today I bypassed the carb heater block. I figure since it's 80+ it isn't totally necessary, and that's what the handbook mentions as well I believe.

It behaved pretty well today. Still a shaky idle, and is occasionally sort of jerky feeling if I'm just coasting... say around 35-40 mph in 3rd. I am definitely starting to enjoy it though, and getting a lot more comfortable driving it. About 100 miles on it now.

 

[69.5Mav]

Ah dang, sorry to hear the lay off

Thanks.

When I pull the wires, each one results in about the same change--a small drop in engine rpm and not a whole lot more than that.

Good compression and what seams to be good ignition and you varied the advance. I think you have a bad carb.

How did you get this car in the first place?

With my carb setup, I can't do the choke thing

Take a piece of card bord and slide it slowly over the carb opening,

So they're mostly white but with a little bit of brown.

Looks lean to me. 3 & 4 should look richer then 1 & 6.

I dropped it back to around the stock spec, such that there is more fuel in the bowl. This seemed to help.

This would indicate a lean condition to me.


Also check your fuel filters.

The one in the carb should unscrew. Then try blowing through it, this should be real easy, If not, try tapping the inlet on a piece of wood to see what comes out.

Next test how much fuel comes out of the fuel line by attaching a long rubber hose to the steel line that ends near the carb and starting the engine with the other end of the rubber hose in a clear gallon jug. You should get a strong flow of fuel.


These old tanks build up a supprising amount of rust particals mixed with varnish in the bottom of the tank. with the newer alcohol fuels this gunk starts to get stirded up blocking up every fuel filter in the system. My 72 Mav is a case in point. It would start and run fine but a mile or 2 away from home it wold konk out. Come back a few hours later and the cycle would repeat. Took the tank off and it had a really large amount of 3/8 to 1/2 inch chunks of that rust and varnish mixture in it. I took it to a radiator shop where they flushed and sealed it and it;\'s been fine ever since.

 

[MPGmustang]

These are what my plugs looked like this morninglugs 1, 3, 6Plugs 2, 4, 5So they're mostly white but with a little bit of brown. I think this indicates it's pretty close to correct? Plug 6 is a little browner than the others

yup, this looks lean. more color!!

It behaved pretty well today. Still a shaky idle, and is occasionally sort of jerky feeling if I'm just coasting... say around 35-40 mph in 3rd. I am definitely starting to enjoy it though, and getting a lot more comfortable driving it. About 100 miles on it now.

This makes me think it's timing, unplug the vacuum line to the distributor and blow, if it holds air it's good, but if not it's leaking and this will cause the 'jerking' when your at speed. or it could be too agressive, see if you can get an adjustable canister, sometime sthe new replacements are even more agressive than the stock canisters.
also it could be the distributor springs, so look at those too

As far as the carb goes, I was wondering about that. I did try to get a reman back in March, but they ended up getting me one without the SCV and I didn't have time to get a new distributor or for them to get the correct carb. Mainly though, I figure if I'm spending $200+ on a reman, I may as well go ahead and put on a H/W 5200 using an adapter.

does this mean your still 1bbl SCV and LOM? what carb and distributor you have right now?

for tuning, ususally what I did for my 1bbl setup and LOM was set timing to 9*, with vacuum disconnected and plugged, then connect vacuum, set idle to 1000 rpm, move the air/fuel screw for max RPM, once found, add 1 turn richer, set idle to 650rpm, if auto then 650 in gear. I've also had success with timing by vacuum, getting the max vacuum with initial timing is a good way too. but I've always found 9* best.

Good luck and glad to see you're still having fun!

 

[electrorc]

Good compression and what seams to be good ignition and you varied the advance. I think you have a bad carb.

How did you get this car in the first place?

Sounds feasible. Car was from Craiglist, and didn't seem to have major issues when I test drove it lol. Carb is just the one that was on there still.

Take a piece of card bord and slide it slowly over the carb opening

I used my hand and blocked it off partially, but it didn't seem to make much of a difference...

Looks lean to me. 3 & 4 should look richer then 1 & 6.

Alrighty. And yeah I was thinking that some thing, which mine aren't.

Also check your fuel filters.

These old tanks build up a supprising amount of rust particals mixed with varnish in the bottom of the tank. with the newer alcohol fuels this gunk starts to get stirded up blocking up every fuel filter in the system. My 72 Mav is a case in point. It would start and run fine but a mile or 2 away from home it wold konk out. Come back a few hours later and the cycle would repeat. Took the tank off and it had a really large amount of 3/8 to 1/2 inch chunks of that rust and varnish mixture in it. I took it to a radiator shop where they flushed and sealed it and it;\'s been fine ever since.

PO replaced the fuel tank and sending unit. I replaced the main hard line from the tank to the pump, as well as the pump itself. The 2 rubber lines are also new by PO or me. The only original line is the metal line from the pump to the carb. I also removed the filter that attaches to the carb, as the nut on it was hitting the carb body, making it go in at an angle and leak. I'm running a generic inline filter between the pump and carb, and it looks clean.

yup, this looks lean. more color!!

Okay, sounds like I definitely need to figure that part out...

This makes me think it's timing, unplug the vacuum line to the distributor and blow, if it holds air it's good, but if not it's leaking and this will cause the 'jerking' when your at speed. or it could be too agressive, see if you can get an adjustable canister, sometime sthe new replacements are even more agressive than the stock canisters.
also it could be the distributor springs, so look at those too

I took a slightly different methodology here. I had tried blowing in the line, and it seemed okay I think. I also did as follows though. With the dist cap and rotor off, I moved the plate like it would if it were advancing. Then I blocked the end of the line with my finger. It moved back most of the way to the starting point after a second or two, then would move back the remaining little bit when I released the line. Seems to me like it's leaking then, or is it an incorrect way of testing it?

does this mean your still 1bbl SCV and LOM? what carb and distributor you have right now?

for tuning, ususally what I did for my 1bbl setup and LOM was set timing to 9*, with vacuum disconnected and plugged, then connect vacuum, set idle to 1000 rpm, move the air/fuel screw for max RPM, once found, add 1 turn richer, set idle to 650rpm, if auto then 650 in gear. I've also had success with timing by vacuum, getting the max vacuum with initial timing is a good way too. but I've always found 9* best.

Yep, still 1bbl SCV and LOM. I have a '63 Autolite 1100 carb, I think from a 170. Manual choke. I think the PO said he rebuilt it, and then I also rebuilt it back in March.
Distributor is factory '65 as far as I remember.

I haven't tried that method, maybe I will later today. I set timing to 9*, and then did a/f to max vacuum. That put me back pretty much right where it was though. Also, leaner or richer doesn't smooth out the idle. And the vacuum gauge still jumps a lot. I'm not sure if it's because of the 264 cam and it probably being an undamped gauge, or if it's actually indicating a problem. Right now it's kind of bouncing between like 12 and 14 in-Hg IIRC.

Good luck and glad to see you're still having fun!

Thanks! And thanks for all the help so far everyone

 

[69.5Mav]

Right now it's kind of bouncing between like 12 and 14 in-Hg IIRC

This suggests a valve problem to me.

Look at senario 5 at this web site.

http://www.secondchancegarage.com/public/186.cfm

Your reading is lower but a bigger cam "264" will do that.

 

[electrorc]

Right now it's kind of bouncing between like 12 and 14 in-Hg IIRC

This suggests a valve problem to me.

Look at senario 5 at this web site.

http://www.secondchancegarage.com/public/186.cfm

Your reading is lower but a bigger cam "264" will do that.

Right, I was thinking valve problem there for awhile as well, and I'm still wondering about it. However, it seems like that should've shown up in a compression test. I guess if it's just sticking a bit it might still let it build compression in the test though. And of course the shop did a valve job, so things *should* be fine...

As far as the vacuum gauge readings, I can see it being at least partially a few of the scenarios on there, which is why I'm hesitant to make a decision based solely on that. Eg Scenario 5 seems fairly fitting, but the drop normally isn't that large, and it seems to fluctuate more consistently. 7 sounds pretty accurate, but mine's pretty quick to fluctuate. The only one that mentions it steadying as you rev it is 8 (mine does steady out a good bit around 14 or 15 in-Hg IIRC if you rev it and hold it there), but mine has smaller swings at idle. 11 has a lower overall reading with pulsation being ignition issues. I'm not experienced to tell the difference on an actual gauge, especially since this is my first car with an aftermarket cam.

I pulled the valve cover again. Everything still looks fine to me in the valvetrain. I didn't roll the pushrods or anything, but I did pull each out and they all looked just fine. Nothing obviously broken anywhere. The wear marks I see on the tops of the valves are about right in the center.

 

[69.5Mav]

should've shown up in a compression test.

Not necessarily. You crank the engine until peak pressure is reached. This does not mean that all compression strokes contributed equally to the reading.

What you are seeing I believe is an intermittent miss.

With the valve cover off use a timing light to stop motion on the valve train. Switch around the spark plug wire you are connected to and look at different cylinders. You are trying to catch an intake valve that is not closing when it should and loosing contact with the rocker arm.

You could also try squirting some penetrating oil on each valve stem while the engine is running to see if that smoothes it out.

I hope this helps.

 

[electrorc]

Not necessarily. You crank the engine until peak pressure is reached. This does not mean that all compression strokes contributed equally to the reading.

True.

What you are seeing I believe is an intermittent miss.

With the valve cover off use a timing light to stop motion on the valve train. Switch around the spark plug wire you are connected to and look at different cylinders. You are trying to catch an intake valve that is not closing when it should and loosing contact with the rocker arm.

You could also try squirting some penetrating oil on each valve stem while the engine is running to see if that smoothes it out.

I hope this helps.

Done and done.
Penetrating oil: No change.
Timing light: Everything looked identical, and I never saw anything lose contact.
It was cool to see though...

 

[bubba22349]

You mentioned that the P.O. installed the plug wires. If you have a Volt / Ohm meter you could try testing the resistance through the cap and wires assembled to see if it's in spec.

 

[69.5Mav]

Done and done.
Penetrating oil: No change.
Timing light: Everything looked identical, and I never saw anything lose contact.
It was cool to see though...

Boy, I'm stumped.

Two last shot in the dark things you could try.

1) Get a propane torch and feed propane dirrectly into the carb at idle while varring the flow rate.

and

2) Change the coil even if its new. Alternately you could get a spark tester and measure the spark voltage with it.

Lastly you could try to find a auto tech with a scope and see if he can see what is going on.

Boy this is toughy but I'll bet when you find it it will seem simple.

On the positive side you are getting an education on debug techniques that can't be taught in school.

Good Luck and keep the info coming

 

[electrorc]

You mentioned that the P.O. installed the plug wires. If you have a Volt / Ohm meter you could try testing the resistance through the cap and wires assembled to see if it's in spec.

Well I did it with the wires out of the car and not together with the cap. I had a range of about 3560 to 6430 Ohms, or what seems like a really wide range of 2809 Ohms/ft to 3680 Ohms/ft. I'm not having any luck finding a factory spec, but that seems to be in the range of general factory style wires I'm seeing. I also threw on a set of old wires but that made no change.

Boy, I'm stumped.

Two last shot in the dark things you could try.

1) Get a propane torch and feed propane dirrectly into the carb at idle while varring the flow rate.

and

2) Change the coil even if its new. Alternately you could get a spark tester and measure the spark voltage with it.

Lastly you could try to find a auto tech with a scope and see if he can see what is going on.

Boy this is toughy but I'll bet when you find it it will seem simple.

On the positive side you are getting an education on debug techniques that can't be taught in school.

Good Luck and keep the info coming

1) Did the propane around the carb mounting and everything with no change. I also did it straight into the carb with no change there either. Which means it probably isn't the carb, right? Of course it's still lean overall, but the idle roughness shouldn't be caused by it, especially since richening the idle a/f didn't help it.
2) I've used 2 coils already. I had a factory style one that the PO installed, and then changed that last week for the Pertronix Flame-Thrower.

I managed to break a valve cover bolt off in the head too... I'm not having very good luck here...
I'll keep trying things as I think of them, but I'm definitely running out of ideas that don't cost a lot heh.

 

[69.5Mav]

An old trick used to find lagging cylenders is to measure the temperature of each exhast manifold outlet with an Infared temperature sensor or lacking that squirt a good quantity of water on each and see if one responds different outlet tube.

The dual outlet tube will be a little tricky but you still may see some difference from the others.

Good luck and let us know where you are with it.