Mustang Owners Club Australia Forum
Technical & General Discussion Area => Tech Torque Pre 1973 => Topic started by: Woz on December 12, 2023, 03:05:13 pm
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Hello,
I have a friend who imported a 67 coupe with a 351W from USA 15 years ago,
now wants to get it on the road.
Old motor no sensors, has a hot cam (don't know what) and roller rockers,
Edelbrock 1403 carb, noticed there is no oil filler cap, 1 rocker cover has no holes and 1 has PCV valve.
Minimum idle is 900 to 1000 rpm, when you select drive it stalls, tried removing the PCV valve, no change.
I know it's hard to diagnose engine problems with no inspection, but any help much appreciated.
Thanks
Woz
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I’d say more info is needed,
When if ever was it driven last, does the engine run through other gears, or neutral,
Does the owner know the condition of the auto,
So many unknowns at this stage..,
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Another note, how long has the car been sitting and has the fuel system been cleaned out,
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Hey Woz,
Watch this YouTube about Edelbrock electric choke adjust.
Are you getting warm up past fast idle.
And is the electric choke working ok.
https://youtu.be/daK-go2PMrk?si=aF8ig2i4iMEcGhaq
Other than that check timing! Air / fuel mixture!
Cheers Phil
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Try connecting a temporary wire from the positive side of the coil to the positive side of the battery.
Also you could try connecting a jumper lead from the engine to the negative side of the battery.
:bolt:
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thanks for the replies,
car was purchased on USA Ebay unseen, driven of the transporter from Melb, owner came home, and the car was sitting in the driveway 15 years ago,
hasn't moved until i drove it 30m around his yard.
engine will run through drive and reverse on axle stands, car not registered, engine and transmission oil look good,
condition of the transmission unknown,
No choke fitted, just close the choke by hand until it starts and warms up,
timing is correct, adjusting the Idle mixture screws does nothing,
fuel has been drained and replaced, new spark plugs,
will try connecting wire next time.
Thanks
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If the idle mixture screws do nothing there is fuel getting in when it shouldn't be. Could be a blown power valve.
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Also, forgot to mention I changed the carby with the 1 on my car, (289 Edelbrock 1404) car wouldn’t start.
Can’t do the wiring suggestion, battery in the boot.
Ok, what’s a power valve?
Thanks
Woz
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I would be figuring out why it won't run with your carb. Sounds like there is a massive air leak that the existing carb is modified to 'correct' but the underlying problem still exists.
The car should run with your known good carb.
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Also, forgot to mention I changed the carby with the 1 on my car, (289 Edelbrock 1404) car wouldn’t start.
Can’t do the wiring suggestion, battery in the boot.
Ok, what’s a power valve?
Thanks
Woz
Hey Woz,
If your sticking on a jetted 289 carburettor on a 351 engine jets will be much smaller, leaner and will stall?
Cheers Phil.
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Yes I did think it was odd that it would not start with my carby, I thought that if I swap the carby and it didn't stall the problem would be the carby,
we have ordered a kit for the carby, will rebuild and see if we still have the issue,
I thought it may be a vacuum issue, as there is no oil filler cap, where does the crankcase breathe from, my understanding is it draws air from the filler cap and exits through the PCV valve.
Someone told me mixture idle screws only adjust at idle rmp, with the cam minimum this car will idle is 900 to 1000, I thought that it would be too fast to adjust the mixture screws.
Thanks
Woz
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Does it have an electronic distributor?
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Yes, MSD Ignition, they installed the coil and MSD Box where the battery normally is.
Thanks
Woz
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Make sure it has a full 12volts going to the distributor . Mustangs only had points distributors and run wiring that cuts the volts down to 9 volts . When an electronic distributor is fitted you must run a full 12 volts to it ,otherwise it will idle ok but stall with its put into gear . May not be the problem but worth looking at .
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Has the ballast resistor in the ignition circuit been bypassed then to give a full 12 volts to the coil?
I had this problem. It would only idle with the revs turned way up and die when I turned it down to a normal sort of level. Putting yours into drive might be pulling the revs down too low for the 9 odd volts of the original circuit when your electronic dizzy needs a full 12. Check the voltage at the coil while the engine's running and see what you've got.
Just read Glenn's post as I previewed mine, so ditto.
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Ok, going there tomorrow will check the voltage at the coil and report.
Thanks
Woz
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I thought it may be a vacuum issue, as there is no oil filler cap, where does the crankcase breathe from, my understanding is it draws air from the filler cap and exits through the PCV valve.
Someone told me mixture idle screws only adjust at idle rpm, with the cam minimum this car will idle is 900 to 1000, I thought that it would be too fast to adjust the mixture screws.
Thanks
Woz
So - a few things to bear in mind:
1] The PCV (Positive Crankcase Ventilation) is designed to suck fumes from inside the engine valve covers (where those fumes come up from the sump after blowing past the rings) to clean up the operation of the engine. The PCV valve opens more at low-vacuum, large throttle openings and uses the remaining manifold vacuum to suck blow-by (which have blown past the rings) into the intake manifold and the engine re-burns the fumes - it's an emissions feature. It should suck a little at idle, and open more when you're WFO and thrashing the engine producing lots of fumes which need to be sucked up by the PCV. It does not 'exit' into the engine.
2] If you have a oil filler cap, with a vent on it, then in theory those fumes travel up a hose to the inside of the air filter. This feature does far call, as there is no valve and little vacuum inside the air cleaner. It's a gimmick as much as useful.
3] The idle screws will work at small openings of the primary throttle blades. If they aren't making a difference, then a couple of things come to mind. There is either an air leak, a fuel leak, or the primary blades are open too far at idle for the idle circuits to work. If it's the last one, then the secondary throttle blades have an adjustment under the carb base plate (on a Holley, anyway) which you can use to open the secondary blades to increase the idle speed. You can then close the primaries using the idle adjustment screw to get both the speed and the mixture correct, because with the secondaries opened slightly, the primaries can be closed enough to make the air bleed circuits work, and the mixture screw settings can be corrected for optimum operation.
4] The comment about your 289 carb being too small for the 351 is both correct and incorrect. At full throttle, the 289 carb is likely to be too small to allow the engine to breathe and produce maximum power. At low engine speeds for troubleshooting purposes, it won't really matter - the purpose of the carb is to get the correct fuel mixture at a given air speed. Assume the carbs are perfectly set up and their AFR (Air Fuel Ratio) is perfect all the way through the range, then the following would be true:
289 carb - max CFM = 500 (for example)
351 carb - max CFM = 650 (for example)
351 Engine speed CFM AFR Percentage capacity used
289 carb 351 carb
1,000 rpm 86 13.0 17% 13%
3,000 rpm 259 13.0 52% 40%
5,000 rpm 431 13.0 86% 66%
5,800 rpm 501 13.0 100% 77% - the 351 would not be able to rev higher than 5,800rpm, with the smaller carb.
7,500 rpm 648 13.0 N/A 100% - with the bigger carb, the engine could run harder, longer, assuming everything
else was capable of supporting those revs.
You can see that the 351 would run ok with a smaller carb, but would run out of the steam 2,000rpm earlier than the 650cfm carb - all examples and probably hard to replicate in the real world.
Simples. Not really, but you know how it goes...
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Hey Woz,
Sounds like jiffy has covered just about everything.
Can’t disagree!
Hope you have success !
Cheers Phil.
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Hi Woz,
A few things with this stick out to me.
Car was bought but never driven, Car runs through the gears when on axle stands. Car also has a decent cam in it.
Unless the auto has a mild stall torque convertor, the car will stall when you put it into gear . Most auto's have a few revs to bring up between idle and when the convertor starts to engage. Yours if its a standard convertor is pulling against the engine soon as you throw it into gear because of the cam specs. (note your idle is up from stock)
If you put your foot on the brakes and keep some throttle in it when you put it into drive does it stall ?
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Hi there,
thanks for the details Jiffy,
I only fitted my carb 500 cfm to see if it stalls when selecting gear, but the car wouldn't even start, so I fitted the 600 cfm back on,
car will only idle 900 to 1100 rpm, is that normal with the cam?
From your description the crankcase can breathe without the oil filler cap.
I checked the voltage at the coil, 12 volts at Ignition stage and running.
the car wouldn't idle at all, just run at 900 rpm then just stop. I removed the carby, took of the top and inspected, nothing unusual except float drop was a bit low.
One strange thing I noticed today, when i put my foot on the brake, the car stalled, doesn't have brake booster.
Yes, if you keep your foot on the brake and keep up the rpm with the pedal you can get in drive, but the rpm is too high, and it bangs into gear.
Unknown what converter is in the car, guess the only way to tell is rip it out, does have a BM shifter. Noticed it will start in gear, guessing that is not roadworthy.
Thanks
Woz
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Not something weird up with the adjustment of the selector rods and NSS is there? Putting into drive opening the NSS?
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Hey Woz,
You said the battery is in the boot, how big are your cables!
Also, now you’ve been turning and turning over the engine make sure you’re recharging the battery!
Cheers Phil.
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Not something weird up with the adjustment of the selector rods and NSS is there? Putting into drive opening the NSS?
Good suggestion Geoff!
B&M cable adjustment on Turbo 350.
https://vimeo.com/250407276
Cheers Phil.
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Unknown what converter is in the car, guess the only way to tell is rip it out, does have a BM shifter. Noticed it will start in gear, guessing that is not roadworthy.
Thanks
Woz
Hey Woz,
Very dangerous as well, are you sure it has a neutral Safety Switch fitted or has it been tampered with!
My son in law has a XW Ute that had a dickie selector, Dog jumped in the car and knocked in reverse, son jumped in started and ripped the door off and damaged the garage pillar, easy adjust, locate pin in hole and lock down. I talked him out of selling it for almost nothing and I stored it for about three years!
Since then the car has been repaired, repainted Green with Gold fleck, Gold GT Stripes, Simmons wheels and is faultlessly beautiful! He’s very glad he didn’t sell it!
YouTube for adjustment.
Not mentioned as yet but I assume it’s a C4 transmission.
Cheers Phil.
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Not something weird up with the adjustment of the selector rods and NSS is there? Putting into drive opening the NSS?
Doesn't the NSS only prevent the starter circuit of the car, I don't believe it can interrupt the ignition circuit....?
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Haven’t got to transmission yet, just want it to idle and go into gear.
We think it was used for drag racing,
Had a 2point roll cage, now removed.
Traction bars, 9 inch diff and disc brake assembly,
10 inch wheels on the rear
The hot motor, BM Shifter.
Has a C5 according to the paperwork
New Battery, cables ok, turns over rapid before starting.
Good video on BM Shifter adjustment, will look into that and check why it starts in gear.
The issue could be it needs a medium stall converter,
Is there any way to tell what it has, without removing the transmission?
Thanks
Woz
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Doesn't the NSS only prevent the starter circuit of the car, I don't believe it can interrupt the ignition circuit....?
Good point Jeff and I mostly retract my thought bubble. While it might be nothing to do with his problem, the NSS situation clearly needs addressing anyway and it does seem the wiring of this car has been messed with a fair bit so who knows.
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Doesn't the NSS only prevent the starter circuit of the car, I don't believe it can interrupt the ignition circuit....?
Good point jiffy,
Long winded post this one.
Cheers Phil.
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The issue could be it needs a medium stall converter,
Is there any way to tell what it has, without removing the transmission?
Thanks
Woz
Hey Woz,
You’ll need the car going first.
Foot flat on brake, start engine, put into gear, and put the accelerator down, converter will fill up and you’ll noticed the engine struggle at an RPM!
This link is basically how you can tell.
https://youtube.com/shorts/FIy770aWvcU?si=_zA7CkSneCOULU1o
Cheers Phil
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Hi Woz,
a couple of things to consider. What really do you want to do with this car? Race it, cruise it, short trips of day outings with friends, say a few 100 klms ?
To understand that is important, is fuel mileage an issue for you? Believe me if you have a wicked motor, a diff ratio that makes sense in the qtr mile but gives crappy mileage if your doing a long run, you wont be happy with the car.
So make your mind up first.
Check what diff ratio is in the car, is it for cruising or racing.
Then if its race you want buy the parts that make sense, a torque convertor with say 2200 or higher . Or perhaps if want just to cruise and the compression and intake etc will facilitate it, change to a milder grind cam for cruising. But you really need to understand what you want from the mustang first
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Hey Phil,
Will do the converter stall test on my car ( 289 C4) first and then on the 351 C5 and compare, never done it before.
I think the owner just wants to get the car drivable, then if not too costly, get it registered, maybe keep it for a while and then sell it.
Good point on the diff ratio, will include that on the check list.
Thanks
Woz
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Try connecting a temporary wire from the positive side of the coil to the positive side of the battery.
Also you could try connecting a jumper lead from the engine to the negative side of the battery.
:bolt:
Hey Woz,
You said you couldn’t do this because battery in boot, but just a positive to your starter solenoid and negative to engine block or chassis. Cable run from boot needs to be at least 70mm2 or better.
Is your alternator making 13.4 volts and well earthed.
You don’t have something electrical in run position down to earth drawing to much voltage draining voltage from coil.
Have you a good size earth strap from the engine to chassis, use WD40 loosen and retighten.
Have you got good spark, what’s the dizzy again, have you tried to run the engine on Aerostart to see if it’s fuel or spark.
You haven’t done something silly like mixing up the plug leads?
Do you have a bad ignition switch, losing 12V back on run after start.
Have you run a multimeter over everything especially coil and run wire.
Eventually you’ll have to return your carburettor to your car, what is the original carburettor and have you disassembled it yet and is it serviceable. Maybe just something simple! Clogged screen, jets or stuck floats or float valve, incorrect float level etc.
You did mention two carburettors, early in post 1403 (2 step electric chock) and later in post a 1404 (manual chock), The electric chock is preferable if you able to set 12v from ignition switch.
Cheers Phil
Cheers Phil.
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Hey Woz,
Only thing left unmentioned is fuel pump or strainer in tank?
Cheers Phil.
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If it has a hot cam as you say ,it needs a hi stall converter. The way to tell how big the converter is you need to drive the car at say 60 kph in 2 nd gear , and floor it , and watch the tachometer and see what it jumps up to , till it stops then that’s what the converter size .it’s called flashing the converter . Putting you foot on the brake is not the correct way . If it needs a converter don’t buy a cheap eBay one . I need details on the car before you determine the size needed . I run a 4,000 rpm in my mach 1 .
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One strange thing I noticed today, when i put my foot on the brake, the car stalled, doesn't have brake booster.
Thanks
Woz
Woz, do you have a shorted brake wire!
Cheers Phil.
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Going there tomorrow,
Will refit the carby ( Edelbrock 1405 600cfm)
Check if it will idle, if it does, press the brake pedal and see if it stalls. If it does, could be brake short somewhere.
If it doesn’t stall, will try the converter stall test.
Can’t do Glenn 70 test, car unregistered.
Will take my multimeter and check everything as suggested
Battery cable is standard 4 gauge, no pump in the fuel tank, just the standard pump on the block.
Will report on tomorrow’s progress
Thanks
Woz
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You can do a bit of a converter test by putting the hand brake on and your foot hard on the brakes and some bricks in front of the front wheels in a safe area , and see what happens ,but it’s only as good as the brakes will be .
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Going there tomorrow,
Battery cable is standard 4 gauge, no pump in the fuel tank, just the standard pump on the block.
Thanks
Woz
Hey Woz,
Cable in boot must be 50mm2 or the size of industrial welding cable direct to starter solenoid unless you’ve got the new type starter motor with its own solenoid.
The cable runs to the boot on mine is 70mm2 about 3 1/2 metres long, it runs to my starter motor solenoid on the starter motor then onto 200amp alternator, I used a standard Bosch 12v relay to initiate start!
A good general rule-of-thumb figure is one amp starter draw for every cubic inch of motor.
You have a sock filter in your fuel tank attached to the pickup!
Cheers Phil.
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Hey Woz,
You do have Automatic Transmission Fluid in the transmission not gear oil.
Just checking.
Cheers Phil.
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Hey Woz,
torque converter seized?
Cheers Phil.