'57 -283 distributor rotation & timing question
12-17-2006, 05:54 PM
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'57 -283 distributor rotation & timing question
We noticed in our 1960 AIM that the '60 distributor rotation is clockwise. When we had the cap off the distributor on our '57 engine, we noticed that the rotor was turning counter clockwise. We wired the dual contact lead to the negative side of the coil, positive side of the coil to the starter switch, etc. And, wired the distributor plug wires like we would a '60. We turned the motor over after identifying TDC and received two loud bangs and flames out of the driver's side and passenger side mufflers (we don't have the tail pipes on yet). Anyone think that we're 180* out? Or, something else? We stopped for the evening and I thought I'd check with you guys.
Any thoughts on the matter would be greatly appreciated.
Respectfully,
Tom Spurgeon
corvettethomas67
Any thoughts on the matter would be greatly appreciated.
Respectfully,
Tom Spurgeon
corvettethomas67
12-17-2006, 07:13 PM
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We noticed in our 1960 AIM that the '60 distributor rotation is clockwise. When we had the cap off the distributor on our '57 engine, we noticed that the rotor was turning counter clockwise. We wired the dual contact lead to the negative side of the coil, positive side of the coil to the starter switch, etc. And, wired the distributor plug wires like we would a '60. We turned the motor over after identifying TDC and received two loud bangs and flames out of the driver's side and passenger side mufflers (we don't have the tail pipes on yet). Anyone think that we're 180* out? Or, something else? We stopped for the evening and I thought I'd check with you guys.
Any thoughts on the matter would be greatly appreciated.
Respectfully,
Tom Spurgeon
corvettethomas67
Any thoughts on the matter would be greatly appreciated.
Respectfully,
Tom Spurgeon
corvettethomas67
I think a good nights sleep will do wonders. The rotor should turn clockwise and the cap should be wired accordingly unless somebody has modified your engine internally.
If your rotor does in fact turn counterclockwise, wire the cap backwards. Then, you'll have four(3) speeds in reverse and one forward.
12-17-2006, 07:33 PM
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Tom,
The only way your 283 is going to run is if the rotor is turning clockwise.
Take a look again. If for some reason it is, (as MikeM said) turning counterclockwise then you must have your starter wired Positive earth and your turning it over in the wrong direction
.
I suspect the rotor is turning in the correct direction (clockwise), and you need to put the plug wires on correctly and follow the firing order. Do a search on the forum for timing your distributor, there was a good thread recently.
Bill
Look at this thread
http://forums.corvetteforum.com/show...ributor+timing
The only way your 283 is going to run is if the rotor is turning clockwise.
Take a look again. If for some reason it is, (as MikeM said) turning counterclockwise then you must have your starter wired Positive earth and your turning it over in the wrong direction
.I suspect the rotor is turning in the correct direction (clockwise), and you need to put the plug wires on correctly and follow the firing order. Do a search on the forum for timing your distributor, there was a good thread recently.
BillLook at this thread
http://forums.corvetteforum.com/show...ributor+timing
12-17-2006, 07:43 PM
#4
Burning Brakes
Rotors turn only clockwise. Pull plug #1 and carefully snake a large allen key or something into the plug hole to see if you are at TDC. If not rotate the engine 360 deg and relocate the rotor accordingly.
12-17-2006, 11:14 PM
#6
Le Mans Master
timing
look at your crank harmonic balancer, the line on it will either be dead on, or 180 out. TDC = TOP DEAD CENTER
get some masking tape, rotate the harmonic balancer to where you can tape off the timing mark on the balancer on each side, and use liquid white out, and paint the line white.
to ensure you are on compression stroke, remove the forward most spark plug on the driver's side of the engine, and stick your finger over or in the hole. have someone crank over the engine with the coil wire removed from the coil. when the engine blows your finger out of the hole, that's compression stroke, #1 TDC.
ok, too dangerous for you ?
ok, take off the driver's side rocker cover. see the rockers, all nice in a straight line? ok. crank over the engine with the coil wire off, and watch the first 2 rockers at the front of the engine.
When they are both loose, with the line on the harmonic balancer up near the timing tab on the timing cover, that's close to TDC.
look at the harmonic balancer. is the line near the timing marks? past it?
If it's past, click the engine around to where the timing mark comes up to the little tab on the timing cover. that's 180 out. Keep clicking the starter till it comes up to the timing tab again, and then if you need to, make the fan belt really really tight, and rotate the engine SLOWLY by rotating the fan till it's on 0.
That's on TDC.
Now, loosen the hold down bolt on the distributor, remove it, and gently rock the distributor out and pull up.
Rotate the distributor till the rotor finger points forward, slide the distributor back in. It may take a couple of tries. It won't go all the way down because the oil pump drive shaft is not aligned.
does the rotor finger point forward still? If yes, have the same person that clicked your starter before click it some more till the distributor drops in the hole all the way down to the manifold.
Replace the bolt on the distributor hold down. Don't tighten it et. rotate the engine 2 more times and find TDC #1 cylinder again.
Set the cap on the distributor, don't lock it down, and determine the #1 wire is where the distributor finger is pointing.
If it's not, and you can rotate the distributor so the vacuum advance cannister is pointing at the middle of the front R/H wheel, and the cap will now point to #1, you are almost there.
Reinstall #1 spark plug, put the wire on it, reinstall the rocker cover if removed.
If the rotor finger is pointing forward, and the cannister is pointing at the axle, and the wires aren't where they look like they should be, take the first 3 wires off that are at the back of the carburetor, on the distributor. reinstall #1 where the finger points to. Then install all the wires where they need to be. latch down the cap.
firing order is 1-8-4-3-6-5-7-2
The rotation is clockwise. If you find #1, the rest is easy.
Make sure when you put the wires in, you are gentle but firm. The wires are made of fragile stuff, and they can tear or break and the casing looks just fine.
One way to tell if the wires are broken inside, is drive the car, and get to where the engine floats at a steady even speed, and if the engine doesn't chug, or seem to miss, the wires are probably ok.
If you get the chugging, you have to use a meter to check resistance cold, and hot.
the bad one will be really obvious.
Ok, Timing the engine.
Clip the timing light on the #1 spark plug wire, put the timing light where it won't get in the way of the exhaust, the fan, or belts, etc. and remove the vacuum hose from the distributor vacuum advance cannister and put a screw in the rubber hose.
start the engine. watch the wires on the timing light!!! you will be able to see where the timing mark is in reference to the tab. If you pull the distributor cannister towards you , that's advance, if u push it away from you , that's retard.
line it up, and put the timing light where it's safe, tighten the distributor, and recheck the timing using the timing light.
Re install the vacuum hose, check around the engine for loose items, and test drive.
Setting the points:
setting the distributor in the engine, is setting a coarse timing adjustment. Setting the points is setting the fine timing adjustment.
The point gap is crucial, in that the gap is said to be Dwell. That is, dwell is the number of degrees in a 360 circle that the points remain or dwell closed.
on 57 and later, there is an allen head adjuster on a breaker plate inside the distributor cap. use a flashlight, and insert an allen wrench into the allen adjuster..attach a dwell meter to the negative side of the coil (distributor side), and the other wire to ground. Start the engine, and watch the dwell meter, and set it at 28-32 degrees by turning the allen wrench..
No dwell meter? set the gap at .028 to .030 thousandths of an inch with the engine not running...
A dwell meter is an invaluable tool to determine the condition of the distributor. When observing the dwell meter, if the needle is oscillating slightly at idle, and the dwell changes more than2 to 3 degrees, more when the idle is raised to approx. 1500 RPM, The distributor shaft bushings are probably worn.
If the reading is steady regardless of the RPM, the distributor shaft bushings are fine.
get some masking tape, rotate the harmonic balancer to where you can tape off the timing mark on the balancer on each side, and use liquid white out, and paint the line white.
to ensure you are on compression stroke, remove the forward most spark plug on the driver's side of the engine, and stick your finger over or in the hole. have someone crank over the engine with the coil wire removed from the coil. when the engine blows your finger out of the hole, that's compression stroke, #1 TDC.
ok, too dangerous for you ?
ok, take off the driver's side rocker cover. see the rockers, all nice in a straight line? ok. crank over the engine with the coil wire off, and watch the first 2 rockers at the front of the engine.
When they are both loose, with the line on the harmonic balancer up near the timing tab on the timing cover, that's close to TDC.
look at the harmonic balancer. is the line near the timing marks? past it?
If it's past, click the engine around to where the timing mark comes up to the little tab on the timing cover. that's 180 out. Keep clicking the starter till it comes up to the timing tab again, and then if you need to, make the fan belt really really tight, and rotate the engine SLOWLY by rotating the fan till it's on 0.
That's on TDC.
Now, loosen the hold down bolt on the distributor, remove it, and gently rock the distributor out and pull up.
Rotate the distributor till the rotor finger points forward, slide the distributor back in. It may take a couple of tries. It won't go all the way down because the oil pump drive shaft is not aligned.
does the rotor finger point forward still? If yes, have the same person that clicked your starter before click it some more till the distributor drops in the hole all the way down to the manifold.
Replace the bolt on the distributor hold down. Don't tighten it et. rotate the engine 2 more times and find TDC #1 cylinder again.
Set the cap on the distributor, don't lock it down, and determine the #1 wire is where the distributor finger is pointing.
If it's not, and you can rotate the distributor so the vacuum advance cannister is pointing at the middle of the front R/H wheel, and the cap will now point to #1, you are almost there.
Reinstall #1 spark plug, put the wire on it, reinstall the rocker cover if removed.
If the rotor finger is pointing forward, and the cannister is pointing at the axle, and the wires aren't where they look like they should be, take the first 3 wires off that are at the back of the carburetor, on the distributor. reinstall #1 where the finger points to. Then install all the wires where they need to be. latch down the cap.
firing order is 1-8-4-3-6-5-7-2
The rotation is clockwise. If you find #1, the rest is easy.
Make sure when you put the wires in, you are gentle but firm. The wires are made of fragile stuff, and they can tear or break and the casing looks just fine.
One way to tell if the wires are broken inside, is drive the car, and get to where the engine floats at a steady even speed, and if the engine doesn't chug, or seem to miss, the wires are probably ok.
If you get the chugging, you have to use a meter to check resistance cold, and hot.
the bad one will be really obvious.
Ok, Timing the engine.
Clip the timing light on the #1 spark plug wire, put the timing light where it won't get in the way of the exhaust, the fan, or belts, etc. and remove the vacuum hose from the distributor vacuum advance cannister and put a screw in the rubber hose.
start the engine. watch the wires on the timing light!!! you will be able to see where the timing mark is in reference to the tab. If you pull the distributor cannister towards you , that's advance, if u push it away from you , that's retard.
line it up, and put the timing light where it's safe, tighten the distributor, and recheck the timing using the timing light.
Re install the vacuum hose, check around the engine for loose items, and test drive.
Setting the points:
setting the distributor in the engine, is setting a coarse timing adjustment. Setting the points is setting the fine timing adjustment.
The point gap is crucial, in that the gap is said to be Dwell. That is, dwell is the number of degrees in a 360 circle that the points remain or dwell closed.
on 57 and later, there is an allen head adjuster on a breaker plate inside the distributor cap. use a flashlight, and insert an allen wrench into the allen adjuster..attach a dwell meter to the negative side of the coil (distributor side), and the other wire to ground. Start the engine, and watch the dwell meter, and set it at 28-32 degrees by turning the allen wrench..
No dwell meter? set the gap at .028 to .030 thousandths of an inch with the engine not running...
A dwell meter is an invaluable tool to determine the condition of the distributor. When observing the dwell meter, if the needle is oscillating slightly at idle, and the dwell changes more than2 to 3 degrees, more when the idle is raised to approx. 1500 RPM, The distributor shaft bushings are probably worn.
If the reading is steady regardless of the RPM, the distributor shaft bushings are fine.
Last edited by coupeguy2001; 12-17-2006 at 11:23 PM.
12-17-2006, 11:49 PM
#7
Burning Brakes
The two distributor hold down clips should be in line with the axis of the front wheels. There is a good picture of this orientation along with the correct plug location in the ST-12 manual. I wouldn't move any wires until you view it!
The Allen head arrangement to adjust the points body started in 59. 57's use eccentric screws to move the breaker plate.
Set the point gap at .015 thousandths of an inch before using a dwell meter. The ST-12 also covers blocking off one set of points at a time to finalize the dwell. I can scan this page and paste it if you don't have a ST-12
The Allen head arrangement to adjust the points body started in 59. 57's use eccentric screws to move the breaker plate.
Set the point gap at .015 thousandths of an inch before using a dwell meter. The ST-12 also covers blocking off one set of points at a time to finalize the dwell. I can scan this page and paste it if you don't have a ST-12
12-18-2006, 02:04 AM
#8
Race Director
There were some direct gear drive hot rod replacements made to drive the cam, years ago. It required a special cam also, as I recall, so I would say that is not the most likely thing to look at, but those cam gear drives w/o the idler gears did rotate the cam and distrib counterclockwise.
Doug
Doug
