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Timing a '57 312 Y block


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Need some help getting the timing set on my '57 with 312/4 brl. The car seems to lack power. I initially set the timing with the vacuum hose connected, the marks jump around pointer but I can get it set close to about 10 degrees - is this a vacuum leak issue? The car idled OK but has a consistent popping and engine jumps slightly when the timing is set close to the marks but seems to smooth out if the timing marks are farther away from the pointer -maybe 1 inch away from the pointer.  I wanted to get a better timing setting so I disconnected the vacuum line (as recommended in the manual - why remove the vacuum lines??) at the distributor and put tape over the hole and also put tape over the line going to the carburetor. The marks are about 1 inch away from the pointer (before removing the vacuum the pointer was close to the 10 degree mark but bouncing), idle is set about 6-700 rpm. As I rotate the distributor the marks come closer to the pointer but the engine runs rougher and almost dies. I checked the points - the gap is about 0.015, as recommended in the manual. Points and condenser have about 200 miles on them but that was over a 20 year period. Any suggestions? Thanks for the help

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Sounds like the distributor might be installed off time, that is it’s off by one tooth on the distributor shaft.  It happens.  The timing marks and running engine won’t line up as you are finding.  By moving the firing order of the spark plug wires in the distributor and readjusting the timing by moving the distributor until the engine runs smooth will make it work.  Downside is the timing marks are now useless.

 

Normally for setting timing the vacuum line to the distributor is disconnected and the vacuum port on the engine that supplies vacuum to the distributor plugged with a rubber cap to prevent an air leak.  The engine idle speed must be set to the recommended value too as the mechanical advance inside the distributor must not affecting the timing as it’s adjusted by moving the distributor.

 

You may have to continue to set the distributor timing position by feel of how smooth the engine runs if the distributor was incorrectly installed or you can go through the process of getting everything correctly lined up and go from there as your shop manual will discribe.

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I agree with TerryB, very easy to get the distributor gear engagement one tooth off. However I think you should try to correct that. Mark the housing position in the block and the rotor location at #1 plug, pull the distributor then reinsert it with the rotor slightly moved, you should be able to feel the gear engage and see that the rotor has moved while the housing stays put. The direction is trial and error but when you get it right the car should run noticeably better. Good luck.

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It's possible the timing marks aren't right. The wrong harmonic balancer  or pointer could cause this. The rubber in the balancer could be failed and the outer ring has shifted. You could test for true top dead center on the #1 cylinder, then see if the marks line up. If you have enough swing at the distributor to bring the timing marks to line up with the engine running ,being a tooth off is not the immediate problem. Sounds like the mark shows more advance than it really is.

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2 hours ago, Bhigdog said:

Read up on vacuum gages and the use of same. Put one on the car as you attempt to time it. It will likely point you in the right direction

Handiest tool in the box until infrared thermometers became affordable.  Three must haves + the sense to read, understand and follow the directions: vacuum gauge, volt/ohm meter and a infrared thermometer.

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Worked on a V-8 Ford before? Cylinder numbers are different than Everyone else!.

 

Distributor off one tooth might prevent be able to set timing to mark, but if you can set the timing of cylinder 1 to the timing mark, distributor off a tooth is a non-issue.  Timing light connects #1 spark plug lead and compares to crankshaft position. Everything in between (crank and cam gears, distributor gear, etc.) is already accounted for if marks line up.   Flame suit on....

 

I am speaking of ignition timing, not valve timing.

Edited by Frank DuVal
To clarify (see edit history)
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On ‎8‎/‎13‎/‎2018 at 8:19 PM, Tinindian said:

Handiest tool in the box until infrared thermometers became affordable.  Three must haves + the sense to read, understand and follow the directions: vacuum gauge, volt/ohm meter and a infrared thermometer.

 

Add a compression gauge set and you've got it pretty well covered.

 

Paul

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check the spark plug wiring as stated ford is different than chev off the top of my head right bank 1-4 right 5-8 left  numbered from front to back plug wire out of order will cause your symptoms usually marked on intake

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So, jumping right to difficult repair before commenting on easy stuff, like do you actually have the timing light on #1 cylinder for a 312 engine? 

 

Not sure what moving the distributor rotor one tooth will accomplish, as you are already setting the timing to where the engine likes to run.

 

Does this 312 have a harmonic balancer? If so, is the outer ring separating from the inner hub? This condition will make timing marks inaccurate.

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13 hours ago, Denver T-Bird said:

Thanks for the help.  For now I am going to leave the distributor "as is" and set the timing based on how the engine runs.  When I have more time I will pull the distributor and rotate the rotor as suggested.  The engine is running pretty smooth now.

Lots of things to explore later on.  Glad to hear it’s running better for you.

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