Timing settings on 1957 312 Y Block

[bobioknight]

I have been trying to get my timing correct, it is a combination of idle speed and timing advance, when I look at the manual the specs are between 6-8 degrees but it does not tell me at what idle speed I should be at. I have read that I should be running 10-12 degrees, does anyone know at that idle speed I should be at when setting the timing to 12 degrees. And is this an exact science or is there some give?

[55Greg&Amy]

Shop manual says idle should be set to 425-450 rpm but on mine it seems too low. Mine really likes 500-525 and I set the timing with a vacuum gauge to get the highest vacuum. I haven't even put a timing light on mine in 6 years so I have no idea where it's even at. At 11-12-1/2º advance the idle should be 1000 rpm according to the manual.

[paul2748]

When checking timing, the vacuum advance hose should be removed and plugged. While specs call for 6-8, at 10-12 they seem to run better. I have mine set at 10 degrees and it runs very well. Idle speed should be set at the recommended speed, which I think is 450.

[CSavaglio]

Agreed on the 10-12 range here too.

You'll have to keep backing the idle down as you advance the timing. As said, the manual says around 450, but 50) is ok if it seems smoother.

[bobioknight]

Thanks guys, the book/manual just said at idle speeds set to 6*. Well idle could mean anything, so with your help I was able to get it dialed in very nicely. Prior to this I was all over the place and I could not get it running good at all. I timed it to 12* at 550 rpm. I do like it idled down closer to 450 it just sounds cooler. I also turned my choke off since I doubt it is necessary and could been part of my fuel smell issues. Thanks for the help.

[bobioknight]

After adjusting the timing I ran to the muffler shop to install new mufflers. In the process I inspected the exhaust flapper thingy and it appeared to not be opening all the way. Which just made me think why I would even want it on there. So we left it out of the install. The passenger side resonator was very near rusted through and deteriorating. There was a large temp difference between the drivers and passenger side exhaust systems. Which made me think one side was flowing better than the other.

I went with the flow master mufflers, the shop allowed my to slip 5 different mufflers brands into position so I could hear what they all sounded like on my car. I chose a medium sound with low tones. Quiet cruising but stepping on the throttle will give a little roar, but not open pipe raspy sounding.

During the drive home the timing was way off and kept missing. Idling poorly. But was good enough to get me home, this morning I reset the timing, 550 rpm at 10*. I used the timing light and vacuum to make the adjustments. Vacuum is a nearly steady 20. I continued adjusting the timing and idle until it was dialed in. The test drive went great, the engine sounded healthy from idle to WOT. Everything is running a bit cooler and I think more efficient without the excessive back pressure. Both sides of the exhaust is now running near exact temperatures. I am also not getting the fuel smell excellerating in the freeways. I expect disengaging the choke helped.

[Joe Johnston]

sounds like you are getting things together and a more enjoyable drive with every day!

[bobioknight]

sounds like you are getting things together and a more enjoyable drive with every day!

Yes Joe it appears to be coming together. Not much left to but drive. I sure hope my going back and forth with you guys cataloging my progress helps someone else in similar circumstances. In my area all the mechanics stay clear of these carbed engines. So guys like me depend on learning via you guys in the forum and YouTube. It can all get very frustrating trying to describe intermittent problems over a keyboard. But y'all have proven to be patient teachers. Thanks fir all the assistance.

[Joe Johnston]

In my area all the mechanics stay clear of these carbed engines. So guys like me depend on learning via you guys in the forum and YouTube. It can all get very frustrating trying to describe intermittent problems over a keyboard.

The list of "old school" mechanics is getting shorter every day which makes studying the old shop manuals more important than ever. Time spent reading with the parts in had while looking at pictures makes you more knowledgeable than a skilled tech trained to repair today's computerized marvels.

Good to hear your Bird is becoming more enjoyable to own and drive.

[bobioknight]

Thanks, it sure has.

[Denver T-Bird]

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 jump 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. I wanted to get a better timing setting so I disconnected the vacuum line 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, 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. Points and condenser have about 200 miles on them but that was over a 20 year period. Any suggestions? Thanks for the help.

[CSPIDY]

The initial timing should be checked with the vacuum to the distributor disconnected, idling 475 to 500 RPM,
along with the vacuum advance there is a mechanical advance so having the engine idle set is important when checking the timing.
You did not mention if you had the fordomatic or standard transmission. Either way the timing for the Automatic should be 6 to 8 degrees BTDC. The standard should be 4 to 6.
The timing marks on the pulley damper are small be can be high lighted with a piece of chalk.
Also the no1 cylinder is most forward plug, located on the passenger side of the motor.
If the timing is jumping around when the engine is advanced you may have a loose timing chain.
Hope this helps

[paul2748]

As noted above, YBlocks run real well at 10- 12 degrees initial advance.

[Denver T-Bird]

Thanks for the suggestions. I have an automatic transmission. Does the vacuum port on the distributor need to be plugged or just left disconnected from the carburetor? When I tried to check the timing with the vacuum disconnected it would run rough when I got the marks close to the pointer. Some have suggested that the distributor is off by a tooth. Any thoughts on this issue? The car seems to run OK with the marks being about 1 inch from the pointer, I just wanted to be sure it tuned correctly. Is use of a vacuum gauge as good as a timing light? If I get max vacuum at 1 inch from the pointer does that suggest that the distributor is off by a tooth? or the chain slipped? Thanks!

[CSavaglio]

Vacuum disconnected and the engine side plugged. Otherwise, you've created a vacuum leak, so it'd run rough. The port on the distributor doesn't need to be plugged.

A healthy stock-ish y-block will easily idle at 425rpm smoothly if everything is set right. Idle for an automatic should be around 425 or 450 in drive and that usually puts it around 475 or 500 in neutral.

The distributor off by a tooth is a bit of a myth and a poor suggestion from people who don't understand ignition timing. Prob the same people who think a timing chain can "jump a tooth" and not be so loose it's off the gears. To get the mark at the pointer, you'd just have to turn the distributor more to compensate so the #1 cylinder is firing when it's supposed to be.

If you've plugged up the vacuum leak you create when you disconnect the advance and it still runs rough, it could be something plugged or set incorrectly in the idle circuit of the carb, valves adjusted wrong, broken component in the ignition system, etc. The other thing is to make sure you're using an automotive multimeter or digital timing light to read the RPMs. The tachs in the car are not super accurate especially if they've never been rebuilt. I tried chasing a problem where the car wouldn't rev past 3k for a long time and finally found that it was the tach...idle and lower rpms read correct, but when the tach said 3k, it was actually closer to 5k.