Engine Timing Question

[JJordan1173]

My service manual says 2 1/2 degrees BTDC (Pictured). I have heard others say advance the timing as far as 12 degrees. What is correct?

Slant 6 225
Holley 1920

Having my first go at this tomorrow, thanks for any info.
JAMES

 

[R413]

Play with the timing, move it around, it's FREE! Go drive the car and see what it likes for timing.

 

[WileE]

The latter is closer to reality. Is gasoline the same as it was when that manual was printed ? Hell, even back in the day we tuned it for performance vs. "manual spec" . You time the engine to what it likes.

 

[JJordan1173]

The latter is closer to reality. Is gasoline the same as it was when that manual was printed ? Hell, even back in the day we tuned it for performance vs. "manual spec" . You time the engine to what it likes.

Will do. I plan on doing this over the weekend. I will let y'all know how it goes. Thanks.

 

[Darter6]

You may find that your car will like 8* running 87 octane
But as said above you can play around to the tune you like.
I dig your 64. Had a more door 64 myself. Cool yours is a Slant 6 with a 3 speed.And it's a Fury !
I have a 63 Belvedere 4 door now.

 

[PurpleBeeper]

These guys are correct...more initial advance than the FSM says. My 2 cents? Mark the base of the distributor/block to know where you're at now. (keeping notes and using a timing light is best, but same approach regardless). Make sure the engine is fully warmed up & no vacuum leaks (check hoses & carburetor area). Advance the timing 1-2 degrees. Floor it under load (like up a hill or with A/C on). If you hear a little "tin sounding rattle rattle", that's spark knock (aka pre-ignition). If you get that rattle OR if the engine is hard to crank over & start once warmed up, turned off, and re-started....retard the timing back that 1-2 degrees.

IF you don't get any "tin sounding rattle rattle" when the engine is floored going up a hill and/or with the A/C on, then you go ahead and advance the timing another 1-2 degrees and repeat.

The idea is to advance the timing as much as you can WITHOUT "rattle rattle" or difficult starting when the engine is warm. So...you keep advancing the timing until you hit that point and retard it back 1-2 degrees. Does that make sense?

 

[JJordan1173]

These guys are correct...more initial advance than the FSM says. My 2 cents? Mark the base of the distributor/block to know where you're at now. (keeping notes and using a timing light is best, but same approach regardless). Make sure the engine is fully warmed up & no vacuum leaks (check hoses & carburetor area). Advance the timing 1-2 degrees. Floor it under load (like up a hill or with A/C on). If you hear a little "tin sounding rattle rattle", that's spark knock (aka pre-ignition). If you get that rattle OR if the engine is hard to crank over & start once warmed up, turned off, and re-started....retard the timing back that 1-2 degrees.

IF you don't get any "tin sounding rattle rattle" when the engine is floored going up a hill and/or with the A/C on, then you go ahead and advance the timing another 1-2 degrees and repeat.

The idea is to advance the timing as much as you can WITHOUT "rattle rattle" or difficult starting when the engine is warm. So...you keep advancing the timing until you hit that point and retard it back 1-2 degrees. Does that make sense?

PurpleBeeper:
Thank you! This helps alot. I will give it a go this weekend.

 

[JJordan1173]

You may find that your car will like 8* running 87 octane
But as said above you can play around to the tune you like.
I dig your 64. Had a more door 64 myself. Cool yours is a Slant 6 with a 3 speed.And it's a Fury !
I have a 63 Belvedere now.

Thanks! It's been a great car to learn on. My first pre 1980s car. I love Belvederes. Thinking of selling the Fury soon, I have mostly done all I want to it. I have my eye on a Barracuda, but the wife says no more than one project at a time!

 

[threewood]

Get a vacuum gauge to help get it dialed in. You will see vacuum rise the more you advance it and when it starts to drop off, rotate it back to just before peak vacuum. Reset the idle rpm back to where you want it. Drive it and see how it acts. May have to play with it a few times

The drawback to tuning this way is it almost always results in total timing being higher (initial + mechanical). It can be fixed with limiter plates and welding up the slots. If not, it could lead to detonation. I do all mine this way.

 

[WileE]

These guys are correct...more initial advance than the FSM says. My 2 cents? Mark the base of the distributor/block to know where you're at now. (keeping notes and using a timing light is best, but same approach regardless). Make sure the engine is fully warmed up & no vacuum leaks (check hoses & carburetor area). Advance the timing 1-2 degrees. Floor it under load (like up a hill or with A/C on). If you hear a little "tin sounding rattle rattle", that's spark knock (aka pre-ignition). If you get that rattle OR if the engine is hard to crank over & start once warmed up, turned off, and re-started....retard the timing back that 1-2 degrees.

IF you don't get any "tin sounding rattle rattle" when the engine is floored going up a hill and/or with the A/C on, then you go ahead and advance the timing another 1-2 degrees and repeat.

The idea is to advance the timing as much as you can WITHOUT "rattle rattle" or difficult starting when the engine is warm. So...you keep advancing the timing until you hit that point and retard it back 1-2 degrees. Does that make sense?

Yeah... ^^ He kinda gave a more elaborate version of my " time the engine to what it likes"

 

[Darter6]

Thanks! It's been a great car to learn on. My first pre 1980s car. I love Belvederes. Thinking of selling the Fury soon, I have mostly done all I want to it. I have my eye on a Barracuda, but the wife says no more than one project at a time!

One project ? What fun is that ?