Is there an optimal setting for the timing?

[johnnycharger]

Hi Guys
I need to get my timing set correctly and I am no master mechanic...
Here is what I have
383 stock cam heads and innards
Holley 750 double pumper
Edelbrock performer intake
Blaster 2 coil
Pertronix box
Fire core wires
Ngk plugs
Vacuum advance disconnected

I think that is all of the details.
What should my timing be set at?

[Ghoste]

You can probably start at 16 initial and 32 total but once you get into it the car may tell you different.

[myk]

The optimal setting is whatever your engine likes; no two engines are the same.  Set your initial timing to highest possible manifold vacuum, then test drive.  My engine went all the way up to 24* initial and highest vacuum, but I settled on 20* initial in the end...

[BSB67]

Try this

Total timing at 38° w/o vacuum advance
Check and record timing at idle  v/o vacuum advance
Reconnect the vacuum advance to ported  vacuum and go for a test drive, and report back how it drives.

[John_Kunkel]

  That's more like it. Fuel quality will dictate final setting.

[68charger440]

That's more like it. Fuel quality will dictate final setting.

"Fuel quality"... Now that's an oxymoron if I ever heard one.

[John_Kunkel]

You can get quality fuel if you want to mortgage your house to pay for it.

[68charger440]

You can get quality fuel if you want to mortgage your house to pay for it.

Courtesy of your EPA public service regulations!

[johnnycharger]

Try this

Total timing at 38° w/o vacuum advance
Check and record timing at idle  v/o vacuum advance
Reconnect the vacuum advance to ported  vacuum and go for a test drive, and report back how it drives.

Ok. So apparently I know less about timing than I thought.  Don't kill me because of my ignorance. So my vacuum advance is disconnected and  I turned my distributor until my timing was about 30 hard to be exact because my marker stops at 10.  Did I do it right? I don't quite understand the different timing terminology.  If I rev it up it goes much farther. I did notice quite a bit of difference from where it was set to.

[johnnycharger]

[johnnycharger]

The second picture is at idle. The first picture is revved up at about 3000 rims or so..... I don't have a tachometer.

[68charger440]

30 seems like way too much initial to me.  I run mine at 18 initial and 34 total all in. , but these other guys know much more than me.

[Ghoste]

30 initial is too much.

[johnnycharger]

So... initial is at idle and total is when revved? Is this correct?

[68charger440]

So... initial is at idle and total is when revved? Is this correct?

Yes, and the total can come in at different rates depending on how your distributor curve is setup.

[johnnycharger]

Gotcha. Thank you. I will dial it back tonight and take it back out and see how it does.

[maxwellwedge]

You need to either buy a timing tape (cheapest) for the harmonic balancer or a roll-back, dial-back.....whatever you want to call them timing light to set total advance. I say invest in the timing light.....you can use it on other cars and it is a good tool to have.

[myk]

Buy a timing gun with an advance/retard feature.  I use THIS: http://www.nationaltoolwarehouse.com/INNOVA-Digital-Timing-Light-P18259.aspx?gclid=Cj0KEQjwnrexBRDNmZzNkf7c4c4BEiQALnlxhWuuLUD2j9JeOFOlQwm93xf3XBVT116TkIWmiWfCRPoaAn5T8P8HAQ

The Innova 3568 features a dial-back/advance feature AND a tachometer, all in one.  It's about a hundred bucks or so, but well worth it so that you can actually know what you're doing. 

Also, 30* initial may seem like a lot, but some guys, like good 'ol Ron, run 34* initial.  Now of course, his fire-breathing motor is a little different from ours, but the point is you have to experiment with your engine and see what it likes.  There is no "ideal" timing, as every engine behaves differently...

[Dino]

That's a good light, I bought one for around $70 I think.  Now that the engine is out it's a great time to stick some timing tape on the balancer though.   

I'm running 24 initial btw.

[firefighter3931]

With the stock cam it won't want a huge amount of base timing. I've found 15-16* to be the sweet spot with stock/mild builds and 36-38* total timing all in by 2500 rpm.

The stock distributor does not have a mechanical advance adjustment so that limits how much initial timing you can dial in. 

Example ; the stock dist has 30* of mechanical advance but your engine wants 15* at idle. Giving it the 15* it wants would result in a total timing of 45* which is too much (15 base + 30 mechanical = 45 total)

For now, just rev it up to 3500 and set the timing to 38* and re-check at idle. The difference between 3500 and idle is the amount of mechanical advance that is set up in that distributor. 

Report back with your findings 


Ron

[BSB67]

38 degrees is 2.38" on the balancer.  No need to buy a dial back light.  One more thing to be wrong and you will be chasing your tale forever trying to figure it out.  I have seen this happen twice, dial backs that were wrong.  And I've only used three.

Just put the make on the balancer, have someone rev it to 3500 rpm, line the 2.38" balancer mark to the "0" degree mark on the tab.

[johnnycharger]

I really appreciate the info guys. Your ways of explaining this has really helped me understand it. I made a make shift tab by tracing the lines on a piece of paper and then transferring it to another piece long enough to get to 38. I don't think it was too accurate. On the test drive it was slightly more sluggish than where I had it at before. I will make the mark at 2.38" below the line that is there now.

Question about 3500 RPMs... how accurate does that need to be? I do not have a tach but I have noticed that at about what I think to be in that range the  timing no longer advances. When it is at what I believe to be 3500 it steadies out. Is that correct?

[johnnycharger]

Sorry... I forgot to mention that after I set it to 38 (or in that area) when back at idle it was at 15*

[68charger440]

38 degrees is 2.38" on the balancer.  No need to buy a dial back light.  One more thing to be wrong and you will be chasing your tale forever trying to figure it out.  I have seen this happen twice, dial backs that were wrong.  And I've only used three.

Just put the make on the balancer, have someone rev it to 3500 rpm, line the 2.38" balancer mark to the "0" degree mark on the tab.

Just curious, why is it 2.38 and not 2.407?  Not that it would make a big difference.

[johnnycharger]

Whoops! I guess the line goes above the existing line when looking from the passenger side.