Little help with initial, mechanical, and total timing on my rebuilt 360

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12-14* initial is NOT sound advice when the OP has found the engine likes 22* initial [ post #36 ].

The OP sounds like he is switched on & knows what he is doing. My 66 GTO was one of nearly 100,000 sold. Every one of them left the showroom idling with 26* timing, 6* initial + 20* of man connected vac adv.

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Bewy said:
12-14* initial is NOT sound advice when the OP has found the engine likes 22* initial [ post #36 ].

The OP sounds like he is switched on & knows what he is doing. My 66 GTO was one of nearly 100,000 sold. Every one of them left the showroom idling with 26* timing, 6* initial + 20* of man connected vac adv.

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Can we wait on the manifold vacuum advice please until he has his initial and mechanical sorted out? I'm not arguing against it, but he's having a lot thrown at him at once and that's a decision he can actually wait on.
 
Bewy said:
12-14* initial is NOT sound advice when the OP has found the engine likes 22* initial [ post #36 ].

The OP sounds like he is switched on & knows what he is doing. My 66 GTO was one of nearly 100,000 sold. Every one of them left the showroom idling with 26* timing, 6* initial + 20* of man connected vac adv.

View attachment 1716543977

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Click to expand...

Bewy said:
12-14* initial is NOT sound advice when the OP has found the engine likes 22* initial [ post #36 ].

The OP sounds like he is switched on & knows what he is doing. My 66 GTO was one of nearly 100,000 sold. Every one of them left the showroom idling with 26* timing, 6* initial + 20* of man connected vac adv.

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Lol.....Come on dude. He didn't even drive the car !!!!!
He started it, and turned it off !
What's his total with the initial set at 22* ? Burnt pistons anyone ? He doesn't even know what camshaft is in the car !
He really doesn't know anything about the motor either !
So why all the ungodly high timing numbers ? Why are you trying to tell him to time it like it's a John Force car ?
Most mild small blocks generally run very well with the timing numbers I gave, which makes it very sound advice.
 
The original initial was 24* and the car now has over 200 miles on it. It ran fine but with over 30* of MA (34* if you go by the stop plate number) once you get on it and raise the RPM's I could hear some detonation. I need to dial back the MA to get the initial and MA to balance out around 34-36*. Starting the initial at 12-14* when the MA adds over 30* is not helping my issue. Too much MA plain and simple. I would need to put the initial at around 4* to get a safe all in of 34* This engine/cam combination wants 22* initial, that I know. So now I have to dial back the MA to around 12-14* to get somewhere around 34-36*. Not hard, I just have to either weld it or use the FBO plate. I will try the plate first since that is non-permanent, or I can use a different stop plate. Anyway, I will try that tomorrow if time allows.
 
Something I did was attached a degree wheel to the distributor shaft. Put the shaft in a vise with rubber hose to protect it. Set it at zero and then pulled the weights out. Remember to double the number of degrees. I only had to do it once to get my 10 degrees of advance.
 
Builderguy said:
The original initial was 24* and the car now has over 200 miles on it. It ran fine but with over 30* of MA (34* if you go by the stop plate number) once you get on it and raise the RPM's I could hear some detonation. I need to dial back the MA to get the initial and MA to balance out around 34-36*. Starting the initial at 12-14* when the MA adds over 30* is not helping my issue. Too much MA plain and simple. I would need to put the initial at around 4* to get a safe all in of 34* This engine/cam combination wants 22* initial, that I know. So now I have to dial back the MA to around 12-14* to get somewhere around 34-36*. Not hard, I just have to either weld it or use the FBO plate. I will try the plate first since that is non-permanent, or I can use a different stop plate. Anyway, I will try that tomorrow if time allows.
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How did you determine your engine/cam wants 22° initial ?


The "best" timing for your motor depends heavily on your camshaft profile and whether you are running iron or aluminum heads. All you know is your camshaft " looked good". That's not enough to go on.

Have you tried running your engine up to 3000 RPM and setting the total around 35°, and test driving the car ?
 
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Johnny Dart said:
Lol.....Come on dude. He didn't even drive the car !!!!!
He started it, and turned it off !
What's his total with the initial set at 22* ? Burnt pistons anyone ? He doesn't even know what camshaft is in the car !
He really doesn't know anything about the motor either !
So why all the ungodly high timing numbers ? Why are you trying to tell him to time it like it's a John Force car ?
Most mild small blocks generally run very well with the timing numbers I gave, which makes it very sound advice.
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What you recommended is even more initial than the 68 340 had and it was clearly a performance engine. What was it like 8 initial?
 

Johnny Dart said:
Have you tried running your engine up to 3000 RPM and setting the total around 35°, and test driving the car ?
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That's what I would try at this point. Then if it still doesn't run well down low, he'll know it "might" need more initial. I wouldn't give anything a gob of initial without experimenting around first. Not all of them need all that.
 
That distributor needs to come apart and get rid of the 30-34* MA in it. It won't run for **** using a total timing approach, too much advance in the distributor. Look at the timing slope he posted. That is straight trash for any engine in todays world. The springs may be holding up the last few degrees in the plate (17 plate = 34*)
Idle is the foundation, go from there. Whatever it likes. You can dial total and curve in after that. I prefer the inside edge of the tower/plate slots filled as it helps with slowing MA a bit. More stretch on lighter springs. Fill the outside edge and a heavier spring is needed to control advance.

With the wheel hitting the pickup and other stuff going on, you need to have things in decent mechanical start to make it work.
No idea what the cam is creates an issue with coming up with a decent baseline. I run totally stock 340's at 14-16 initial. More cam, more initial. If it's mildly larger, maybe 16-20.
 
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crackedback said:
That distributor needs to come apart and get rid of the 30-34* MA in it. It won't run for **** using a total timing approach, too much advance in the distributor. Look at the timing slope he posted. That is straight trash for any engine in todays world. The springs may be holding up the last few degrees in the plate
Idle is the foundation, go from there. Whatever it likes. You can dial total and curve in after that. I prefer the inside edge of the tower/plate slots filled as it helps with slowing MA a bit. More stretch on lighter springs. Fill the outside edge and a heavier spring is needed to control advance.

With the wheel hitting the pickup and other stuff going on, you need to have things in decent mechanical start to make it work.
No idea what the cam is creates an issue with coming up with a decent baseline. I run totally stock 340's at 12-16 initial. More cam, more initial. If it's mildly larger, maybe 16-20.
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I agree, if that's what that governor is and it appears to be. He'd have what, like 2 degrees of MA? LOL
 
RustyRatRod said:
What you recommended is even more initial than the 68 340 had and it was clearly a performance engine. What was it like 8 initial?
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Factory Timing Specs 1968 340

Manual: 5° to 7.5° BTDC at 700-800 RPM

Auto: 2.5° to 5° BTDC at 600-700 RPM ( in neutral)

Having said that if you want the car to drive like it did in 68 but on today's s*** gas, you should aim for between 12° to 14° initial, 34°- 36° total.
 
Johnny Dart said:
Factory Timing Specs 1968 340

Manual: 5° to 7.5° BTDC at 700-800 RPM

Auto: 2.5° to 5° BTDC at 600-700 RPM ( in neutral)

Having said that if you want the car to drive like it did in 68 but on today's s*** gas, you should aim for between 10° to 12° initial, 34°- 36° total.
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Right. Conversely, if you have an engine with sho nuff stock compression that "possibly" blueprints in the 7s and any kind of cam, you "might" need that 20 degrees or more to achieve decent performance. It's just something you have to experiment around with. "ASSUMING" something arbitrarily wants 20 plus degrees initial might end up being a costly mistake.
 
Come on... starting point at 10-12 sure. Saying he should tune it there, with no other adjustment for best performance/idle quality, absolutely not.

I fixed a lot of cars that were and weren't stock that had a factory settings or someone else told them what they should run regardless of other factors.

The distributor set up is a fubar mess to start with.
 
crackedback said:
Come on... starting point at 10-12 sure. Saying he should tune it there, with no other adjustment for best performance/idle quality, absolutely not.

I fixed a lot of cars that were and weren't stock that had a factory settings or someone else told them what they should run regardless of other factors.

The distributor set up is a fubar mess to start with.
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100%
My suggestion was to set the total and take it for a drive.
Looking for a baseline.
Evidently, that is to difficult.
 
Johnny Dart said:
Yes, and setting the initial at 22° isn't going to work either.
He would be at 52° all in. No bueno
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Right that’s where this thread started. Had you read back and looked at dates and the suggestions already given you would have realized that your advice was as bad as where he started.
 
Johnny Dart said:
What's wrong with my advice ?
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Generally speaking, nothing, it’s good advice. In this situation where we’ve already seen the timing curve and a plot, and we know how fubar the distributor is, it’s not valuable and I know you’re smart enough to know that.
 
Johnny Dart said:
100%
My suggestion was to set the total and take it for a drive.
Looking for a baseline.
Evidently, that is to difficult.
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What he's saying is, that 17R governor in the distributor has 34 at the crank. That's 34 degrees of mechanical advance. If he gives it 12 initial, then he has 46 total. Way too much. He needs to get rid of that governor, OR get a different distributor.
 
TT5.9mag said:
Generally speaking, nothing, it’s good advice. In this situation where we’ve already seen the timing curve and a plot, and we know how fubar the distributor is, it’s not valuable and I know you’re smart enough to know that.
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Yah, this thread is all over the map. Not knowing what camshaft in the car isn't helping anything.
And yes, with 30°+ degrees built into the distributor, is not optimal for performance. Especially when you have your initial set at 22°. :eek:
 
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