Let's talk timing....

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sledger46

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With my current setup, the low compression 360 likes 42 degrees total timing. I currently use 21 degrees initial and 21 degrees of mechanical advance.

That seems to be working well, but I am also getting 24 degrees of vacuum advance so I am getting 66 of total timing running down the road at 3200 RPMs. This seems excessive to me, so what total timing number should I shoot for in a light cruise situation?
 
sledger46 said:
With my current setup, the low compression 360 likes 42 degrees total timing. I currently use 21 degrees initial and 21 degrees of mechanical advance.

That seems to be working well, but I am also getting 24 degrees of vacuum advance so I am getting 66 of total timing running down the road at 3200 RPMs. This seems excessive to me, so what total timing number should I shoot for in a light cruise situation?
Click to expand...

50* to 55* is as far as I've done.....

If you're running ported adv, my checks for too much vac adv are.....

1) A quick rattle/ping off idle as the vac advance kicks in.....
2) A slight stumble/surge at cruise rpm near the point of the mechanical totaling. Around 2500 rpm's in most cases.
 
I run a 10.7cr 360. About 57* has been determined to be optimum at about 2800 to 3200rpm. I run power timing of 32* to 34* max and initial is about 14* to 16*. I say "about" because Im always playing with it, so Im not sure where it is just now. I have a dash mounted dial-back timing device with a range of 15*. I have run cruise timing as high as 60*@3200rpm. There was no advantage to it for my combo.
42* seems excessive but Ive never had a low c/r 360 to experiment with. Have you verified your TDC mark?
If I had your combo, after verifying the mark, Id probably back the initial up some, maybe to 13*to15*, giving you 34to 36* power timing, and 58*to60*cruise. Then play with the vacuum can adjusting screw to see how it affects driveability.
But if she really wants a bit more, I dunno. As long as you are sure its not detonating....... keep in mind; more is not always better.
 
Nothin wrong with 66* timing including vacuum advance. The vacuum can only works at part throttle. As long as there's no detonation, don't sweat it.
 
RustyRatRod said:
Nothin wrong with 66* timing including vacuum advance. The vacuum can only works at part throttle. As long as there's no detonation, don't sweat it.
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Actually, with the mini heat wave we have going on in the Midwest I am sweating. My engine seems to be sweating too with coolant temps closing in on 200 degrees when tooling down the highway. That is what got me thinking the excess timing could be resulting in excess heat in the engine. In town it cools down to 185 - 190 degrees sitting in traffic.

I was playing with different centrifugal weight springs and actually went way too light and had full mechanical advance at 1300 RPMs. When I put my dial back timing light on it I was getting 73 degrees BTDC in park at 1300 RPMs. I fooled around with the adjustable vacuum advance can and got the number down to 66 degrees. From what I read the can adjustment only changes the rate at which timing comes in, it doesn't limit the amount of timing from vacuum advance. You either have to swap vacuum cans or weld up the slot on the can.
 
sledger46 said:
Actually, with the mini heat wave we have going on in the Midwest I am sweating. My engine seems to be sweating too with coolant temps closing in on 200 degrees when tooling down the highway. That is what got me thinking the excess timing could be resulting in excess heat in the engine. In town it cools down to 185 - 190 degrees sitting in traffic.
Click to expand...

I'm not sure why you are overly concerned about normal temps.
 
Retarded timing causes too much heat in the engine, not advanced. Closing in on 200*? Most electric fans in new cars don't turn on until 230 in some instances. "Closing in" on 200 is WAY FAR from over heating. You're worrying about nothing.

...plus, you cannot measure the vacuum advance timing with no load on the engine. It does not work that way. It must be measured with a vacuum gauge in high gear in either a flat stretch at a stead speed at part throttle or a very slight incline.


sledger46 said:
Actually, with the mini heat wave we have going on in the Midwest I am sweating. My engine seems to be sweating too with coolant temps closing in on 200 degrees when tooling down the highway. That is what got me thinking the excess timing could be resulting in excess heat in the engine. In town it cools down to 185 - 190 degrees sitting in traffic.

I was playing with different centrifugal weight springs and actually went way too light and had full mechanical advance at 1300 RPMs. When I put my dial back timing light on it I was getting 73 degrees BTDC in park at 1300 RPMs. I fooled around with the adjustable vacuum advance can and got the number down to 66 degrees. From what I read the can adjustment only changes the rate at which timing comes in, it doesn't limit the amount of timing from vacuum advance. You either have to swap vacuum cans or weld up the slot on the can.
Click to expand...
 
Yeah, what Rusty said. If you really saw that much advance at idle, then your hose is hooked up wrong. To measure the vacuum timing, I usually apply a vacuum to the hose at idle and measure the increase from initial. And yes the screw in the can just changes the rate. If you want more/less you will likely need a different can as they arent all modifiable(is that a word).
I have run my 360, on purpose, at well over 200*F for most of its 14 years.
 
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