total timing is set at what rpm

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If your spring rate is in thats fine but i,d run it up a little more and if it advances more you arent setting total at 2000. Total is where it stops during acceleration at normal operation.
 
It all depends on what you want and are doing. I've found through the years that small blocks love lots of timing and they love it early. I usually get mine as close to 40 degrees by 2000 rpm as possible. Sounds like a bunch, but they really like it. Of course, with that much and in that early, premium gas is usually necessary. Also, if it's a street car, run a vacuum advance. I always use the Mopar Performance adjustable unit because the vacuum cans usually pull a little too much in. If you don't run vacuum advance on a street car, you're missing out on some bottom end performance and you'll not get the fuel mileage you could get by running one.
 
Not always and if the motor is on the edge of detonation using the vacuum advance could blow a hole in the piston. Then you really save money on gas cause your motor won't be able to burn anymore of it, ha ha ha.

It comes down to compression ratio, camshaft, gearing-weight of car or truck and the fuel you can buy which is not the same all across the us-canada-any place.

Go for 32 and carefully increase it from there. Better to have not enough timing then too much and blow a piston. Retard timing does cause a motor to run hotter so its best not to unless its pinging.
 
ok well i have that msd all in one billet dist and he was the one that set up the springs inside the dist and told me 34 deg total timing.
 
dodge freak said:
Not always and if the motor is on the edge of detonation using the vacuum advance could blow a hole in the piston.
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That's just not true. At least not with an adjustable can. That's why it's adjustable so that you can limit the amount of advance the vacuum can has because they always have too much. TOTAL timing means mechanical PLUS vacuum advance, so as long as you set total in that way, you'll not have a problem.
 
StrokerScamp said:
That's just not true. At least not with an adjustable can. That's why it's adjustable so that you can limit the amount of advance the vacuum can has because they always have too much. TOTAL timing means mechanical PLUS vacuum advance, so as long as you set total in that way, you'll not have a problem.
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Literally total timing would mean the sum of initial timing, mechanical advance, and vacuum advance, but most everybody refers to total timing as initial and mechanical only as the vacuum is removed from the equation (plugged) when setting the total timing. An example of 34* total timing would be 17* initial and another 17* mechanical. Vacuum advance could add another 17* for a total of 51*. Total timing on many vehicles with vacuum advance in the circuit can easily run in the 50`s depending on the needs of the engine. Most everybody running their cars on the strip will plug the vacuum advance since the only throttle position the car sees is wide open. I agree with Stroker Scamp on the use of the vacuum advance around town where most of your driving is below 3000 rpm. The car will have smoother throttle response and get slightly better gas mileage. Detonation can be a problem with the gas that`s available today but with moderate compression and several high gear/low rpm acceleration tests, you should be able to find a timing setting that you and the car can live with. As already mentioned both the mechanical and vacuum advances are adjustable so you can fine tune where and how much advance you add to the initial timing.
 
There is a process for properly dialing in a distributor to provide optimum power and efficiency. The ignition must ignite the mixture early enough to result in maximum cylinder pressure at approximately 20-30 degrees after TDC to obtain the most power and efficiency.

1. The initial timing for your combo must be established. Setting the timing to a total number at a rpm that has all the mechanical advance in typically winds up with to little initial timing. To little initial results in a a rough idle, difficulting seting the carb at idle and power off idle throttle reponse. The initial timing can be determined very accurately but increasing or decreasing the initial timing setting in small increments to obtain maximum manifold vacuum while maintaining the idle rpm constant. Cams with a more overlap than stock will require more initial timing. It is not unusual to wind up with 20 degrees BTDC or more of initial to obtain maximum manifold vacuum. The caveat here is there can be a point when the engine will kick back against the starter before you have reached the ideal initial setting. Your choices are to back off and be good enough or add a timing retard to the engine for starting. Get this right and you will have a crisp idle, with great reponse and you will have little difficulty adjusting the idle mixture.

2. Now you need to set the mechanical advance timing. To do this accurately you need a dyno or much trial and error on the track. But you can get close with the typcial recomendations you see posted for different engines. The efficiency of the chamber design has a large impact on the number. The small block mopar open chamber head typically produces maximum power with 34-36 degrees of timing. If you have modern closed chamber heads it will be less, magnum heads for instance produce max power in the 32-34 degree range. If you have after market heads use what the manufacturer recomends. If you have a stock distributor that was set up at the factory assuming you are using much less initial timing then you will now have to much and will have to take the distributor apart to reduce the sizze of the slots. If you have a Mopar Performance distributor or MSD, Accel, etc then this is adjustable with stops or bushings. Take the total mecahnical, say 34, subtract the initial, say 20 and you come up with 14. That is the number you want to adjust the mechanical advance to provide.

3. Now you want to set up the rate at which the timing comes in. Again this can only be accurately adjusted with adyno or track time. But just like the mechanical you can get close enough. The number you see posted varies much more widely for this parameter, anywhere from all in at 2000 rpm to all in at 3000 rpm. The stock distributor had a two step rate where some of it came in relatively early but the rest wasn't all in until high 3000's of rpm. So you will need to get it down below 3000. After market distributors either come with a selection of springs or you can purcahse a kit. If you are working with a stock distributor the simplest thing is to get the two spring kit from Mopar Performance and replace the heavier stock one with one of these springs. Don't use both of them it will have all your timing coming in a couple of hundred rpm off idle. Hear driving the car will help dial it in. If you put a load on the car (slight up hill) and accelerate, if the car pings then goes away as the rpm increases then the rate is too fast and heavier springs are needed. You can try lighter springs if it isn't but if you are in the 2000-3000 range you are close.

4. Now is the time to set up the vacuum advance. The vacuum advance only operates at part throttle cruise conditions when manifold vacuum is high. At WOT the manifold vacuum is so low it doesn't add any timing. Because the cylinders are not filling completely with mixture it takes more timing to ensure it completely burns and you need to add timing and this is what the vacuum advance does. When working properly what it will do is require you to use less throttle to maintain the same speed making the car more effiecient and increase gas mileage. Start by measuring the manifold vacuum as you drive the car on level road in the 30-40 mph range. Then use a hand vacuum pump to set up the vacuum advance to be fully in at this vacuum reading (you could do this by trial an error but it will be time consumming). No drive the car and if you get any signs of detonation on throttle tip in or constant rpm that goes away the seconf you open the throttle you have too much vacuum advance. Start backing it off until it stops. Or, if you don't have it come in sooner until you do get detonation then back off.

Once you have the distributor all set up it's time to move to carb tuning. NOTE: you may need to go back and adjust your timing settings if you develop detonation.
 
Mine comes in 35 at 2500 rpm. To get that though my base timing is 18. Seems high but car does not ping. Should I bring lower to about 10-12 base and recurve to 35 @ 2500 rpm. stock 360, 904
 
1wild&crazyguy said:
you sound more like you're suspicious and don't trust the builder.

why not ask him why he's doing it and see what he says.
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Yup... If you don't know, ask why over and over until he tells you. Dave's (DGC333) also got a good process there if you want to work on it yourself some too.
 
Longgone said:
Literally total timing would mean the sum of initial timing, mechanical advance, and vacuum advance, but most everybody refers to total timing as initial and mechanical only as the vacuum is removed from the equation (plugged) when setting the total timing. An example of 34* total timing would be 17* initial and another 17* mechanical. Vacuum advance could add another 17* for a total of 51*. Total timing on many vehicles with vacuum advance in the circuit can easily run in the 50`s depending on the needs of the engine. Most everybody running their cars on the strip will plug the vacuum advance since the only throttle position the car sees is wide open. I agree with Stroker Scamp on the use of the vacuum advance around town where most of your driving is below 3000 rpm. The car will have smoother throttle response and get slightly better gas mileage. Detonation can be a problem with the gas that`s available today but with moderate compression and several high gear/low rpm acceleration tests, you should be able to find a timing setting that you and the car can live with. As already mentioned both the mechanical and vacuum advances are adjustable so you can fine tune where and how much advance you add to the initial timing.
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LOL. You're preachin to the CHOIR and don't even know it. Let me break it down for you. "I" don't worry about initial timing. It's irrelevent. All you need is enough for the engine to run so you can set the rest. I remove the vacuum hose from the can and run an extension to a vacuum gauge taped to the windshield. I note my vacuum reading in high gear at 2000 RPM while just cruising. It is at this point that the timing should be all in.....at least for "me". Then, I go back to the driveway, disconnect the hose and reconnect to the vacuum can and take a timing reading at whatever reading I got on the vacuum gauge. It will of course be at a higher rpm, since we are now static in the driveway and not under load. This is why you don't use a tach to set timing. I let the mechanical advance in the distributor alone. I simply limit the vacuum can to whatever I want the total timing to be at at whatever given vacuum reading I got on the test drive. This is actually the most accurate way. While it's true you can play around with the mechanical advance some, I have found through the years, very little performance advantage in doing so on a street car. Of course, if using only a mechanical advance distributor, you must address adjustment, since that is your only means of advance. I have only on one or two occasions in better than thirty years found it necessary to adjust mechanical advance in a distributor using a vacuum can. I've read all the books. I've spent time at the tracks. I've set it to the inth degree as described above, but this method has worked best for me. It will on any street car, too. It's a good shortcut that will get you so close if not right on top of the technical guy's timing, it ain't funny.
 
He's Greg at SS/AFX out of town right now. i dont doubt him, i was just curious if there was a general rule of thumb for timing on these motors.
 
StrokerScamp said:
LOL. You're preachin to the CHOIR and don't even know it. Let me break it down for you. "I" don't worry about initial timing. It's irrelevent. All you need is enough for the engine to run so you can set the rest. I remove the vacuum hose from the can and run an extension to a vacuum gauge taped to the windshield. I note my vacuum reading in high gear at 2000 RPM while just cruising. It is at this point that the timing should be all in.....at least for "me". Then, I go back to the driveway, disconnect the hose and reconnect to the vacuum can and take a timing reading at whatever reading I got on the vacuum gauge. It will of course be at a higher rpm, since we are now static in the driveway and not under load. This is why you don't use a tach to set timing. I let the mechanical advance in the distributor alone. I simply limit the vacuum can to whatever I want the total timing to be at at whatever given vacuum reading I got on the test drive. This is actually the most accurate way. While it's true you can play around with the mechanical advance some, I have found through the years, very little performance advantage in doing so on a street car. Of course, if using only a mechanical advance distributor, you must address adjustment, since that is your only means of advance. I have only on one or two occasions in better than thirty years found it necessary to adjust mechanical advance in a distributor using a vacuum can. I've read all the books. I've spent time at the tracks. I've set it to the inth degree as described above, but this method has worked best for me. It will on any street car, too. It's a good shortcut that will get you so close if not right on top of the technical guy's timing, it ain't funny.
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Your post is confusing and could tend to mislead folks trying to set up a distributor on a significantly modified engine.

The mechanical advance is rpm dependent and vacuum advance is load dependent. Together they do a pretty good job of providing the timing the engine needs over it's operating range. For full out performance the mechanical advance is the only thing that matters because in these situations the throttle is open and there is little or no manifold vacuum and the vacuum advance does not work.

If your engine is close to stock the way the distributor is set up from the factory is close and what you describe is OK. But if significant modifications have been made then you need to take structured approach to dialing it in; initial, mechanical, rate and vacuum will all need to be addressed. The process I described in my post will minimize the interaction between these and minimize the back and forth fiddling.

To say initial timing is irrelevant is simply wrong. If you don't care about a stinky rich idle that you can't adjust out, or having to set the idle in park of your auto car at ~1200 rpm to keep it idling in drive at 700, or you don't care about sluggish response off idle then by all means ignore initial timing. Of course if your engine is basically stock setting the initial to the factory number or reving the engine until the mechanical stops and set the total timing you are close. But if you have made significant changes to the engine especially in cam duration/overlap then it just won't run as well as it can if you don't.

If you have significantly changed the initial timing then you need to address the total mechanical timing or in most cases you will have more timing than the engine needs to make max power and can also create detonation problems. Also, if you have replaced your old school heads with modern heads with efficient chamber designs you will need to address total mechanical since in these heads typically require less than the old school heads.

The rate at which the timing comes in is a place where the factory made significant compromises to address the bad driving habits of the people that purchased these cars. They gave up performance to protect the engine from detonation folks using the wrong fuel or lugging the engine or general poor care. Speeding up the rate with lighter springs even on a stock engine will give you noticeable improvements in the performance.

After all these items have been addresses you can adjust the vacuum advance.
 
67DARTGTCONV said:
Mine comes in 35 at 2500 rpm. To get that though my base timing is 18. Seems high but car does not ping. Should I bring lower to about 10-12 base and recurve to 35 @ 2500 rpm. stock 360, 904
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Mine on my 408 with small cam is total 34 degrees at 2500 rpm...if yours does not ping or detonate and does not kick back on starter..you are fine. More initial gives better low end and mid range torque. In the past I have seen guys set the timing initial at 10 or 12 degrees thinking all is okay...however when the engine was at high rpm total timing was over 40 degrees because of worn out dist and springs. That much timing can cause engine damage. Just my experience.
 
dgc333 said:
Your post is confusing and could tend to mislead folks trying to set up a distributor on a significantly modified engine.

The mechanical advance is rpm dependent and vacuum advance is load dependent. Together they do a pretty good job of providing the timing the engine needs over it's operating range. For full out performance the mechanical advance is the only thing that matters because in these situations the throttle is open and there is little or no manifold vacuum and the vacuum advance does not work.

If your engine is close to stock the way the distributor is set up from the factory is close and what you describe is OK. But if significant modifications have been made then you need to take structured approach to dialing it in; initial, mechanical, rate and vacuum will all need to be addressed. The process I described in my post will minimize the interaction between these and minimize the back and forth fiddling.

To say initial timing is irrelevant is simply wrong. If you don't care about a stinky rich idle that you can't adjust out, or having to set the idle in park of your auto car at ~1200 rpm to keep it idling in drive at 700, or you don't care about sluggish response off idle then by all means ignore initial timing. Of course if your engine is basically stock setting the initial to the factory number or reving the engine until the mechanical stops and set the total timing you are close. But if you have made significant changes to the engine especially in cam duration/overlap then it just won't run as well as it can if you don't.

If you have significantly changed the initial timing then you need to address the total mechanical timing or in most cases you will have more timing than the engine needs to make max power and can also create detonation problems. Also, if you have replaced your old school heads with modern heads with efficient chamber designs you will need to address total mechanical since in these heads typically require less than the old school heads.

The rate at which the timing comes in is a place where the factory made significant compromises to address the bad driving habits of the people that purchased these cars. They gave up performance to protect the engine from detonation folks using the wrong fuel or lugging the engine or general poor care. Speeding up the rate with lighter springs even on a stock engine will give you noticeable improvements in the performance.

After all these items have been addresses you can adjust the vacuum advance.
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No, it's not wrong for ME. It's different. Everybody won't do the same thing the same way. Just because my way might be different from yours doesn't mean it does not work. I've done it by the book more years than I can count. I came up with my own short cut that works very well. I'm still in agreement with everything you've posted on the subject, it's just that we go different routes to acheive the same result. My way may be confusing to some but it's as clear a crystal to me.
 
Im lost #-oI know how to set stock timing on engines,but I am lost on timing the modified 360 on my Duster.And non of this advancing at 30 deg at 2000 rpms is really making sense.I need to find a video on how to do this.lol
 
I you go back and read my first post that is the process by which you dial in the timing. If you get a book or a video it will be that process. Anything else and you are only addressing part of the equation to obtain the ideal timing curve for your engine.
 
1BadDodge71 said:
Im lost #-oI know how to set stock timing on engines,but I am lost on timing the modified 360 on my Duster.And non of this advancing at 30 deg at 2000 rpms is really making sense.I need to find a video on how to do this.lol
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You need an adjustable timing light..to set it as i do bring the motor up to 2500 rpms set the dial on 36,shoot the timing and turn the distributor til the timing mark lines up with 0, lock the dist. and your good to go been setting my timing like this for years,on my 416 and 360 no ping hesitation or any other issues of coarse i'm running an msd system,so no vacuum advance to deal with...34 degrees may be just fine for your motor run it and find out...
 
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