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#1
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Timing Question?
I know that a big block mopar distributor wheel or arm rotates in the counter clockwise direction.
So, if I twist the distributor in the clockwise direction, will I be advancing or retarding the engine timing? I'm guessing advancing? |
#2
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That`s right. Advancing. Twisting a dist. the way it turns delays the time it takes for the rotor to get to the next pole, thus, retards it. So, turning against rotation advances.
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#3
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Thanks!
Next question: Are the degrees I move the distributor equal to the degrees I advance or retard timing? I would guess yes? |
#4
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Since the distributor turns at half crankshaft speed, the crankshaft will rotate 720° compared to the distruibutor's 360°; therefore, each degree the distributor is rotated is 2 crankshaft degrees.
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#5
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Thanks! (We got some smart guys on this website!)
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#6
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Quote:
Yep. That`s why most folks set their dist. advance weights/springs to 12 degrees total. So, 12 times 2 equals 24. Most people like to run around 12 degrees base timing. So, 24 plus 12 equals 36 where most engines like to run total. Just gotta remember, the 12 drgrees you set in the dist. are in dist. degrees, so half of crank degrees. If you put 24 degrees in, you would have 48 degrees even with the balancer timing at 0. So, if you put 12 in at the balancer one would end up with 48 plus 12 or 60 total. |
#7
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No you are wrong.
I set my timing off of the balancer. I dont know how you would set it off of the dist. Cut a hole in the side of the dist and mark out the degrees the base has, LOL no reason to do that, so I dont get how you came up with most folks. I like to run as much initial timing as I can. So I have to weld up the slots a bit and trial and error till it runs right. So if I get it down towhere it advances only 18 degrees, I will set it at 18 initial. This is 18 at the crank, no reason to ever think about the dist advance, no where to check it, no reason to either. |
#8
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Quote:
Set your timing off the balancer? What do you think total timing is? |
#9
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Quote:
The only reason one wouldn`t worry about dist. degrees is in a race situation where the dist. advance is locked out and all timing is from the balancer. Then, most folks will use a retard box for starting, or nos. But, what do I know. |
#10
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Of course I have heard of advance weights and springs, have you ever heard of the slots the weights slide in to limit mechanical advance.
Who cares about the degrees in the dist, as long as you get what you want at the crank, or balancer. Who cares about what you said, it just is useless info that will confuse 99.9% of the people that read it. Thats all Im saying, your just arguing with yourself. I dont have a spin thing for setting dists, Im also sure 99.9% of the people on here dont have one either. |
#11
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Quote:
And yes, I do know about limiting timing using weights. I`m not going to get into a pissing match over something that I don`t need help with. |
#12
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Your just telling me that people get confused when they set their advance by putting to much in when they have it on the spintron or whatever by not knowing it spins at a diff rate than the crank, but who has a spintron, and who cares is all Im saying, useless info to 99.9 of the people in this place. Actually it is confusing. It is impossible to set a stock dist at 12, and get 60, I would like to know how that is done, you would have to file the weights to clear the housing and make them come out of the groove that limts the advance.
I think it says on the firewall of my old crap that it is supposed to be set at 8 degrees, so that is 28 degrees mechanical. I dont own anything that will run on that little initial, so I weld up the slots and get maybe 18 or so initial out of it, sometimes more, depends if it is hard starting or not. I also like my timing all in at around 2500, so I put lighter springs in. I have never once said, Oh crap, it is at 60 degrees cause I added to much in the dist. LOL @ 48 degrees mechanical advance. I also dont know anyone that would open up the stock slots to get that. If your that dumb, you shouldnt be messing with this kind of stuff. |
#13
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Who said everyone is using the same distributor? Slots? Does everyone have slots?
All i`m saying is that there is a certain amount of timing to be had INSIDE the distributor [unless it is locked out] and BASE timing. When you add the two, you get TOTAL timing. If someone wants to adjust the amount of timing that the weights provide, they need to know that it is half of crank degrees. So, if they are using a stock mopar dist, a msd or a mallory, the method of adjustment will be different. |
#14
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I think I answered Bob`s origional question anyway. I`m done.
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#15
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crisser, I think your running dist and cranktiming together and getting some people confused.
I have 20* initial, 12* mechanical (this would be 6* if on a dist machine) and 15* vacuum for a light throttle total timing of 47*. All mechanical is in at 2500 rpm (showing 32* on balancer) and when vac is hooked up timing goes to 47*. |
#16
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Do you guys think that the curve in the Mopar distributor that comes on the distributor in the "P3690426 - Mopar Performance Electronic Conversion Kit" is O.K. for a mild 340, right out of the box? They say is has a "high performance advance curve".
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#17
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Yep.You can even adjust the vacuum advance.
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#18
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what kinda tranny and rear gears, etc. It may be too aggressive of a timing curve. I'd talk to a dealer like Mancini, Summit, MP, etc., also. There are many different timing curves depending on the cars engine and driveline characteristics.
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#19
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#20
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I like how he mentions everyone of his sponsors.
How can a dist make it knock, unless you advanced it way to far, not the dist fault, and being to retarded, again, not the dist fault either. |
#21
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Your vast knowledge on every possible subject makes me wonder why anybody else even bothers posting.
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#22
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727 trans, 2000 stall speed, 3.23 gears & 26" tire, 340 cu in, 268/276 .464"/.464" cam, with Edelbrock heads, 10.5:1 compression, and 650 Holley. What do you recommend?
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#23
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Quote:
I have a very aggressive curve, because i have a 3500 stall, 3.91 gears, radical cam, etc. Yours is probably going to be less aggressive, so that the timing advances slowly up to 3000 rpm or so. I think mine jumps to total advance of 36 degrees by 2200 rpm. On a heavier car, that may cause serious detonation. |
#24
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Quote:
It's often a birth defect or a genetic issue. |
#25
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Once optimum idle timing is set, the engine will knock if advance comes on too fast or if the centrifugal advance is too much. There is no comparison to a properly tuned distributor. OK, I take that back, a computer that modifies advance on demand (PCM) does a little better than a properly tuned distributor.
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#26
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I've MSDs 7 digital ignition, it goes one better, you can set the timing curve for each cylinder... now if I can just figure out how
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#27
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OK, that's one that I don't get. Why would you need a different curve on each cylinder? Someone please school me on this.
I looked up the manual for this. It is called ICT and it allows you to retard timing on an individual cylinder. It doesn't tell me why you would want to do this. Ok, I found it in a review. It kind of makes sense now. Quote:
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#28
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It's a big part of how they get so much out of these import cars, along with controling the fuel injection. Simply put if one or two cylinders are knocking you can back them down without backing all eight down. You can also program different curves for each gear, alittle less aggresive in first if your having trouble hookin up for example.
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#29
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Makes sense if you can adjust timing for each cylinder. Always something different going on in each cylinder, as sometimes indicated by plugs looking different, or different temps observed at the exit of each cylinder, and usually each cylinder will not have the same peak pressure. Also, each plug can give a different spark intensity, and each combustion chamber can have a different burn pattern, etc. Many variables, though I wouldn't think it would mean more than a few horsepower per cylinder. I did read however that one miss on a spark plug can be roughly an instantaneous loss of 50 or more hp, depending on engine size. Detonation is also supposed to cause a significant power loss, not to mention holes in your pistons.
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#30
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Cranks aren't always perfect especially in a production car. So there can be a few degrees off for each cylinder. Then their is fuel distribution, thermodynamics, cylinder flow, ETC. for each cylinder. That way you can dial in the optimum timing for each cylinder.
By the way you can do that with a plain old distributor too. You just have to grind the reluctor to move the timing advanced or retarted for that cylinder. Of course the total advance number will be the same for each cylinder but the base timing changes. |
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