Idiots guide to timing
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From: Michigan
Car: 83 Camaro
Engine: 350
Transmission: th350
Idiots guide to timing
can somebody direct me to or basically tell me exactly how to time in a non CC carburated 350. I know on some motors you have to unplug stuff and such to set base timing. and what about keeping it at 3000 rpm and such?how exactly do you tell how many degrees of timing you are running. Base is 36 right?
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From: Toledo, OH
Car: 1992 Firebird
Engine: forged 357
Transmission: 700r4, 2200-2400 stall, vette servo
Axle/Gears: stock pegleg 2.73 drum (temp)
first, get a timing light.
second, I don't know how much easier it could be... pull the EST(?) wire, the tan one, and turn the distributor until your car doesn't like it anymore.
second, I don't know how much easier it could be... pull the EST(?) wire, the tan one, and turn the distributor until your car doesn't like it anymore.
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
He said non-CCC, so there's no EST wire.
To measure the initial timing, disconnect and plug the vacuum advance hose and connect your timing light. Let the engine warm up and idle normally and aim the light at the timing comb on the balancer. The timing light flashes when the #1 cylinder fires, and you look at where the balancer mark is "frozen" when it flashes. You can see up to 12 degrees of advance or so on the stock timing comb.
If you haven't modified the timing curve, there's not much more you'd be interested in than the initial timing.
To measure the initial timing, disconnect and plug the vacuum advance hose and connect your timing light. Let the engine warm up and idle normally and aim the light at the timing comb on the balancer. The timing light flashes when the #1 cylinder fires, and you look at where the balancer mark is "frozen" when it flashes. You can see up to 12 degrees of advance or so on the stock timing comb.
If you haven't modified the timing curve, there's not much more you'd be interested in than the initial timing.
Originally posted by idiot
can somebody direct me to or basically tell me exactly how to time in a non CC carburated 350.
can somebody direct me to or basically tell me exactly how to time in a non CC carburated 350.
Originally posted by Token
first, get a timing light.
second, I don't know how much easier it could be... pull the EST(?) wire, the tan one, and turn the distributor until your car doesn't like it anymore.
first, get a timing light.
second, I don't know how much easier it could be... pull the EST(?) wire, the tan one, and turn the distributor until your car doesn't like it anymore.
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Joined: May 2003
Posts: 1,995
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From: Toledo, OH
Car: 1992 Firebird
Engine: forged 357
Transmission: 700r4, 2200-2400 stall, vette servo
Axle/Gears: stock pegleg 2.73 drum (temp)
Originally posted by kevinc
You gotta love watching one idiot try to talk down to another idiot...
You gotta love watching one idiot try to talk down to another idiot...
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
Crane kit. 'nuff said.
Crane adjustable vacuum advance kit, use it with instructions on the main page of TGO (How to tune for performance on non CC HEI ignition...)
And get an MSD timing tape, $4 or so.
If you need a little help on timing, here is a picture I've stolen from another website, an invaluable picture:
Crane adjustable vacuum advance kit, use it with instructions on the main page of TGO (How to tune for performance on non CC HEI ignition...)
And get an MSD timing tape, $4 or so.
If you need a little help on timing, here is a picture I've stolen from another website, an invaluable picture:
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From: Michigan
Car: 83 Camaro
Engine: 350
Transmission: th350
alright so jsut keep it at idle and plug the vaccum advance going to the dist? now what about the other timing figures, do those come when you modify the curves from the distributer weights adn springs? how do they work exactly
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Unless you've modified the distributor with something like the Crane kit that Sonix mentioned, there's nothing you can do about the other values, so you might as well ignore them.
The actual advance you have at any time is called total advance, or total timing. It's a combination of the initial timing, plus the advance you get from the centrifugal advance mechanism, plus the advance from the vacuum advance mechanism.
The centrifugal advance mechanism uses a pair of weights the fly out against the tension of a couple of springs, which advances the timing as engine speed increases. By varying the weight and shape of the weights, and the tension of the springs, you can change how much centrifugal advance there is, and how soon it comes in. Usually there should be able 34 degrees or so of centrifugal advance plus initial advance by around 2800 RPM or so. That's why some people set their timing with the engine spinning at 3000 RPM.
Vacuum advance increases when the load on the engine is low at part throttle (since manifold vacuum is somewhat related to engine load) and disappears completely at WOT. The amount and rate of vacuum advance needed varies depending on the car, and so it's usually set experimentally.
The actual advance you have at any time is called total advance, or total timing. It's a combination of the initial timing, plus the advance you get from the centrifugal advance mechanism, plus the advance from the vacuum advance mechanism.
The centrifugal advance mechanism uses a pair of weights the fly out against the tension of a couple of springs, which advances the timing as engine speed increases. By varying the weight and shape of the weights, and the tension of the springs, you can change how much centrifugal advance there is, and how soon it comes in. Usually there should be able 34 degrees or so of centrifugal advance plus initial advance by around 2800 RPM or so. That's why some people set their timing with the engine spinning at 3000 RPM.
Vacuum advance increases when the load on the engine is low at part throttle (since manifold vacuum is somewhat related to engine load) and disappears completely at WOT. The amount and rate of vacuum advance needed varies depending on the car, and so it's usually set experimentally.
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
Aperion: Out of curiosity, when setting total timing, should I put on my springs of desired strength, then get a buddy to hold it at 3k rpm say, and set timing to 34-ish say.. Is that with vacuum disconnected ?
Right now I'm using manifold vacuum and it's working awesome, finally figured out I need to turn out my mixture screws
2 turns just wasn't cutting it...
Beenyboop or whatever, check out :
https://www.thirdgen.org/newdesign/tech/hei.shtml
That'll get you started. The "recurving" deal is all explained in there, and remember: the crane kit (or whatever brand you prefer, crane is preferred by some here for a reason tho...)
is about $30, pretty cheap considering it's benefits... -J
Right now I'm using manifold vacuum and it's working awesome, finally figured out I need to turn out my mixture screws
2 turns just wasn't cutting it...Beenyboop or whatever, check out :
https://www.thirdgen.org/newdesign/tech/hei.shtml
That'll get you started. The "recurving" deal is all explained in there, and remember: the crane kit (or whatever brand you prefer, crane is preferred by some here for a reason tho...)
is about $30, pretty cheap considering it's benefits... -J
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
That's pretty much it. Take it for a few WOT passes and listen for detonation afterwards, you might need to adjust it a few degrees in either direction.
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
yea, that's about what I thought..
I just figured with about 15* centrifigual (sp?), i'd end up with loads of initial timing... I was thinking about grinding out my stops in the HEI to allow more centrifigual advance...
And I hopefully will not have too much timing after vacuum kicks in... I can just figure out how to lock out more if that's the case.
I just figured with about 15* centrifigual (sp?), i'd end up with loads of initial timing... I was thinking about grinding out my stops in the HEI to allow more centrifigual advance...
And I hopefully will not have too much timing after vacuum kicks in... I can just figure out how to lock out more if that's the case.
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
should yes.
but I put about 10* initial, then revved it and made 25* and no more. With no vacuum...
err, wait, my crane setup (heavy and medium spring), started at 800RPM... I think I was at 900 or so.... maybe i'll put in two heavy and reset the base...
Anyway, bennyboopy, is this helping you
as a side note, with stock HEI, do we have much choice with weights? Or is it just spring adjustments?
but I put about 10* initial, then revved it and made 25* and no more. With no vacuum...
err, wait, my crane setup (heavy and medium spring), started at 800RPM... I think I was at 900 or so.... maybe i'll put in two heavy and reset the base...
Anyway, bennyboopy, is this helping you
as a side note, with stock HEI, do we have much choice with weights? Or is it just spring adjustments?
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From: Michigan
Car: 83 Camaro
Engine: 350
Transmission: th350
yes very much so...i actually knew most of the basics before but there was jsut a few little things i needed some clearification on...which was accomplished already
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Originally posted by Sonix
as a side note, with stock HEI, do we have much choice with weights? Or is it just spring adjustments?
as a side note, with stock HEI, do we have much choice with weights? Or is it just spring adjustments?
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