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383 Stroker Timing and other headaches.

This is a discussion on 383 Stroker Timing and other headaches. within the TBI Tuning (87-95 / OBD I) ECM/PCM forums, part of the Performance category; Ok gents, been a while, thanks for the prior help. I have run into many issues in getting this motor ...

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    Registered User Spaceman's Avatar
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    383 Stroker Timing and other headaches.


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    Ok gents, been a while, thanks for the prior help. I have run into many issues in getting this motor to run. After having a rocker stud break and finding the builder (Motorcrate) did not use hardened pushrods with the guidplates (send me a message for more details if ya like), I am finally back to tuning. I solved the O2 sensor problem of the erratic swinging with my proportional gain reduction, much better now. My WBO2 hops between 14.0 and 16.0 during cruise, it used to be leaner however I had to adjust by O2 voltage up by about 100 mv. Now something just does not feel right with my spark tables and I am afraid to put in too much timing, the headers seem to get really hot the more I bump the timing up, but it runs much better. No Knocking from what I can tell. But so far this engine feels like my old 350 with 225K miles on it! Anybody willing to share a spark table that might help or take a look at mine? I also need to pass AZ emissions, anyone here live in AZ? How will my timing strategey affect my emissions?

    -Thanks.
    1994 K1500
    383 Stroker 9:1
    Roller Valvetrain,Comp Cams 480/488;206/212,LSA 112, 1.5:1 rockers
    Dart Iron Eagle 165
    350 TBI,25 psi,65 lb/hr,Edelbrock TBI intake.
    MSD 6AL and Billet Distributor
    Summit (Flowtech shortys), my y-pipe
    High Flow Cat
    TunerProRT, 0D bin
    Built 4l60E

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    Re: 383 Stroker Timing and other headaches.

    Where do you have the cam timing set at? Where do you have the base/dist ignition timing set at? And where do you have the bias/initial set at in the bin??? Pretty small heads and cam, should'nt be too hard to breath some life into it.
    Also what do you mean by no knock "as far as I can tell", are you not datalogging the knock sensor??
    Last edited by MSlewis; 07-27-2008 at 07:40 PM.

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    Registered User Spaceman's Avatar
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    Re: 383 Stroker Timing and other headaches.

    Quote Originally Posted by MSlewis
    Where do you have the cam timing set at? Where do you have the base/dist ignition timing set at? And where do you have the bias/initial set at in the bin??? Pretty small heads and cam, should'nt be too hard to breath some life into it.
    Also what do you mean by no knock "as far as I can tell", are you not datalogging the knock sensor??
    MSLewis, thanks for the reply. Distributor timing set at 0 degrees with timing wire removed. Initial spark advance 0 degrees, main spark bias at 9.8 degrees. I have not seen any knock counts on the data log, maybe too far retarded? I am just getting my feet wet on ECU tuning and taking small steps. Maybe too small, I just don't want to break something. I pulled plugs they look ok, not perfectly tan, but not white either. I degreed the cam when I installed it, straight up, matched the cam card perfectly.
    Last edited by Spaceman; 07-27-2008 at 09:46 PM.
    1994 K1500
    383 Stroker 9:1
    Roller Valvetrain,Comp Cams 480/488;206/212,LSA 112, 1.5:1 rockers
    Dart Iron Eagle 165
    350 TBI,25 psi,65 lb/hr,Edelbrock TBI intake.
    MSD 6AL and Billet Distributor
    Summit (Flowtech shortys), my y-pipe
    High Flow Cat
    TunerProRT, 0D bin
    Built 4l60E

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    Re: 383 Stroker Timing and other headaches.

    Are you running the big block injectors? And if so do you have both the injector constant and cylinder volume changed in the bin?And do you still have all the factory equipment hooked up?

    That cam in a 383 is only slightly larger than stock and should be fairly easy to tune for emmissions. Start pulling the bias out in 2-3 deg increments making sure you don't have knock counts. This will simulate actually advancing the dist timing and will give you a gauge of how far you can go without knock. My guess is you can probably pull it all out. After you get a ceiling you can backtrack from there pulling back to a safe curve. If your bin is stock it can pull 10 degrees so dont worry about burning anything up,just don't go crazy at first.

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    Kick Ass!! Red94Chev's Avatar
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    Re: 383 Stroker Timing and other headaches.

    Are you running EGR? Have you finished with fuel tuning? There are a lot of timing tables that are working simultaneously (coolant spark table, EGR spark table, main spark table, PE spark table. plus all the various biases). There is no right or wrong way, but I usually tune fuel first and then timing. I model my timing curve after the old school distributor setups with mechanical/vacuum advance. It works very well. Max advance will be ~42 degrees. The true distributor max is 45 degrees (360 degrees / 8)

    This should help: http://www.thirdgen.org/techboard/di...cs-anyone.html

    A distributor is a distributor, whether it is controlled electronically or mechanically. The same principles of old school spark tuning apply: http://www.chevyhiperformance.com/ho...438/index.html

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    Registered User getsideways's Avatar
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    Re: 383 Stroker Timing and other headaches.

    you should be able to pass az emissions with that setup if you have egr and a cat hooked up. i have a little bigger cam with similar heads and i passed in az with all levels at 50% or less of allowable's. you could probably pass without egr if tuned right. i think fast305 has used those heads on a 350 before. if i recall they like alot of timing. i have world torquers and i need alot more timing than i would have thought as well. just keep logging and getting you fuel closer before messing much with the timing. is your tbi stock bore size? i have those same injectors and i need more fuel psi than you have to feed my 350. you might need a little more fuel at some point.
    95 1/2 ton short bed, 350 .02 over,world torquer s/r heads,edelbrock 3704 manifold, comp roller 210/214 (.510,.472) 114 sep, comp pro magnum roller rockers, 2" tbi, 65lbs injectors, walbro 190 pump, ceramic coated shortie headers. msd blaster coil.

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    Registered User Spaceman's Avatar
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    Re: 383 Stroker Timing and other headaches.

    Quote Originally Posted by MSlewis
    Are you running the big block injectors? And if so do you have both the injector constant and cylinder volume changed in the bin?And do you still have all the factory equipment hooked up?

    That cam in a 383 is only slightly larger than stock and should be fairly easy to tune for emmissions. Start pulling the bias out in 2-3 deg increments making sure you don't have knock counts. This will simulate actually advancing the dist timing and will give you a gauge of how far you can go without knock. My guess is you can probably pull it all out. After you get a ceiling you can backtrack from there pulling back to a safe curve. If your bin is stock it can pull 10 degrees so dont worry about burning anything up,just don't go crazy at first.
    MS, thanks for the info. The injetors are 67 lb/hr at ~25 psi. I have adjusted the injector constant and cylinder volume also, all the emission stuff is hooked up, new egr, new cat etc. My laptop died this week so I am down for now. I think i need to read more on the timing and be sure I understand all the tables and what they are doing.
    1994 K1500
    383 Stroker 9:1
    Roller Valvetrain,Comp Cams 480/488;206/212,LSA 112, 1.5:1 rockers
    Dart Iron Eagle 165
    350 TBI,25 psi,65 lb/hr,Edelbrock TBI intake.
    MSD 6AL and Billet Distributor
    Summit (Flowtech shortys), my y-pipe
    High Flow Cat
    TunerProRT, 0D bin
    Built 4l60E

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    Registered User Spaceman's Avatar
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    Re: 383 Stroker Timing and other headaches.

    Quote Originally Posted by Red94Chev
    Are you running EGR? Have you finished with fuel tuning? There are a lot of timing tables that are working simultaneously (coolant spark table, EGR spark table, main spark table, PE spark table. plus all the various biases). There is no right or wrong way, but I usually tune fuel first and then timing. I model my timing curve after the old school distributor setups with mechanical/vacuum advance. It works very well. Max advance will be ~42 degrees. The true distributor max is 45 degrees (360 degrees / 8)

    This should help: http://www.thirdgen.org/techboard/di...cs-anyone.html

    A distributor is a distributor, whether it is controlled electronically or mechanically. The same principles of old school spark tuning apply: http://<br /> http://www.chevyhiper...438/index.html
    Red, thanks for chiming in and the good links I have some more learing to do. I am running my EGR. I have been used to a standard mechnical advance curves without vaccum advance. The thing that throws me in the spark table is not the rpm vs. advance, but the vacuum vs. advance. Are there any rules of thumb?
    1994 K1500
    383 Stroker 9:1
    Roller Valvetrain,Comp Cams 480/488;206/212,LSA 112, 1.5:1 rockers
    Dart Iron Eagle 165
    350 TBI,25 psi,65 lb/hr,Edelbrock TBI intake.
    MSD 6AL and Billet Distributor
    Summit (Flowtech shortys), my y-pipe
    High Flow Cat
    TunerProRT, 0D bin
    Built 4l60E

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    Registered User Spaceman's Avatar
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    Re: 383 Stroker Timing and other headaches.

    Quote Originally Posted by getsideways
    you should be able to pass az emissions with that setup if you have egr and a cat hooked up. i have a little bigger cam with similar heads and i passed in az with all levels at 50% or less of allowable's. you could probably pass without egr if tuned right. i think fast305 has used those heads on a 350 before. if i recall they like alot of timing. i have world torquers and i need alot more timing than i would have thought as well. just keep logging and getting you fuel closer before messing much with the timing. is your tbi stock bore size? i have those same injectors and i need more fuel psi than you have to feed my 350. you might need a little more fuel at some point.
    Sideways, thanks for the good thoughts, I didn't think this cam would be a problem for smog, thanks for the sanity check. My tags expired last month, they said if I bring in the repair reciepts when I smog there will be no penalty. I suppose they are expecting me to bring in some reciepts from a shop I do have the stock tbi, I was afraid based on some of the posts I have seen that the 454 bores may be sloppy on the low end. This is a towing motor, if it ever sees 4500 rpm it would be rare. Do you have a 383 or is it your 350 that passed az smog?
    Last edited by Spaceman; 08-03-2008 at 12:46 AM.
    1994 K1500
    383 Stroker 9:1
    Roller Valvetrain,Comp Cams 480/488;206/212,LSA 112, 1.5:1 rockers
    Dart Iron Eagle 165
    350 TBI,25 psi,65 lb/hr,Edelbrock TBI intake.
    MSD 6AL and Billet Distributor
    Summit (Flowtech shortys), my y-pipe
    High Flow Cat
    TunerProRT, 0D bin
    Built 4l60E

  10. #10
    Kick Ass!! Red94Chev's Avatar
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    Re: 383 Stroker Timing and other headaches.

    Quote Originally Posted by Spaceman
    Red, thanks for chiming in and the good links I have some more learing to do. I am running my EGR. I have been used to a standard mechnical advance curves without vaccum advance. The thing that throws me in the spark table is not the rpm vs. advance, but the vacuum vs. advance. Are there any rules of thumb?
    Yeah, I wish. Every engine combination is different. What my engine likes may not be what your engine likes. Depends on how much idle vacuum your engine is pulling helps set where your vacuum advance-like timing comes in. Same thing is true for the main spark table. EGR complicated things by adding timing and needs to be taken into account when tuning timing. Mechanical advance-like timing is the easiest to understand and the rule of thumb is "all in" by 2500-2800 RPM. Initial timing is built-in and there is no need to physically advance the distributor. Doing it in an electronically controlled distributor creates two situations: 1. adds timing to all timing values (unless you compensate for it by the initial spark bias), and 2. leads to total timing in excess of the max 42 degrees (i.e. 42 degrees from "electronic" distributor and xx degrees from distributor initial timing advance). More timing is okay for decel/cruising/part throttle situations and for some engines, it works well. I'm running 42 degrees of timing in the low MAP, mid-high RPM area of my spark table and my engine loves it.
    Last edited by Red94Chev; 08-03-2008 at 01:23 PM.

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    Registered User Spaceman's Avatar
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    Re: 383 Stroker Timing and other headaches.

    Quote Originally Posted by Red94Chev
    Yeah, I wish. Every engine combination is different. What my engine likes may not be what your engine likes. Depends on how much idle vacuum your engine is pulling helps set where your vacuum advance-like timing comes in. Same thing is true for the main spark table. EGR complicated things by adding timing and needs to be taken into account when tuning timing. Mechanical advance-like timing is the easiest to understand and the rule of thumb is "all in" by 2500-2800 RPM. Initial timing is built-in and there is no need to physically advance the distributor. Doing it in an electronically controlled distributor creates two situations: 1. adds timing to all timing values (unless you compensate for it by the initial spark bias), and 2. leads to total timing in excess of the max 42 degrees (i.e. 42 degrees from "electronic" distributor and xx degrees from distributor initial timing advance). More timing is okay for decel/cruising/part throttle situations and for some engines, it works well. I'm running 42 degrees of timing in the low MAP, mid-high RPM area of my spark table and my engine loves it.
    I am also around 41/42 total, you're all in is pretty quick but I suppose if the motor is for lower rpm in a way that makes sense, I used to use 3000-3200 as a rule. You would think by now someone would have come up with some software that you could put in the engine combination and have it spit out some fuel maps, and timing curves! I hope to be back tuning this week been doing a lot of reading on this topic over the weekend. I will keep ya......posted.
    Last edited by Spaceman; 08-03-2008 at 10:03 PM.
    1994 K1500
    383 Stroker 9:1
    Roller Valvetrain,Comp Cams 480/488;206/212,LSA 112, 1.5:1 rockers
    Dart Iron Eagle 165
    350 TBI,25 psi,65 lb/hr,Edelbrock TBI intake.
    MSD 6AL and Billet Distributor
    Summit (Flowtech shortys), my y-pipe
    High Flow Cat
    TunerProRT, 0D bin
    Built 4l60E

  12. #12
    Registered User getsideways's Avatar
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    Re: 383 Stroker Timing and other headaches.

    Quote Originally Posted by Spaceman
    Do you have a 383 or is it your 350 that passed az smog?

    its a 350
    95 1/2 ton short bed, 350 .02 over,world torquer s/r heads,edelbrock 3704 manifold, comp roller 210/214 (.510,.472) 114 sep, comp pro magnum roller rockers, 2" tbi, 65lbs injectors, walbro 190 pump, ceramic coated shortie headers. msd blaster coil.

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