How Much More Timing is needed if the "Blue Line" is 1/3 to 1/2 Down the Strap???

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Scotttrod, Nov 3, 2014.

  1. Scotttrod

    Scotttrod Member

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    Ok guys and gals,

    This might be an interesting thread......

    How much more timing is needed if the "Blue Line" is 1/3 to 1/2 down the ground strap??? I did my last run for the season and the straps were starting to show temp and the Cad was starting to burn around the ring of the plug (10 to 20%). I have been reading Mike Canter's article and as I understand things, more timing makes the motor act leaner. So, will I kill two birds with one stone advancing "X" degrees? Any Ideas? All the plugs are showing even heat, just not hot enough...........

    Veney Fuel headed 4.310 x 4.5 526 with C at 129 over.

    I can't afford to run more than about 20 runs a season (time, work schedule, and money of course) so wondering if someone can help ballpark the next tuning move.

    TIA
    Scott
     
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  2. promodracer

    promodracer Member

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    how much timing

    Leave timing alone and lean out till 90% cadmium is burned of base. Then move timing 1/2 degree at a time.
    Where is timing now Scott?
     
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  3. aj481x

    aj481x Member

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    Mike ???????????
     
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  4. Mike Canter

    Mike Canter Top Dragster

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    Both timing and fuel mixture result in the temperature in the chamber. So if you have a lot of ignition timing you need a lot of fuel and if you have it retarded then you can get away with it real lean. The problem here is that you can end up chasing your tail. That's why in my Reading Sparkplug article I recommend running the timing at a know tried and proven point then adjust the fuel mixture for the cadmium burn you want which will also move the "Blue Line" on the plugs. So to answer the question first put the timing at a known point for these Veney heads then adjust the fuel mixture.
     
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  5. Scotttrod

    Scotttrod Member

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    Pics inside

    I got some good advice from friends here to stay conservative on the timing as the car is a little heavy (2800) and the rear gears (4.29) were loading the motor. I started with 29 degrees and got the burn I described above. Most advice was 32 was safe, but to sneak up on it with the heavy weight of the car and 4.29 gears.

    Here are some pics

    http://i874.photobucket.com/albums/ab309/scottfarley/IMG_4541-Version2_zps5f746d35.jpg

    http://i874.photobucket.com/albums/ab309/scottfarley/IMG_4541_zps5cd7d8a6.jpg

    I am putting in a lower gear this winter and losing around 200 lbs.

    Would you go with 3 more degrees (32) if plugs looked like this?

    Thanks...
     
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  6. Mike Canter

    Mike Canter Top Dragster

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    Yes, I would. Then balance the cylinders so the burn is even. No reason at 32* to go greater than 50 to 60% burn.
     
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  7. Scotttrod

    Scotttrod Member

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    Thanks

    Thanks Mike, and thanks to all who have helped with timing advice. I wanted to get a few actual runs without total carnage and post up how things look before I snuck up on the sweet spot.:cool:
     
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  8. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    disclaimer

    Just a disclaimer...

    Before you go cranking on that mag or trigger and going to 32 degrees...timing will wreck more parts quicker than being lean will.

    How many people have run a C blower at 128 over with a heavy car? Compression and cam timing come into play.

    I don't care if 32 degrees is the magic number, going from 28, 29 to 32 is a big, big swing. Half a degree too much and it will beat the hell out of it. One degree over center and something is going to be on the ground.

    I would bump timing a little bit and lean it some. Use the 8973, run it at full timing for a little bit, then retard it back to 'safe.' As you prove it's safe, you can extend the time it see's full timing a little more each lap.

    Timing is like sneaking up on a rattle snake.
     
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  9. blown1969camaro

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    scott


    I have to agree with will on this

    I would make your car run as fast as you can probly low 4s consistant before I leaned on it or went over 28deg or leaned on plugs
    more timing and less fuel can only help you tweek a tune good running car with the correct trans and converter and timing graph . we ran all last year high 90s and just recently thought to start on leaning motor and timing p.s rember we have a identical set up (2680pd veney c rotor 105%)other than heads wich are similar , so you may get away with 30+ but I don't know ,

    BRING IT TO THE SNOWBIRDS I am sure mine canter will be there , and we can help u get in the correct direction , lots of good people there and damn good racing call in sick to work and come on down 4 weeks away
     
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    Last edited: Nov 6, 2014
  10. Mike Canter

    Mike Canter Top Dragster

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    Will and Cris have either of you looked at the plugs in Scott's photobucket.
     
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  11. blown1969camaro

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    plucg

    I have , and by all means you have way way more experience than me , in my opinion since he has a car capable of 3.90s and at the time he runs 4.40s he does not need to push luck with 32deg or lean on fuel sys
     
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  12. Mike Canter

    Mike Canter Top Dragster

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    Somebody correct me If I sm wrong but those big chamber heads are normally set up at 32 degrees. I also didn't say yo lean it out said to keep it at 50-60% burn on the plugs.
     
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  13. blown1969camaro

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    plugs

    yes you r correct .
     
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  14. Torment

    Torment Member

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    Lot's of sharp people above - I'll share my 2 cents.

    I run ethanol through my conventional head BBC, Whipple screw in the 20-25psi range. Food for thought... I can put a light on my engine and see 28deg, hand it to the next guy and maybe he sees 27 or 29? Parallax? Point being to me is I'm not going to split hairs over a couple degrees if I'm in the ballpark of what should be typical for the engine. I'm going to trust the plugs at that point. I've produced by and large the same performance running 25deg and 100% off the face as I have running 28deg and 75%, but no parts breakage at 25deg. I like Will's approach and I've done a variation of the same thing running lean'er' for 'x' seconds during the run then snapping the lean out solenoid shut to run out the back 'safe'. Good way to see if the engine likes it, and if it does whether the chassis or track can handle it too.

    Your plugs in the pics look fat. Timing mark isn't much short of where I run mine, and with ethanol I'd get up to/in the bend with 1deg from where you're at. Methanol you might get away with more... but fat looks to be the bigger issue in my opinion. If you do bump it 3 to your 32 I'd add some fuel as well, then go from there. Gdlk!
     
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  15. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    Plugs

    There's definitely room on the plugs, but 3-4 degrees is a huge swing.

    I have been told by several guys who have ran very fast in TAFC trim at 92 over with a veney motor that 28-29 was tops on timing.

    I'm not arguing with the number as much as I am the swing. I would rather see a guy on a budget take smaller steps than one big swing. If the magic number is 32, how much is there to gain between 29-30 and 32? Sure there might be some performance, no argument there. If 30 is the edge and you go run 32 in February Florida air, it might be ugly.

    Maybe I have just had bad experiences. In my experience damage from leaning on a motor is usually less than too much timing damage. Too lean causes detonation from hot spots - preignition. Too much timing takes a sledge hammer to it every spark. How big the hammer is depends on how far over center you are.

    I will shoot Bennie McDonald a message. He ran a C rotor Veney. Maybe he can shed some light on this.
     
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  16. z28a

    z28a Member

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    Were also running Veney heads but insted of C-screw we have a procharger at 50+ psi. 2425lb car running in the 3.9 area

    I see 129, 105 and 95% overdrive in this thread, that doesent really tell me so much, how much boost will those different overdrives make on a veney engine?

    Also wonder what cranking compression you have?

    Were at aprox 160psi cranking pressure, 50-55psi boost and havent been higher then 27 degrees timing yet..
     
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  17. blown1969camaro

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    bennie

    bennie had 2 sets of heads ,,funny thing is scott has his 1 set and I have his other , its a small world
     
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  18. Mike Canter

    Mike Canter Top Dragster

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    Will, I would be very interested in what Bennie has to say
     
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  19. belair55

    belair55 New Member

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    I ran a 2.6 valve veney in my doorslammer first with whipple blower 47% over then with psi d at 106% it would run around 4.02 to 4.06 at around
    185 to 189mph with around 27 degrees of timing car was 2780 pounds and it would do that with out burning hardly any cad of plugs they would look
    like new when they come out bob newberry told me around 28 is a good number to stick with and up to 30max if air was bad around 5500feet or more
    I would stick to around 28 and it wont beat it self up
     
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    Last edited: Nov 7, 2014
  20. big wheel

    big wheel New Member

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    26 to 28 always worked the best for my veney motors with screws.'32' well the parts people loved to give free advise. low gear lean outs always worked best to move the car. good luck .will and chris m are right.
     
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