Is this the right rod for a C rotor hemi??

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Scotttrod, Apr 20, 2014.

  1. Scotttrod

    Scotttrod Member

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    New Bryant crank, new rods purchased from a friend. 4.310 bore, 4.5 stroke, fuel heads, C rotor at 1.88 over.
    rev limiter at 9900.


    Bradco 2 speed with 4.29 rear, 2,900 lb door car.

    First run of the season and window the block and kill rod 3 and 4. When looking at the crank from the outside of the block the crank looks ok.

    I have built this car literally from 300 foot of chromoly from the ground up and am not getting results. Should I just throw the motor in the trash?

    My ultimate goal would be to do 3.99 anything. I don't need to set any world's records but this hemi thing is getting old.

    Before the motor came apart, ran 1.13 60, (can put more power to it, the track was really good, not usual), 2.90 330, then bang......

    Don't need any hugs, maybe just some advice, almost everything I now run I purchased off this site from other racers,
     
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    Last edited: Apr 22, 2014
  2. jody stroud

    jody stroud ZOMBIE Top Dragster

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    Number one. Where are you from? Number two. Did you have anyone set your fuel system up for you to get you a base line tune up? Number three. What pump are you running and what are the fuel system details? Assuming it was assembled correctly it could be ignition,fuel or combo. What is the compression ratio? Plus on a first pass on a totally new deal, doing on your own, you should make a few sixty foot hits looking at the plugs and bearings after the runs. Then run it about halfway to the 330 and do the same. Do the same thing to about 450 to 500 ft and finally run the whole 660. It will take a few weekends to do like this but doing it on your own it's the only way that you will be able to sneak up on it. Run these thing lean or with to much compression or timing and bad things happen fast. Find and read Mike Canters article on how to read spark plugs. Also, I may be wrong but 4 1/2 in stroke is a lot for a newbie to this type of racing combo. 4 in stroke or less would be a lot easier on parts I would think. In other words....... For anyone on here to help you we need details, details and details. My best advice is to get someone who knows these motors to help you assemble the long block and send the fuel system to a professional. You don't need a fancy fuel management system but a basic system will help.
     
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  3. Scotttrod

    Scotttrod Member

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    Live in Southern Indiana.
    Yes, system flowed, Enderle 1380 20.9 gallon pump, 4 jets (.079 and .082) top. 8 port 66-80 with cylinder 6 heavy. .045 leanout for the first 1/2 second. 10.87 compression. .095 main jet and .075 pump loop. 32 total timing with 15 out for the first .5 second then ramped in with the power grid by 2 seconds (190cc chamber fuel heads). I was working this combo last year except for the crank (on teardown the old 4.25 crank had serious crack). The plugs all looked good after the run (explosion) about 2/3rd of the cad burned on ring of plug. 1.88 over

    Let me know if I left anything out, thanks
     
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  4. jay70cuda

    jay70cuda Member

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    Does that thing have a 44 mag. That's a ton of timing. I've seen 28 the most with a 44 mag . Is the mag phased ? I did that to a set of rods after finding out the mag wasn't phased to the cap properly. For rods to just fall out like that it had to be wicked lean and detonating a ton. Fowler makes a good rod.
     
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  5. jody stroud

    jody stroud ZOMBIE Top Dragster

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    How did the rod bearings look after the run ?
     
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  6. Scotttrod

    Scotttrod Member

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    44 Mag

    Yes, 44 mag.

    I am running off a trigger, set TDC with dial to make sure it is perfect. I did start it once off the mag, not phased well at all, retarded.

    32 is the number I got from several here at ITA running old Veney Fuel heads. I know the small chamber heads run less timing, there are lots of threads on this. Let me know what you think.
     
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  7. Scotttrod

    Scotttrod Member

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    I will be looking tomorrow, lots of family and friend stuff today.
     
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  8. Dale Finch

    Dale Finch New Member

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    Jody is asking great questions. The question about the fuel system is critical. Was the system flowed by a professional? To me thats a lot of timing and the compression is high. If it was lean because of the normally open, lean period and then add timing and lots of compression....detonation is not far away. Do you have a data recorder on the car? When did the rpm roll over? that is the rpm graph when it turns right...on the run.
    What do the bearings look like? Do you know how to measure them to see if they have been squished. When you took it apart, had it loosened up any header or intake manifold fasteners? that indicates detonation. What are the color of the valves? lots of indicators. Maybe you should post some pictures or the components and or the computer graph if you have that.

    Dale
     
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  9. Scotttrod

    Scotttrod Member

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    Yes, flowed by a professional. Came back safe and a little fat, have been leaning carefully.

    Need some gouge on timing, fuel head guys say 32 to 34. I will see bearings tomorrow and post pics. Power grid data log is corrupted, I am having trouble getting any real info on this pass to pass along in the data arena. I think a recepac is in my future, the grid is not user friendly.

    I will check for squish and post that info tomorrow. Will pay attention to any loose fasteners too.
     
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  10. overkill69

    overkill69 Member

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    hemi

    I think you did your homework.
    I know the car was soft last year and it looks like it still is. There are cars that can go pretty quick with full cad on the plugs. Your timing ramp was reasonable. 32 in by 2 seconds should've started moving.
    I've seen a lot of mystery blowups that were claimed to be the fuel shutoff vibrating closed downtrack. They can bang so quick the plugs don't show any heat.

    The only flaw I see, Like Jody said is I would've made some 60ft shots first. Esp. with no data logger. Maybe an oiling or clearance issue?
     
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  11. TOL

    TOL Active Member

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    When you tear it down, pay close atention whether any of the other rod bolts are loose feeling. Are you using a stretch gage on the rod bolts? I think the key is going to be to closely examine the failed rods and rod bearings, and then work backwards from there to figure out why/how things failed.
     
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  12. Will Hanna

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

    That's a lot of timing for that much compression and blower. If you have enough fuel in any combo you can get away with more timing. Was the whole system flowed or just the pump? Is that flow number at 8000 or 9000?

    Timing can wreck some shit in a hurry. If you are supposed to be able to run x timing, sometimes I like to start a new combo with x-2 or 3 and make a run. Looks happy, feed it half a degree. Hell with the grid, you can feed it a tenth of a degree a run if you wanted to nut cut.

    It could be an issue outside of the tune up. Maybe something causing fuel cavitation like an tank vent, pump going away, etc. Ignition problems can really cause some bad, bad issues. I have even been told oil leaking down the spark plug hole into the cylinder causing massive detonation and parts failure.

    Motor aside, you probably are going to need a more aggressive rear gear in a car that heavy with a two speed. the flyweight pro extreme guys are running 5.0.
     
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  13. john348

    john348 Top Alcohol

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    You changed cranks correct from 4.25 to 4.5
    how much more head gasket did you put on it
    i have my whole life only ran veney stuff !!
     
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  14. Scotttrod

    Scotttrod Member

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    System flowed and the pump number is at 4000 pump rpm.

    I can start with less timing and move it all around, all "fuel head" advice on this board has been in the 32 to 34 range, but I am game to try anything that will keep my motor together for more than 4 seconds.

    I'll go over all my fuel system and have the Enderle pump flowed again to be sure. Have had really good luck with Enderle over time.

    Comprende on the rear gear, getting there......
     
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  15. Scotttrod

    Scotttrod Member

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    Crank Change


    Yes, changed to 4.5 and a shorter rod. Went from 10 to the 10.87.

    We talked about timing in the past as I remember.....
     
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  16. Critical Mass

    Critical Mass Member

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    Scotttrod,

    Just curious but what is your piston to deck clearance?
    Joe
     
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  17. TAFC 5 81

    TAFC 5 81 Member

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    The mags today are hotter than when I raced, so the timing today is a good bit less. But as several have suggested; sounds like you are detonating some cylinders. Sometimes more stroke w/ a shorter rod can create a rod angle the engine does not like too (someone please correct me if I am wrong). I have no experience with that type of blower but will guess if the air fuel mix is not happy; bad things can happen. If you are losing fuel pressure at any point, that will hammer a motor.

    I was lucky in my early days that when we hurt something, we usually knew what caused it (including our stupidity). However, I have had some performance issues that took months to figure out why the car was a dog. Take baby steps like Will and others suggested.
     
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  18. blown375

    blown375 New Member

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    You said you set TDC with and indicator, did you bring it up both directions and split the difference ?
    4.5" stroke will have a lot of piston dwell.
     
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  19. Scotttrod

    Scotttrod Member

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    Timing

    Yes, split the difference from both sides, That is dead on.
     
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  20. Scotttrod

    Scotttrod Member

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    Motor is out, heads are off, I am going to have to own a total screw up

    Critical Mass,

    You hit on at least one huge piece........

    Heads are off and all 8 pistons have barely kissed the heads (I did playdough on valves, not the sides of the piston) I missed on ordering rods, .070 to .090 too long, I am pounding myself on the head right now, compression in the 14s and a time bomb.

    I own it, I screwed up, hope to save things and get back to trying to roll down the track, what a dumbass I am.


    Here is a video I was able to take with my phone while playing it from facebook on the computer.

    https://www.youtube.com/watch?v=2Li7VptESaI&feature=youtu.be
     
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    Last edited: Apr 21, 2014

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