385 sbc dyno results

Discussion in 'Engine Topic' started by Aml383, Nov 16, 2021.

  1. Aml383

    Aml383 Veteran Member

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    On another note I called howards today to ask about lash .
    Specifically about how much more or less than the recommended lash could I safely run .

    Guy said 3 or maybe 4 more or less than the .016 for this cam .
    Then he added and I quote " every. 001 lash changes duration about 3 degrees .

    Now here's the thing: guy who assembled motor set lash at .016 at his shop . Why the hell he did that is another matter but lol....so I go to dyno and do nothing with the lash
    Engine gets hot and now I'm upwards of .005 too loose = 15 degrees short on duration and according to the guy at howards im .020 to .030 less on lift .

    Soooo My [email protected] .628/.590 cam turns into a
    [email protected] .606/.567 cam
    And that's best case
    Combine that with no changing of ignition timing to see what is best along with an afr that was anything but optimal = there's a fair amount of power left on the table there.

    Even given those adverse conditions the engine made
    493 hp @ 6000 and 483 torque @4500
    With the strip dominator

    473 hp @5800 and 488 torque @ 4100
    On the air gap intake running about 1.5 to 2 points too lean
     
  2. G72Zed

    G72Zed Veteran Member

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    One thing I have learned over the years is if at all possible is to work with one dyno operator/engine building shop who keeps detailed files and notes on all his testing and builds. He may, or may not share his info, but may guide you along in the right direction.

    Having a clear build plan on paper (spec sheet) and working with a machinist/builder/dyno operator to share your plans, and your testing goals often helps in avoiding costly, or unnecessary mistakes, and saves time. It's also an effort in futility to compare builds from magazines and different dyno's across the county/province/country. There was a cylinder head that made it's rounds with the EMC guys to test on their respective flow benches, do you think they all had the same results? same with dyno's.

    Trust me Aml383 when I say this, I have seen MANY DYI/very well built and assembled engines come in for testing, they rime off the goods and specs like a menu, and lay down their expectations, sometimes with bets with their buddy's.

    And then after doing the break in and regular checks, the testing begins, and you can just tell right from the first pull of the handle, if it's going to be a good day, ... some are happy, and some so gutted at the results they actually tear up....and then the conversations start, you provide some insight on what you see, then, they may agree, or become the deer in headlights, or start to contradict or argue....

    Aml383, you have a great package, top quality parts, and there is potential in there for sure, you have not tapped into it, but it's in there, you just need to let it come out....I think you did great for the first time, I hope you have a detailed build/spec sheet that came with your engine.
     
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  3. sandlapper

    sandlapper Veteran Member

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  4. Aml383

    Aml383 Veteran Member

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    I didn't build it. .
    I chose all the parts though.
    I guess you could say i actually did build it just for the fact that I picked the parts but a 40 year veteran builder/ machinist put it together for me .
    Thanks for the vote of confidence.
    Yes I agree . I think there's still a fair amount still on the bench in the barn lol
     
  5. G72Zed

    G72Zed Veteran Member

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    Ah, ok, understood. I thought you were the builder as you mentioned you also were going back and forth setting the pushrod length and changed 3 sets to get it right.

    As you remember, I said the break in and first things to do on the dyno are not "changes" but "checks" and in checking all the vitals, the lash is one of the first critical checks. The valve covers come off right before, and after initial break in, it's part of our SOP's.

    You would think the valve covers came off to change the intake, takes 2 minutes for a quick rocker wiggle and an experienced person would tell it's on the "Loose" side.

    Question, do you have, or have you been provided an assembly build sheet, here's a pic of what I use for my builds. This would give you an idea what to focus on to improve the package.


    1.jpg 2.jpg 3.jpg
     
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  6. Aml383

    Aml383 Veteran Member

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    Yes the assembler/ builder tried a few different pushrod lengths Before hitting the bulls eye .
    I however did my own work on the head swap on my truck and dialed in pushrod length/geometry.

    No I don't actually have a build sheet and in the defense of the guy who assembled it that was on me .
    I basically started by handing him a block and then giving him everything I wanted to put in the engine.

    Yeah man this guy just wanted it done.
    It was BS . dyno .
    I'm going to another guy in about 2 weeks with an outlined plan for maybe 6 to 8 pulls if I can get em in.

    Id like to fill that sheet out for myself though. It would be good info to bring to the next dyno .
    Can you email a pdf of that sheet or some other way ?

    And yes I'm gonna set the lash cold before dyno and then when the engine gets hot we'll check them .
     
  7. 1980RS

    1980RS Veteran Member

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    Put a cam with another 10° duration effective at .050 in there single pattern cam on a 108° LCA I think you need more to take advantage of those AFR's. I don't think IMO that with the good heads you have you need anymore exhaust duration over the intake side. What size headers were on the dyno? and are they the same size as the ones you will use on your car?
     
  8. G72Zed

    G72Zed Veteran Member

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    The sheets I provided, need to be filled out (1st draft) during the initial mockup and test fitting stages and then updated in the final assembly stage, all notes and specs on a new set of sheets, that's what I do. Don't think you want to dig into the bottom end to measure stuff out.

    Usually Jesel/T&D provide the fixture to set the pushrod lengths, some follow it to a T, some 1/2 way, others do it differently .

    Give me your email, Ill send you the Pdf.

    1980RS is right, I would even put less dur. & lift on the Exhaust, but it would need to be tested to know for sure.

    NB: Please don't add any of that STP oil supplement to this engine.
     
  9. Chevyforever

    Chevyforever Veteran Member

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    STP, means Stay Together Please, we used to say.
     
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  10. Aml383

    Aml383 Veteran Member

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    Yeah maybe but let's see what its gonna do with the 12 to 15 degrees I've already left behind.
    Engine was running on dyno at about a 230 duration. .it peaked hp 6000 like that.
    The cam is 243 @050 with .0016 lash.
    And that is a single pattern cam.
    I didn't want more duration because I didn't want this thing peaking hp past 64 or 6500 .
    Once I get the right lash I'm guessin ill be about 6300 peak with the SD intake If so thatll be nice. I won't need crazy deep gear in order to see this engine with its tounge hanging out at the end of 2.5

    1.75 headers on dyno . 1-5/8 headman headers layin on the floor of the garage. I can put whatever on there .
    What size you think id want?
     

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