Cam timing

Discussion in 'Tips 'n' Tricks Topic' started by Dennis Wilkie, Dec 16, 2020.

  1. Dennis Wilkie

    Dennis Wilkie Veteran Member

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    I just installed a new scat 9-10526 crankshaft, comp cams timing set CCA-2100, and a Lunati 10120101LK in a small block 350. The heads are 10088113 zz4's with 1.94/1.5 valves and comp cams CCA-981-1 valve springs. Would there be any noticeable gains or advantages to advancing the cam timing, or should I jusy go with the factory timing? The cam has 5° of advance ground into it, and the crank sprocket has 3 keys for factory 0° or to advance or retard the timing by 4°. I'm thinking the 5° from the cam might be sufficient, but i'm not familiar enough with all of this to make these kind of "executive decisions" without questions, lol. It's all going into a truck, so i'm looking for more torque on the lower end rather than mid range or top end
     

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  2. COPO

    COPO Veteran Member Lifetime Gold Member

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    If your not racing it on the track then you won’t notice any diff. Go with 0 on the crank sprocket (12:00) and the dot on the cam (6:00) at TDC on #6 comp stroke.
     
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  3. Dennis Wilkie

    Dennis Wilkie Veteran Member

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    That what I was gonna do. I just wanted to see if I could get some insight on whether i'd see any gains or losses on either end of the spectrum. I actually just finished putting the sprockets and harmonic balancer back on. I'll hopefully be breaking everything in this weekend, but i'm taking my time on everything this time around to make sure I leave as little room for error as possible with all of the new parts. The 1st time I was just hoping the crank and bearings were still good, and replaced everything around it. This time, it's all new and I know i've done everything to the best of my abilities, so i'm pretty optimistic about the outcome. It's taken about 6 months, but I think it's going to be worth it this time
     
  4. Dennis Wilkie

    Dennis Wilkie Veteran Member

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    Quick question...should my lifters be that far down at #1 tdc...and when exactly should I adjust the lash? Is it as soon as the intake comes up a little, or just after, when the lifters are at the same point? There's ALOT of conflicting information out there, and it's been awhile since i've had to do these, and I can't afford for anything to go wrong with all of these new parts again.
     

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  5. COPO

    COPO Veteran Member Lifetime Gold Member

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    Kate them using the EOIC method. Do not spin the pushrod, only move it up and down until all slack is gone then turn nut down 1/2 turn. Once I get 0 lash before turn 1/2 turn I put a dot with paint at 12:00 on the nut, the I know my 1/2 turn will place the dot at 6:00.

    Obviously if you have a hydraulic cam you won’t be using a feeler gauge but will only go as I stated 1/2 turn after you find 0 lash first.


     
    Last edited: Dec 28, 2020
  6. biker

    biker Veteran Member

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    That is a roller block with taller lifter bosses to accomodate the taller factory roller lifters. If I recall correctly, you are using a flat tappet cam.

    One of the guys here may know better, but as far as I know, you just have to make sure your pushrod length is correct for the shorter flat tappet lifters.

    You have had it running in that configuration, so there can't be anything terribly wrong.
     
  7. Dennis Wilkie

    Dennis Wilkie Veteran Member

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    I've tried the EOIC method a few times, and haven't had any more success with it than the others. But it could have had something to do with most of the valve seals being pushed up, and all of the bearings being 25+ years old. Yeah, it's a hydraulic flat tappet, but the block was made with roller provisions. I usually just go 1/4 turn after 0 lash to be on the safer side...especially after what happened last time. I did soak the lifters in Seafoam and pump it through before I soaked em in oil, so hopefully I won't have the same problem. I just had to ask because i've REALLY been taking my time and measuring every little detail with this one. I can't even begin to explain how nervous i'm gonna be when I go to turn the key for the break-in. Everything is rotating nice and smooth, and I can definitely feel the difference with a brand new crank and bearings. I've got to get it perfect this time, because I don't think I can go thru all of this a 3rd time.
     
  8. COPO

    COPO Veteran Member Lifetime Gold Member

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    So it fires right away I would also stab the distributor in either at 8* or 10* on the timing mark for cyl #1 comp stroke rather than 0* for TDC. Align the oil pump slot with #5 intake pushrod. Make a mark on the dist housing for #1 firing position from where the cap sits. When lowering the dist down the hole, rotate the rotor ccw 1-11/16” then let the teeth mesh. Once in the rotor should be pointing to the #1 position you marked and lock down the dist hold down bolt.

    If you drop your distributor in when the balancer is at 0* and TDC on #1 cyl comp stroke and line up the rotor just a bit past #1 dist post, you will have 12*-14* initial timing adjustment when the vacuum advance can hits the intake so you’ll need to restab the distributor 1 tooth or you won’t be able to get any more timing in. And if you have points the points window will be facing the rear of the intake which is hard when adjusting points.
     
    Last edited: Dec 29, 2020
  9. G72Zed

    G72Zed Veteran Member

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    Regardless, I always put a degree wheel on it to make sure the cam is correctly phased in, I have seen it being more or less advanced than what the cam card stated, even though it was setup "dot to dot", does not mean it can't be off +/-.

    On that note, if you have the right cam for the combination, your slitting hairs moving it 2* +/-, do it on EMC stuff for points, or race stuff so you know what cam is next to be cut, and start all over again.

    If it's within 1-2* of the cam card with the * wheel on it, your OK.
     
  10. Dennis Wilkie

    Dennis Wilkie Veteran Member

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    It doesn't have a vacuum advance, but i'll definitely keep it in mind when the time comes. I coated everything really good with Permatex Ultra Slick and graphite lube before I started closing it up, and i'm using Lucas 10w-30 break-in oil. Still haven't decided what brand or weight to use afterwards, but i'm not really thinking that far ahead yet
     

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