12 Second N/A Slant 6?

Slant 6 Engines

  1. VIOLENT\6

    VIOLENT\6 12 second N/A Slant 6?

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    OK, we added lift W/more aggressive opening ramps by employing 1" lifters.

    Now, can we add more lift by going to (affordable) higher ratio rockers?

    Is there any way to modify the stock rockers?

    We don't need exotic roller rockers for 5500 RPM so a simple 1.6 or 1.7 ratio rocker would be nice.
     
  2. Charrlie_S

    Charrlie_S Well-Known Member

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    I have a head that has .125 off, and doesn't look like that. Also a head that has 39 cc chambers, that doesn't look like that.

    You can get a pretty good idea of how much the head has been milled, by measuring the thickness of the head from the deck surface to the valve cover surface. The "nominal" stock dimension is 3.600 inches.

    As for Quench, I spoke to a company at the PRI show, that can weld up the compustion chambers, and remachine them, to give quench, and/or a high swirl confiuration. They gave me an estimate of $100 per chamber. The thing to consider with modifing the chamber, is how it would effect air flow. It might help, or it could hurt. Would need to be checked on a flow bench. I was think of sending them a single cyl section of a head, to try, and work on the port flow. Never did as I could afford to do one cylinder, but not a complete head.
     
  3. VIOLENT\6

    VIOLENT\6 12 second N/A Slant 6?

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    I'm also thinking about the feasability of machinning the pads in the combustion chamber (somewhat) flat & running positive deck on the pistons.

    Running .035" quench helped my Gen III 5.7 run high cranking pressure W/aggressive ingnition timing.

    It took a 175 shot W/O any KR until the car shifted to 4th gear & lugged.

    The pre '09 5.7 is a positive deck situation W/stock pistons.
     
  4. VIOLENT\6

    VIOLENT\6 12 second N/A Slant 6?

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    OK, this 89mm KB 2.2L turbo piston has -18cc voluume.

    [​IMG]

    If a head milled .113" & has 44cc chambers W/about -.087" deck, then a positive piston/block deck of .067" that would leave .055" quench. (.035" compressed head gasket)

    Opening up the quench area to 89mm will add 1cc volume.

    So 45cc - .035" deck (difference between .087 & .055) would reduce the voluume by about 6cc. 39 + 18 = 58cc

    240 cu in /6 = 40 cu in per cylinder = 656cc per cylinder + 58cc = 714cc total cylinder/combustion chamber voluume.

    714cc/58cc = 12.3:1 CR.


    I would need to increase the combustion chamber voluume by 11cc (W/O increasing quench distance) to get down to 10.5:1. That would be hard to accomplish.

    Would .055" quench allow me to run 93 octane W/a cam that would not build chamber pressure @ lower RPM coupled W/a less aggressive spark timing curve?
     
  5. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    Good luck at finding high-lift rocker arms for a slant six. There are some 1.6:1 forged aluminum units available that are really nice, but they are expensive.... around $700.00 I think.

    I don't have that kind of money, so I attempted to modify stock ones by removing a slice of material .110"-thick from the body of the arm on the pushrod side of the fulcrum and re-welding the two pieces back together. I haven't run them yet, so I can't say if the operation was a success.

    I first took them to a heat-treating facility and got them annealed (they are case-hardened at the factory) so they could be more easily machined and welded (T.I.G.'d.)

    I did some measuring and learned that to achieve a 1.6: ratio by removing material from the rocker and pushing the two pieces back together and welding them, I'd need to take out .110" of material.

    I bought a steel 4" metal-cutter blade (about $100.00) of the correct thickness and chucked it up in a vertical mill (Bridgeport-style) and fabricated a jig to accurately hold the rocker arms for the cutting process. There is a photo of this jerry-rigged jig in the link, below.

    Once the cut was made, the two pieces were welded back together and it's back to the heat-treatment shop for a return to the original hardness, an absolutely-necessary step.

    The car is a turbocharged slant six with a 5,500-rpm redline and the cam is a mild one (219/210 @ .050"-lift with .484"-lift with stock rockers) so a lot of val spring pressure is not necessary. We run 340 outer springs with a small, pretty weak, inner for a total of 135 pounds on the seat and a little over 300 pounds at full lift. I am hoping that won't break these welded rockers.

    Here's a link for you that shows the finished product and a picture that shows where the cut was made. It's a simple process.

    http://www.forabodiesonly.com/mopar/showthread.php?t=233534


    Good luck!:blob:
     

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  6. RustyRatRod

    RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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    RAS can modify Buick straight 8 rockers to work with the slant. They can relocate the shaft bores to change the rocker ratio. I have a set of the Buick rockers that I thought about sending, but I don't think I am going to get that technical. Like I said, I just want to have fun.
     
  7. VIOLENT\6

    VIOLENT\6 12 second N/A Slant 6?

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    Changing rocker ratio isn't all that technical.

    You can get various ratios stamped rockers for a SB Chevy just about anywhere. It's a very common modification. I ran 1.6 on the intake, stock 1.5 on the exhaust in my last SBC.

    I am interested in the Buick straight 8 rocker mod.

    Do you have anymore information?
     
  8. RustyRatRod

    RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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    I talked to Gary a while back and that's what he told me. So I found a set. lol That's about all I know. I'm sure he'd be glad to tell you all about it. Give him a call. He's a super nice guy. And I know it's not rocket science. I was throwin it out there for another alternative. The Buick pieces are ductile iron, much like the adjustable small block rockers. They are usually MUCH more accurate to begin with. You'd probably pick up some HP just by having them bushed (they have a different shaft size) and installing them, much less having them changed to 1.6.
     
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    • VIOLENT\6

      VIOLENT\6 12 second N/A Slant 6?

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      I'm really interested in this. Where they the 320/272 rockers?

      Cheap easy HP.

      The ratio increase make a moderate cam into a big cam W/O the added duration & the issues that come W/it.

      Who is RAS & what is their contact information?

      About 198 rods.

      How much did you have in yours when it was all said & done?

      K1 rods are about $500 & unless there is a substantial savings going to 198 rods I would just go that route.

      Did you change the rod bolts?

      I've been researching deck heights, rod length, compression hieght, etc & I think I could build a 12.5:1 long block W/.050-.055" quench W/O doing anything exotic.

      I may have to go that way & find a way to live W/the high CR.

      This is getting interesting now.
       
    • TXDart

      TXDart Legandary Member Legendary Member

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    • RustyRatRod

      RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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      Skyooze me. Gary changed the name. It's Rocker Arms Unlimited.

      http://rockerarms.com/

      I replaced the rod bolts myself and with resizing, I have a little over 300 bucks in them, including the original purchase price.

      Live with the higher compression ratio. Yeah, that's called 8 bucks a gallon. lol
       
    • VIOLENT\6

      VIOLENT\6 12 second N/A Slant 6?

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      Well, it's not going to be a "daily driver".
       
    • TXDart

      TXDart Legandary Member Legendary Member

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      • Like Like x 1
      • VIOLENT\6

        VIOLENT\6 12 second N/A Slant 6?

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        Just got off the phone W/Garu @ RAU.

        Very nice guy to talk to.

        They will modify the rockers & supply a smaller diameter SS shaft for a complete assembly for about $340. $300 W/the customer's core.

        For the advantages of 20% better lift ratio, this is money well spent I think.

        Thats 20% more lift, .450" lift W/stock RA will be .540" W/1.6 RAR & the valves will be opening faster for better cylinder fill.

        Now, how to get the CR down under 11:1 & still maintain quench.
         
      • VIOLENT\6

        VIOLENT\6 12 second N/A Slant 6?

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        OK, Molnar part #DH7005UHB6-A $456 from Connecting Rods .net.

        I think this is the way to go.

        1.6 ratio rocker arm assembly......$340
        Molnar rods...............................$456
        KB 89mm SKB 268 pistons............$363

        Aussie intalke manifold................$565
        Aussie headers..........................$739

        Total so far.............................$2463

        I read somewhere (I think it was an FABO post) that there is a V-6 Toyota application that will have the proper ribgs & will save $$$ on bying 2 sets for a 2.2.

        Anyone have a link to that post?
         
      • RustyRatRod

        RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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        Did Gary say which bwoowack rockers? Sorry, I just couldn't remember.
         
      • VIOLENT\6

        VIOLENT\6 12 second N/A Slant 6?

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        The 272/320 big block.
         
      • RustyRatRod

        RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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        Yeah I just couldn't remember. Mine are the 320 now that you threw a familiar number out. I hate gettin old. lol I'm like you. It's a cool mod that's worth some power and worth the money to do.
         
      • vynn3

        vynn3 Well-Known Member

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        I'd confirm that the Aussie headers will work on left-hand-drive. Seems like there was some question of that when they were released a few years ago...

        Also, just to reiterate, if you're serious about this, go to slantsix.org and read, read, read. There's some great slant info here on FABO, but .org is the slant bible. That's where the hard-core slanters are.
         
      • VIOLENT\6

        VIOLENT\6 12 second N/A Slant 6?

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        Yes it's definately on the to do list.

        Stock RAR is 1.36 according to Gary.

        He says that the Buicks are "close to 1.6".

        Even at 1.5, it's a pretty healthy jump from 1.36.
         
      • VIOLENT\6

        VIOLENT\6 12 second N/A Slant 6?

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        The Aussies I referenced are for pre 67 LHD "A" body.

        [​IMG]

        As far as the Aussie intake, I have been informed that the small cross section runners are restrictive. The Clifford is supposed to make more HP.

        [​IMG]

        What people aren't taking into account is that long narrow cross section runners will build intake charge velocity. That will make more TQ in the midrange.

        A gas is a fluid just like a liquid, but a gas will change voluume (compress/expand) where a liquid can't.

        I'll give up 15 HP & 5500 RPM to gain 10HP & TQ @ 3500.

        HP makes speed, but it's TQ is what gets the car rolling & accelerating.
         
      • RustyRatRod

        RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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        I was told as early as last month that those new headers have not been confirmed on the LHD cars yet. Directly from Aussie.
         
      • VIOLENT\6

        VIOLENT\6 12 second N/A Slant 6?

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        Since they are not yet listed as available that doesn't surprise me.

        Descibed as:

        "Suit LHD to 1967 early A bodied 170"

        Besides, if they don't work I'll find something that does.

        This project isn't going to be started tomorrow anyway.

        Lots of time to research.
         
      • VIOLENT\6

        VIOLENT\6 12 second N/A Slant 6?

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