Dart Aluminum Small Block Head Gasket

Discussion in 'Tech Questions' started by dlgerard, Feb 7, 2006.

  1. dlgerard

    dlgerard Member

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    I am having problems with head gasket sealing on our 4.155 bore Dart [Rocket] SBC block using the FelPro gasket and 70ft/#-75ft/# torque that Dart recommends.

    This is a 18:1 compression alcohol engine. The block and heads are flat and true, but several cylinders are leaking at the 12-2 o'clock position into the water jacket and valley.

    Needless to say, this is less than diserable <g>.

    Outside of the very "old school" [O-ring the heads; annealed copper gasket, and lots of sealer], what is the best 4.155 head gasket to remedy this problem?

    Thanks...
     
  2. Will Hanna

    Will Hanna Administrator

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    o-ring

    old school or new school i don't see how you're going to pull off that kind of compression without o-rings.

    what size head studs are you running? you may be able to use moly lube on the studs and crank the torque up.

    i dont think you're going to be able to put enough torque to eliminate the problem. but then again, i've never run a sbc with that much compression. anyone that i know that has that kind of compression has their block/heads oringed. i got away with 13:1 on my sbc in my bracket dragster w/o oring, but 18:1 is making some serious cylinder pressure....

    maybe someone else has the fix...but i think the 'right' fix is orings...

    the old skool aint all bad.
     
  3. Baltered5266

    Baltered5266 Member

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    Not to sure I've heard of anyone ever running that much compression using alcohol.....Always thought you wanted to stay 14.5 or under when using alcohol, but I might be wrong.
     
  4. Steve Polhill

    Steve Polhill Well-Known Member

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    Wow thats a ton of compression. I'd be o ringing that block and lowering the compression to about 15 to 1 or so. But then again I don't know your set up..
     
  5. Al Reed

    Al Reed Member

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    Hi David,
    We have had experience, and just recently as well, with similar deal.
    One of our current cars has the Dart/Buick heads, with 17:1 comp in it.
    Tin (OEM Chev) gaskets, no O-rings, blew 'em out first run. 7 out of 8 cylinders went bye bye.
    Now we have soft copper, with O-rings.
    Only way to go.
    Don't take comp out, as you'll lose a bunch of HP/torque.

    Alcohol, specifically Methanol, has a very high RON rating (octane). Thats why 'alcohol' dragsters/funny cars etc, supercharged, use it. It will cool as well.
    Use it with 17:1, no problem. Toque the heads to 75ft/lbs, use oil/moly on the threads, and use studs in the block. At 75 ft/lbs, the bolts tend to 'pull' the threads of some of the holes in the block. Use copper gaskets, and spray them and let them go off after each light spray (copper coat) for about 10 minutes, depending on temp at the time. The deck and heads have to be dead flat and free of contaminants too.
    Hope this helps.
     
  6. Steve Polhill

    Steve Polhill Well-Known Member

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    Wow Al I would have though 17:1 even on Alcohol was High.. Hmmmm Learn something new everyday..
     
  7. dlgerard

    dlgerard Member

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  8. Steve Polhill

    Steve Polhill Well-Known Member

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    Almost all new cars come with this type of multi layer steel gasket
     
  9. Adam

    Adam Guest

    Gaskets

    I´ve used both chopper gaskets and Cometic MLS (multi layer steel) with no problems on a injected motor
    where we had 16.8-1 compression.

    Swede
     
  10. dlgerard

    dlgerard Member

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    TITAN ISC Gaskets

    The ISC are not a MLS style gasket, Titans offer a new approach to the O ring and solid gasket challenge [from their ad]:

    The New ICS TITAN Features:
    Integral Combustion Seal
    Built in Coolant Sealing
    Solid Metal Construction

    Benefits of ICS TITAN:
    No Machining Required
    No Messy Sealants
    No Layers, No Leaks

    Has anyone tried these?
     
  11. RCC Copper & O-ring w/receiver groove

    Flatout sells both MLS & Copper and I can tell you, you're WAY beyond the capabilty of ANY composition gasket. Especially if you have any type of tune-up issues, a conventional gasket cannot recover from a detonation/headlift condition. An MLS is a little better, but copper with .041" SS wire w/receiver groove combo is the only way to successfully seal such a beast.

    We have a copper design that we spent a couple of years developing/reconfiguring water holes/sizes to optimize this deal and it works pretty well. (9001.3)

    You're going to have to change your mindset/build strategy to use it successfully though. Good luck!

    Mark
     
  12. IGO1320

    IGO1320 New Member

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    Gaskets

    I ran 17:1 comp w/alchy, used fel-pro head gaskets no problem.....maybe you have too much cylinder pressure too early in the power cycle (too much timing), how much timing you running, the buick head is pretty shallow in the combustion chamber correct?
     
  13. Craig Bourgeois

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    Not too much?

    You said you have 18 to 1, static I assume. But the actual cylinder pressure in any givin engine changes alot when you throw in all the variables, like r/arm ratio, camshaft centerline, lift & duration. So what is the actual cylinder pressure? Keep the timing low. The Fel-Pro 1143 is hard to beat & will work. And if you are off on your tune-up, then say good-bye. It won't hold either. Been there, done that. Keep the timing down low. If you have a Buick head, you don't have the heat problem between 3 & 5, and 4 & 6. Definetely use studs, arp moly lube, but I wouldn't go that tight. You may pull the stud past its yield strength, then it gets very weak. I personally wouldn't go past 60 with the A.R.P Moly lube and good A.R.P. studs. And did I mention to keep the timing down low? I hope this helps you.
     
  14. blown375

    blown375 New Member

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    I have to agree with Will Hana O-rings receiver groves and copper gaskets and go easy on the timing to start .Take small steps till you get a good tune up .One question that I do have is ,were the heads ported or milled to a point that would weaken the head in this area? You may want to take a look at your upper rod bearings for signs of detonation. You aren't making any more mechanical compression or cylinder pressure than a supercharged engine and the copper gasket and o-rings work just fine in those applications as long as you don't run to much timing or too lean and detonate it . As far as the fel pros go forget it ! Some people like to compare apples to oranges the fel pros may work ok in a all cast iron small block that has rigidity and tons of clamping force but forget them in an aluminum motor .

    Best of luck !
     
  15. Craig Bourgeois

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    David,
    I thought you said, Outside of the very "old school" [O-ring the heads; annealed copper gasket, and lots of sealer], what is the best 4.155 head gasket to remedy this problem?
    My answer is as I posted earlier. However, if you want the BEST way to solve your head gasket problem, then you are stuck with the "old school" way, as you stated. I hope this helps you.
     
  16. blown375

    blown375 New Member

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  17. dlgerard

    dlgerard Member

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    Sealed it Up!!

    After all of the good advice, we went old school with solid copper gaskets, Halomar, etc.

    Looks great after a number of runs, but it appears that the culprit was not compression ratio, but fuel distribution. Our new name brand alcohol carb was only pulling fuel from three barrels... Not good!

    Thanks for all of your help!
     

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