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Bad Head Torquing?

Discussion in 'The Garage' started by Sundie, Feb 16, 2010.

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  1. I'm thinking this head gasket which i just pulled off my '78 standard that only had 60lbs/90lbs compression was the issue.

    To me, it looks like whomever did the engine last time didn't do the head torquing pattern properly. Thought i'd post the pic.

    Note the warping on the right.
     

    Attached Files:

  2. Oh, and one more thing - i know the main bolts are 37lbs, the rear is 7, and the rest are 11, and i have the pattern.

    I'm thinking of torquing in stages
    1 - the mains at 10
    2 - the mains at 20
    3 - torque to spec the 7 and 11's
    4 - the mains at 30
    5 - the mains at 37

    Doing this *should* eliminate squish-out of the gasket.

    Does anyone have an issue with this, or any other suggestions?
     
  3. retiredgentleman

    retiredgentleman XS650 Guru Top Contributor

    This is what I used:
    8 of the 10 mm large studs =30 ft-lbs
    4 of the 8 mm on engine top plus 2 under the plugs = 14 ft-lbs
    1 of the 6 mm at the engine back centre = 7 ft-lbs

    I also used 3bond 1104 gasket sealer around the centre camchain tunnel, and around the 4 outside studs that are exposed to oil pressure..............just a small amount required.

    Caution,37 ft-lbs is much too high.
     
  4. yamaman

    yamaman xs650 addict

    734
    25
    16
  5. grizld1

    grizld1 Grumpy old man Top Contributor

    I've never seen a fire ring distorted that way before--ugly.... Sundie, you don't want to exceed 30 ftlbs. I usually step up pressure in 5 lb. increments. To get (and keep) more stable pressure, replace the rubber covered sealing washers on the 4 outside studs with copper washers, Suzuki part #09168-10017. You might want to set the head cover on a piece of plate glass to make sure it's flat; if any top end component has been damaged by uneven/excessive torque, that'll be it. If it's warped you'll need a new head cover and matching head.
     
  6. Gordon

    Gordon XS650 Junkie

    Sundie,Griz is correct, along with RG. Too much torque can & does pull the stud's out of the top case. Never mind warping the head. The head can be machined, but only a very small amount, less than .005". Anymore will cause cam timing to be too advanced, causing even more leaness. Xs John has allot of info. on all this headwork, you might want to PM him, or any of these guy's who posted, as their knowledge is far superior to mine.
    The trick to good cylinder head gasket sealing is to re-torque the head several time's after running up to temp a few time's. First re-torque should be done after 1st.warm up, before riding. Second after 75-100 mile's.:thumbsup::D:thumbsup::bike:
     
    JAX71224 likes this.
  7. grizld1

    grizld1 Grumpy old man Top Contributor

    Right, Gordon, the head can be milled, but the head cover can't without putting pressure on the camshaft bearings. Holes for bearings are line bored (bearing bosses are drilled with head and head cover bolted together) and the components are paired. You'll seldom see the head warping without damage to the cover as well, since the cover is much less robust than the head. I don't know of any reliable method for straightening. BTW, there's more variation than .005" among different brands of replacement head gasket, and dropping the deck retards cam timing, which can actually enhance performance. Years ago, the first XS650 engine I played with performance mods on had the deck dropped .030" with cam timing unaltered--thought I'd run it first and move the sprocket later. There was a bit of a flat spot between 3000-3300 rpm, but a helluva kick up high--so much fun I left the sprocket where it was.
     
  8. xsjohn

    xsjohn 8-1 lover

    If you guys want cams moved on the chainwheel for engine compression mods get with me...........I'm good at it......all I need to know is how far you moving the head and which way.......up or down......ships right back quick............xsjohn
     
  9. Gordon

    Gordon XS650 Junkie

    Yea Griz, I got a little confused as to advance or retard, no matter. The box& all related part's would have to be refinished to work together. Not worth the time or money involved.
    You really took that much off the head? Must of had allot of cylinder pressure. Run only 100+ octane! I was hoping to defer him from thinking that a 'head shave' would take care of everything.
    That gasket he showed was very strange indeed.Almost looks like it did a walk through the cylinder, although the fire ring is still in one piece. Weird.
    Hey John, long time,bud.
     
  10. grizld1

    grizld1 Grumpy old man Top Contributor

    I took the material off the tops of the cylinders. It put the CR in the neighborhood of 9.25:1, nothing drastic; 10:1 works fine with 93 octane pump gas if you set the ignition timing correctly. With 2nd over pistons there were no interference issues, but if you drop deck height very much with 700 or 750 pistons the squish bands will have to be recut.
     
  11. angus67

    angus67 Welder's penetrate deeper!!

  12. angus, one through eight are the 25ft lb. nine through eleven are 7 ft lb and twelve through fifteen are 14ft lb?
     
  13. i have taken clinder heads from cars that are warped , bolted them to a 3\4 plate of machined flat steel and baked then in an oven at 500 degrees then let them cool natually. they were way out of specs before but afterwards they had to be machined but very little. on severe cases ive had to use shim stock . ive repaired heads that were so bad that the cams were locked up.
     
  14. Hi Lads,
    you might find this usefull.:thumbsup:

    Leslie

    [​IMG][/IMG]
     
  15. Mikeyoung1138

    Mikeyoung1138 XS650 Enthusiast

    one through eight are the 25ft lb. nine through eleven are 7 ft lb and twelve through fifteen are 14ft lb......is this right ?
     
  16. jchrisk1

    jchrisk1 XS650 Junkie

    1-8 are the 25ft. lbs. but you should go up to 30-35 for these. 9,10,12-15 are 16 lbs, and 11 is 7 lbs.
     
  17. Is it insane to think of losening the bolts to below tourque specs and bringing them back up to correct torque in sequence?
     
  18. 5twins

    5twins XS650 Guru Top Contributor

    20,192
    12,283
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    No, in fact you should do that on a head that's never been touched. The nuts and bolts can become stuck on their threads and give a false torque reading - they may read tight when they're really not. I pull the fasteners right off one at a time, clean and apply anti-seize, then torque back up to spec.
     
  19. Thanks, some buds and me are trying to become gurus ourselves! There is SOOOOOO much info out here it hard to sift through the rumor and urban legend to the accurate info. I have a haynes manual but it leave out some stuff I feel.
     
  20. so if im going to retoque my head gasket then 7ft pounds means 7ft pounds ,is that what im hearing.i cant tightin it to tight ft pds.and to redo with a new head gasket does the moter have to come off the bike?xs650 heritage speciel
     

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