Head and Cylinder Studs

Discussion in '2-Stroke Engines' started by Chookawatts, Aug 9, 2012.

  1. Chookawatts

    Chookawatts New Member

    Can anyone tell me what type off metal the head/cylinder studs are made out of? And, has anyone used stainless studs and would you or wouldn't you and for what reasons.
    And is stainless strong enough to use?
     

  2. Fabian

    Fabian Well-Known Member

    Other people have had negative experiences with standard head studs, but my experiences has been the opposite. So far i've never broken a head stud and all of my engines use the smaller 6mm studs.

    Part of the problem may be excessive torque applied to the head studs, but i can't vouch for that as i've never put torque wrench on such an engine to measure the stud nut tension.
     
  3. FelipeCobu

    FelipeCobu Member

    The studs should be made of a specific steel alloy that comes in tensile grades from 5 to 12,
    anything coupling these specifications would work. But there is no guaranty that the material and/or
    the process used at the chine factory.

    So the best procedure is change those studs for good quality hardware. I made this w/ every single
    bolt/stud in my kit, except the engine studs ('cause I can't find then here in Brazil) but mine are 8mm so
    even unknowable quality can take the stress, about the jug nuts i replaced then with genuine VW head bolt
    witch are 12 grade.
     
  4. V 35

    V 35 Member

    My solution was to buy a length of Hardened M6 Rod, some plain nuts, and some Whiz Nuts. I put plain nut near cut, so after cutting, removing nut would chase thread. I screwed in the studs, using RED loc tite and used Whiz nuts to hold head. Torque to 10 ft lbs and check torque every few rides on a new motor. So Far, so good. Scraps of M6 rod can be used for motor mounts, far better than the China junklets included in kit.
     
  5. Chookawatts

    Chookawatts New Member

    thanks for your input FelipeCobu i might just go get some VW Head nuts
     
  6. Chookawatts

    Chookawatts New Member

    Stainless Steel Head Studs

    Well I've now made and fitted the head studs and we will see how they go, I still have to go get a new gasket as the old one has a bit of a groove where the head wasn't machined properly. I used the blue loctite should be sufficient enough, as I can tighten the studs till they push through the casing if I'm not too careful. I was thinking of torquing the head to say 12lbs and then fitting another locking retainer nut, so we will see how that goes. $24 AU dollars for a meter of stainless all thread just in case anyone is interested to know. I will keep you posted.
     
  7. Chookawatts

    Chookawatts New Member

    Hi Fabian,

    when I checked my head the bolts were almost loose so I torqued them to 12lbs but was worried about them stretching due to the torque pressure
     
  8. Chookawatts

    Chookawatts New Member

    Thanks V 35,

    That's basically what I have done but with a length of stainless, I believe stainless is a pretty strong metal, I possibly should have hardened it though, but I will see how it goes for now and if not as expected I will harden the studs
     
  9. Fabian

    Fabian Well-Known Member

    If the engine is installed with a brand new head gasket, you will need to re-torque at 30 miles and then 100 miles, followed by every 500 miles, as the head gasket will compress over time.
    Other people may have found things to be different, but that's how it's worked out with my current engine which has been reliable for 5,000 miles.
     
  10. Chookawatts

    Chookawatts New Member

    Thanks Fabian,

    I've milled the head and made a copper gasket for it, fitted it with gasket goo and torqued it down to 10nm for now. I will take it for a spin and re-torque it at your recommended intervals and see how it goes.
    Anyone on here who wants a copper gasket, whatever you do dont pay $20 for one, make your own, it will cost you nothing! I rang my local sheet metal place "Bronson Sheet Metal" Ive never met this guy before and when I asked him if he had a peice of thin copper sheet about 80mmX80mm he said "yes", I said "how much" he said "come down to the factory and you can have it" (a piece of scrap enough to make a spare or two) spent an hour in the garage and its done one copper gasket, see pics below
    IMG_0698.jpg IMG_0699.jpg IMG_0700.jpg
     
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