1. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    Has anyone else had issues with head bolts backing off? As in the threads keep pulling out of the cylinders? Seems if a bolt hole was fine. A few 1000k's later, they will be stripped.

    I've kinda solved the problem with the next size up SAE hardware-with a crap load of washers(all I could get locally).

    Maybe the meal of my old cylinders wasn't the best casting?
  2. mati0921

    mati0921 Loyal Comrade

    Don't ever tighten more than 45 nm. it seems like not much, but i have stripped threads at 50 nm...
    check them again after a test run or it will blow gaskets in short time... i have blown them in as little as 2000 km once, because i was too lazy to take it apart to re tighten them. :)

    I saved one of the thrads by getting a longer stud and threading it all the way to the bottom of the hole. :)
  3. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    My guess is numerous folks through the years torqued them way pass 45nm. Other than re drilling/ tapping them. Your fix is the easiest, use longer bolts.. Should've done this last year before drilling 2 out for larger stuff. Our hardware store now has these longer ones in. Metric bolts, in person- are a bit of a dark art here state side.... Even the tool selection too. Most common wrench sets skip 9,11,16,18mm. Socket sets don't....:rolleyes:
  4. RogerDerSchrauber

    RogerDerSchrauber Premium Member Forum Donor

    Generally anytime you undo the cylinder head bolts, you have to retighten them (always with a torque wrench to the right specs) again after 200 km. In your case, having had many hands go through your Trabi’s motor over the years, the threads are probably pretty tired...
  5. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    Had the car out , shortly after my last message. Made the usual rounds, and on the way back- Herr head gasket busted. Those pesky wittle bolts came loose. She limped home, and made it 3/4 up the driveway. Had to get the snow plow truck out to yank it all the way. Serves me right for not dealing with this last year(before it went back on the road). :D

    Today I drilled, and tapped ALL of the cylinder holes to 7/16-14 SAE bolts. The drill basically fell through the threads, so yes they were shot. I'm back on the factory style of head gasket(just aluminum). The heads were a lil warped. With a piece of window glass, and 400 grit sandpaper- this was quickly solved. To make things more difficult, the only 7/16 bit I had to open up the head holes uses a larger chuck size. Never had anything to fit it. Mr. Drill bit met the lathe, and "Presto" the bit fits.

    Anyway, it sounds perky now. Had to lower the idle too. That thinner gasket raised the compression ratio! :cool:
  6. mbeamish

    mbeamish Loyal Comrade

    a better repair would have to make a stepped stud and not widened the head holes
  7. A Spooky Ghost

    A Spooky Ghost Loyal Comrade

    Very true, never thought about it. It would have been a measure, and order from a random online bolt place. Now thinking about it, I could have cut the bolt heads off, and turned the bolt shoulders down, then cut some new threads with a tap/die.... :eek:

    I do have another 4 heads, so I'll do it better next time.

    To be fair, the holes were barley widened up. Not really even noticeable...o_O
    Last edited: Apr 22, 2019

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