Section : General

Getting back on the road

Posted By : Neil Pannett, 31-Jan-2006, 02:00pm

• Getting back on the road

  Posted By : Steve Cureton, 31-Jan-2006, 02:36pm

  Neil, are you sure it's the head gasket that's blown? Can you actually see where the gases and fluids are getting past the gasket? What are the symptoms you're experiencing?

  • Getting back on the road

    Posted By : Neil Pannett, 31-Jan-2006, 03:19pm

    Yep - when I took the head off you can clearly see the ring around cylinder 3 is disformed.
    As for symptoms - at first there was a lot of smoke - then there was a lot (and I mean A LOT) of water coming through the exhaust. At first I just put it down to a faulty gasket, but when I was torquing up the two bolts nearest the failure point they both slipped a thread as I approached final torque level - so I figured that if the threads were worn then they may have slipped under engine pressure causing the gasket ring to bend out of shape. Ever seen this before?
    
    Neil

    • Getting back on the road

      Posted By : Steve Cureton, 31-Jan-2006, 04:45pm

      Unfortunately I haven't got to much experience of blown head gaskets, only dealt three in a lifetime but none as dramatic as yours. The ones I've repaired have never required skimming, in all cases I've changed the gasket and I've not had trouble again. The latest one I've done was about 3 months ago and was my wifes Fiat (now you've made me use bad language) and that's been fine since despite being an alloy head.
      
      Either those threads stripped big time, the gasket was faulty, the head wasn't skimmed properly (tried the edge of a steel rule?) or there's a problem with the face of the block. Have you ever had this engine running properly, ie are you confident the block face is okay?

      • Getting back on the road

        Posted By : Mark Palmer, 31-Jan-2006, 05:42pm

        Neil,
        
        You may have had a hairline crack in the gasket which allowed water to get sucked across into the respective cylinder, at quite a rate. If the exhaust valve can't get rid of the water quick enough during compression in that that single cylinder, and out of your exhaust in your case, then you rapidly get hydraulicing. This could lead to minor damage to the respective head retaining nut, but unlikely. You could test to see if you have hydraulicing again, by simply turning the engine over with the spark plug out - water should hit the roof of your garage at a tremendous rate - gives you an idea of the power of hydraulicing too!
        
        More likely is the opposite - a damaged thread could provide incorrect torque on the head as you tighten down. You might create the correct torque between the bolt and nut, but not between the head and nut, leading to a weak interface. This creates the damage to the gasket as the water crosses into cylinder. You might want to run the nut down the whole length of the bolt and off again, prior to placing the head back on, if you ever need to do this job again! That way you'll eliminate this potential problem - either that or simply replace the bolt - can sometimes be a pain!
        
        Hope this helps.
        
        Mark
        
        PS I remember once, having a minor indentation on the underside of my head, and, being quite poor at the time (still am I guess), I decided to fill it with araldite it and gently rub down the next day. The car continued to provide trouble-free motoring for a further 15k before I sold it on as a going concern! It was a Rover 414 too! Not the best bit of advice to give for a head fix, but when needs are a must and all that.....
        

        • Getting back on the road

          Posted By : Neil Pannett, 03-Feb-2006, 03:52pm

          Thanks for all the advice.
          
          I have already changed ALL of the studs and nuts (I got cross and just ordered the lot in my rage!) - but before I finished the job I moved house and I think I lost a few bits and pieces in transit (the water pump has only just turned up!) so I need to replace these before I can test the sucess of it.
          
          Fingers crossed it'll come together this summer - just to annoy the neighbours if nothing else (it's by far the loudest car I've ever owned - something to do with the silly exhaust I think!).
          
          

          • Getting back on the road

            Posted By : Colin Lindsay, 03-Feb-2006, 05:06pm

            "PS I remember once, having a minor indentation on the underside of my head, and, being quite poor at the time (still am I guess), I decided to fill it with araldite it and gently rub down the next day."
            
            I entered this thread halfway down and after a lot of head scratching - no pun intended - realised it was the cylinder head. Thought it might have been some sort of DIY plastic surgery...
            Colin