Section : Engine

Engine, cooling system, fuel system, exhaust system.

Light Fracture in top of engine block

Posted By : Mark Wessendorff, 09-Apr-2005, 07:48pm

Hi, I am in the process of changing my head gasket on my MK1 GT6 and have run into a problem when screwing down the cylinder head studs. I torqued down the studs using the double nut method and on one stud caused the surrounding area to start fracturing as shown in the attached picture. The picture has beem magnified. There is no sign of cracking down the inside of the stud hole or the side of the pushrod wall. The 3 cracks run outwards away from the pistons and collant channels. Where you see the 1mm scale ruler at the top of the picture is the section where the pushrods are installed. I am sure I was worng to torque down the studs before putting the head back on and cried blue murder when I realised the fracturing that this caused!! I spoke to a couple of dealers who were open this morning (Jigsaw and Quiller) and they both advised that I should be using new studs and nuts anyway as the old ones I was using can only be correctly torqued once. I have therefore stopped installing the gasket and ordered in a complete set of new stud and nuts (&163;60ish quid!) and plan to complete the install later next week when they arrive. Please can I have some advice as to whether this fracture will give me any problems and will I be OK to as it is or will I need to renew the engine block (god forbid!) or get it skimmed, fracture welded / soldered or just put in a small amount of liquid stud lock when I install the new stud (as suggested by Jigsaw).

How tight should I tighten down the studs before putting the head back on? Really P***ed off and desperate for help/advice on this.

Followups :

Light Fracture in top of engine block

Posted By : Mark Wessendorff, 09-Apr-2005, 08:05pm

Sorry the picture did not attach in my first post. Here it is..

Any help most appreciated

Mark

Light Fracture in top of engine block
- Light Fracture in top of engine block
  
  Posted By : Colin Wake, 09-Apr-2005, 08:42pm
  
  I wonder if there was a bit of liquid or similar at the bottom of the hole as hydralic pressure can cause that sort of damage.
  
  Colin
  - Light Fracture in top of engine block
    
    Posted By : Steve Smith, 09-Apr-2005, 11:06pm
    
    Mark,
    The first thing I observe is that you should have a 1-3 thread chamfer on the top of the stud bores to relieve the likelihood of pulling the top threads proud of the block. As you see no evidence of a crack in the threads I'd advocate starting with that and see where the cracks go.
    Your risk here is having the cracks progress after the engine is on the road and relaxing the clamping force on that section of the head with a possible blown head gasket. Worst case would be a section of block breaking loose and falling into a lifter cup chewing up the pushrod. That said, the MK 1 with the 3/8"? studs isn't providing all that much clamping force to start with. I'd say take a cut with a countersink and then have your local auto machinist give it a chemical crack check and determine how extensive the cracking is. On a street car you may well be fine.
    
    As others have indicated, the studs should only go in finger tight.
    
    Hope that helps and Good Luck!
    
    Steve in Las Vegas
    - Light Fracture in top of engine block
      
      Posted By : Mark Wessendorff, 10-Apr-2005, 09:51am
      
      Thank you all for your help on this. I think I will try the cement paste and only torque the nuts down to 46lbs/sqft and see if it holds and in then look for an old donor MK1 engine incase it doesn't.
      - Light Fracture in top of engine block
        
        Posted By : Adrian Lee, 10-Apr-2005, 03:27pm
        
        Mark,if it needs a new engine I have a spare MK1 2 litre, out of a Vitesse ,it was running 150 comp/per cylinder but obviously i cannot garuntee it.I have not had it in bits so have no idea if it's been rebuilt or not.The car had 65000 on the speedo when i took it out ,though that does not mean anything.Though it did not blow oil or rattle before i took it out.Contact me off board if you need it.Or if anyone else out there needs one,the skip is beckoning !!!!!!!!!!!!!
        
        Light Fracture in top of engine block
        
        Posted By : Colin Wake, 10-Apr-2005, 07:12pm
        
        Adrian
        
        If it is an early one then someone out there will be looking fof it!!
        
        Is the engine number less than 5000???
        
        Colin
        
        Light Fracture in top of engine block
        
        Posted By : Adrian Lee, 10-Apr-2005, 09:18pm
        
        HC 1384 E.........?
        
        Light Fracture in top of engine block
        
        Posted By : Colin Wake, 10-Apr-2005, 10:26pm
        
        That is one of the desirable ones with the 1600 bottom end.
        
        Reportedly the best of all the 6-cyl engines.
        
        Colin
        
        Light Fracture in top of engine block
        
        Posted By : Chris Taylor, 10-Apr-2005, 11:00pm
        
        May be of the best engines , but bearing shells are just about unobtainable now........
        
        Light Fracture in top of engine block
        
        Posted By : William Davies, 11-Apr-2005, 03:57pm
        
        If you speak to a proper engineering shop they will invariably have a way around this kind of issue. I know of several 948 engines which have been rebuilt using A-series engine bearings, this solution should be equally applicable to the early 6 cylinder engine. A quick check through my bearing suppliers references shows several different applications with a main journal diameter of 2.0".
        Cheers,
        Bill.
        
        Light Fracture in top of engine block
        
        Posted By : Nathan Gabbott, 14-Apr-2005, 04:11pm
        
        I have a 20thou undersize set(mains and big ends) of NOS Vandervell bearings for the 1600 engine, bought in error for my GT6. If anyone is interested drop me a mail through my profile.
        
        Nathan
        
        Light Fracture in top of engine block
        
        Posted By : Colin Wake, 15-Apr-2005, 04:15pm
        
        Rimmers had loads of Vit 1600 bearings in their sale at the end of 2003, mostly STD's mind, but they were about &163;8 a set.
        
        They had the same at the end of 2002 and it appeared they sold 1 or 2 of the 50+ sets they had. At that rate they should still have plenty left!!!
        
        Colin
        
        Light Fracture in top of engine block
        
        Posted By : Chris Taylor, 10-Apr-2005, 11:00pm
        
        May be one of the best engines , but bearing shells are just about unobtainable now........
        
        Light Fracture in top of engine block
        
        Posted By : Adrian Lee, 11-Apr-2005, 07:59am
        
        That may be true Chris,but if some-one can make use of it rather than it gathering dust in my garage,surely that is better.I thought the idea of this club was to help each other out if we can.I will never use this engine again, somebody has a need for it.I don't see the need for a negative comment about it.
        
        Maybe i'm wrong or have i misinterpreted your post?............
        
        Light Fracture in top of engine block
        
        Posted By : Colin Lindsay, 11-Apr-2005, 08:16am
        
        How I could have used it some weeks back when my Mk1 block turned out to be a Mk2; however it just came too late and it would cost me too much money and time to swap back again as I now have the Mk2 tubular manifold and the unleaded head, which has turned out to be a domed piston late Mk3 - but thats another story, and thanks for the kind offer, Adrian!
        However: as with all Triumph bits the bearings might be unobtainable on a commercial basis but some suppliers have stocks of them on the shelf which are probably the last available from these sources; a set appeared on eBay recently as NOS and I'd advise anyone with a Mk1 engine to buy them while you still can...!! I believe it's also possible to adapt Spitfire bearings so the engines should be catered for in the foreseeable future one way or the other.
        
        Light Fracture in top of engine block
        
        Posted By : Chris Taylor, 11-Apr-2005, 06:02pm
        
        I'm sorry, the last thing I intended to be was offensive or negative, especially of the kind offer of a replacement block.
        I AM a big fan of the early six cylinder engines and have decried the derision in the "classic car press" of the 1600 engine as not worth considering. I think it is the sweetest running of all. (Not the greatest fan of the solex carbs mind.......!)
        What I was warning about before any final decisions were made about the best course of action, was that one should not just assume that replacement bearings (if needed) will be readily available.
        The more people that speak out and show an appreciation for and reflect a demand for engine parts for the Mk1 engines the better as it might prompt either a restocking of parts or at least an acceptable, soundly engineered alternative fitment.
        
        Light Fracture in top of engine block
        
        Posted By : Adrian Lee, 11-Apr-2005, 06:22pm
        
        I must have misunderstood your post Chris,apologies.
- Light Fracture in top of engine block
  
  Posted By : Jonathan Binnington, 09-Apr-2005, 09:04pm
  
  Mark, the tread lock cement repair may work, but Ithink a replacement block is needed. Mk1 engines come up on ebay from time to time, I'll keep a watching brief for you, unless anyone has an unused block out there?
  
  I have two Mk2 blocks but they aren't easily interchangable because the head studs are different sizez
  
  bin
Light Fracture in top of engine block

Posted By : Colin Lindsay, 09-Apr-2005, 08:45pm

I've done a few heads / blocks now and never torqued the studs down, just screwed them in finger tight once the end of the thread had been reached. Be very careful when referring to the Haynes manual; after the head has been fitted the nuts on the studs should be torqued down to 42 - 46; I think Haynes has a very confusing reference which seems to quote an incorrect figure of 64 - 68 or thereabouts. I found this the hard way after wringing three studs in quick succession!!
- Light Fracture in top of engine block
  
  Posted By : Mark Wessendorff, 10-Apr-2005, 12:54pm
  
  With the Haynes manual not being accurate in the torque settings I would like to get another workshop manual. Please can I have any advice on which are the best ones and where to get them. Thanks