Section : Engine Rebuilders

Engine overhaul

Posted By : Johan Rutgeerts, 20-Jun-2006, 09:05pm

• Engine overhaul

  Posted By : Chris Taylor, 20-Jun-2006, 09:29pm

  If you feel confident to strip down the engine in full, and to assess the wear and rectification needed, why don't you rebuild it yourself?
  Obviously you need the engine shop to do the rebore and crank grind, but the rest is basically straightforward assembly work, done in CLEAN conditions.
  All gaskets and seals should be replaced, the THRUST WASHERS, (with the best quality ones you can find!) the timing chain and tensioner.
  IF the camshaft needs replacing, it's probably worth looking at new cam followers (but again, good quality ones, some replacements are poor quality (see Tony Lindsey Dean's recent article in the Courier). You can measure all the tolerances in the oil pump with a straight edge and feeler gauges. Replace if out of wear tolerances (although it is quite feasible to reduce end float by rubbing the body on smooth emery paper on a surface block (or thick sheet of plate glass).
  In the head, you have three choices:
  Leave well alone and deal with later as and when necessary!
  Replace guides, and replace valves if stems are worn. (If exhaust valve show seat damage/wear, replace ALL exhaust valves. If one inlet is poor, replace just that one. Then recut seats (probably best to get the machine shop to do this) and regrind, OR
  GET AN EXCHANGE LEAD-FREE HEAD. This will have had all the wearing parts replaced, AND harder exhaust valves and seats. (If you have to replace valves or recut seats (even possibly just lapping them in, you are likely to remove the "lead memory" from the valve/seat and the standard engine's ability to deal with unleaded for many thousands of miles will be reduced or eliminated).
  While the engine is out, it makes sense to replace the clutch, or at the very least the driven plate and release bearing, unless the clutch is known to be pretty new. Check the flywheel ring gear is not chewed on the teeth, and replace the little spigot bush in the end of the crank.
  
  Make sure things like tappets go back in the same bore (if reusing), same goes for pushrods, and all bearing caps MUST be marked so they can go back together exactly the same way they were assembled.

  • Engine overhaul

    Posted By : John Davies, 20-Jun-2006, 09:49pm

    Johan,
    I thoroughly agree with Chris - re-building your engine is not rocket science!
    
    I recommend Calum Douglas' "Building a Reliable Spitfire Engine for High Performance".
    You will find it on the Totally Triumph Net website at http://www.totallytriumph.net/spitfire/engine_buil...
    Although Calum writes about the Spitfire engine, all his advice on techniques and methods and most of the details of the actual engine are transferable to the six cylinder engine. Calum is UK based, so no US bias towards suppliers or nomenclature, and he is an expert engineer who writes clearly and informatively. IMHO his article - it's almost a book! - is required readuing for any Triumph engine builder, of whatever experience.
    
    I would also recommend the books of Dave Vizard, if you can find one now. The one for six cylinder Triumph engines is available as a pdf file on the net: http://www.141.com/triumphs/vizard.pdf . Be warned if you aren't on broadband - it's over 1Mb long!
    
    Just to add to Chris's useful answer, it is not "worth looking at" new followers to go with a new camshaft, it is mandatory! The lobes and followers wear together, and a new shaft will soon be ruined by old followers. Don't forget 'assembly lube' on the cams - they take some of the greatest wear pressure of any engine part and need that lithium base when first started.
    
    And buy an engine stand - it makes assembly so much easier and helps to keep things clean.
    JOhn