Conference terri::cars_uk

    I would recommend that the bigend shells are replaced before the crank
    is damaged beyond salvation - that is if it is not too late already.
    Reshelling, and a possible crank regrind, will be cheaper than a new
    crankshaft.
    
    I would not advocate using "straight" oil in what is a relatively
    modern engine. For many years engines have been designed with the
    detergent, anti-corrosion and multigrade properties of modern lubricants
    in mind.
    
    Synthetic oils only surpass mineral oils in extreme conditions, and/or
    allow extended oil change intervals.
    
    My personal view on oil additives is - if they are so good why does no
    oil company put them in their products?
    
    Bite the bullet - get it fixed before it goes bang!
    
    - John.

    Wasn't the low gear blocked off, so that you were effectively
    starting in 2nd gear ?
    Due to the drive train having been lifted from the Austin A-90 saloon
    and the 100/4 not needing such a low starting gear?
    
    Terry

    3 speed automatic gearbox with manual shift only!

	.7 is correct. They wanted to achieve the magic ton for top
	speed and in the frugal early fifties the choice of transmission
	bits was limited. So the arrangement used gave the top speed
	but resulted in 1st being so low it was blanked off, hence
	producing what may well have been the only 3 speed car with 
	a 4 speed gearbox.

	-John

    
    	But isn't the 100/4 a wonderful shape?

     re -1.
    
    Yes.

    
    Closer investigation into the noise from my engine compartment has
    revealed that my rocker/tappet settings desparately need resetting,
    rather than big end trouble.
    
    I have now had one go at it, but it seems to be one of those tasks
    that takes lots of patience and lots of time.
    
    BTW. I have changed the oil to Castrol GTX 20/50. It is definitely
    better than the 10/40 I was topping up with.
                                                 

    There's a handy tip for tappets, assuming you're dealing with a four
    cylinder engine, with the conventional 8 tappets. It's called the "Rule
    of Nine". Basically, deduct the number of a tappet FULLY down (ie
    valve open) from 9, and that's the one you adjust.
    
    In other words, ensure valve 5 is fully open, right on the cam, and
    then adjust tappet 4 for gap. Wipe the oil off those adjusted so you
    can keep track of them.
    
    Another tip, is to take the plugs out (they usually are anyway), put
    the car in second gear (on level ground!), and "pull/push" the tappets
    up and down. Much easier than trying to pull on the fan belt.
    
    Laurie.

Also that the engine is either cold or hot at the time of checking/adjustment,
some manufactures prefer in inflict burns as well as scratches when manually
turning the engine over.

Nigel.

	A good tip for moving the tappets, Laurie, only the last time I did
	that I stood the car on my foot.  Not painful, just embarassing.

	Dave

	'Adjusting the tappets' - fine old expression which strictly
	speaking only applies to side valve engines but always seems to
	get used for OHV ones too.

	Since it's a six you need to use the rule of x (can't remember)
	instead of 9.

	One thing I learnt early on adjusting rocker arm clearances is
	that with use the valve heads wear a groove (of considerable 
	depth relatively speaking) into the rocker arm. This means that
	if you just put feeler gauges between the two, you end up setting
	the gap far too large ie. feeler gauge + wear. I used to have 
	a set of feeler gauges which had been narrowed down so that they
	would fit in the groove to overcome this. Also there was a tool
	coloquially known as a "Tappet Adjuster" which worked by closing
	the gap fully and then backing off by the desired amount as 
	indicated on a scale. This could be used with the engine 
	actually running (idling) with a bit of practice and made the
	whole exercise a doddle.

	If you should get tired of messing about with this old toad
	of a car I'll see if I can find some room in may garage for it.

	-John

    RE: .17	The possibility of local or uneven valve wear is not one
    		I had considered.
    
    		I do know, that when I drove the car from the garage at
    		Christmas (I had had the head reconditioned) it drove very
    		smoothly. If I was still in the U.K. I would get the same
    		engineer to set them up again - I had been told that they
    		would need checking after 500 miles.
    
    		The HAYNES manual seems clear as to which valve to adjust
    		when - valve 1 fully open -> adjust valve 12.
                       valve 2 fully open -> adjust valve 11 etc
    
    		There definitely seems to be an art to it so I shall
    		persevere.
    
    		Any more tips I shall be grateful of.
    

	Well, the engine eventually seized. Last year I had it completely
	rebuilt - it needed it anyway.

	Having now run the new engine in I am left with a problem,
	caused by the oil pressure of a healthy engine. Basically,
	oil is forced up through the breather pipe in the rocker
	cover, through the air filter and drips onto the exhaust
	manifold!

	Here is the layout:

        Air
        filter
        _____
	|   |        Flexible hose
	|   ---------------------         Breather
	|   ___________________  \         T-bar
	|   |                  \  \------ o----------o
	|   |                   \________ o___   ____o  to tappets  |
	|   |                                 |  |                  |
	|   |                    _____________|  |_____________     |
	|   |                   /                              \    V
        -----                   |                              |
      v                         |                              |
      v                         |                              |
     Oil                        |     ROCKER COVER             |
     drips                      |                              |
      v                         --------------------------------
      v                         |                              |
                                      CYLINDER HEAD


	The flexible breather hose goes from the air filter to the
	rocker cover and then to the tappet cover.
	The air filter is an old-fashioned oil-filled wire gauze type.

	The air filter probably pulls the oil up the flexible pipe
	since there is a vacuum in the air filter caused by the air
	intake.

	If I remove the flexible hose from the air filter, the oil
	leak is not so severe. But then I have no filtering for the
	air in the rocker cover.

	Any suggestions on how I can maintain an air filter on the
	rocker cover breather pipe and stop the overflow of oil?

	- Jonathan

    

    
    The problem you describe is indeed excess 'oil' pressure. I assume that
    you have checked the oil level, for excess ?. This problem is usually
    caused by a pressure build up in the crank area. On most manufacturers
    engines there is a 'sump' breather hose with a pressure valve attached.
    As the engine has been 'rebuilt' this hose may be trapped, obstructed
    or the valve may have been reversed. It was common on Ford OHV engines
    to block this pipe and increase crank pressure when 'tuning' for
    endurance sports, somthing about extra pressure below the pistons
    acting as a cushion. Is the dipstick a tight fit ? does it tend to
    'pop'out of it's holder ? this is usually evidence of high crank
    pressure, which forces the oil into the rocker box very violently and
    fill the breather tube void.
    
      Alan.
    ex 'stage 3' escort owner who has the same problem. 

    The engine has done 1200 miles. I suppose that by 3000 miles I could
    consider it truly run in.
    
    Re: -1 the oil level is OK and the dipstick is not tight and doesn't
    pop out.
    
    The oil pressure is about 60, dropping to 40 when warm and idling.
    
    The problem does not seem as bad now as it did, but I assumed it was
    because I removed the breather pipe from the air filter and let it
    dangle away from the exhaust manifold (you can imagine the smoke!)
    
    I seem to remember the garage having to manufacture an oil
    recirculation pipe because there wasn't one before.
    What do you mean by "blow-by"? Is this the oil redirected to the
    rocker arms?
    
    Thanks for the pointers.
    
    - Jonathan 
    

    The breather pipe is there to allow any excess gases in the sump/rocker
    cover to escape (via the inlet manifold so that any oil gets burnt).
    
    Normally there is only a small amount of gas that has to go this route.
    
    In an old engine the valve guides and piston rings get worn, and allow
    more gases to escape from the cylinder into the sump and rocker cover.
    This is known as 'blow by'. Another possible source of gas is a gasket
    leak, which might allow the coolant to evaporate. If you get too much
    flow of gas via the breather pipe then it can carry oil with it. If the
    breather is blocked these gases buildup, and will eventually exit via
    some other path. E.g. via the dipstick.
    
    Andrew

    Years ago when I worked as a BMC mechanic we often had Healeys come 
    in with exactly the problem you describe. It always turned out to be 
    worn rocker arm bushings and shaft. The Rocker cover vent is located 
    where it gets a direct shot of oil thrown off the rocker arms, and 
    there is no baffle to prevent this oil from going up the pipe.
    
    I'd start by putting a good oil pressure gauge on the engine to make 
    sure someone didn't jack up the pressure to delay the inevitable 
    rebuild; if pressure is out of spec, look for the relief valve on 
    the filter mounting block and adjust if needed. (only if NEEDED !!)
    
    The most likely fix, but not cheap, is replacing the rocker shaft and
    bushes.
    
    As a last resort, a baffle inside the rocker cover will keep most of
    the oil out of the vent.
    
    	Good luck with your Healey, It's a fun car
    
    	- Bill
    

    Thanks for the replies, esp. .-1.
    
    I have not doubt that the engine rebuild was a good one - I watched it
    progress. Also it was "blue-printed" - the major moving parts were
    machined to within a high tolerance and then dynamically balanced.
    
    However, the rocker assembly is not new so I can imagine that the
    explanation of "worn rocker shaft and bushes" is valid.
    
    As long as there is sufficient oil reaching all parts of the rocker
    assembly and there is no harmful vibration then I reckon they should
    be alright. But I'll have a good look.
    I shall investigate adding a baffle in front of the breather hole.
    
    The existing rocker cover is a very old bashed tin one. It does not
    give a good seal so oil leaks out the side. When I tighten down the
    two securing bolts it lifts at the edges. I have bought a new allow
    cover in the hope that this will be much more rigid.