Worldly Scions,
Having a car that exhibits the death rattle sometimes on startup, &
recent discussions with members of this list have prompted me to
undertake 'rebuilding' a Spit motor. I decided to practice on a spare
motor first. I've had one laying around for years. The PO of this
car (& motor) told me the motor was seized, but I was able to turn the crank
fairly easily with a wrench on the front pulley nut. I contemplated
'running' the motor to see what sort of noises it would make, but
as I'd already taken it out of the car I decided against it.
The motor is now fully disassembled & my untrained eyes have
noted the following.
-The top rings were broken on #1 & #4 pistons, although there is no
detectable ridge at the top of any bores.
-The crank is broken, already mentioned to the list. It appears from the
shear angle & position this may have resulted from a heavy blow to
one end of the crank. The donor car did not have any indication of a
front end hit though.
-The cam followers must be extremely hard. There is no evidence of
any wear to the bottom of these things. Some wear is noticable inside
them.
-Someone has been in the bottom of this motor before so WhoKnows
what's been replaced.
-The 'cylinder liners' shown in VB's catolog are nowhere to be found.
(someone asked about these on this list a few months ago)
***Warning WAG follows feel free to correct me***
Although there is evidence of some bearing wear, I don't see anything
shocking. The 'little end' con rod bearings seem fine. What *does* seem
a little strange is that the con rod is able to slide back and forth about
1/8 inch along the gudgeon pin. I can't find a spec for this. I'm guessing
what stops the rod from slapping the piston in this manner is that the rod
is held in place by the 'big end' bearing. Therefore, a small amount of wear
in the 'big end' bearings might be not severe enough to be audible as
<big end knock> but it could permit the rods to move enough to cause
<little end slap> or 'death rattle'. It would be worse with low oil
pressure.
^^^^^^^^^^^^^^^^^^ Highly technical terms here :-)
*** End of WAG, am I onto the "death rattle here? ***
I have no intention of re-assembling this motor. I will be repeating this
exercise soon with another motor I want to run. Is there any point in
saving parts like pistons, or the cam to use in another motor? I'm
aware of all the caveats about matching bearing caps, push rods,
cam followers etc. But assuming these parts are 'servicable' are they
ever transplanted? Is this false economy? The crank is obviously
toast. Thanks to those who affirmed this.
Bob "greasy keyboard" Sykes
75, 78, 78 Spitfires & a "well ventilated" motor
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