OK, fellow Stanpart Scions, especially you who revel in the hallowed
traditions of Triumph motorsport, this one has me stumped.
Background:
1964 Spitfire 4, built, as best we can tell, as an SCCA-legal GP race car
from a very low mileage wreck (or two), probably in the late 1960s. The car,
in most respects, appears to be a "textbook" example of the original
"Competition Preparation Manual" and practically screams of "V" part
numbers. ;-)
Recently, I brought the car to my house to try to find the problem that has
led most notably to greatly increased fumes, primarily from the crankcase.
Having sat for over two years, the car nonetheless started almost
immediately. And, given the confines of a small, circular, dirt driveway, the
engine felt as strong as ever. (BTW, it is the 1147.)
A compression test, though, told a different story. Readings from cylinders
1-4 were approximately as follows: 158/0/162/160. A repeat test yielded
identical results. A squirt of motor oil and a recheck of #2 yielded a 120
reading. OK, rings are shot; that would explain everything. I'll deal with
that.
Last night, I finally finished getting the head and sump off and the #2
piston out of the block. (BTW, bearings, standard size mind you, still looked
almost new, as did the journal.) As the piston came out through the top of
the block, I immediately saw the cracks in the top piston ring, which fell to
pieces as I finished removing the piston. All else looked quite good, though:
piston looked clean, no scuffing, oil ring looked good, the top two ring
grooves looked pretty clean.
Only one thing was strange: I have yet to find any evidence of the middle
ring! And this brings me to my only real question at this point. Does anyone
have any good ideas as to 1. where the middle ring went or 2. why it would
not have been used when the engine was last assembled (long before we got the
car)? I've never claimed to know EVERYTHING about Triumphs, but...
AM I MISSING SOMETHING HERE?
There's nothing in the sump, there's no markings on the piston or cylinder
wall to indicate that the second ring somehow went astray and wreaked havoc
anywhere? Is this some good ol' racer trick, not to use the center ring?
Forgive my naivete, but I'd really have expected all three rings to be
present! Note: I haven't yet pulled the other three pistons; now I'm really
afraid to!
Oh, one other thing. The pistons appear to utilize "floating" wrist pins. The
piston/rod assembly I pulled last night also has some sort of white nylon(?)
"buttons" inserted as caps on each side. Another racing trick? What for? (I
didn't pull the caps off, so I don't know what is behind them.)
Fellow Scions, I humbly ask your advice, speculation, WAGs, learned
treatises, etc.
Andy "at least as baffled as the sump" Mace
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