An update: back in May, I had lamented to the list about my spit's
low oil pressure - when hot, I had 20 lbs at 3500 RPM and barely
registering at idle. I got a lot of good advice - some of it
over my head, technically speaking - from too many listers to
name and thank individually, but thanks to all.
Special thanks to Gary Kristjansson, whose advice I did follow
with much success. Gary suggested that I replace the main and
rod bearings by dropping the oil pan and working on the engine
from underneath. This was the route I decided to take since a)
it was cheap and b) there is something irrestibly macho about
messing with critical motor innards. (One lister did try to
dissuade me, warning of engine leaks from over-stressed seals
when the crankshaft is unsupported by the main bearing caps.
He was right - a moderate leak got somewhat worse - but this is
an acceptable trade-off to me).
I was able to get all the bearings replaced this way - previously
I had problems shifting the upper shells on the bearings closest
to the front and back of the engine. I did run into some re-assembly
problems, but they were due purely to me not carefully noting
which way the rod bearing caps went back on. Also to my surprise,
the main bearings, while worn and showing quite a bit of copper,
were in better shape than the rod bearings. I always heard that
1500 mains were weak...
All of the bearings had scratches in them, assumedly from small
bits of dirt or such in the oil. This worried me a bit, athough
the crank still felt very smooth, without a regrind, I was
concerned that new bearings would wear very quickly indeed from
small scratches that my fingers couldn't feel. I was hoping
that the crank was so much harder than the bearings that it might
be undamaged.
Frustratingly, TRF did not have thrust washers in stock at the
time, so I was unable to replace them while the pan was off. I
now have them and need to go back in again.
The immediate verdict after all this hard work was success as my
oil pressure was a respectable 25lbs at idle and 50 lbs at 3500
rpms when the engine is thoroughly warm. More gratifying still
is that 4000 miles later, including several long (long in a
spitfire!) highway trips, these pressures have remained unchanged.
I think we can call the operation a success! B-)
My apologies for the length of this post, but several listers
had requested a follow-up. Again thanks to all for their assistance!
Greg Rowe
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