Hi,
Some folks talk about running their car from time to time during the
winter just to make sure that everything is okay. I would not want to
dissuade folks from any sort of ritual to this regard, but wanted to offer
an observation with my case.
Last week, I ran my race motor up in order to get a more accurate leak
down measurement... I noticed one cylinder is down about 30 pounds (of
235 pounds) during a regular compression check while I was getting the car
"ready for winter". At any rate, the leakdown is best done on a warmed up
motor.
I started the car in the garage (ambient temp. mid-20's F - IT WAS
FREAKIN' COLD!) I ran the motor temp up to 180 degrees and even observed
some movement on the oil temp guage, although not much movement at that...
but the oil temp was probably approaching 100 F. I let the motor run at
increased idle (about 1500 RPMs) for about 20 minutes. The motor was
"warm" for all intents and purposes.
I then proceeded with my test which indicates bad rings on at least one
cylinder. I need to look into that!
But the interesting thing was what I observed yesterday. On a hunch that
my leak-down tester was not sealing to the cylinder (and hence giving me a
bogus leak-down reading), I set up for the test again. Without an
assistant, all readings are done with the cylinders at BDC (as when you
pressurize the cylinder the piston finds BDC on its own), but this means
that you need to yank the rocker shaft off so that the valves close.
So, off comes the valve cover.
What I observed was that despite having fully "warmed" the engine in the
garage (stationary), there was enough humidity present to form
condensation internally in the motor. In fact, there was enough water
vapor present that the water froze onto several parts taking on almost a
"hairy" appearance. This "hair" was on all the surfaces that were not oil
soaked, so the rocker adjustment screws and nuts and valve cover studs
etc. were all exposed to moisture.
I then double checked the inside of the rocker cover - there were white
oily deposts there.
Whoops - running the car in the garage is not enough to boil off all the
water vapor in the sump. I'll wipe off all the water/ice that I can see
from beneath the valve cover, but I should change the oil to be sure.
Changing the oil presents the problem of then running the motor to
circulate the new/good oil which will in turn create more condensate.
So - do the right thing with your car in storage... turn the motor by hand
to make sure the rings don't stick, but don't run motor in the cold garage
if you can avoid doing so. Either that or change your oil every three
months while the car is in storage.
That's all for now,
rml
------------------------------------------------------------------------------
Bob Lang Room N42-140Q | This space for rent
Consultant MIT unix-vms-help |
Voice:617-253-7438 FAX: 617-258-9535 |
------------------------------------------------------------------------------
|