OK, here's the latest on my oil gulping 1500.
Tonight I finally got around to doing the blow-down test and another hot
engine compression test. This was necessary because the car was getting
very hard to start and to keep running when cold. I swapped out for a
clean set of plugs (Autolite 404) and it starts fine now. These were not
as oily and carboned as the ones I took out after 2000 miles, but then
these only had 283 miles on them since August 26. My consumables are
getting expensive!
Anyway, while I had them out I did another compression check. Engine was
about 140 F:
Cylinder #1 165#
Cylinder #2 90#
Cylinder #3 95#
Cylinder #4 150#
This is similar to the check I got cold a couple weeks ago, but about 15#
higher in each cylinder. Instead of cranking for a set number of
compressions this time, I just ran it until it stabilized at it's highest
point. This was about 8-10 revs.
Then I did a blow-down test as suggested by several of you. I've never
done this before, so let me know if I did anything incorrectly. I rotated
the engine with plugs out until #1 was TDC (and I checked the dizzy to
make sure it wasn't on the "blow" cycle (Thanks for the great descriptive
"Suck, Squeeze, Bang, Blow". Mine just seems to suck!) I then screwed the
air hose adapter into #1 cylinder and turned on the air. Listening for
where the hissing was, I found it was coming from the oil filler in the
rocker cover. This is indicative of rings, from what I was told, but it
was gurgling a little when I first turned on the air, and this is my good
compression cylinder, which leads me to think it might be coming around
the valve stems.
Cylinder #4 was just like #1, in that there was no noise coming from the
carbs or exhaust; just the filler tube, again with a little gurgling at
first (oil blowing back up the guide?) Oh, and both #1 and #4 maintained
a little pressure when I took off the quick connect on the hose, so I
think they are not a big problem.
Cylinders #2 and #3 on the other hand, lead me almost inescapably to the
conclusion that I have blown a bit of the head gasket between the two.
Putting the air hose to #2 (with it at TDC) blows right back out #3, with
nothing coming from the tailpipe, carbs, or filler. Same with #3 (comes
out #2.) Well, I've got a gasket in my boxes of extras I got when I
bought the car...I just didn't expect to be using it so soon.
When I had each cylinder at TDC, I could shine a flahlight into the spark
plug hole, and each cylinder top was covered with built-up carbon. More
in the center, but I'm definitely burning up the oil. Still at 100-150
miles/quart. No mosquitos in our neighborhood, though.
I keep checking for mingling of fluids, but so far there isn't a problem.
I'd like to run it until the weather gets cold, but I don't want to ruin
anything by putting it off. I still want to check the valve adjustment,
but I didn't get to it tonight. Sounds like I'm doing a new set of valve
guides over the winter.
Any thoughts or additional suggestions are appreciated.
Thanks,
Steve
Steve Morris Avon, Ohio
1958 MGA 1500 Red/Black
NAMGAR #5987
http://www.en.com/users/smorris/mga/
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