In a message dated 96-11-24 22:38:31 EST, you write:
<< The TR3 we purchased a
month ago seem to be developing a loud regular knock at the front of the
engine, which I am hoping is the big end of number one cylinder, and not
a crank bearing.
<snip>
Help!
All you regular TR wrenchers. It has come on fast, less than 200 miles;
almost sounds like it could be from the water pump, but I feel it is from
the cylinder #1 area. Rattles at idle, up to around 4,000 RPM, where it
seem to go away, maybe. I was planning on checking out the bearings this
winter because of low, 15 psi oil pressure when hot. The cold oil
pressure is 70 psi, limited by the pressure relief valve. I took it out
cleaned it, and later adjusted it to be sure that it was working.
If the problem is a crank main bearing, can that be done from underneath
also like the big ends? I only discovered this noise today and my
preliminary reading of the manuals is not clear.
If anyone has any ideas or things to check out, I would appreciate your
guidance. Also, if anyone has redone the bottom end with the engine in
the car, I would appreciate your titbits of wisdom. >>
Jack-
It sounds like good news/bad news time...
The good news is that winter time approaches, the bad news is that you're
gonna need the time to fix it.
Its definetly difficult to diagnose sounds "over the net", so give these
ideas a try.
First, remove the fan belt (new to TR3's ?, you'll love removing it), then
run the engine and check for the noise. No noise = good news. Noise must be
coming from water pump, generator or front hub/pulley (check for tin halves
of pulley bent/cracked). Still have the noise = bad, go to two.
Two, with engine running and noise at maximum sound, remove each plug wire
one at a time and listen for lessening of noise. Less noise with wire off =
sorta good. When the plug wire is removed, there is less strain (no fire, no
expansion of gases and no "push") on the piston, hence less noise. Whichever
cylinder has the most effect on the noise, probably has a bad bearing or
wrist pin. No change in noise level = bad, go to three.
Three, final desperate act, as you probably have bad main bearings, with
engine running, depress clutch pedal. These motors are not noted for losing
their thrust washers, however, I have seen more than one of them with the
washers inserted backwards. Surprisingly, this usually seems to have only a
small effect on the crank, but the washers just fall apart due to the high
heat generated on their steel backings. Change in noise here = good as a new
set of washers may get you down the road. No change in noise = bad, we're
back to the main bearings.
Rod bearings and even the thrust washers can be changed from under the car.
Not a fun job on your back with old oil and grease droppin in your eye at
some crucial moment, but do-able. YOU can change the main bearings in the
car, but you're gonna wish you'd have pulled the motor. The center main is
piece-o-cake, and the rear isn't too bad, but the front one is tougher. The
front cap has two bolts through the front plate into the face of the bearing
cap. You can get to these bolts, and you can even get the cap off, but the
front of the cap mates to the back plate of the front timing cover and there
is a gasket between them. If your luck isn't perfect (and we know that it
isn't, or you wouldn't be in this mess), there's no way to replace that
section of gasket that's gonna tear out with the bearing cap, and its gonna
leak like the devil. Be sure to use lots of "gorilla snot" (technical term
here for 3m or rtv) stuffed up there.
Of coarse all this talk of changing bearings, assumes that the crank is
perfect and does not need to be turned. (Remember the plastigauge !)
Glad its you, not me...
Nick in Nor Cal
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