In a message dated 11/6/2000 9:32:34 AM Mountain Standard Time,
sppchicago@excite.com writes:
<< have had my TR3 for almost a year. I haven't driven it much because the
car spent probably 8 of the last 12 months in storage. This weekend I
changed the oil for the first time. The previous owner told me he changed
the oil every 6 months. Well, the oil looked like it was crude oil - black
and thick.
Oil, oil, toil and trouble.
Oil exposed to combustion byproducts will continue to deteriorate over time,
even without use. Particularly if there is a lot of residual 'sludge' in the
bottom of the pan.
This might expalin the condition of your oil.
Anyway, I added Castrol 10W-30 and replaced the the existing spin-on oil
filter with a Fram PH2825.
I would suggest 20W 50W oil in warm weather. Not sure about the filter. I
don't think it is the one I have been using. Is that the number of the one
you replaced? There are several cans which will fit the TR spin on adaptor.
They probably differ in things like flow rate, porosity, etc. Can anyone on
the list discuss oil filter types, differences etc.?
For good measure (I think and I hope), I added
CD-2, an oil detergent, with the thought that I will change the oil again in
a month before I put my car away for seasonal storage.
The oil you used had detergent in it already, right? I guess the added
detergent might maintain more of the particulate matter in suspension in the
oil allowing the filter to filter it out and then carrying more out of the
pan when drained, BUT. I sure would not drive it for a long time or distance.
All the junk you are suspending in the oil with the detergent does get
pumped throughout your lubricating system till its drained or filtered out,
so all that possibly abrasive junk is being pumped to your bearings, valves,
etc. I would not think there would be any advantage to running it much
longer than up to running temp, then draining it out and filling with fresh
oil.
Now my question: Before changing the oil, oil pressure was consistent at
50lbs (at idle and at speed). After changing the oil, the pressure was at
60lbs, then quickly stabilized at 50lbs. Good. I took the car for a spin
to get the engine very hot and to check for leaks. After a bit, the oil
pressure, at idle, dropped to about 30lbs. At speed, the pressure was about
50lbs. By the time I got home, oil pressure, at idle, varied between 20lbs
and 30lbs. There are no leaks (other than normal) that I can see. The
engine and operating performance ran like a charm; very strong.
I looked at my TR manuals that said that oil pressure should vary between
30lbs and 70lbs. Should I be worried that oil pressure drops to 20 lbs at
hot idle? Should I worry that hot at idle oil pressure droped to 30lbs from
50lbs previously? Or is this simple a result of clean oil? Should I be
using a heavier weight of motor oil?
>>
Yes, use 20W50W when the ambient temp is high. 10W30W is ok when the ambient
temp drops to freezing. You will amost always see an increase in pressure at
hot idle with 20W50W over 10W30W. Remember also when you are concerned
about absolute measurements that you are probably using a 35+ year old gauge
to measure the pressure. Is it accurate? Also there is the perceptual issue
of parallax. Are you looking at the gauge from exactly the same angle each
time? Probably not.
My guess is that when you got the earlier idle pressure of 50 that you had
not really gotten the car up to temperature. Also the oil you drained out
might have been 20W50W. Very, very few cars will hold that high of a
pressure at idle when hot.
I would change the oil to 20W50W immediately. That extra detergent, in my
ignorence, would make me uncomfortable. Have you ever heard the stories about
people adding detergent oil to cars that were always run on the older
non-detergent oil? Engines did not last long. After chaing the oil, run it
good and hard for a couple of days or a good long 60Mile or so trip. Watch
the pressure and see how it responds. Since this is a new car to you, I'd
check the dipstick to see if it gets dirty quickly, change it again if it
does.
I think reading a variation of 10 Lbs + or - at hot to very hot oil is pretty
normal. It is with my cars. This will get me flamed good, but....A
helicopter mechanic friend with a 56 TR3 that he built shows about 10Lb at
idle. He's not concerned about it. The pressure runs right up to 50-70 with a
stab on the gas pedal. I'd be concerned mostly if the top pressure at, say
2,500 to 3,000 RPMs drops below 45 or so consistently. Remember, the oil
pressure will respond to how hard you are pushing the car, total temp, etc.
as well and the type and volume of oil in the sump. As you get to know your
car by driving you'll be more comfortable with the variations you see and
know better how to differentiate a trouble sign over the normal variations.
Another flame dodging question is synthetic oil over regular oil. I'll
maintain that the synthetic oil is superior only at operating temperatures
higher that your TR should be able to run and in perhaps very, very extreme
situations, like racing a well built and balanced engine at very high rpm
for long periods. Under the conditions that most of us will drive the
oldsters, there will be no measurable benefit, but a much higher cost. I'd
use regular 20W50W in summer and lighter in winter if you drive a lot and
change it and the filter often.
Bob Paul
Corrales NM
59 TR3
55 TR2
36 F2 Morgan Three Wheeler
All running 20W50 in the summer.
|