Thanks to everyone for your responses to my question on oil weights. A
few things surprised me. I figured that most people would suggest the
multigrades, although I was surprised with number of people running
synthetic, because these are engines designed with wider tolerances and
heavier oils. The big push today to 5W-20's is based on tighter
toleranced engines using less horsepower to pump thinner oil. I am glad
synthetics are working for people with tight engines, I like synthetics,
they work well (sorry Larry).
I do have low oil pressure when hot. Down to 15-20 psi, assuming my
gauge is right. The blowoff valve on the oil filter is setup right, at
70 psi. I just removed and checked it hoping it was jammed partially
open. No such luck. I have not yet changed the oil in the car as the PO
had a receipt for an oil change less than 1,000 miles ago. The problem
is, he has no clue about what the mechanic put in. He had virtually no
clue about anything the mechanic did, but it was a former Jaguar
mechanic, and there are a lot of receipts from Moss, so..... Tomorrow, I
think I will put in a 20W-50 or heavier multigrade and see how the
pressure reacts. I will report back to the list next summer, if I
switch to a single grade.
Wouldn't an extremely dirty filter cause low pressure? As I recall, the
oil pressure blowoff valve dumps right back into the sump.
The bottom line is that I am trying to determine how deep I need to get
into the engine this winter, which is rapidly approaching. The car
appears to have been well cared for. The top end is tight, no smoke on
start up and a little black smoke on hard acceleration. No oil is
getting out through the exhaust. That's why I am surprised that the oil
pressure gets so low, everything else in the engine appears tight.
BTW, I also asked about clutch shudder about a month ago. I ran the
clutch and whole car pretty hard over the past few weeks trying to
uncover weaknesses. The clutch shudder went away after about 50 miles.
I assume it was dirt, rust, oil or grease on the clutch face, but it is
gone.
Thanks everyone for your help. If you have any additional input, please
let me know. I am hoping I don't have to get into the oil pump or
big/small ends this winter.
Further ramblings on synthetics:
I have run Mobil 1 since 1981 and use synthetics in everything, including
my lawnmower. I have used synthetic oils and greases in gearboxes,
diffs, balljoints, even 2 cycle lube for the chain saw. Our SAAB, with
116,000 miles, has virtually no measurable oil consumption between oil
changes. I did find, however that my Norton motorcycle (old, British,
and designed for straight 40W) had low pressure with any thin multigrade.
So I switched to a Klotz brand synthetic, straight 40W. Worked great.
Yes, they are a lot more expensive. I figure it costs $15 more per oil
change ($3-4/qt more). But, better heat transfer, higher heat
resistance and extended oil change intervals, if you desire. Plus, I
don't know about Syntec, but Mobil1, pours (slowly) at -40F. I usually
go 12-15,000 miles between changes on the daily drivers, SAAB & Chevy.
My previous two cars, Buick & Toyota, used Mobil 1 and went 156,000 and
195,000 with extended oil change intervals and no engine work at all.
The engines were in great shape when I got rid of the cars. I don't know
what I'll do with theTR3 yet.
Also, I don't know if the synthetic gear lubes are GL4's or GL5's; and
safe for the yellow metals we have in our gearboxes. Neither of my
current vehicles uses gear lube, the SAAB uses Mobil 1 5W-30 in the
gearbox and the Chevy is an automatic.
Thanks again. I apologize for the maximum verbosity tonight. I was on a
roll.
Jack Brooks
Hillsdale, New Jersey
1960 TR3-A TS69032L
1974 Norton Commando Roadster
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