Jack I Brooks wrote:
>
> 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.
Try another hooking up an external oil pressure guauge, one you know to
be accurate or at minimum a new one, they are cheap from auto parts
stores, and get another reading.
>
> Jack Brooks
> Hillsdale, New Jersey
> 1960 TR3-A TS69032L
> 1974 Norton Commando Roadster
--
Lenny Seidman
Elkins Park, Pennsylvania, USA
email: lseidman@erols.com
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