What does your manual say?........I think your engine is almost the same
engine as the TR4 and 4A......mine says 30 wt for 40-70 deg F. and 20 wt for
10-40
deg F, and 40W for over 70 deg F..
My idea is that these engines and guages were meant to use these grades of
oil.........not muliple viscosity oils.......
I would think that to be absolutly safe.......I would use what the manual
says!
My 4-107 Perkins Diesel says 30W........that's what I use........(I can't
pull up to the side of the road in my boat.........<g>.........)
I compromise a bit with my wife's '67 Jag and my TR4A, and use 10W30. We are
coolish here in western Washington........with a few days below freezing and
a few above 90 deg.
The Jag's oil pressure is supposed to be 30 psi at 3000 rpm.........it never
drops below that, even when hot. At an idle it appears to drop almost to
zero. 120,000 miles on the first engine rebuild (65,000 not ours) and we are
approaching 80,000 miles on this rebuilt without a problem........
The TR4A pressure is 80+ psi when cold........runs about 50 at 2500-3000 when
hot, but then drops off to 20 or so at idle........outside temp seem to make
no difference!
I don't think that there is anything wrong with your pump!
If you are willing to change viscosities of oil for summer and then again for
winter.......I would follow the manual.......20W winter, 30W
summer...........................50W sounds way too thick for New
York........unless you are
running months on end of 120 deg temp up there............<g>.......
Just my thought!
Cheers!
Clark
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