Some time ago I promised to inform the list of the results of my
experiment with changing to synthetic oil.
The results are simply: no change.
I switched from 20W50 Castrol GTX2 to 5W50 Mobil 1. The hot and cold
pressures remained exactly the same at the same revs. If there was
any change at all, and I may be imagining it, the pressure with Mobil
1 seemed to drop away more quickly as the temp rose (presumably the
effect of 5 weight oil when cold).
There are no more oil leaks than before.
However, it looks like I need to fix the bottom end bearings soon.
The hot pressure at 2000 rpm is about 35 to 40 psi. Egil Kvaleberg
said two years ago that the hot pressure at 2000 rpm is the important
parameter to watch and that it should be 40 to 60 psi. Dave Massey
tells me that he is getting 40 psi at 880 rpm and 70+ psi (relief
valve operates) at 1500 to 1800 rpm with newly rebuilt bottom end
bearings and a new oil pump.
Is there any way to tell whether the bearings or the oil pump is the
principal cause of low oil pressure (other than removing the sump and
replacing one and then the other).
Trevor Jordan
74 TR6 CF29281U
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