DAN MASTERS writes:
>In a message dated 1/15/98 10:15:17 PM Eastern Standard Time,
>74137.3420@compuserve.com writes:
>> I'm not a mechanical engineer, so I'm guessing. I do run 20W-50 oil
>> year round however, as I only drive occasionally in the winter and my
>> 30-year old engine might be less happy with 10W-40. If you've ever seen
20W
>> oil at even 35 or 40 degrees, it's no great stretch of the imagination
to
>> think that perhaps some of it might be bypassed during engine warmup.
As I
>> said, I don't know, and since the stock engine had a bypass, I thought
I'd
>> keep it that way.
>Tom,
>This is well outside any area of expertise I may have also, but if the
bypass
>allows unfiltered oil into the engine, under any condition, I would think
that
>would be a very bad thing, and should be avoided at all costs -- even to
the
>point of changing oil seasonally if need be.
>Someone else pointed out (my apologies for losing his name) that the block
>bypass ran filtered oil back to the sump, whereas the filter bypass ran
>unfiltered oil back to the block, if I read his post correctly.
>Dan Masters,
>Alcoa, TN
Dan,
You are right that the bypass in the filter allows unfiltered oil to the
block. The purpose of the bypass is to guard against a blocked filter.
If the filter element gets blocked by debris and stops oil flow the
bypass will open and allow unfiltered oil to pass. Although unfiltered
oil is not good it is better than no oil!
Remember the old days before full flow filters. The filter received only
a small amount of the oil flow. They would EVENTUALLY catch everything.
And VW engines (the air cooled ones) didn't even have a filter, just a
screen.
Of course, I'm no expert either.
Dave Massey
71 TR6 (undergoing a bearing replacement)
74 TR6 (Having open radiator surgery)
78 TR7 (Promises to be a stillborn project here lately)
St. Louis, MO USA
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