----- Original Message -----
From: "Anthony Rhodes" <spamiam@comcast.net>
To: "Tim Hutchisen" <hakhutch@adelphia.net>
Sent: Wednesday, March 23, 2005 4:09 PM
Subject: Re: Wix Filter for TR4a spin-on adapter?
> Did you know that the 51034 has no bypass valve? If it clogs, then no oil
> flows, I suppose.
> Anyway, filters like the Fram PH3600 _DO_ have bypass valves. I suppose
> the TR7 filter should.
> I checked my car and it has the NAPA 1374 (Wix 51734). Which is virtually
> identical to the 51034 except for the bypass. The dimensions are almost
> identical.
>
> -Tony
Tony-
No, I did not know the filters were that close. It doesn't matter much
now that the car has changed owners however. I know that I changed the oil
(Castrol 20W50) and filter (Wix #51034 or NAPA Gold #1034) three times a
year over the course of 2000 miles annually and after 31000 original miles,
the oil was always _golden_ in color when I went to change it out. From my
point of view, a bypass valve becomes more important with a badly maintained
vehicle (IE: lack of oil changes). If you are one of the typical Triumph
guys, you probably do not subscribe to the wait 'till it breaks theory and
change your oil quite regularly. Using a good quality oil and a good
maintenance plan, I would doubt that a bypass valve would come in to play
unless the oil filter orientation allows for drainback into the crankcase,
let me explain....
What is more important is the orientation of the filter in regard to
gravity. A filter that holds oil after shutdown (vertical orientation) is
more likely to give good start-up oil pressure than a filter mounted
"up-side down" or horizontal. This is why filter adaptors are offered by the
vendors. Those filters that are mounted in a position of being gravity
challenged (MGB as an example) will have a better benefit of having a bypass
valve. The valve will hold some oil into the filter until enough pressure
builds to open the valve, therefore allowing for some initial oil pressure
upon start-up. This is something the old "canister style" filters of our
beloved Triumphs did not have. The TR7 filter and adaptor is oriented in
such a way (approximate 60 degree angle) that it holds some oil after
shutdown. About 2/3 of the filter stays filled with oil. The oil light (I
know, I know, it should have had a gauge from the factory but that is
another thread unto it's own) never stayed on for more than a split second
in the wedge on start-up, even after a long winter's nap. I can sleep at
night knowing that without a bypass valve in the Spider, that it did no harm
internally with the maintenance it received. I will go on record that the
TR6 gets a Wix#51516 or NAPA#1516 when the oil is changed. I don't think the
bypass valve matters a whole lot in that application either, it just offers
more filter area and fits the application.YMMV.
Tim Hutchisen
71 TR6
Flame retardant suit now on
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