The filter itself does not contain a bypass, although most contain anti
siphoning valve (rubber disk on the inside that lays against the ring of
holes on the bottom of the filter). The actual bypass valve is in the
oil pump or in the block where the filter is attached.
Your assesment of the operation of the bypass valve is correct! A
smaller filter WILL be more restrictive to the flow at higher rates, and
thus the preasure will be higher at the filter base. When this preasure
begins to exceed the preasure of the relief spring, the bypass valve
will open. Depending on the engine, the oil going through the bypass
valve will still be pumped through the engine. On others, it will be
dumped back into the pan.
I believe the Alpine 1592 engine dumps back into the pan, because when
I had a plugged filter along time ago, my oil preasue gauge would bounce
between 5 and 15 lbs at idle when warm, and wouldn't go above 20...Ever.
When I changed the filter and the oil (same weight and brand) the
presure at idle was 20, and would climb to as high as 50, with no
bounce. The bounce was caused from the oscilating of the bypass valve
at idle.
Rich
>----------
>From: marrone@wco.com[SMTP:marrone@wco.com]
>Sent: Wednesday, October 23, 1996 10:26 PM
>To: Rick Fedorchak; tigers@autox.team.net
>Subject: Re: Renault Spin on Filter
>
>What I have heard is the smaller the filter the "sooner" the bypass becomes
>activated. Even largish (PH8A) filters have their bypass open at higher RPM
>(and viscocity) but smaller filters bypass sooner and you end up spending
>more time without the filter in the circuit.
>
>
>>
>> I've seen one of these critters installed on the Ford
>>motor........and it's pretty tiny. Makes me wonder what the intended
>>filtering capacity is versus what the Ford motor needs.
>>
>>Can anyone provide any feedback on how these small filters worked on their
>>cars. Any problems encountered by using them ??
>>
>>
>>
>Frank Marrone MK I Tiger B9471116
>marrone@wco.com 1966 LTD
> Series I Alpine (2.3L powered by Ford)
> Yamaha Seca 900
>
>
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