[TR] Purolater Oil Control Head

[Randall]

The adjustable "relief" valve limits oil pressure to the galleries; the
fixed "bypass" valve limits the pressure drop across the filter element.  

If the output to the galleries rises above 75 psi or so, the relief valve
opens and allows the excess oil to flow back to the pan.

If the filter element gets clogged (or is otherwise unable to pass enough
flow to keep the pressure drop low enough), the bypass opens and passes
unfiltered oil to the galleries.  This (fixed) pressure is fairly low,
something like 5 or 10 psi.

One of the oddities of the TR3-4 engine is that the pressure shown on the
gauge is taken off before the filter element.  So the pressure you see may
be higher than the actual pressure in the oil galleries.

-- Randall 
56 TR3 TS13571L once and future daily driver
71 Stag LE1473 - awaiting engine rebuild
71-2-3 Stag - awaiting gearbox rebuild

> -----Original Message-----
> From: Triumphs [mailto:triumphs-bounces at autox.team.net] On Behalf Of Jerry
> Van Vlack
> Sent: Saturday, May 26, 2018 2:08 PM
> To: triumphs at autox.team.net
> Subject: [TR] Purolater Oil Control Head
> 
> List, there are 2 ball and spring assemblies contained in the TR4
> Purolator Oil Control Head. I understand the function of the adjustable
> assembly. I don't understand the function of the non-adjustable ball and
> spring assembly. What function does it serve? Might it be a relief valve
> for an over pressure within the filter and if so does it somehow result in
> limiting full flow thru the filter?
> I seem to recall reading about how the control head works a number of
> years ago but can't find that article now.
> Thanks,
> JVV