[Spridgets] Oil Over Pressure

rrengineer at dslextreme.com rrengineer at dslextreme.com
Sun Oct 7 17:03:25 MDT 2007


I know I should have at least pulled the relief valve for inspection,
maybe later.  I was just so disgusted with all the problems at once I just
garaged it and resigned myself to tackle it later.  The adjustable relief
valve was also suggested earlier today by a Healey restorer friend.  I'll
pull it out and look first.  Don't know how I will be able to tell if the
spring is too strong though.  Maybe the cup is stuck in the seat.
Mike MacLean


Wm. Severin Thompson
> Regarding the excess oil pressure. I chased a problem with REALLY
> excessive
> oil pressure on a race motor. On start up it blew out a solder joint in an
> oil cooler. It blew out the rubber gasket on an oil filter.
>
> The oil pressure relief valve goes horizontally in the block. The strength
> &
> length of the spring, along with tolerances between the check valve
> piston,
> seat, and the passage way the piston slides in.
>
> Upon achieving oil pressure, the relief valve allows oil to drain down to
> the pan. At a certain point, oil pressure is equalized on either side of
> the
> plunger, and a secondary hole allows oil to drain off from the back side
> of
> the plunger.
>
> In my case, someone had tried to drive out one of the brass plugs the
> factory puts in the block, and a chunk had wedged out of sight in the
> drain
> passageway. So, after the pressure tried to equalize and drain, oil had
> nowhere to go, and it zoomed over 100psi.
>
> In your case, pull the large nut holding the spring & plunger, and
> inspect.
> Make sure you can feel the seat in the block. If all is right, either
> shorten the spring, or purchase an adjustable pressure relief valve from
> one
> of the usual suspects.


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