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ACRO E-mail Archive Thread: [Acro] Re: M14P Engines

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ACRO E-mail Archive Thread: [Acro] Re: M14P Engines


Thread: [Acro] Re: M14P Engines

Message: [Acro] Re: M14P Engines

Follow-Up To: ACRO Email list (for List Members only)

From: "Rparker" <rparker at>

Date: Tue, 07 May 2002 20:40:19 UTC


Most likely need a new spring in the relief valve, the current one is weak.
Bob Parker
Mena, AR.
----- Original Message -----
From: "John Cornwell" <jwcornwell at>
To: "Randy Reed" <reedrandy at>; "Richard Goode"
<richard.goode at>; <acro at>
Sent: Tuesday, May 07, 2002 1:44 PM
Subject: [Acro] Re: M14P Engines

Oil type, wt., viscosity?

Randy Reed <reedrandy at> wrote:
Ok, what if;
1.  oil presure is fine when the engine is cold
2.  all oil screens are clean
3.  oil presure adjustment is clean
4.  when the engine is hot and has only 55psi at high

    rpm when the adjustment is screwed all the way in
any ideas?

--- Richard Goode <richard.goode at>
> M14P
> In reply to Chad Bartee's questions:
>   a.. Sukhois and Yaks have pressure instruments in
> bar - = 1 atmosphere = approximately 15 psi.
>   b.. At operating speeds - above 60% - oil pressure
> must be in the range of 4-6 bar - = 60-90 psi. The
> Russian's are very emphatic that 4 is the minimum
> for flight.
>   c.. Minimum at hot idle is 1 bar - = 15 psi.
>   d.. Note that on a cold start-up pressure will
> remain low until oil begins to warm up - this is due
> to cavitation in the oil pump. However a minimum of
> 1bar is sufficient during this time, but no less,
> and if it shows less, it demonstrates that the oil
> should have been pre-heated.
>   e.. Low oil pressure is often due to a piece of
> grit under the pressure release valve, which is
> fairly easy to remove.
>   f.. The pressure release valve is easy to adjust,
> and 1 turns of the adjuster = approximately 1 bar
> difference.
>   g.. If an engine displays low oil pressure, and
> the pressure release valve is clean, and increasing
> the tension on the release valve spring does not
> bring the oil pressure into operating limits, our
> experience is that it is unlikely to be the oil
> pump, although possible with older engines, and
> probably bearing wear - this being most likely in
> the front of the gearbox section. However typically
> this will be accompanied by metal particles in the
> oil filter screens.
> Hope this helps.
> Richard Goode Aerobatics
> Newport House
> Almeley
> Herefordshire
> HR3 6LL
> Tel: +44 (0) 1544 322200
> Fax:+44 (0) 1544 322208

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