The problem is that the front cover is very flexible
and there is no fastener near this junction. (Thank you
Mazda)
On a cold start the oil pressure at this junction can
far exceed the pop pressure of the stock pressure relief
valve located at the base of the rear iron. On some models
of front iron there is a relief valve just below this
junction set at 140 pounds. This is to protect the oil
cooler, which is a good idea but is too high a pressure to
keep the junction from pushing open and releasing the "O"
ring.
The object of the thick glass reinforced white washer
(probably Teflon or Nylon) fitted at this junction was to
create added pressure between the aluminum and the cast
iron. It's a spacer.
If Mazda had left the aluminum tube .060" taller than
the gasket surface Or installed a fastener close by, they
would never have had this problem
This was a Mazda fix for the problem that had some
success. The washer took up some space and then a thicker
"O" ring was installed to do the sealing. The washer might
have done some sealing if oil had slipped past the "O"
ring, but it could have been made of any sturdy material.
Steel or aluminum.
Later versions of the front cover gasket had extensions
of hard paper that fit around the washer. (And did
nothing). Later still a composition gasket with a
stainless face replacing the washer. There was never an
attempt to fix the cause. Just cheap gags to prevent the
outcome.
Your fix looks just fine. I would make the ID of the
brass tube just a bit bigger and taper the ends for less
drag. Oil goes through here at a fairly high rate.
I have not seen how this was done on FD or Renesis
engines.
Lynn E. Hanover
In a message dated 2/17/2013 5:57:16 A.M. Eastern
Standard Time,
msteitle@gmail.com
writes:
Todd,
What happened to the counter-bore in the front
iron? Did your model not have a counter-bore? It
appears to have been filled in with Devcon (or JB)?
The walls of the counter-bore are supposed to hold
the o-ring in place and prevent it from being forced
out under pressure. At least that's my
understanding of how it works.
From the pictures, it appears that the thick-wall
bushing will be choking off much of your oil flow,
possibly causing other problems (bearing failure).
Mark S.
On Sun, Feb 17, 2013 at
1:34 AM, Todd Bartrim
<bartrim@gmail.com>
wrote:
Hello All;
It's been awhile since I last posted,
though I've been reading almost every post
to sort of keep up with the latest
developments.
The last time I flew I was seeing
lower oil pressures around 35-40 psi, so I
decided to pull the front cover the other
day. I had previously had a complete O-ring
failure so had done the recommended fix at
the time. When I pulled it the other day,
everything looked good but obviously wasn't.
I recalled Chris having a repeat of this
last fall so searched the archives and found
a reference to him pushing a small cylinder
in there. There was also a previous post
where Lynn commented on somebody else's idea
of a Teflon washer being a good idea. So
I've decided to do both. Attached pics
should show in better detail than I could
explain. I've done a trial fit, but will
await comments before I assemble with
sealant.
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