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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