Date:         Fri, 9 Aug 2002 00:54:56 EDT
Reply-To:     FrankGRUN@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Frank Grunthaner <FrankGRUN@AOL.COM>
Subject:      Re: Why this type IV engine caught fire,
              spun the mains and ruined everything.
Comments: To: wilden1@JUNO.COM
Content-Type: text/plain; charset="US-ASCII"

In a message dated 8/8/02 7:19:57 PM, wilden1@JUNO.COM writes:

<< If you look at the bearing you'll see that the pin missed the bearing
alignment hole.
The pin applied undue pressure on the bearing that may have been a
friction factor as well.
The bearing became ever so lightly egg shaped as the case tightened, this
condition may not have caused the crank to lock while the rods / etc were
being installed but eventually it caused the engine to fail from oil
starvation to almost all engine bearings.
Every bearing shows signs of operating under extreme heat and are failed.
I can visualize that the engine may have held 5/8 pounds of oil pressure
and the idiot light might not have signaled the operator but as heat
built up and the oil thinned it could have continued with enough pressure
that the sender might not activate the oil indicator light.
During installation the case may have originally dropped together
properly but considering Murphy's law the bearing could have moved as the
case was rotated, rolled over or handles in the bolting together process. >>

Stan,

Good observations as usual but I think my experiences may have been a bit
more harsh than yours.

First, I personally think that a few more pictures (if you have them) would
be really instructive. In the air cooled cases I have cracked (almost all
type 1 spinners) I often encountered strongly warped sealing surfaces and
oval bearing recesses due to gorillas drawing down misaligned and
contaminated case halves. I also often encountered the spun main or rod
bearing because the journal to bearing surface had not been properly measured
with plastigage.

Second, in every case I saw of bearing deformation due to overcrush or pin or
slot alignment, the journal seized in a few tens of hours of operation. As
you well know, any metal to metal contact in the engine will destroy it. Its
the thin oil film that staves off the ultimate disaster for millions of
revolutions. If that gap is too thin, then metal to metal and gone. Of course
a similar threat lies in waiting if the gap is too large. A too large bearing
gap will make it impossible to define a standoff film with adequate shear
strength.

Third, a key lesson for the amateur engine rebuilder is cleanliness,
cleanliness, cleanliness. Put that thing together wearing a clean white
cotton glove and it will sing. Throw it together with an air gun to keep
moving the dirt away from the area that you are wrenching and the extra parts
inside that flying ball mill will come back to bite you.

Just a comment.

Frank Grunthaner