vintage-race
[Top] [All Lists]

Re: ASM session on motorsports

To: vintage-race@autox.team.net
Subject: Re: ASM session on motorsports
From: Simon Favre <favres@engmail.ulinear.com>
Date: Thu, 05 Dec 1996 14:08:13 PST
>I've never had an engine failure that I couldn't honestly attribute to
>faulty assembly, maintenance, operation or cheapness on my part.

Exactly.  One of the examples cited in Circle Track was putting the
motor together wrong so that you got coil bind on the valve springs.
This led to a broken valve spring which led to a valve getting in the
way of a piston, which led to a bent con rod, which, *ta-da* led to a
broken con rod and a hole in the block.  The racer figured, "&%#&!% rod
broke on me!"  Wrong.

When I got my race car, I was told, "The motor was just freshened up."
I did put a whole season on it, but I didn't take the pan off.  The
first race of the next season, the crank snapped.  On dismantling the
motor, I found the center main cap was loose.  It's only got 3 mains!
There were no lock plates on the main bearing cap bolts.  The way I
figure, the center main came loose, the crank "wandered" and snapped
from the stress.  It took the front main cap with it (cracked) which
meant a new block.  It also bent 2 rods.  Sigh.  I probably could have
prevented this by checking the mains periodically.  I do now.  Not only
did I have the new crank Magna-fluxed, I had the entire block
Magna-fluxed.  It got boiled, baked, decked, line bored and honed. ;=)

When I put the new motor in, it seized the cam after 3 laps.  The
machine shop had not sized the custom bronze bushings properly.  With 3
different size journals (thank you, FIAT!), you can't line-hone the cam
bushings.  Double sigh.  I got another cam with std size journals, fit
factory bushings, and it ran OK.  I had the original cam built up,
ground down and sized to the low end of the factory spec.  It now works
better than the replacement one.

Moral of the story:  forget "if it ain't broke, don't fix it."  My
version is, "If you don't want it to break, fix it again."

<Prev in Thread] Current Thread [Next in Thread>