[AT] Mustang

[George Willer]

Spencer,

Here comes a bit of heresy...

I recently fixed up a couple Cub engines that were near the upper wear
limits.  To help somewhat with the end gap problem, I used +.020 rings and
filed them individually to the correct minimum end gap.  Both engines ran
well without smoke after the assembly oil was gone.

Both engines were found with badly stuck rings.  As you know, the sides of
the ring grooves are a very important part of the sealing.  They were
cleaned very carefully.  I've been curious what would have happened if the
original rings and grooves were carefully cleaned so the rings could do
their job and the engine re-assembled without even honing?  I'm sure it
would have made a huge improvement.

A bore worn with a slight taper would keep the rings moving slightly in the
grooves and make them less likely to stick... so the wear isn't necessarily
all bad.  What do you think?

George Willer

----- Original Message ----- 
From: "Spencer Yost" <Spencer.Yost at piedmontsystems.com>
To: <at at lists.antique-tractor.com>
Sent: Sunday, April 18, 2004 10:02 AM
Subject: Re[2]: [AT] Mustang


> *********** REPLY SEPARATOR  ***********
> Larry Voris wrote:
>
> >Spenser:
> >    Did you put oil on the new rings when you installed
> >them.  There is one company that I buy rings from says,
> >to install the rings dry and they will seat on the first
> >few times up and down in the holes. Granted the compression
>
> I do oil the grooves and the rings(and the bores too).   These were
Hastings rings and they indicate that the grooves and rings should be oiled.
However you do have to oil the piston and the compressor when installing the
pistons so I am sure plenty of oil gets on the rings just as a by-product of
that process even if I didn't oil the rings directly.  Having said that, I
can see where at least not over-doing the oil at assembly may help in the
initial seating.  I like to hear some other comments on this.
>
> *********** REPLY SEPARATOR  ***********
>
> On 4/18/2004 at 5:47 AM bwhdon wrote:
>
> >Ive rebuilt quite a few engines and always oiled every thing up real good
> >before starting, turned the engine over with out ignition to prime the
oil
> >pump and all bearings etc and never experianced an engine burning oil as
> >long as 15 minutes on start up. Might have been a stuck ring or valve
seal
>
> I failed to mention that the flat-head Continentals don't have valve
seals.   Stuck ring is possible since it was about 3-4 weeks between
assembly and start-up.
>
> I do prime the engine before start-up and had strong flow and pressure out
of the oil pressure gauge line at the dash before I started it.
>
> One thing I failed to mention - I did not re-bore that engine.  This
engine had cylinder wear within specs.  I just honed it and moved forward.
I had never done that before either.  Maybe that was a factor?
>
> By the way, here are the parameters and specs:  My notes say the max wear
was .004"(average of .002"-.003") and min. of .002".  Max bore variance was
.002"(range of measurements was unmeasurable to .002")   The Continental
manual say those limits are .007 and .004 respectively.  Oil pressure was
great and no oil leaks.   Oil ring gaps were a bit loose (understandably)
but within specs.
>
>
> Thanks for the input.  I'd love to hear some more...
>
> Spencer
>
>
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