Magnesium Case with pitted degradation

Hi,

We took apart a used 1600 motor that had been sitting for years and found
degradation in the bottom of the case around the oil filter screen. There
appears to be no problem with any mating surface or bearing surface. Our
guess is moisture and magnesium don't like each other. It visually looks
rough and chewed up on the interior bottom

Should we continue with line bore and rebuild or throw away and look for
another case to rebuild?

If we should throw away...why?

thanks
marshall

I had an old Harley 30 years ago that had pitting on the cam cover.
The pits didn't look so bad when I was assembling the engine, but they
were bad enough to let oil weep through them to the outside. If money
is tight, then I might agree with line boring and taking a chance.
However, sometimes taking a chance is like spending dollars to save
pennies. If the case turns out to be no good, then your oversized
bearings are of no use and the time it takes to pull the engine and
swap everything over to a new case is a hassle. - Bob

MarshallE wrote:
> Hi,
>
> We took apart a used 1600 motor that had been sitting for years and found
> degradation in the bottom of the case around the oil filter screen. There
> appears to be no problem with any mating surface or bearing surface. Our
> guess is moisture and magnesium don't like each other. It visually looks
> rough and chewed up on the interior bottom
>
> Should we continue with line bore and rebuild or throw away and look for
> another case to rebuild?
>
> If we should throw away...why?
>
> thanks
> marshall

Post some pics.. maybe after someone sees the actual condition, they
could help. You use words like chewed up.. I would automatically say
trash can.. but I don't know if you are exagerating or not.. and I
would hate to see a good case go to the dumpster.


MarshallE wrote:
> Hi,
>
> We took apart a used 1600 motor that had been sitting for years and found
> degradation in the bottom of the case around the oil filter screen. There
> appears to be no problem with any mating surface or bearing surface. Our
> guess is moisture and magnesium don't like each other. It visually looks
> rough and chewed up on the interior bottom
>
> Should we continue with line bore and rebuild or throw away and look for
> another case to rebuild?
>
> If we should throw away...why?
>
> thanks
> marshall

Many of them are like that. I wouldn't worry about it.

In case the though crossed your mind: I wouldn't try to fill it with
anything either, just leave as is and stick with regular oil change
intervals.

Engine oil gets contaminated with sulphur among other things, as the
engine runs. If you don't change your oil often enough, the sulphur
content grows so high that the oil will actually start eating weak
resistance metals. This is one reason you should never use used motor
oil for protecting the pans from rusting... if you are hell bent on
oiling your pans, do it with clean, unused oil. (mixed with vaseline or
other goop of your choice, as people often do).

This is also why when preparing an engine for long time storage, you
should leave it with fresh, unused oil in it. Not let the old,
contaminated oil sit there. Maybe that's what happened to your case at
one point of it's life. Long improper storage, or way too long oil
change intervals. You know how some people just run their vehicles to
the ground.

Jan


wrote:
> Post some pics.. maybe after someone sees the actual condition, they
> could help. You use words like chewed up.. I would automatically say
> trash can.. but I don't know if you are exagerating or not.. and I
> would hate to see a good case go to the dumpster.
>
>
> MarshallE wrote:
>
>>Hi,
>>
>>We took apart a used 1600 motor that had been sitting for years and found
>>degradation in the bottom of the case around the oil filter screen. There
>>appears to be no problem with any mating surface or bearing surface. Our
>>guess is moisture and magnesium don't like each other. It visually looks
>>rough and chewed up on the interior bottom
>>
>>Should we continue with line bore and rebuild or throw away and look for
>>another case to rebuild?
>>
>>If we should throw away...why?
>>
>>thanks
>>marshall
>
>


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