Any oil EXCEPT synthetic is fine for break in. The rings need to hone
themselves into the cylinders, and synthetics are too slippery for this
to happen. You can end up with an oil burner with low compression,
which is probably what you had before the rebuild!
I prefer 30w or 40w HD straight weight mineral based oil for break in.
I also am careful for the first 500 miles not to do any constant speed
cruising or get stuck in traffic where the engine has to idle a lot.
Around town driving with its constantly changing speeds is best for the
first 500-1000 miles, this type of accellerate/decellerate driving
provides constant cycling of compression to seat the rings alternated
with high vacuum to suck up lubricating oil on to the cylinder walls. I
also change the oil and filter after 500 miles.
Switch to synthetic if you wish after 3000 miles. See
http://www.vtr.org/maintain/lubricants-redline.html for another person's
opinion on the subject of oil and engine break in.
I've broken in at least six rebuilt engines this way over the years,
including two MGBs, and it's always worked for me.
--
Stuart MacMillan
Seattle
'84 Vanagon Westfalia w/2.1
'65 MGB (Daily driver since 1969)
'74 MGB GT (Restoring sloooowly)
'01 Toyota Tacoma (Something I don't have to fix!)
Personal mechanic for:
'70 MGB GT (Daughter's)
Assisting on Restoration (and spending OPM):
'72 MGB GT (Was daughter's, now son's)
'64 MGB (Son's)
Stripped and gone but their parts live on:
'68 MGB, '73 MGB, '67 MGB GT
///
/// mgs@autox.team.net mailing list
/// (If they are dupes, this trailer may also catch them.)
|