In a message dated 4/1/04 9:09:14 AM Pacific Standard Time,
mattspit@worldnet.att.net writes:
> Subj:Re: Re Clevite bearings
> Date:4/1/04 9:09:14 AM Pacific Standard Time
> From: mattspit@worldnet.att.net (matt matthews)
> To: Guyots3@wmconnect.com, Herald948@aol.com
> CC: fot@autox.team.net
>
> Not all clevite bearings are tri-metal. Bought a set for my triumph and they
> were aluminium.
>
> > From: Guyots3@wmconnect.com
> > Reply-To: Guyots3@wmconnect.com
> > Date: Fri, 26 Mar 2004 23:14:25 EST
> > To: Herald948@aol.com
> > Cc: fot@autox.team.net
> > Subject: Re Clevite bearings
> >
> > In a message dated 3/26/04 5:04:14 PM Pacific Standard Time,
> > owner-fot-digest@autox.team.net writes:
> >
> >> NAPA online lists Item#: CEB MS1112P for $69.99!
> >
> > Hi Andy,
> >
> > I don't care really 'where' people get them from, just as long as they get
> > the best deal.
> > In this case, I would still suggest that a print-out of NAPA on-line's
> price
> > is obtained, and taken along to the local CSK for a competitive price match
> > less 5% = $66.49
> >
> > Best Regards
> >
> > Leon.
At what point in this thread did anyone say how the Clevite bearings are
constructed?
I must have missed that :-(
Surely, 'Pure' Aluminum bearings do not provide both hardness & plasticity,
which of course is what bearings need to provide, in addition to 'oil
retention'.
Bearings are usually alloys consisting of a soft matrix in which are embedded
crystals of a harder metal, the soft matrix wearing at a greater rate than
the hard crystals during the running in period, the depressions left in this
way
act as oil reservoirs which provide the initial film on starting.
Bearing materials in my understanding are usually:
'White Metal' : (1860 Isaac Babbitt): originally 85% tin, 10% antimony, 5%
copper.
Nowadays, 1 - 2% more tin, 1 - 2 less copper.
In Vandervell 'Thin Wall' bearings, the steel shell is usually about 0.030 to
0.040 inches thick, with a white metal lining 0.015 to 0.020 inches thick.
The second type are Lead-Bronze bearings, usually 2/3rds copper and 1/3rd
lead.
Not an alloy but a mechanical mixture.
One advantage over white metal is the higher limiting load factor, two
disadvantages are (a) that it tends to wear the crankshaft more readily than
white
metal, and (b) larger running clearances are necessary. The former can be
countered successfully by the provision of hardened journals and crankpins on
the
shaft; the latter calls for a higher oil pressure and a larger capacity oil
pump to compensate for the losses from the bearings.
Nowadays, some of the lead bronzes have a small amount of tin alloyed with
the lead. Another disadvntage of lead-bronze as a bearing metal is its poor
resistance to corrosion by acid oxidation products in the lubricating oil.
Frequent oil changes are beneficial.
The latest (1960), types of shell bearing use a protective layer of tin or
indium, about 0.001 inches thick, and without regular attention to air & oil
filters, road dust and combustion contaminants in the oil will gradually wear
away this protective skin.
The third and final type are the roller bearing crankshafts as used in the
more highly developed of the Porsche models. These are made under patents of
Albert Hirth A.G. Maschinenfabrik of Stuttgart-Zuffenhasen. This crankshaft is
an
expensive item, but it has enabled the Porsche engineers to extract five
times the power from an engine originally designed to produce pnly 25 bhp.
{extract above from 'The Sports Car', it's design and performance, by Colin
Campbell, 1960, Robert Bentley books).
I doubt that the Clevite bearings are simply 'aluminum;, or they wouldn't
last very long at all.
I suppose we could try asking Clevite?
I do know that Vandervell bearings have long been preferred over Glacier
bearings, which seemed to replace them in recent years, although old stock
Vandervells do deteriorate if poorly stored.
I don't know if Vandervells are available any longer?
Can anyone add anything?
Regards
Leon
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