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MG Midget and Sprite Technical - Bearing clearance

Going to be checking over an old engine.
Want to check main and big end bearings.
What us an acceptable clearance ?
Tim
T Dafforn

what is the engine? If its an old white metal bearing I can give you a calculation for the correct clearance... if its just shells like most MGs... just replace them as standard... I think its 25 for a full set of shells for my midget.
C L Carter

C L Carter

I would be intersted in the clearance calc for white metal bearings.
Is it possible to email it to me.
Thanks

Les
Les Robinson

Les,
A little while ago in answer to another thread I posted details of an engineer in Lancaster. Just thought he might be of interest to you as well as he does do remetalling of white metal bearings. http://www.lancasterengines.co.uk/
If you don't have a nearer contact then he isn't too far away from you.

Guy
Guy

Les here is the formula... to measure the clearance, you need to get some platigauge... which are thin strips of "playdough" which won't damgage the bearing surface... when torqued up... they squish out flat...and you compare it to a piece of card to see the clearance. Simple = clever


c= ( N^0.5 * D^2.5 ) / 360

Where C is clearance in thou,
N is RPM
and D is diameter in inches

Need to make an assumption as to average RPM

There are very few white metallers out there these days... I'd guess about 20 in the UK... so if you find a good one... let me know. I can tell you a bad one to avoid but have no good ones to reccomend. At my motor club we've begun experimenting casting our own!
C L Carter

Sorry, its a 1275..
Cheers
Tim
T Dafforn

1275... just buy new bearings if it needs them... you'll be able to tell if it sounds clunky once its running... and if you are going to strip the engine down for a rebuild... i'd put new ones in as a matter of course.

if i was testing an old engine... step one... does it turn over by hand - get a socket on a timing wheel and turn it over... if it moves... the bearings will be fine to start her up on... if it doesn't... well then theres a whole different kettle of fish... I'd start with WD40... although many would dissaprove of this

=]
C L Carter

Guy and C L Carter, thanks for the info.

Les
Les Robinson

This thread was discussed between 12/12/2011 and 14/12/2011

MG Midget and Sprite Technical index

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