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+--- Thread: New big ends: end float (/showthread.php?tid=434)
New big ends: end float - "Slack Alice" Simon - 09-11-2017
Good evening, assembled gurus,
What, if any, is the recommended end float for big ends on a re-ground crank with re-metalled rods?
3 of the rods move back and forth a little, the fourth not at all, though not tight, since the engine turns by hand.
I have yet to remove the block and see if they have been "barrelled" - or whatever it is called.
Thanks
Simon
RE: New big ends: end float - Zetomagneto - 09-11-2017
Woodrow says up to 1/16"'. That would be excessive for a pressure fed crank, but probably ok for a splash feed
RE: New big ends: end float - Alan - 09-11-2017
12 to 15 thou.
RE: New big ends: end float - "Slack Alice" Simon - 10-11-2017
(09-11-2017, 11:32 PM)Alan Wrote: 12 to 15 thou.
Thanks
Three are 10 thou ish and one is near zero - I will get scraping!
RE: New big ends: end float - Zetomagneto - 10-11-2017
(10-11-2017, 10:50 AM)Slack Alice Wrote:(09-11-2017, 11:32 PM)Alan Wrote: 12 to 15 thou.
Thanks
Three are 10 thou ish and one is near zero - I will get scraping!
A file would be easier than scraping for side clearance, or a piece of abrasive paper placed on a surface plate with cap assembled to the rod.Measure the width with caliper or micrometer before you start, then keep checking until you have reduced sufficiently to give the target clearance.
RE: New big ends: end float - Ruairidh Dunford - 10-11-2017
Be very careful which abrasive paper you choose, if you go that route.
I have noticed carborundum, for example, will attach (embed) itself (in)to soft metal.
RE: New big ends: end float - Chris KC - 10-11-2017
(10-11-2017, 12:56 PM)Ruairidh Dunford Wrote: Be very careful which abrasive paper you choose, if you go that route.
I have noticed carborundum, for example, will attach (embed) itself (in)to soft metal.
Spot on - plain bearing materials are specified such that hard particles easily embed in the surface, as this is preferable to them sitting proud. Clearly highly desirable that they do neither!