LittleAl
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posted on 7/4/11 at 09:08 PM |
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Big end bearings
Hi I have just stripped my 1600 x flow only to find it is a 1700 x flow. The bearing shells on the pistons look slightly worn with the upper ones
having copper showing through. It is possible i have a oil pump problem or pickup problem. Is it always necessary to grind the crank before fitting
new shells? would it be worth getting the details of the shells fitted and get a new set ? don't really want to start taking out crank etc.
Thanks
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britishtrident
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posted on 7/4/11 at 09:21 PM |
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You need to polish up the big end journals then check journals for ovality using a micrometer or digital calipers.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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britishtrident
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posted on 7/4/11 at 09:28 PM |
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see http://www.tpub.com/content/construction/14050/css/14050_73.htm
You can use solder wire instead of Plastigauge for measuring the clearance -
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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austin man
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posted on 7/4/11 at 09:29 PM |
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go for a regrind , polish and new oversize bearings while your at it have the flywheel clutc etc balanced as well
Life is like a bowl of fruit, funny how all the weird looking ones are left alone
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snapper
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posted on 8/4/11 at 06:09 AM |
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As long as the crank journals are clean and round, just fit new bearings, no point in getting the crank ground unless it is scoffed or oval.
Fit a high pressure, high capacity oil pump, you'll be fine.
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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cliftyhanger
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posted on 8/4/11 at 06:47 AM |
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Ditto. I have rebuilt many engines without grinding the cranks. If you look at some of the old workshop manuals they recommended changing thj
ebearings at intervals, Triumph suggested 40K for BE and 50K for mains, helpful or what!
Anyway, a visual inpection is often enough, and even the odd light score has little effect. Check the oil pump is in tolerance or just fit a new one,
but ask about as some repro stuff is out of tolerance before it is fitted. Likewise bearings, cheap is not usually good. Worth checking the thrusts
washers too while you are at it, and the mains.
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britishtrident
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posted on 8/4/11 at 08:01 AM |
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Unlike the very early Kent engines the xflo wasn't prone to bearing problems in normal tintop use, however the pistons are relatively
heavy and when revved hard the bearings are subject to accelerated wear. The early pre-xflo Kent engines were prone to the oil galleries sludging up
causing big end failure as low as 25k miles but Ford addresed this problem but the xflo still tends to produce a lot of tarry sludge so requires a
highly detergent oil with a relatively low cold end viscosity.
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perksy
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posted on 9/4/11 at 02:46 PM |
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ANY Doubts, Definetly get a Micrometer on the crank journals and check them for ovality and taper
DON'T be tempted to just slap a new set of bearings in and go for it
Have seen this done a few times now and they started knocking again within 100 miles
Whilst its in bits, get it measured (doesn't take long) and then go from there...
You'll then have solid base to work from
[Edited on 9/4/11 by perksy]
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