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

You need to polish up the big end journals then check journals for ovality using a micrometer or digital calipers.

see http://www.tpub.com/content/construction/14050/css/14050_73.htm

You can use solder wire instead of Plastigauge for measuring the clearance -

go for a regrind , polish and new oversize bearings while your at it have the flywheel clutc etc balanced as well

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.

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.

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.

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]