Peugoet Mi16 engine knocking.

It is all very well the bearings looking OK, but you need to measure the bearing journal diameters and then fit appropriate bearings. Just fitting new shells will not reduce excessive clearance - the crank would be regound and then under-sized bearings fitted. It sounds in your case that the crank does indeed need re-grinding. The low oil pressure is due to massive loss of oil through the sides of the bearing, due to the excessive running clearance.

The crank journals would need to be measured with a micrometer to determine any wear. A check could also be carried out with 'plastigage' to determine the bearing clearance.

HTH

Anthony Remove eight from email to reply.

When rebuilding a bottom end, always at least measure the crank journals for wear and ovality- i would personnaly *always* have a grind to no.1 undersize and fit oversize bearings especially on an unknown crank- its too much work to strip it again as you have found if you have problems.

Either you have one bearing wiht a massive clearance loosing the oil pressure or you have one of the crank oil way inspection bungs missing- either way that particular bearing will be shot again already.

Tim..

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Don't know that particular engine but on the old BMC/Leyland units it was essential to prime the system-there was a threaded hole with a short bolt in the gallery by the pressure relief valve just for this purpose. Then spin the engine without plugs until the gauge showed presure and the oil warning light went out. I also made sure every moving part was dripping in fresh oil as I rebuilt the engine. Failure to prime ensured bearing death within seconds on startup. (Crankshaft regrind then). DaveK.

I measured the crank journal diameters while rebuilding and they were all bang on, so I opted to fit standard size bearings. I probably should have just left the engine alone as the old bearings looked pretty good and measured up well too. Anyway too late now :-/

I haven't measured up the new bearings since the rebuild to see if any have exessively worn, just given the big-ends a visual check along with two of the main bearings to see if any had any obvious problems. Maybe I'll get my micrometer out to recheck those. I really can't imagine the crankshaft journals would have worn excessively in the few miles the engine has done since the rebuild.

I'm not aware of any particular priming requirements, but on start-up after having the sump off (i.e drained of oil) and refilling with oil, it sounded noisey for a few seconds before going quiet and sounding like it should; so obviously the oil is getting around. However after a few minutes of warming up it starts to get noisy again. Subsequent start-ups have been reasonably rattle free. I also coated everything in oil while rebuilding too, and kept it all as clean as possible (even did it in my spare bedroom!).

Definately sounds like you have an oil way plug missing somewhere- whilst the oil is thick enough is getting to the bearings to keep them quiet, but as it thins, more is finding the easier route out through the missing plug.

Tim..

Have you checked and double checked the crankshaft pulley tightness?? The oil pump on the XU9J4 has a friction driven gear, that's totally dependant on the tightness of the crankshaft pulley bolt. There's no woodruff key or anything.... I've seen several of these fail, including Car and car conversions own one in 205 conversion.

That's a thought, not really sure of the arrangement of all of the passages and position of plugs though. I do have an old block I could use as a reference to compare.

That was the first thing I checked and its well torqued up, and turning the crankshaft a bit with the breakers bar does turn the oil pump too. IMHO its a crap design, particularly as there's wordruff key on the cambelt gear a few mm away, so it can't have been too much effort to design one in.