Has anyone had a problem with their oil pumps, my engine started knocking and i found that no.1 cylinder has spun the big end bearing damaging the crankshaft and con rod annoying af to say the least. anyway my concern is why this has happened the engine was rebuilt 3000km ago and properly run in then all of a sudden it goes knock knock no warning of any sort also i have no oil pressure gauge wired up so could not tell if it had pressure or not the cluster was faulty anyways. thank god i did not sell this engine as i was planning to before it had the spun bearing.

thanks in advance for any advice jack.

Sorry to hear that, hope you can sor something.

Sorry to hear that mate!

 

If the engine was only rebuilt 3000km ago, then one would have thought that the oil pump would have been subjected to a refurb as well..... Apart from observing the run-in period, was the oil changed shortly after - for a decent grade/quality? And for that matter, was the oil maintained at the proper level during run-in as well? With barely 4 litres in the sump, these engines cannot afford to run too low on oil, especially if any "enthusiastic" cornering is involved, as it can result in oil starvation!!

oil pump seemed ok, my thinking is that the engine would have more damage than just a singular bearing fail if the oil pump had failed though? oil was changed to a good 5w 40 oil 500 miles after and i drive it the red line enough but haven't tracked it or cornered hard in it at all. it took around 5 litres ish cant remember exactly but the dip stick indicated a correct oil level just before i removed the sump to check the bearings and has been checked often enough. just trying to work out why only that one bearing has gone bad and it has really gone bad almost nothing left of it at all.

I would say that if your oil pump had failed, you’ve have more damage than just one spun rod bearing. Given how the crank is fed, your Main bearings would had suffered oil starvation before the big ends in the event of a pump failure. Unlike their RB counterparts, VG oil pumps are sturdy bits of kit that rarely fail. However rod bearing failure is a fairly common thing on VG’s.

 

We’re all the engine internals thoroughly cleaned prior to reassembly, including the oil galleys and sludge traps in the crankshaft?

What were you bearing clearances set to?

What brand bearings were used?

Who built the engine?

With all due respect NOT having a working oil pressure gauge was a big mistake, particularly with a newly rebuilt engine.

Any low pressure oil readings would have been picked up at the onset and could have saved the engine from serious damage.

 

Why was the engine rebuilt in the first place? What components were damaged and/or replaced?

 

Have you inspected the other bearings for any onset of damage or unusual wear? This could help narrow down the problem.

It may be that one bearing let go first with the others on their way.

 

As to the failure of an individual bearing this could be down to a single factor or combination thereof. This link provides a

pretty comprehensive list:

 

http://www.twinturbo.net/nissan/300zx/forums/technical/view/769063/Online-infogtgtgtgt.html

Denting the sump is easily done with these cars and with not being much clearance between it and the pick up tube it’s easy to cause starvation.

ok nick so it had the usual no.6 piston damage so it had to be bored out and new forged pistons, it had king racing big ends and main bearings and was assembled by myself i was thorough with checking everything was clean and right when installed. the engine parts were sent off to a company for proper inspection and the bore work prior. no.2 big end has some scratches beginning to appear barely feel it with your nail but i assume its because swarf from no.1 bearing has gone through the system possibly. i agree with the oil pump failing would cause more damage i just wanted to clarify as i should have had a proper oil pressure guage setup but thats why im her now trying to figure were the fault has started.

i will check the sump for clearance between the pickup and bottom of the sump thanks stephen and ill take a look at that article cheers andrew, i just dont want to put a new oil pump, crank, rods and build it up to have a recurring problem as i already spent a couple grand building it and its failed in about 2000 miles of use.