Debris in oil - can you identify?

[ragpicker]

The tappets on the 3.4 are used on loads of different cars aren't they, its almost like the pre variocam plus block was machined to take a pre-existing tappet. I seem to remember them being used on Kia's too..

By comparison, half a dozen inlet tappets for my turbo cost the thick end of £1k! :what:

 

[coullstar]

So I rotated the engine by hand bit by bit to see any issues with crank and I found this very small section where it does appear the crank has been rubbing ever so slightly.
I moved a screw driver across the groves on the bit before and after and they did seem less pronounced in the small leading section.

If that is it what it is what could it be rubbing on, is there anything with a very close clearance to it?

 

[infrasilver]

The crankshaft cage the crank sits in has quite close tolerances but nothing too much to actually touch or be very close, if this has happened this would have been done in the first few revolutions of a newly built engine I would assume and not something that would get worse with time.
In theory the damage may have been done and nothing else will get worse than it is, hopefully if this is where your debris is from they may have been in the engine for a while.

This is how the crankshaft sits in its cage and doesn't protrude from this, it can only have caught on the cage or something got wedged in there, if this is what has happened?

 

[coullstar]

Tempted to get tensioners looked at then run it for a little using a magnetic sump plug for a little while and see if it continues to produce these flakes as I agree it may have been in there since day 1 and not been removed completely.

 

[infrasilver]

Tempted to get tensioners looked at then run it for a little using a magnetic sump plug for a little while and see if it continues to produce these flakes as I agree it may have been in there since day 1 and not been removed completely.

I'm swaying towards this now, tensioners and cam chain pads looked at/replaced and see how it goes with any pick up on the magnetic sump plug as it will pick everything metallic up in the sump, if you are confident that the debris is from the crankshaft.

 

[coullstar]

Total area of the metal pieces I've found is very similar to that area on the crank I found.

It would account for the markings as well and the fact that no one has ever seen the sort of flakes before. The colour could be down to oil staining as well.

 

[Harv]

Looks like you've found the source, great work :thumb:

I can't tell the orientation from your pic but is that web the leading edge for the cranks rotation (so the the pulley -if it could be seen- in your pic is to the left and flywheel to the right?) as if it is then this would help confirm what might have caused this could be casting defect on the crank carrier for that web which took a chunk off on first start.

The cranks are forged using sintered powder so the other theory could be there was an issue during manufacture with the microstructure in that web which simply came away in use.

Gives a bit more confidence that you should be ok once the other issues are fixed.

Have the tensioners removed and inspected, I would think they are the updated versions with internal springs. They are so simple there's not much in them that can fail other than a broken spring or binding issue.

 

[coullstar]

Correct, flywheel to the right and pulley to the left.

 

[Y2K]

Looks like you've found the source, great work :thumb:

+1 :thumb:

Best of luck with the fix. Hope it won't be too costly.

 

[coullstar]

Okay sump back on this afternoon then I'll add oil tomorrow after letting sealant have a good set. Magnetic sump plug added.

One question though is the car has been sat for about a week with no oil so is it prudent to prime the car or just fill and wait another day or so before starting regards the tensioners?

 

[Locosaki]

Could you not just pull the fuel pump fuse and crank it over to pressurise tensioners then go from there, filling and leaving I don't think will do much if anything.

Good work by the way.

 

[infrasilver]

I wouldn't bother priming the engine, it will have as much oil around the engine as it would if the sump was still on and full of oil.

How many miles are you going to give it before checking again?

 

[coullstar]

Still speaking to a specialist about when he could look at it. I was going to do a couple of hundred then check sump plug and repeat that for a while.

 

[coullstar]

Found this thread
https://rennlist.com/forums/996-for...lve-noise-fixed-my-findings-and-solution.html

Bloody annoyed that I've put the sump back and filled with oil and could have had those pots out in the sump to check.

 

[Harv]

Sounds exactly the same as what you are experiencing. If in doubt then just pull the sump again, it's only 20 bolts or so and some sealant.

I assume you are going to get the 4 vario guides in both banks changed before running it further :?: