300tdi bigend bearings after 100k mi

[cipx2]

Following Scotian's mishap with his bigend bearing fail on his 200tdi I finally got the "round tuit" to take the sump off and take a peek at the bigend bearings on my 300tdi (on a '98 Discovery).

Here's how the they looked like after exactly 100k miles, 1 through 4 from left to right, top shells on top of the picture:

Here's a closeup of the top shells:

[Les Henson]

That looks about right to me - mine were the same as yours on the 300TDi.

Top shells always wear first.

Les.

[western]

dare I look at mine after 290,000 miles?

[Les Henson]

Well you could, but they might not be there anymore

Les.

[western]

must be there's no knocking & oil pressure is still good

[cipx2]

Yes, the top shells wear first as they take the "bang" in the cylinder. Also, the #4 wears first being the furthest away from the oil pump (the oil pressure is lower).

I would say they look somewhere between fair and good. I didn't expect to see the copper but since I didn't owned it from new (although it was well serviced) I'd say it looks fine.

There are some pics from 250-300k km tdi bigend/main shells on the forum down under, I can dig for some links if someone's interested.

[Jon White]

They look alright - when i looked at the ones in my 195k rangie they were actually much better than those. In fact I put them back in again as they really didnt warrant changing.

Only enough the ones in the 200 in my series were in far far worse condition (I changed them) and it had done a lot less miles.

Guess it shows what proper servicing does as my rangie has a FSH even up to nearly 200k miles!

Jon

[cipx2]

What engine does your RR have?

[JimAttrill]

The big ends and crank on the 300Tdi are often perfect after large mileages where the engine has to be rebored. Remember the 300Tdi engine has a much better oil pump than the 200Tdi and it doesn't wear much with mileage. I think taking your big ends out just to look at them, or even change them, is a bit silly. Don't you have anything better to do?

[cipx2]

Is a bit silly to make assumptions when you don't know the facts, i.e. the engine history/mishaps with the oil system the previous owner experienced (who knew zilch about engines). I didn't just do that out of the blue or after getting out of bed the wrong side.

[Happyoldgit]

Was it knocking or have low oil pressure - if not why did you feel the need to take a look?

[Jon White]

What engine does your RR have?

300tdi

[Jon White]

On mine the crankshaft end float was found to be excessive after the auto flex plate broke.

You obviously need to take the centre main cap off the change the thrust washers and so whilst I was in there a took a few of the other caps off too just to have a looksee. We took the engine out to sort it out as I changed all the oil seals on it at the same time as it was leaking oil from every oriface.

In short we changed the thrusts to sort the end float out but otherwise left the bottom end alone.

Jon

[cipx2]

Thanks Jon.

MOG, no, they were not knocking and oil pressure is within specs (that's why I didn't take the main shells out after seeing/measuring the bigends). When the bigend bearings start to knock under load it's too late to do something, most likely the cranckshaft needs to be regrinded to do a proper job.

There was a tiny weeny bit of bigend knock on a couple of cold startups (hot days) when I first took the car - which couldn't be heard after changing the oil (the oil used by the previous owner was of good quality synthetic but a bit too thin for this engine and due to change at that time).

Two other things:

- the previous owner used, at some point in time, a wrong oil filter which blew (or at least leaked an important amount of oil) under pressure on cold; this happened 2 times until they managed to find the cause; the mechanic even took out the sump to check the oil relief valve; since I don't trust mechanics by default (unless I know them very well), I wanted to make sure he put everything back by the book (and it wasn't - no new gasket/o-ring on oil pickups, no locktite on 2 bolts - one of them being dangerously loose).

- an oil hose was replaced and I couldn't find out if the old one was just leaking or blew up (leading to massive oil loss).

In all these cases I don't know how the situations were handled, if it was driven with low/no oil pressure or a low level of oil. So I had to know what's in there before being too late and for my own peace of mind.

[JimAttrill]

Fine, so you did do it for a reason. I thought you had just removed the big end shells to have a look see.

[Rotor]

The big ends and crank on the 300Tdi are often perfect after large mileages where the engine has to be rebored. Remember the 300Tdi engine has a much better oil pump than the 200Tdi and it doesn't wear much with mileage. I think taking your big ends out just to look at them, or even change them, is a bit silly. Don't you have anything better to do?

I dont think its silly if you are capable of doing it yourself on a high milage engine, preventative maitanence is better than buying a new crank, if you have to pay a garage UK labour rates then I`d think twice,I saved a 4.2 Land Criuser engine by doing the same (and around Five thousand pounds!),

It dose not hurt to remove the sump on high milage engines if you dont know the history, often they are full of sludge and oil pick ups are at risk of becoming blocked.

Rgds

Rotor

[JimAttrill]

Got this out of a TD5 oil pickup. The engine had no oil pressure, the camshaft seized but the big ends and mains were ok.

Caused by the fanbelt breaking and forcing its way into the sump where it was chewed up by the chains: