New engine bearing wear?

[tsifreak]

On a new engine is it true to see some small bearing debris in the oil filter?
From my understanding when the bearings are newly installed they are not perfectly round as the journal they are riding on is?
I have seen this on 2 new engines and the wear found is no longer found after about 1000 miles and 4 oil changes.
Both engines were pre lubed with oil and clearances verified.
Just looking for some truth to this.

 

[MikeHalloran]

That's why the filter is there.


Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

tsifreak,

On a recip piston engine with journal bearings, there will be lots of "bearing" debris generated and collected in the lube system filter during the first few minutes of operation. But this "bearing debris" usually consists of soft tin and babbit overlay materials and is fairly harmless.

The filtration level selected for most oil filters is set such that any debris particles passing through the filter are still small enough to pass through the journal bearing HD oil film without causing abrasion to the journal or bearing surfaces. For a typical crank bearing, this would be about 50 micro-inch or less.

So to answer your question, yes it is true.

Regards,
Terry

 

[tsifreak]

Cool thanks guys!

 

[SMOKEY44211]

OEMS no longer use traditional babbit material. Aluminum alloy is now the material of choice. The way it was told to me was that they wanted to eliminate lead for fear of possible lawsuits. I guess someone must have been afraid that someone would dissassemble an engine and start chewing on the rod and main bearings. Curiously cam bearings seem to still be trimetal.------Phil

 

[BrianPetersen]

The elimination of lead is due to environmental / safety regulations in the worldwide market.

It's not a matter of disassembling an engine and chewing on the rod and main bearings ... it's a matter of the engine being shredded indiscriminately at the end of its life in the junkyard, and the lead getting mixed in with absolutely everything. You can magnetically separate the bulk of the iron, but lead alloyed with other stuff is hard to get out, and it ends up contaminating everything and partially getting airborne in the process (lead melts and vaporizes well below the temperature at which aluminum melts, for example). Lead in the journal bearings also gets into used motor oil during normal engine operation, and contaminates that, also.

 

[franzh]

I had a 1999 Ford F-150 with a 4.6 liter engine. It blew a spark plug out while under warranty. The Ford dealer replaced the head and performed some other TSB repairs (dont remember which ones). Apparently, the technician used one of those rollock pads on a high speed tool to clean the gasket surfaces and it all went into the pan.

The engine lasted about 2 weeks when the bottom end and cam bearings were wiped. Another Ford dealer did the disassembly work and asked who did the initial work. They replaced the complete engine when they found the fiber debris from the rollock pad embedded in the inserts and the filter.

Franz

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[dgallup]

I think one of the major reasons for getting the lead out is it poisons catalytic converters.

 

[ivymike]

Terry, are you saying that the filtration level of your typical oil filter is such that particles down to 1.3 microns (50 micro-inches) are removed? That'd be about 30 times smaller particles than I thought were caught.


tsifreak, How much bearing debris is being seen in your filter? On the engine production lines I'm familiar with, each engine is "hot tested" before being shipped. During the hot test, the engine is run and a special filter is used to catch debris for examination. If much debris is found, the engine is sent on a trip through the service area to figure out what's wrong. Either way, the oil is removed and replaced, and a brand new filter is installed. There's not much left after hot test for the customer to find.

 

[BrianGar]

Thats very interesting Ivymike, Ive always wondered exactly how that procedure was carried out on the line.

Brian.

 

[tsifreak]

Mike not much debis is found in the filter just looks like a little sand at the bottom of it.

 

[ivymike]

"truly new" new engines, or rebuilt?

 

[tsifreak]

Mike this was a rebuild. The block was line honed with ARP studs and the scat H beam rods got honed to size as well so everything was dead on. Bearings used were ACL race tri metal.
The crank is a virgin crank uncut. Bearing clearances were set at .0028. Oil to be used will be Brad Penn 15/40.
Engine is a 4 cylinder mitsubishi 4g63 turbo motor that will see 600 HP.

 

[ivymike]

as franzh noted, build cleanliness can be an issue (on a production line too, but particularly in a small shop). I've heard that some intentionally introduce abrasive materials to the cylinders to "seat" the rings... I've only ever done that in a lab to simulate accelerated wear - it works great to wear out an engine in a hurry - I'd personally avoid (to the extent possible) contaminating an engine I intend to keep.

 

[tsifreak]

Mike I build all my stuff hospital clean. After the I picked the short block up from the shop I cleaned off the cylinder walls with wd 40 and paper towels as the wd 40 lifts all the crap off the cylinders to wipe away.

 

[ivymike]

what's done to keep the oil passages clean?

 

[EHudson]

Some pistons are tin plated. The tin can melt and coalesce into tiny beads that can end up in the oil.

 

[NormPeterson]

Ivymike - on those engine "hot tests", do you have any information regarding the maximum rpm encountered?


Norm

 

[ivymike]

depends on the rating - rated speed in each case.

 

[NormPeterson]

Would that correspond to peak power or redline? Or something else?


Norm