How Long To Run In New Bearings?

[sky30]

I have put new mains and rod bearings in a old forged motor, how long or kms before the bearings are run in and ready for full power?

[R31Nismoid]

People usually just bed/seat the rings on the dyno, and full power off you go. So bearings all sorted then too would be what one would take from that.

[abr33]

Were they checked for clearance or blueprinted?

[SilverECR33]

people have different techniques and times, and depending on the clearances, condition etc. some guys say hard and fasst, after bed in go full power. otherwise some suggest bed in then wait 1,000kms while doing some loading processes before full power, but really,,.. if your unsure, call a tuner/engine rebuilder.

[AngryRB]

im bit curious here, what would be the reason for replacing the big end bearings on a tired motor? ... would replacing them on a motor with highish km's be a good preventative measure against spinning a bearing or would that make you more likely to spin one if you have say 300kw's?

Edited September 26, 2012 by SliverS2

[SilverECR33]

its not so much power related as it is related to clearances and proper preperation during assembley.

[sky30]

Blew an oil pump, had new bearings here so put them in while it was apart, bearings that i took out were in good condition.

Sumone must have a general rule for fresh bearings in a motor with pistons already run in. ??

10kms? 100kms ? 1000 kms?

[SiR_RB]

_{when i bought my r33 gtr engine and took the sump off to fit a tomei sump baffle, we changed the main and rod bearings just as a preventative measure}

_{stock bearings and journals were still great, so standard size replacements went back in, i was advised to do 1000kms to "take the sharp edges off" before giving it hell.}

[JustinP]

My view for "running in" bearings, 0km.

Blew an oil pump, had new bearings here so put them in while it was apart, bearings that i took out were in good condition.

Sumone must have a general rule for fresh bearings in a motor with pistons already run in. ??

10kms? 100kms ? 1000 kms?

[GTSBoy]

Bearings do not run in.

How the hell can a hydrodynamic bearing need to run in?

Nonsense question is nonsense.

[DVS JEZ]

Last time i did bearings on my drifter due to snapping oil filter thread with a cheap sandwhich plate

Start it.

Check for noises.

Rev it.

Put on trailer

Thrash at wakefield

[NoFigJamHere]

_{when i bought my r33 gtr engine and took the sump off to fit a tomei sump baffle, we changed the main and rod bearings just as a preventative measure}

_{stock bearings and journals were still great, so standard size replacements went back in, i was advised to do 1000kms to "take the sharp edges off" before giving it hell.}

Can you please let me know which brand bearings you used? I just want to avoid this brand that has these "sharp edges"... Most bearing failures are caused by detonation, failed oil pumps (no oil pressure,oil surge on track cars) and the thing you rarely get told about....... Foreign materials ie: DIRT.... and blocks,heads and every single part not being thoroughly cleaned...

[sky30]

Bearings do not run in.

How the hell can a hydrodynamic bearing need to run in?

Nonsense question is nonsense.

Thanks for the nonsense answer.

[GTSBoy]

In a hydrodynamic bearing there is no metal to metal contact. The bearing interface is a layer of pressurised oil. Thus, there is no "wear in" period, because when the bearing is running metal to metal, it is destroying itself.

Nonsense question did not get a nonsense answer.

[AngryRB]

isnt that like saying the pistons and rings dont need bed in cause if there was metal to metal they'd sieze up?? just trying to learn here excuse if i am totally wrong..

[LANDSCRIBBLE]

i thought the rings were metal to metal? how else could it seal?

[portaz]

After changing bearings I just do a few hundred K's and watched oil pressure behavior then it went to dyno, even though there is no metal contact it's just good practice to make sure there are no issues.

[89CAL]

Last time i did bearings on my drifter due to snapping oil filter thread with a cheap sandwhich plate

Start it.

Check for noises.

Rev it.

Put on trailer

Thrash at wakefield

I like your style

[AngryRB]

so you had a trailer to tow it back just in case hahaha

[nick81xd]

ive always just gone easy for first 500klm doing low to mid load as the klms rack up. just so if theres any issues it can be noticed and shut off early rather then when its on song in high revs