big end bearings keep breaking

[jamedd]

hi ive got a 99 sxr i dont know whats happening but somthing keeps breaking my big end bearings i thought it might be somthing blocking the oil channels. not to sure tho so was just wondering if anyone else has gone through this before.

[skidlid]

Never known a big end bearing break, they normally wear out through lack of lubrication but they knock long before that happens.

I have known an engine where a big end bearing cap broke but that was caused by incorrect assembly using a non-matching part.

[jamedd]

44 minutes ago, skidlid said:

Never known a big end bearing break, they normally wear out through lack of lubrication but they knock long before that happens.

I have known an engine where a big end bearing cap broke but that was caused by incorrect assembly using a non-matching part.

Didn’t mean break didn’t know how to put it but it’s not doing what it’s meant to be don’t think it’s getting any oil and I feel like something might be blocked just don’t know where to look 

[Mjolinor]

Pictures would probably help.

[Xanadu_999]

4 hours ago, jamedd said:

Didn’t mean break didn’t know how to put it...

You mean seized, like this?

[jamedd]

15 hours ago, Xanadu_999 said:

You mean seized, like this?

yeah seized thats the word i was looking for it doesnt seem to be getting oil just not sure where to start looking 

 

[Mjolinor]

So your bearings look like that picture?

That has not seized badly, it has worn out and has suffered from a few late oil changes in its life.

Post some pictures.

 

[flash22]

are you running them in, correctly, if you are just slapping in bearings STOP they are precision-fit items you need to get the crank and rods checked for size a roundness and the bearing sized correctly with the correct running  clearances as there are differences in bearing suppliers

with that sort of bearing damage in a short period shows oil contamination and/or the bearings being too tight - the engine needs a full strip-down inspection and clean

 

[jamedd]

On 9/12/2024 at 5:52 PM, Mjolinor said:

So your bearings look like that picture?

That has not seized badly, it has worn out and has suffered from a few late oil changes in its life.

Post some pictures.

 

ill get some when i get home im at work for the next few weeks 

 

[jamedd]

On 9/12/2024 at 6:19 PM, flash22 said:

are you running them in, correctly, if you are just slapping in bearings STOP they are precision-fit items you need to get the crank and rods checked for size a roundness and the bearing sized correctly with the correct running  clearances as there are differences in bearing suppliers

with that sort of bearing damage in a short period shows oil contamination and/or the bearings being too tight - the engine needs a full strip-down inspection and clean

 

alright thanks ill strip the engine down and tighten up the bearing to the right specs and ill take the crank and rods to a shop to get them looked at 

[flash22]

you need to have the correct clearances between the bearing and crank so you get the correct lubrication, too tight and you get metal-on-metal contact/oil starvation, too loose and you get low oil pressure and and rapid wear like a hotdog down a hallway

if you are going to a machine shop take the block in and get them to check the complete bottom-end

I assume it is the 2.2 5s-fe engine

[Shared]

6 hours ago, flash22 said:

you need to have the correct clearances between the bearing and crank so you get the correct lubrication, too tight and you get metal-on-metal contact/oil starvation, too loose and you get low oil pressure and and rapid wear like a hotdog down a hallway

if you are going to a machine shop take the block in and get them to check the complete bottom-end

I assume it is the 2.2 5s-fe engine

This is the best advice, replacing worn big end bearings without having the crank journals measured is akin to changing a clutch & using the old thrust bearing.

If you really dont want to take it to a workshop and have them accurately measure & advise you should at least try to determine journal wear/bearing clearances with some of this ..

https://plastigauge.co.uk/about/how-plastigauge-works/

[Mjolinor]

I used to scrounge dental wax off my dentist to do the same job many years before that was invented. 🙂