failed bearings (no oil) - is this 'machinable' (4age)

[Grega]

hi
for those in the know more than i am

is that 100% time for a new one, or, could it be ground/linished and made better?
appreciate folks' thoughts.

ta

[river]

Hi,

Engine? Please put that in the title or his thread is goneski!

seeyzuz
river

[ed]

day of the week it died? about as relevant river?

jeeze?

anyway, in pursuit of being constructive... take the crank out, scrape all the bearing debris off it. see if theres any score marks in the journal proper, is theres any cracking, or if theres any significant bluing or overheating then id junk it

from here it looks slavageable though, but thats one pic only

plus i dont know what day of the week it died yet

cheers
ed

[Grega]

river. done. sorry.
ed. its only idled. it died yesterday.
the mains are scored yes, sorry the photo doesn't really show much does it - apologies.
it died on a saturday. siezed tight.

i figure its about as useful as a paper weight now is the poor crank

[hosking1991]

The best thing to do is to take the crank to a engine reco shop and ask them to give you up a quote

They'll useally tell you whether it is fixable and give you a appropriate bearing undersize and than if your able to get that undersize (30 thou is useally the smallest undersize you can go) the crank will be ground

But if the journal is worn past that minimum undersize you'll have two options either get it metal sprayed (where the journal is built up with new material and than ground to the appropriate size)

Or find another crank

Luke

[ed]

doesnt really looked scored on that photo. looks more like streaked gauling of bearing material

ah yes, sat's a bad day for spun bearings. maybe put that in the thread title? lol

[Ben Wilson]

It's a 4AG crank, is it even worth machining?

I've got 2 spare in the shed, I'm sure many others do as well...

[pandaah]

best thing to do to that crank is get some hydrocloric acid, some safety gloves and glasses and a toothbrush... and rub the acid all over the bearings on the crank and it let eat away at the melted metal... works really well with aluminium dunno how it would work with crank bearings but give it a go!

then just wash it with water and take it to a machinest

[Grega]

ben i don't have a spare unfortunately.
its going to the machinist this afternoon on the way home from work...
big thanks to all for the input here

[thechuckster]

any clues as to why there was no oil/oil-pressure?

[Grega]

failed oil pump by the looks of things, whilst i apparently had oil pressure my lines to my remote filter were dry. yes my filter was pre-primed with oil etc..

[allencr]

Bad mains yet good rods, I think there might have been a problem besides 'no oil'.

[fergo308]

^^^
That journal may have picked up a bit of crap from the failed oil pump and had it's supply feed blocked off. That would be one explanation for why only one bearing failed.
Another is varying clearances. - the tightest bearing failed first...

Either way,make sure the crank gets hot dipped to clean out any gunk inside it's galleries and give it a good spray out yourself before reassembly once it comes back from the machine shop.


Justin...

[Grega]

hi
off to machinist we go

allencr - machinist said the same thing - bad mains, good big ends.
i pulled the pump apart and the back face of the pump is worn badly

anyway, it can be ground if need be. 220 to crack test, then grind all surfaces (if bent) rah rah

then the usual wash of everything, and, dare i say it hone, balance, put back together new rings, new bearings ect ect and yeah off we go again...

wasn't planning on an engine build, was planning on an adaptronic instead....grrrrrr

[stradlater]

so just go ahead and buy another 4age instead of building this one?