If a ej20 has got bottom end knock can this be repared by oversize bearings if the bearing has spun or is it a new block jobbie?
thanx

 

If it's just picked up due to debris or bad oil supply/pressure, you might be able salvage the crank (just a polish... NOT a regrind - it's no no!). Normal size big end shells would then be required - seize the opportunity to upgarde to decent ones like ACL 'Race Series' jobs.

If it's happened at any sort of meaningful engine speed/duration, chances are the crank will, at the very least, have scoring and microscopic bits of big-end shell embedded in the offending journal's surface. In such a scenario the crank is scrap I'm afraid. If you were to regrind it, you'd be removing the specially hardened journals' surfaces and, if refitted with oversize BE shells, it'd be a lottery of how long crank/big end will last.

 

i dont mind forking out for a new crank as im looking at stroking it anyway but if the actual bearing has spun in the block i take it is un-repairable iv heard that sometimes you can bore out the mains to afew microns and run oversize to compensate? or am i chattin out my **** lol?

 

If you have spun a bearing in the block (main bearing),then the best option is to replace the block.
If you have spun a big end which is more likely,then a new crank and rods will sort it out.

Mick

 

Well, if funds are not a prob, then yes, get a new crank (that would be a no-brainer, if it was me, anyway) and decent mains and bigs - sorted.

Regarding the further technical questions then, for no bull answers, contact THE Subaru engine guru: APIDavid. He'll also advise on the best products for your wishes/requirements, etc...

Thing is though, you really need to know the real reason why the big-end started knocking in the first place. Some investigative work is required when the engine is out/apart, and can be checked over for, hopefully, a big, obvious clue staring you right in the face.

 

ive heard so many horror stories with re-ground cranks its just not worth the hastle i think.. no point in doing half a job! im going to api in afew weeks to get my new box so i might have a chat with them their see what they have go to offer.. going to be a project and hopefully is can do a step by step guide to build an engine. Thanks for your advice i will have a good looker over when i rip it appart