WRX STI Type RA.

GUYS....You hear such a lot of both piston and bigend problems on the boxer/Flat4 engine....Just out of curiosity,What are the first signs on these engines of worn bigends please....????

morpheous

iTrader: (9)

Low oil pressure
"Knock" noise when underload probably more when cold
Metallic look to the oil
Knocklink activity
And the famous KNOCK KNOCK
Piston slap can usually be heard with the throttle snapping open from idle or underload with the throttle down sounds like a magpie on steroids LOL

WRX STI Type RA.

Thanks for that Morpheous,,,,Can you tell me where on the block the oil pressur`s tested from....And what should the normal pressure`s be HOT & COLD....???????

morpheous

iTrader: (9)

You'll need a t-piece from the oil pressure switch if you run a gauge or see if you can get someone from a garage who has the universal adapter kit and gauge and let them plumb it up and check it,saves you buying a gauge
oil pressure around 4-7kg/cm3 (i think)

StickyMicky

never relised piston slap meant the big ends were ****ed or on the way out.

Scoob+Bike=Fun

neither did I!

AvalancheS8

Assuming you are being sarcastic, but in case you aren't - it doesn't. Piston slap that goes away when the engine is warm has little or no effect other than the noise and isn't a cause for concern.

morpheous

iTrader: (9)

Thats the problem with scoobynet,theres too many sarcastic ***** and not enough people with brains,They're fast enough to offer useless comments but it seems they've not got enough knowledge to offer assistance..

Also a good point before people spill out a load of sh#t
Would be to read the posts correctly,if you have any difficultys with the wording i'm sure people will spell it out for you

Maybe we should'nt have PM and then everyone will understand..................

Normski

Any knocking or rattling noises from an engine tells you that there is excessive clearence between mechanical components. What type of noise and when it occurs, can lead you in the right direction.

Big end knocking only happens when the engine IS NOT under load. (As opposed to what was said above). When the engine is loaded, either accelerating or decelerating, the noise will go away (if it is big ends).

morpheous

iTrader: (9)

Well done
But i have to disagree with the underload business,We are talking about a flatfour engine,
I can only speak from experience and underload pronounced the noise for me.

STI-R/A

"Thats the problem with scoobynet,theres too many sarcastic ***** and not enough people with brains,They're fast enough to offer useless comments but it seems they've not got enough knowledge to offer assistance.."


About time someone said that. My sentiments exactly. : )

womandriver

GUYS....You hear such a lot of both piston and bigend problems on the boxer/Flat4 engine....Just out of curiosity,What are the first signs on these engines of worn bigends please....????

Ill second that
Seems like someone read the post

Normski

The configuration of the engine doesn't matter. Whats happening is, when the engine is under load, the big-end (of the conrod) is being held against the crank journal. So you don't hear the noise (knocking). But when not under load, the big-end is free to move and this causes the noise.

What you experienced is more likely to have been main bearing wear, this knocking does get worse when the engine is loaded.

This info is NOT just some stuff i've heard about, but comes from actual engines i've 'wornout' and driven, and then rebuilt (mostly coming from oil starvation from surge).

jmca

Hi,

Just hoping to try and follow up on this - would the noise be big end related if it's smooth running (except for the noise) and it doesn't have the indication of low oil pressure.

Does sound a bit tractory - but also sounds like tin banging but muffled (well inside the engine)?

Regards

Johny.