Spun Big End Bearing?

[Ultimategtr]

When did you last change the oil? Sorry if i missed it.

[MBS206]

Dead bearing fo shizzle...

Sounds like my engine exactly and the sound seems to be coming from the crank, even disappears and is only there in that rev range.

[Duncan]

oil analysis? there was a thread in the last week where someone (elite I think) posted phone numbers for capital cities. if you don't want to pull the motor analysis is 100% the way to go....couple of days and you will know.

too drunk to find it myself its a bacheloring weekend for me

[boostn32]

if its a spun big end bearing the noise gets louder as the rev's go up, the more load/rpm, the more cylinder pressure the bigger the bang.

sounds like a hammer on the crank as said before. the noise will NOT go away as rev's go up. and it WILL get worse with each time a load is put on it.

The noise of a spun big end bearing is actually a gap between the crank and bearing allowing the big end bearing to bang down each time

that cylinder fires and then slams the big end down on the crank.

[ali-turko]

Hey man did u end up finding the problem for this?? Iv hot the same problem, iv already pulled the motor out but not stripped down yet

[Simon-S14]

Could also be a ex manifold leak. Oil analysis for sure to confirm bearing wear.

[Beer Baron]

yeah I don't know why people are so afraid to spend $40 on UOA? i've been doing it for nearly 10 years on my GTRs and it tells you everything you need to know. especially if you start when the engine is still good, that way you have a solid baseline and if something starts to go wrong you know straight away. it also helps you set accurate oil change intervals etc.

[kristafa]

i dropped my oil into a bucket through a strainer, told me right away if it was bearing failure, which it was. looked like someone had chucked stripper glitter into my oil filler.

[GTScotT]

For me the 'cut spark' method has never failed.

Am not sure why more people don't have the same faith.. I think it was particularly clever of the OP and thought it showed he had a decent understanding of what he was doing.

Meh.

[ali-turko]

mine got pulled down and spun num 2 big end bearing..

[AngryRB]

so what would be causing a spun end bearing???

How do you avoid having one?

[ACTIVE-LSD]

Is it possible to repair the big end bearings without removing the head? for eg, engine out..put on stand..flip the motor upside down to work on it???

[GTScotT]

so what would be causing a spun end bearing???

How do you avoid having one?

A done bearing is normally caused by an oil related or stress related issue. Oil related would mean it was starved of oil or was poorly serviced.Stress related is not as simple as it sounds.. It does not mean ringing the neck out of the motor, it more so means stress directly on the bearing itself. That could be caused by ping/detonation, piston contact with valves (rarer case but something not to be missed if you do have a piston meet a valve) or abuse. By abuse, I particular mean starting the motor and giving it too much stick before its at operating temperature.

A brief summary of my experiences... I have never owned a motor that blew anything more than a head gasket. I have never owned a motor for less than 40,000km and I have never owned a motor that did not see its redline daily nor for less time than it sat idle at the lights. I NEVER give my car any sort of 'stick' within the first 5 to 10 minutes of driving. My last 2 cars were thrashed the most, both of them are still running with the new owners and both have high KMs on the factory bottom ends.

Every friend or acquaintance I know who has thrashed their car from start up, has had it bite them in the bum sooner or later. We are currently repairing my own brothers 911 motor at a cost of over 20 grand due to his sheer lack of care for my advice.

Turn the key and drive it unreasonably before its truly at a reasonable operating temp and you WILL run into problems sooner or later. My brother thought he could get away with it because he always owned newer cars, now either hes owned this car long enough, the previous owner also did the same thing, or hes just simply got the kind of motor that couldn't take that kind of abuse for that long, but I'm sure he will remember the debt.

Is it possible to repair the big end bearings without removing the head? for eg, engine out..put on stand..flip the motor upside down to work on it???

Provided that the only damage done is to the bearing itself, then yes. It really depends how much damage has been done.. Sometimes you will have a bearing look like its lost its first layer or two when it makes the noise, others will start to knock and utterly destroy themselves soon after. What that means is, the bearing does not evaporate to the magical land or none.. It will grind away into metalic dust and contaminate your oil.. Your oil, being the life blood of the engine, will carry the said contaminants throughout the motor and will possibly damage other aspects of it in the long run.

[DVS JEZ]

^^

[ali-turko]

mine was caused to to oil starvation,

simply to stock sump cant keep up with a TOMEI oil pump for ever, lasted a year..

even with a liter of oil overfilled or to the top of the H on the dipstick

[DVS JEZ]

Ali which number bearing was dead?

What size restrictors did u use and what rpm were u revvin too?

[ali-turko]

num 2 big end,

i was reving 2 bout 8500

and i was using the tomei head restrictor which i think is 1.5mm

im goning 1.2 mm this time round

[meet07]

Is glittery oil normal after a fresh engine rebuild. I just rebuilt my motor and im hearing a noise as weel from cylinders 5 and 6. Sounds like more of a top end noise with the stethescope but im curious about the glittery oil during the break in period. Looks like a goldish color.....

[DVS JEZ]

Get an oil analysis done.

Also cut the oil filter open with an oil filter cutter and inspect the filter.

Did u rebuild the motor ur self? Did u thoroughly clean the block before assembly?

[Duncan]

Is glittery oil normal after a fresh engine rebuild. I just rebuilt my motor and im hearing a noise as weel from cylinders 5 and 6. Sounds like more of a top end noise with the stethescope but im curious about the glittery oil during the break in period. Looks like a goldish color.....

Sorry but that is almost certainly not OK. If someone else built the engine, talk to them before you start it again.

If you built it...I guess you can start with oil analysis but 99% you are going to have to pull it out.

How is the oil pressure?