3S Big end problems, fact or fiction?

[fivebob]

I hear a lot of stories that 3S engines have problems with the big end, but I've never had a issue, and I know of plenty of high mileage 3S engines with no problems. Big ends don't usually fail if you maintain things properly and do frequent oil changes.

I hear a lot of stories about freshly rebuilt engines failing, but I think that can be put down to not cleaning and measuring things properly before re-assembly.

So what's everyones actual experience with this and what's in your opinion was the likely cause of the failure if you had one.

My experience is that none of my engines has given any problems, though none of them have more than 160,000kms on the clock.

[MR2SIK]

Mine busted at about 165,000km's had a handful of high boost runs during drags etc..
Was driving it rather hard when it did go though..

[strx7]

i personally think lack of maintainence - not checking oil ----> engine being on a lean/lack of sump baffling = bearings bite the dust before they do on other engines.

[Cahuna]

The 3SGE in the boss's MR2 rally car eats bearings for lunch - he blew 3 motors in 12 months, including last year's Silver Fern Rally. The main culprit seems to be oil starvation but we can't quite get a handle on why; the Silver Fern motor was assembled by Lynn Rogers and was running the recommended Motul synthetic, he runs an Accusump (to boost the oil pressure if it drops for any reason) and an oil cooler directly across one of the vents to the engine bay.

Conversely, another mate has run a 3SGE in his AE92 Corolla circuit car for a number of seasons with no problems at all, although I believe he has made some changes to the oil system.

For the road, mum's Corona had a 3SGE that had done 330.000km when she sold it and it was still running sweet as a nut.

So, make of that what you will. Our thoughts are that the 3SGE doesn't like prolonged high revs - the Silver Fern engine was fine for the first 4 days but lunched itself after around 15km of the first stage of the event with prolonged high-speed and high-revs. We thought it could be oil surge because it went twice on the tarmac but the Accusump didn't stop it the second time and the car is also okay doing Motorkhanas/Autocrosses (which will give more surge than tarmac)

[fivebob]

The 3SGE in the boss's MR2 rally car eats bearings for lunch - he blew 3 motors in 12 months, including last year's Silver Fern Rally. The main culprit seems to be oil starvation but we can't quite get a handle on why; the Silver Fern motor was assembled by Lynn Rogers and was running the recommended Motul synthetic, he runs an Accusump (to boost the oil pressure if it drops for any reason) and an oil cooler directly across one of the vents to the engine bay.

If I was your boss I'd be logging the rpm,speed, oil pressure, oil temp, lateral and maybe longitudinal g forces. At least you'd be able to tell what was causing oil starvation if you're getting it.

Our thoughts are that the 3SGE doesn't like prolonged high revs - the Silver Fern engine was fine for the first 4 days but lunched itself after around 15km of the first stage of the event with prolonged high-speed and high-revs

Could be just a simple matter of oil not returning to the sump fast enough at high revs, in which case a bigger sump would certainly help. Though, for a race car, I'd be inclinded to go for a dry sump set up

[postfach]

my friend broke a 3SGE in his fraser clubman but they have a modified (smaller) sump for ground clearance and it was losing oil pressure in corners due to starvation, i think it may have been using oil as well so level may have been lower than optimal.

[Mr Revhead]

Mine busted at about 165,000km's had a handful of high boost runs during drags etc..
Was driving it rather hard when it did go though..

isnt there a bit more to that story?



the 4age can have a tendancy to run bearingd at high rpm/g loading.
they only hold about 3 litres in the sump.
the 3sge holds a fraction more than that, maybe its the same issue?
not enough oil in the sump for sustained rpm/gs.

from my experience of ppl asking for parts, it would seem lack of maintanece, either lack of oil changing or oil top ups, that is the major cause.

[fivebob]

Actually I think we might be on to something here. The oil drains in the block are not very large, and if an engine had positive crankcase pressure it might be enough to stop oil from flowing down the returns at high revs. Maybe enough oil could accumulate in the head to lower the sump level to the point of oil starvation.

I also note that Phoenix Power make a larger sump as a means to control oil temp and reduce the possibility of oil starvation.

Although I'm also inclined to agree that poor maintenance causes most failures

[vvega]

how bout we add a case of frothy oil
one of the reasons for large compasity is to stop airated oil from getting back into teh lubrocating system
airated oil will give periods of were the bigends will atually be runing dry

a acusump will not stop teh oilpump from sucking up airated oil and pumping it to the bigends............

i doubt race failures are from lack of people putting oil in there cars
if we concentrat on racing issues then we can almost discout teh supidity factor

[vvega]

Mine busted at about 165,000km's had a handful of high boost runs during drags etc..
Was driving it rather hard when it did go though..

isnt there a bit more to that story?



the 4age can have a tendancy to run bearingd at high rpm/g loading.
they only hold about 3 litres in the sump.
the 3sge holds a fraction more than that, maybe its the same issue?
not enough oil in the sump for sustained rpm/gs.

from my experience of ppl asking for parts, it would seem lack of maintanece, either lack of oil changing or oil top ups, that is the major cause.

from my experanc with high km 4ages there shells have a tendancy to delaminate teh babbet from teh copper base
ive found 6 sofar that have done this
changinf 4age bearing at around 160km forgoes this problem

[RomanV]

My gen 2 3SGE did ~210,000kms when I pulled it out, and everything in side looked *immaculate*. I suspect that it had a rebuild at some stage, as someone had used the gen 2 turbo TVIS gasket on the intake manifold for some reason! No signs of bearing wear or anything, but it possibly got that far thanks to a rebuild at some stage along the way.

I havent heard of anyone running bearings with the gen 4+ engines, but I suppose that there arent a huge amount of those around with high kms yet.
Apparently the titanium valves smashing or breaking in half is more likely to kill the m/t altezza engines.

[TRD Man]

My rally car had a gen 3 which had done about 20,000 kms when we installed it.

We didn't even open the bottom end leaving it exactly as we got it. Ran it for 4 seasons and over 50 rally events without issue. It even ran upside down a few times.

Admittedly, I'm not the hardest on gear but we did a reasonable amount of winning with it so it wasn't exactly sitting idle.

And we weren't that fussy on which oil we tipped in it either. GTX2 or 3 I think was what we had in the workshop at the time.

[Mr Revhead]

We didn't even open the bottom end leaving it exactly as we got it. Ran it for 4 seasons and over 50 rally events without issue. It even ran upside down a few times.

Admittedly, I'm not the hardest on gear but we did a reasonable amount of winning with it so it wasn't exactly sitting idle.

does anyone else spot the contradiction there?

[Leon]

Maybe he ran it gently upside down?

50 events is pretty damn good on any engine I would have thought. Apart from a 4k, which would need 300+ to be impressive

[92mr2paddy]

lol, well my gen2 3sge popped bearings at 95kms!! i was sitting at 110km/h then tap.tap.tap , so for what you guys wrote and what ive experienced it might just be a weak design in toyota's 3sge engine???

some get lucky and they last like they should and sum just sh*t themselves for no reason.

haha and no i didnt have 'no' oil in the engine

[sergei]

3SGTEs are not weak by any means.
I have not seen one fail from other than neglect.

[MR2SIK]

haha yes Warwick there was more to it, I got a bit lazy with the general maintanence, didnt notice it had dumped a decent amount of oil a day or so before it went bang... It also had a few tell tale signs of a blown head gasket when I got it home too

[Celica RA45]

i have had 1 spin the big ends as well ,we think it might have something to do with the oil pump ,maybe its cavatating the oil and thats why they blow ,speaking of ,hence going to dry sump so hopefully no more problems

[avinesh]

lol, well my gen2 3sge popped bearings at 95kms!! i was sitting at 110km/h then tap.tap.tap , so for what you guys wrote and what ive experienced it might just be a weak design in toyota's 3sge engine???

some get lucky and they last like they should and sum just sh*t themselves for no reason.

haha and no i didnt have 'no' oil in the engine

mates gen 1 3sgte mr2 has 220,000kms on it an he drivers it daily on 15psi on ct26 an drives it quite hard an drags it at meremere as well, he does service it properly though an he always says if it blows up on him now he wouldnt mind because it has lasted him this long.....

[3SGEMAD]

all of our 3sge's (gen4&5) have never had any problems, and pull to 10k rpm. the biggest thing we have done is enlarged all our sumps due to the oil pickup being under designed. more oil and mo0re baffling and no probs
been running hard for 4 seasons too