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The mkiv Supra Owners Club

big ends


piehound

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foooking great i decatted had all the paint work done and today while driving at a leisurly 40 mph i hear an odd sound , stops the car and listens to a low grumble , which is actually a knocking sound, popped into the local engine place and low and behold as i thought the it appears the big ends have gone or at least a shell has gone as i caught it straight away it should be ok if its a shell, so my question is can these be done with the engine in and where do i get a set of shells for uk spec auto,and any idea on price. it may be far more sinister than this even though the car still drove fine till i parked it so as not to do any damage?

if its an engine out then i may well be selling a now mint supra with a knocking bottom end as i dont think i can be bothered with all the hassle of taking the motor out

i may be wrong and it may be something else but the first job is to get a look in there, so can i get the sump off easy enough to see , i have a car lift available so access wont be a problem

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It takes so much work to get the sump off with the engine in-situ it's actually easier to pull the engine, apparently. Have a word with the Phoenix boys, they are bloody good with Supras (from a technical and attitude perspective) and their costs are low too. Don't panic and sell the car at a big loss until you can get a more firm opinion on what's wrong with it :)

 

-Ian

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oh well if it turns out to be a ball ache to get it off i will just sell the thing i aint spending shed loads of money on it, damn thing drives great too but i know if a do drive it i may and likely will kill it, i guess i will know at or by the weekend

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so its not really to difficult to access as like i said i can get the car up to about 6ft 6" in the air easy enough, in my mates garage

 

ok next question is where do ya get big end shells from apart from mr t and are they all the same j spec and uk spec??

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where do ya get big end shells from apart from mr t and are they all the same j spec and uk spec??

 

Why not get them from Toyota? Seems the logical place. I got mine from Steve Manley (at Inchcape Toyota in Oxford).

 

Prices and part numbers as follows :

 

13041-46013-0x CONROD BEARING (5 POSS SIZES) £8.83 (Qty6)

11071-46020-01 FRONT CRANKSHAFT BEARING £12.37 (Qty1)

11701-46020-02 CRANKSHAFT BEARINGS £11.59 (Qty6)

 

90910-02104 CRANKSHAFT BOLT (x14) £2.59

13265-46020 CONROD BOLT (x12) £1.69

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If a big end has gone it WILL need a crank grind and a FULL strip and clean of all the oilways, the oil pump, sump, et cetera. Cutting corners will be like burning money. A good used engine will be by FAR the cheapest option. Hard luck, what a PITA. There WILL be a reason it's gone. Low oil level, detonation, overheating and a piston picking up are the most common.

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cheers chris oil was fine i changed it a week ago no sighn of det and no overheating but thinking about it when you had it in im sure you said there was grumble on start up from the bottom end that was a few thousand miles ago oh well looks like i will look for an engine although i dont hold out much hope if someone wants a mint knocking soop let me know lol

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cheers chris oil was fine i changed it a week ago no sighn of det and no overheating but thinking about it when you had it in im sure you said there was grumble on start up from the bottom end that was a few thousand miles ago oh well looks like i will look for an engine although i dont hold out much hope if someone wants a mint knocking soop let me know lol

 

Ahh, right, was this one I did the turbos on? I seem to recall it now, it did have the start of a rattle on cold start up. That sort of problem never gets any better with usage :(

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When you guys talk about dropping the front subframe do you just mean undoing the main mounting bolts (the ones you have to tighten every now and then when you get a knock on low speed / full lock maneouvers) and letting it sag down on the suspention? Or do you have to take it right off?

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yes...the suspension top mounts are removed..you lower the whole thing , you also have to undo the engine mounts, the engine being supported from a beam across the inner wings....I think i only had to drop it about 6-8" to get the sump pan off

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The shockwaves drive the oil film out. If a piston picks up 9det or overheating) the drag causes abnormal permanent loading on the big end oil film, with a similar result.

Don't you just wish you could buy Mr Wilson in a tin, drink it - and absorb all this information?

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I had big ends start to go on my celica. I caught it real early as I knew the warning signs as I had it happen on my MR2 proabably about a year or so earlier. I changed the shells and did another 30K miles on it before I sold it without any problems. No strip down and rebuild required.

The trick is catching it REALLY EARLY. When the ones on my MR2 started knocking, I didn't really know much about anything so continued driving it for proabably a month or so (50 mile round trip to work 6 days a week) But then the engine was proper fecked. I've got half a piston on my desk from the resultant destruction.

The other problem you may have is with the mileage that the car has. Before the catastrophic meltdown, I had replaced the bearings... twice infact. But the car had done close to 160K miles, and the crankshaft was not as round as it once was. So when I put new bearings in, it just knocked them out within 50 miles or so. Lessons learnt and all that!

From my experience, and others may have experienced different, but this has been the case on 2 cars that I've owned, when a big end bearing is worn, it will rattle when the engine is under no torque. Now if you think about it, this will only happen as you lift off and the engine is shifting from driving the wheels to being driven by the wheels. So just as you lift off, you get a distinctive rattle for a second or so. Obviously as they get more and more worn the rattle gets more pronounced. (When mine finally let go, I was driving the car and could feel the vibrations through the pedals, by then I was only running on 3 out of 4 pistons, with large chunks of number 4 floating around in the sump!) If it's got so bad that it's rattling more than when in the "no torque zone" then it's gone too far.

Hope that helps.

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Mine has a rattle when I first start it up. As soon as the oil pressure lamp goes out the rattle stops. I'm pretty certain its a slightly worn big end bearing(s). Thing is, its been doing it for about three years and it doesn't get any better or worse so I'm kind of living with it.

 

Posts like this scare me to death, though. :( For the sake of about £100 worth of bolts and shells I wouldn't mind changing the big end bearings, especially as I have access to a service pit.

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  • 3 weeks later...
If a big end has gone it WILL need a crank grind and a FULL strip and clean of all the oilways, the oil pump, sump, et cetera. Cutting corners will be like burning money.

 

Have to say from personal experience that is dead right. I've tried just replacing shells before with very light crank damage, lasted a few hundred miles and then as soon as you put your foot down, booooom, wasted time, effort and money!

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  • 2 years later...
Why not get them from Toyota? Seems the logical place. I got mine from Steve Manley (at Inchcape Toyota in Oxford).

 

Prices and part numbers as follows :

 

13041-46013-0x CONROD BEARING (5 POSS SIZES) £8.83 (Qty6)

11071-46020-01 FRONT CRANKSHAFT BEARING £12.37 (Qty1)

11701-46020-02 CRANKSHAFT BEARINGS £11.59 (Qty6)

 

90910-02104 CRANKSHAFT BOLT (x14) £2.59

13265-46020 CONROD BOLT (x12) £1.69

 

Hi

At what end is the FRONT CRANKSHAFT BEARING, is it at hte olie pumt or the flywheel ?

 

Sorry need to ask :)

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