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Engine Knocking! :( Big End Bearing!

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mikeb
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Re: Engine Knocking/Rattle! :(

Postby mikeb » Mon Jan 26, 2015 11:31 pm

RS Tom-Hundred wrote:Good thinking but it's nit got the dual mass still as previous owner replaced with a lightened aluminum one ;-) ( that's what he told me anyway)

Ah, nevermind. Although it might be worth double checking before you tear the engine apart, if there's an inspection hole somewhere.

If it's not the flywheel then it sounds probable that it's a bottom end bearing. You might not be able to feel the slop in it via the piston until it gets much worse. Your earlier comments that the noise reduced when you unplugged the coilpack would suggest that it can't be top end related.

The inlet and exhaust vvti mechanisms are externally different, so it's likely that they are internally as well. The inlet definitely has the helical mechanism (and quite possibly no locking pin). Whereas the exhaust side might have a locking pin, which would explain what you are seeing when you turn it.

Tosh21 I'd be really interested in a write up /photos of your vvti pulley rebuild. I think the intake side must be similar/same as the red top beams, like these pictures? http://www.6gc.net/forums/index.php?showtopic=91467

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Re: Engine Knocking/Rattle! :(

Postby mikeb » Tue Jan 27, 2015 12:11 pm

Actually, having looked at those photos (on the link above), and the vvti solenoid wiring, the solenoid is only 1 way. Most Toyota vvti solenoids seem to be 2 way (and infinitely variable). I suspect the 3s-ge beams is basically a two position (fully advanced or fully retarded), oil pressure sends it one way, and the spring sends it back. It could use the camshaft position sensors to do closed loop control, but I don't think it would be very accurate, working against a spring.

So, the spring looks pretty strong, should be enough to return the cam to it's home position after you've manually turned it. It might even be strong enough to hold it locked (like the exhaust side), and turning the cam turns to whole engine over instead of shifting the vvti mechanism. But that doesn't sound like it's happening with your intake - you can turn it and it isn't moving back by itself? I guess it's possible (but unlikely I'd have thought) that there is too much friction to allow the spring to return the cam home. I would try removing the cam belt, hold the cam shaft still and turning the pulley by itself. If it is good, it should definitely spring back home, if you can even move it. If it's still flapping about then it suggests that the spring inside the vvti pulley is broken.

Just to throw you even more, the fault codes you listed appear to be:

14 - Ignition signal ION1
15 - Ignition signal ION2
18 - Exhaust VVT system = (P1357 Exhaust VVT Sensor/Camshaft Position Sensor Circuit Malfunction (Bank 1))

14 and 15 are probably caused by you unplugging the coilpacks during testing? 18 is odd that it's listed as exhaust, but I can't seem a similar code for inlet vvt, so it might be a general bank 1 error. If the exhaust vvt mechanism is broken and flapping about then it could definitely cause an 18 / P1357 error code, perhaps the intake one does give the same code on the altezza?

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RS Tom-Hundred
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Re: Engine Knocking/Rattle! :(

Postby RS Tom-Hundred » Tue Jan 27, 2015 1:53 pm

Thanks for the replies, Mike :)

Not sure if theres an inspection hole on the back to look at (or to lock up?) the flywheel - does anyone know please?

That's correct about my intake camshaft, you can turn it but it doesn't return on its own, you have to turn it back again manually. Also it doesn't turn the whole engine/camgears/belt etc.


As extra info. I had the VVTi solenoids out last week to look and here's a photo of the intake side solenoid, if that helps btw:
Image
Think they are fully variable (rather than just on or off) from that, aren't they?

Thanks. That is what I found as the fault code descriptions too, so that's reassuring :) I don't know how historic they are though and when they were logged. I got all those codes before I ran the engine or turned ignition on with the coil plugs off though, so wont be tied into that. However, the previous owner had to replace a coil pack, so they could just be historically logged from that. I'm going to try resetting the ECU and clearing the fault codes again soon though.
That is the odd thing about the code for the exhaust VVTi. Unless of course, the intake cam is fine (as a guy on Altezza club in NZ has confirmed and it should move) and its actually the exhaust one that is fooked and it should be able to move too and isnt!!!!
Really need someone to check the movement on both camshafts of a known good engine so I can rule this out before I go too much further tbh.

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Re: Engine Knocking/Rattle! :(

Postby mikeb » Tue Jan 27, 2015 5:19 pm

I did just write a huge post about the vvti and then my browser crashed and lost it. :x

Anyway they gist of it is that the bloke on th NZ forum is basing his statement of the cams moving freely on the 2jz vvti, which is different from the 3s-ge vvti (inlet at least), as it doesn't have a spring in it, and is definitely two way - the oil pressure/flow is to both sides of a twin helical mechanism so oil works it both ways. The only purpose I can see for such a huge spring in the 3s-ge vvti is to act as a return one way. I'd expect the 2jz vvti to rotate freely with the engine off, but I not convinced that the 3s-ge is like that.

Reason you can't see any movement at the pulley when you rotate the cam is because the part of the pulley attached to the cam is the inner helical gear, and that's right inside the pulley. If you remove the centre end cap, you should see the retaining bolt turn with the cam.

I totally disagree with the poster over there saying the inlet vvti relies on valvetrain drag to stop the timing floating about. In my opinion that would leave to a rattling/chattering that could sound like what you are experiencing (I'm speculating on that).

Tosh21 might be able to say what the purpose of the spring is, and if the mechanism should be moveable without resistance? It's difficult to see exactly where the spring pushes onto from the pictures I've seen.

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Re: Engine Knocking/Rattle! :(

Postby Tosh21 » Wed Jan 28, 2015 9:51 am

I didn't take any pics unfortunately. Was top busy trying to make sure I rebuilt it properly lol both pulleys are locked to the cam otherwise you wouldn't be able to time it, you would have to time it by measuring love position and crank position.

Altezza vvti, from what I read is constantly variable through the whole 15° advance and Retard on each cam so it's not an on and off. As you go past the 4700 rpm you can hear the timing change as the exhaust note changes and you can hear it change slowly as you accelerate if you listen out for it Youl see what I mean.

I presume the spring rate is know so they know how much force is needed to overcome it through the whole range of travel and the helicut gear angle is known so you can figure out how much oil pressure will move the gear which in turn tells you the angle of the pulley.

I dont know this for sure it's just how I think it works from what I saw inside the pulley and reading up on it but it seems pretty plausible to me although incredibly complicated when there are much simpler systems out there.

The pulleys and cams should not move separately with the engine off. How would you time the cam if the cam spins independently to it? Your markings will be way out

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Re: Engine Knocking/Rattle! :(

Postby mikeb » Wed Jan 28, 2015 11:04 am

Tosh21 wrote:I didn't take any pics unfortunately. Was top busy trying to make sure I rebuilt it properly lol both pulleys are locked to the cam otherwise you wouldn't be able to time it, you would have to time it by measuring love position and crank position.

Altezza vvti, from what I read is constantly variable through the whole 15° advance and Retard on each cam so it's not an on and off. As you go past the 4700 rpm you can hear the timing change as the exhaust note changes and you can hear it change slowly as you accelerate if you listen out for it Youl see what I mean.

I presume the spring rate is know so they know how much force is needed to overcome it through the whole range of travel and the helicut gear angle is known so you can figure out how much oil pressure will move the gear which in turn tells you the angle of the pulley.

I dont know this for sure it's just how I think it works from what I saw inside the pulley and reading up on it but it seems pretty plausible to me although incredibly complicated when there are much simpler systems out there.

The pulleys and cams should not move separately with the engine off. How would you time the cam if the cam spins independently to it? Your markings will be way out


It would be possible to time the cam, even if the vvti did 'float' about when the engine is off. The cam shaft is keyed onto the inner pulley, so it only fits in one position, then you just align the markers on the outer pulley. The when the engine starts the vvti closed loop control takes over and works out the rest.

If the vvt is continuously variable it would be possible to smooth the transition around the 4700rpm point, so you would feel the change in torque curves. Every other continuously variable timing engine that I know of does this, and you can't feel the transition because it is gradual. So either the 3s-ge vvt isn't continuously variable, or toyota deliberately mapped a sudden transition at 4700rpm.

But I think we are agreed that the big spring inside the (intake) vvti pulley pushes (and holds) the variable bit to one end of it's travel when the engine is off?

What is the difficulty with reassembling the pulley, is it just overcoming the spring force as you put it all back together? The 1/2jz vvti pulley is different (it has no spring and dual helical gears), but it has some similarities I think. Here is a rebuild guild for that, which may give some clues: https://www.youtube.com/watch?v=1KQGRulDJSk

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RS Tom-Hundred
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Re: Engine Knocking/Rattle! :(

Postby RS Tom-Hundred » Wed Jan 28, 2015 2:58 pm

Thanks for the info and that video is interesting too (though no doubt the Altezza one is much more complicated from what Tosh says)
Im thinking that rather than get bogged down in the technical side of this, I reallt just need to confirm whether another, known healthy Altezza has the same movement in the intake camshaft and no movement in the exhaust one really. That would at least give me a heads up as to whether I need to look more into this or leave it as-is.

For info though, I have attached some pages from an Altezza workshop manual regarding the VVTi bits specific to our cars, that may shed some light? Unfortunately, the text is in Russian so its only any good for photos for me but thought its worth posting up :)

Image

Image

Image

Also unfortunate that its not 100% clear whether it is intake or exhaust cam but shows the mechanism being triggered by putting compressed air into the hole to work the camshaft by pressure (like the oil would) presumably?

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Re: Engine Knocking/Rattle! :(

Postby Gojira san » Wed Jan 28, 2015 3:27 pm

Testing this on a healthy engine is a great idea.


just wondering........ what's your budget for the fix? like, to just throw the toolbox and wallet at it?

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Re: Engine Knocking/Rattle! :(

Postby mikeb » Wed Jan 28, 2015 4:00 pm

The altezza pulley is no more complicated than the 2jz one, in fact I'd say it's less complicated as it only appears to have a single helical mechanism. Toyota say that neither of them can be rebuilt, but it's clearly possible to in both cases (with care, and knowledge). Photo's of an actual altezza mechanism are in one of my earlier links. Here is a video of inside a 3s-ge pulley, although it doesn't show very much of interest: https://www.youtube.com/watch?v=T_wsjEjpGO8

One thing that is probably common to the 2jz pulley is that the bolts holding it together are holding the timing calibration of the mechanism (towards the end of the video). If you do end up taking it apart mark the two parts before undoing the bolts, so you can realign it perfectly later.

The 1/2jz and 3s-ge vvti systems came into production around the same time, so it's interesting that they are not mechanically identical.

I think I need to brush up on my Russian! Do you have any more of that manual, it looks like it might be useful, even just the diagrams?

What I suspect, looking at those drawings, is they are using compressed air on the exhaust vvt mechanism, as it doesn't look like the intake one. I wonder if they've removed the outer casing on the exhaust pulley, and that's what it looks like underneath? Compressed air will work the mechanism in a similar way to oil, although it may not overcome that spring in the intake pulley. It also risks blowing out seals.

On later toyota vvti mechanisms (fully two way hydraulic), they use a hydraulically actuated pin to lock the vvti mechanism in one position, presumably for starting, or some sort of fail safe when oil pressure isn't available. https://www.youtube.com/watch?v=2LqP_zDi9qU The service procedure is to use compressed air to release the pin and unlock the mechanism. So it is possible that the exhaust vvti mechanism is the same as this (at least as far as the locking pin), and that is what your service manual is depicting?

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Re: Engine Knocking/Rattle! :(

Postby Tosh21 » Wed Jan 28, 2015 5:25 pm

Have you got the whole manual? I can read Russian that would be incredibly helpful on other bits of the car. The altezza is different to the jz. Very similar but not the same. I don't remember my pulley moving without the cam. If it does, you can't time the engine as the pulley and timing gear are all bolted together. Your timing marks would be out.

Take the pulley off using the Venter bolt. Hold it in a press or have someone put loads of weight on it and take it apart slowly easing off so the spring slowly opens instead of firing open.

You will know if its broken straight away, put up a pic too. As long as you do it right the gears won't come out so you can rebuild it easy.

Mark up where the timing gear sits relative to the pulley and the orientation of the 2 bits which separate.

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Re: Engine Knocking/Rattle! :(

Postby Gojira san » Fri Jan 30, 2015 9:23 am

Okay, So i went back to my Guru (the guy who said it was the vvti cam gears) to ask a few more questions for you.

i read your posts to him, explaining as best i could what you have tried. and what you found with the gears.

he said that your problem also happens to 5 valve 4A-GE VVT-I engines. so people switch to solid cam gears. the inlet gear is only supposed to go one way for the vvti as mentioned by MikeB before. and it is operated by oil pressure, with the spring to return it to zero. or provide needed resistance. we got a fax from a guy at toyota, and discussed other possibilities while waiting.
3sg3 camshaft diagram.jpg
3sg3 camshaft diagram.jpg (63.45 KiB) Viewed 2145 times


My Question to him was : could this be a result of poor oil pressure?? like a faulty oil pump? he pondered for a second, and replied with : the pump should be fine, but the solenoid to the vvti gear could be faulty. and it's best to try swapping that before spending the $$$ for the new cam gear. as it's much cheaper. :)

conclusion:
- so while the cam gear looks to be the obvous problem, faulty oil pressure from the solenoid to the cam gear could be the unseen problem.
he had no objections to you using a recycled (used) part just to test the theory. or perhaps a guy here could mail you one for a few days?

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RS Tom-Hundred
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Re: Engine Knocking/Rattle! :(

Postby RS Tom-Hundred » Fri Jan 30, 2015 10:50 am

Thanks very much mate :) That is very interesting and seems he could be onto something.
Do we 100% know if the 4A-GE cam gears operate in the same way to the 3S-GE ones though? Makes sense if the 4A-GE has a spring to return it and Tosh explained there being a spring in the 3S-GE one too.
If so then mine definitely doesn't return on a spring when moving the camshaft by spanner (with the belt on) and I can definitely turn it backwards by the same amount after I have turned it forwards. Would still feel happier if anyone with a healthy engine could 100% confirm that there's is different before i buy any parts though.

Also wondering if I can test the solenoids as the diagram on that last page I posted up seems to show them supplying a feed to it to test it.

Tosh - Was it the intake cam gear or the exhaust cam gear that you had apart? Just to double check :) How much did it differ to the one in the 2JZ / 1JZ rebuilding video please? (https://www.youtube.com/watch?v=1KQGRulDJSk) Was it pretty much the same but with a spring in there?

Mike - Did you say there were some pictures of the insides of the Altezza one somewhere? Couldnt find them but probably missed it in all the text :)

Tosh21 wrote:Have you got the whole manual? I can read Russian that would be incredibly helpful on other bits of the car.

I have got the whole manual and wiring diagrams, which a member on here sent me. i have PMed him to ask if I can share them on. They had been scanned in from the original and only a couple of pages missing that I noticed so far :) Also they were in reverse order so I painstakingly moved the pages into the right order for the first 210 pages (the manual not the wiring diarams bit)
If you can read Russian, can you translate the gist of the procedure in those few pages please to see what they are doing/testing on the VVTi system and which bits are exhaust and which are intake please?

As an extra double check, I had the intake manifold and throttle body off yesterday to check that. The only thing that seemed odd was that when I turned the throttle wheel fully open (where the cable would attach), the butterfly only seemed to go half open but it felt fine so I presumed that either the potentiometer or the other electrical plug onto it worked something inside when its connected up with engine on and ECU telling it to and then would allow full throttle to open the butterfly. So presumed this is normal?
Will give the whole thing a clean out (apparently its normal for the Altezza intake to collect oil from what the boys on the NZ forum said) and put it back on at the weekend.

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Gojira san
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Re: Engine Knocking/Rattle! :(

Postby Gojira san » Fri Jan 30, 2015 12:25 pm

from zero point. can you turn it backwards? or only after rotating it forwards?

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Re: Engine Knocking/Rattle! :(

Postby RS Tom-Hundred » Fri Jan 30, 2015 2:44 pm

Only after rotating forwards.

Basically its got forward and backward movement but only within a certain degree of travel and doesn't "spring" either way. I plan to measure how many degrees roughly when I next get chance :)

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Re: Engine Knocking/Rattle! :(

Postby Gojira san » Fri Jan 30, 2015 2:49 pm

so that confirms it's a one-way vvt-i right?

you have a 50% chance it's oil pressure (my guess) or the pulley (my Guru's guess) .

here's a vid of a guy with the 20v 4A-GE. vvt-i. check it out.
https://www.youtube.com/watch?v=ekkXQR2AY-s
of coure there will be differences, but it's useful.

and i can get you a pulley..... be cause it's for " a random friend on the interwebs", and he's curious about your problem. i can get it at cost. :wink:


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