Knocking sound after cambelt change

So in my ongoing torrent of problems in making my Supe up to speed whilst having the valve seals and everything else done that was needed I had my cambelt done of course. Back and forward it went and now I finally have it back and it is making a knocking noise, especially on idle, which to me indicates a slack cambelt, am I right on that? It is especially noticable on idle and wasnt there at all before I had the new cambelt done. I've recently gone BPU and when it came back with a new cambelt it was fine, but then my FMS went and needed a new cambelt and this is the one thats faulty so I am thinking defo needs re-tensioning or replacing? I can barely get one repair finished before it needs a new one this year, its been a massacre!

You might be able to see enough if you take the cover off from over the spark plugs. Straightforward to undo and lift up

I had something like this, davidp knew the noise and i had the crank pulley tightened and it sorted it.

Knocking from the engine? Did it lose a lot of oil when the fms went?

If so get it checked out properly and don’t use it. I’ve seen a few with fms going,

Losing a lot of oil then getting piston slap etc on idle.

Get it looked at and don’t use it. Or upload a video on here?

Only lost a litre and its all been looked at again and everything dealt with so must assume its cambelt pulley related most likely?

So heres a video of the knocking what do we think? Mechanic says I have a bearing which is slightly loose on the alternator pulley which he thinks is causing it but he's having another look today.

I never like saying this but are you sure of your mechanic? (I say that because the next bit)

Leaving that aside, with the engine stone cold you can remove the main fan belt (in the video) which means none of the ancillaries (including the alternator) will be moving (also including the water pump which is why it needs to be done when the engine is cold and not for long - you don't want it getting hot with no water flow). So you can rule out a lot of things by this one simple test, if it still knocks then you are looking at the crank pulley or something on the cambelt run, tensioner/idler pulley (or worse but let's no go there yet!).

Do you know if the guy compressed the cambelt tensioner and fitted a pin to release it as should be done? As someone else said whip the top green cover off with a Allen key, I think you can remove the vertical cover underneath it too to expose more of the belt run to inspect.

As said above that would be the first thing i'd be doing

Hope it's something like this?

http://www.mkivsupra.net/vbb/showthread.php?303109-Strange-resonant-rattle&highlight=tensioner

The cambelt tensioner has a plunger that needs a vice to compress but also needs to be compressed in stages, not just whacked in a vice and compressed, it needs a compress (say a mm or two) - pause (only a few seconds) - compress again- pause procedure until a pin (small allen key) can be put through the body and hole in the pin.

Sometimes people don't bother and just screw the tension in towards the belt, I don't intuitively know why this wouldn't end up with the tension being ok but the above procedure is the proper one.

http://www.mkivsupra.net/vbb/showthread.php?94550-Thinking-of-changing-cam-belt-and-pulley-Easy-or-difficult&highlight=cambelt

So Ian confesses to not doing the tensioner the text book way, then (ok 7 years later!) the tensioner packs up.....

After much diagnosing the bearing has worn in the alternator pulley it seems so he's going to see if he can fix it and if not they're 180 plus vat for the whole enchilada. I'll update with results use or bar for anyone else with similar issues

That was supposed to say results yae or nae stupid phone auto correcting....

I uploaded this just for you, my 2JZ-GE had the same noise, was told by DavidP it was the crank pulley, had it done at a garage and the noise went.

https://www.youtube.com/watch?v=Jtl_mN9oMUA&feature=youtu.be

Certainly worth trying in case its not been torqued up enough

330 Nm

crank pully

Just to keep everyone in the loop the problem was the alternator tensioner which was worn out I have a new one on its way (£193 if anyone wants to know genuine) and this should make the knock knocks be at someone else's door for a change. Hopefully after that and my new oil pump fitted I can actually get some driving in!

Just to keep everyone in the loop the problem was the alternator tensioner which was worn out I have a new one on its way (£193 if anyone wants to know genuine) and this should make the knock knocks be at someone else's door for a change. Hopefully after that and my new oil pump fitted I can actually get some driving in!

Awaiting to hear results as my automatic tensioner went and n

made a totally different sound. I used a gates one for like 80 quid

Yes its not the tensioner in itself, thats still doing its job in a 'tensiony' way, its the bearing within which is allowing play on the rotation slightly, hence making the intermittent knocks. It's defo the problem as unloaded the sound totally disappears at all revs. Its unusual as it sounds like crank pulley I agree but had that all checked too just in case and no issue there. Its all good fun owning a Supe isnt it....

By the way I spent some of yesterday reading your awesome history thread Evin, just superb mate top marks! Does anyone else think the lights on the proto were actually better than what became production shape? Probably going to get mugged for saying that but its the only thing I always thought could be improved in terms of looks on a Supra, smaller lights. Plus I'm a sucker for pop ups which probably shows how out of touch I am with reality.

If you mean the *auxiliary* belt tensioner then the rubber isolator in the pivot can fail and the arm will knock. Removing the auxiliary belt will show if this is the case. Even with a hot engine you can safely run it with the car stationary for a minute with no belt on at idle, or a quick rev. I am seeing a lot of these pivot bushings failing these days.