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  • Oops, overtightened timing belt...

    Well, we fixed the b***er! Jiggled the pump a few degrees around and suddenly it's firing nicely, just like it was before.

    However, when I bolted the engine back together, I noticed it started whining at higher RPM. My neighbour and I didn't notice this before as we were only thinking of the idling engine.

    From what I can tell, we've overtightened the timing belt - a high-pitched whine gets emitted from the front of the engine at Idle-Up speed and above; it's about 50% louder than the turbo. I read a warning not to overtighten the belt when changing it, but I guess we bolted up the tensioner too tightly.

    I'm out of time to strip the engine back again, but I can get back to it in a few days. How damaging will it be to leave the belt like this and drive? Would I be risking the belt snapping/stripping teeth/dangerous damage? Or would it just knock a few hundred KM off the life?

    Thanks in advance,
    Gargravarr
    An unmuddy off-roader is an unloved off-roader!

  • #2
    If you fit it correctly, it's not possible to overtighten the belt. You just let the spring do the tensioning and nip the bolts up.

    The whining is probably something else though, take the fan belts off, see if it stops. Check the front pulley isn't rubbing on the timing case too.
    Do you know that, with a 50 character limit, it's

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    • #3
      Originally posted by gargravarr View Post
      I read a warning not to overtighten the belt when changing it, but I guess we bolted up the tensioner too tightly.
      Just re-read your post, missed this the first time round.

      You saw warnings, but still ignored them?
      Do you know that, with a 50 character limit, it's

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      • #4
        Originally posted by Albannach View Post
        Just re-read your post, missed this the first time round.

        You saw warnings, but still ignored them?
        Yeah, but my neighbour (who has experience changing timing belts) actually did the final assembly of the new belt. He was a massive help, so I didn't second-guess him. I figured he'd know about not overtightening the belts.

        PS. thanks for the really quick response!
        An unmuddy off-roader is an unloved off-roader!

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        • #5
          There is no way I would let my neighbour anywhere near a vehicle of mine, no matter how good he says he is. As said, the spring is what does the tensioning and anyone who thinks it needs a bit more (tension) is asking for trouble.

          Do not drive at all with the belt overtensioned. I would even throw the belt away and use a new one, just in case.

          Nev

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          • #6
            Originally posted by NiftyNev View Post
            There is no way I would let my neighbour anywhere near a vehicle of mine, no matter how good he says he is. As said, the spring is what does the tensioning and anyone who thinks it needs a bit more (tension) is asking for trouble.

            Do not drive at all with the belt overtensioned. I would even throw the belt away and use a new one, just in case.

            Nev
            Thanks for the quick reply, Nev, I've taken your advice and stopped my mum taking the truck back.

            A little background: it's my mum's Hilux, I'm a student with some engineering skills but not a lot. My neighbour has fitted timing belts to Hiluxes before, and had the manual to back it up. He definitely knew what he was doing, and we got the machine into pieces and back together again okay, so I'm pretty confident in his work.

            If the tensioner is foolproof, as people say, then maybe we overtightened a different belt - perhaps the fan/alternator or water pump belts (I've already eliminated the A/C belt). I'll test them tomorrow. If not, and it is in fact the timing belt, how tight should the two movement bolts be on the tensioner?

            Cheers,
            Gargravarr
            An unmuddy off-roader is an unloved off-roader!

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            • #7
              The tensioner has three bolts. Only one will actually be doing any real work when all are tightened. Two are just there to support the tensioner and allow it to pivot during belt install. These two have a step that the tensioner fits onto. They are installed through the tensioner and should not clamp down on tensioner at all. The centre one through bearing is installed with tensioner in the belt loose position (spring stretched) and then nipped up a little to hold the tensioner in position. Once belt is on, release the centre bolt, and rotate the crank a little so tension is applied to the side of belt between crank, pump and cam. The spring should then apply proper tension to the other side of belt. This is when you can tighten the centre tensioner bearing bolt. When this is done, rotate crank a few times and triple check timing marks. Sometimes it is a little difficult to get correct alignment between pump and crank, so what I do is have the crank one tooth before TDC before installing belt. This helps get the tension right between pump and crank.

              Hope all that makes sense.

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              • #8
                If you want to check that the noise is from timing belt only, then remove the other belts. You can start and run the engine for a short period of time without water pump or alternator to isolate the problem.

                Nev

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                • #9
                  Originally posted by NiftyNev View Post
                  If you want to check that the noise is from timing belt only, then remove the other belts. You can start and run the engine for a short period of time without water pump or alternator to isolate the problem.

                  Nev
                  Yeah, process of elimination

                  Thanks for the hints, I'll let you know how I get on!
                  An unmuddy off-roader is an unloved off-roader!

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                  • #10
                    Quick question , how did you remove the crank pulley, did you use a puller or did you "tap" it off with a hammer etc.
                    If its the latter then chances are may have damaged the harmonic balancer on the pulley, and the squeel you are hearing is the outer ring spinning on the rubber ring. My old 2.4 did this when I clicked the idle up button . New pulley fitted and all good again.
                    PayPal for stickers : scuffsnscrapes@hotmail.com

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                    • #11
                      Hi all,

                      Thanks for the help. Against the odds, it was the timing belt that was too tight - I tested each belt as I worked my way into the engine, and it was still whining when I got the timing cover off. From what I can tell, my neighbour pushed the tensioner wheel into the belt before he tightened it up.

                      I followed Nev's advice and it worked great (especially offsetting the crank pulley by one tooth, it all tensioned up perfectly!) - no whining when I got the engine back together, much quieter and the performance - we've been blown away!

                      To give it a good test, I drove it home - 50 miles of motorway. It hummed contently all the way home, and it has overtaking power now! That new fuel pump has made so much difference! When my mum took the car back, she powered out of a roundabout and said she was astonished when the engine responded with a ROAR. It's like a completely different beast now. I tested the power around a field, and if I hadn't had 4WD on I could have kicked the tail out!

                      Part of the motorway journey involved a long hill (J2-J1 of the M20 if you know it), and I did notice with concern that the temperature gauge was rising. It went no higher than 3/4 (never even touched the red), but then I was maintaining 70MPH and even accelerating, so the engine was working seriously hard, I guess, and the temperature dropped to normal as soon as the road levelled out. I mention this because we removed the radiator the first time and drained the cooling system. Any air gaps should work themselves out, right? This machine's had the head replaced, anyway.

                      Last thing I need to investigate is the air conditioning, which I managed to short out when trying to get the compressor connection to work - the power connection on the compressor is dodgy, and I was trying to straighten it but pulled the cable out of the plug by mistake and touched it to the compressor housing, earthing it. The A/C light no longer glows, and the compressor doesn't engage, nor does the idle speed change. Anyone know of any fuses that might have blown doing this?

                      Cheers for all your help, guys, our Black Beast is back!
                      Gargravarr
                      An unmuddy off-roader is an unloved off-roader!

                      Comment


                      • #12
                        Glad you fixed the problem. Now you can teach your neighbour how to do it properly.

                        Hope you have had the heaters (front and back) set to hot for a while just to make sure all the air is out.

                        Get an aftermarket temperature gauge. The factory gauge will go to 3/4 and sit there until you go oh sh!t, the engine just overheated. They have a dead spot built into them like many vehicles. There is a mod you can do to the factory gauge to make it more accurate.

                        http://www.toyotasurf.asn.au/forum/v...ic.php?t=14717

                        There's a couple of fuses beside glove box so remove it and check them.

                        Nev

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                        • #13
                          I modded my temp gauge and to me yours sounds like it has been done too.
                          You can tell only by opening it and looking at it.

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                          • #14
                            Originally posted by NiftyNev View Post
                            Glad you fixed the problem. Now you can teach your neighbour how to do it properly.

                            Hope you have had the heaters (front and back) set to hot for a while just to make sure all the air is out.

                            Get an aftermarket temperature gauge. The factory gauge will go to 3/4 and sit there until you go oh sh!t, the engine just overheated. They have a dead spot built into them like many vehicles. There is a mod you can do to the factory gauge to make it more accurate.

                            http://www.toyotasurf.asn.au/forum/v...ic.php?t=14717

                            There's a couple of fuses beside glove box so remove it and check them.

                            Nev
                            Thanks for the info, I took the machine to pieces today and found the fuses behind the glove box, the A/C fuse had indeed blown (who the blazes thought it would be a good idea to put fuses THERE?) - replaced it and the AC comes on again.

                            I've looked into the temperature gauge mod - I'll do it if I can find the resistors.

                            Well, today, in addition to fixing the A/C, I also:
                            -fitted a nudge bar
                            -fitted spotlights to the nudge bar (ran out of cable before I could wire them in though!)
                            -reverted the 'fog lamp' to its original job of the driver's reversing lamp
                            -fitted a fog lamp (seriously, the fog lamp took less time to fit than it must have to modify the reversing lamp!)
                            -tightened the plastic fan onto the viscous unit - came loose while I was redoing the belt

                            My hands look like I've just fought a cheese grater, and may never be clean again, but I'm getting proud of that truck now! ^_^

                            Cheers,
                            Gargravarr
                            An unmuddy off-roader is an unloved off-roader!

                            Comment


                            • #15
                              Originally posted by gargravarr View Post
                              Thanks for the info, I took the machine to pieces today and found the fuses behind the glove box, the A/C fuse had indeed blown (who the blazes thought it would be a good idea to put fuses THERE?) - replaced it and the AC comes on again.

                              I've looked into the temperature gauge mod - I'll do it if I can find the resistors.

                              Well, today, in addition to fixing the A/C, I also:
                              -fitted a nudge bar
                              -fitted spotlights to the nudge bar (ran out of cable before I could wire them in though!)
                              -reverted the 'fog lamp' to its original job of the driver's reversing lamp
                              -fitted a fog lamp (seriously, the fog lamp took less time to fit than it must have to modify the reversing lamp!)
                              -tightened the plastic fan onto the viscous unit - came loose while I was redoing the belt

                              My hands look like I've just fought a cheese grater, and may never be clean again, but I'm getting proud of that truck now! ^_^

                              Cheers,
                              Gargravarr
                              I may still have some resistors left from doing mine. let me know if you want a pair posting when or if i find them!
                              I'M ALWAYS IN THE SH'T, IT'S ONLY THE DEPTH THAT VARIES!!!!!!!!

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