Guest RZtt Posted February 5, 2010 Share Posted February 5, 2010 Hi Guys, I have a problem with my car as the timing belt walks off the cam gears at high rpm and rubs against the front timing belt cover. The car is 1995 model JDM spec Twin turbo Toyota supra (2jzgte). This problem started after I replaced my camshafts to 264 BC cams. When we were installing the camshafts, we did find a small problem on the Intake camshaft. The problem was we couldn't tighten the bolt that holds cam gear in place. The intake camshaft had shorter thread for the bolt to go right in. The cam gear on the intake side was pretty much lose. We then had to shave the bolt shorter so we could tighten the cam gear. The Exhaust camshaft was fine had no trouble tightening the bolt. We also changed almost everything to new like aftermarket cam gears, new tensioner, new timing belt, new crankshaft gear and new damper. And the problem still not solved. Do you think my camshaft could be faulty? The camshaft is the only thing we haven’t change. We did think about putting standard cams back on to see if that fixes the problem. Is there any way I could get the camshaft checked to see if it’s faulty or not? This has costed me a lot $$$ I have no clue what causing this problem. Your advice and help would be appreciated. Thank You Manesh Quote Link to comment Share on other sites More sharing options...
nevins Posted February 5, 2010 Share Posted February 5, 2010 possible that the pulleys are not level so may get travelling that way. Quote Link to comment Share on other sites More sharing options...
Guest RZtt Posted February 5, 2010 Share Posted February 5, 2010 possible that the pulleys are not level so may get travelling that way. When I had the oem pulleys on it was still walking off the cam gears It only moves at high rpm other on high boost Quote Link to comment Share on other sites More sharing options...
nevins Posted February 5, 2010 Share Posted February 5, 2010 have you checked to see that the pulleys are level, as in one of them not sat further forward Quote Link to comment Share on other sites More sharing options...
Guest RZtt Posted February 5, 2010 Share Posted February 5, 2010 As far as i know we checked everything. The only thing is left to do now is to change the cams back to oem cams Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 5, 2010 Share Posted February 5, 2010 Get a decent straight edge, and check across both cam pulleys, that will tell you if there is an aliment problem. Quote Link to comment Share on other sites More sharing options...
TLicense Posted February 5, 2010 Share Posted February 5, 2010 100% sure something will be bent. My immediate guess would have been the tensioner pulley bolt as that usually gets a load of abuse when people fit a cam belt without removing the belt tensioner. It only has to bent by the smallest of fractions and it will drive the belt off. I've seen it a couple of times on 3SGTE's. Are you sure you've fitted the washer behind the tensioner? Why wasn't the thread deep enough? Did you fit a stock bolt? Do BC sell the cams like this for a reason, or do you think it was just poor quality control? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 5, 2010 Share Posted February 5, 2010 The belt is bottom pulley guided, are you sure you have assembled everything on the bottom pulley area correctly, and, as Tony says, have you got the tensioner assembled properly? Quote Link to comment Share on other sites More sharing options...
Chiefgroover Posted February 5, 2010 Share Posted February 5, 2010 Aftermarket cam gears........try your stockers, they are very good, and sure to be a good mate with the belt. You may have bent exhaust valves, and if they are not bed the car will still go quite well, as mine did, but better to have it sorted or it may destroy your valve seats. Did you defo fit the tensioner correctly? the washer on there is special steel and finish, and it wont work properly with any washer. Did you threadlock the bolt also? Quote Link to comment Share on other sites More sharing options...
Guest RZtt Posted February 6, 2010 Share Posted February 6, 2010 (edited) 100% sure something will be bent. My immediate guess would have been the tensioner pulley bolt as that usually gets a load of abuse when people fit a cam belt without removing the belt tensioner. It only has to bent by the smallest of fractions and it will drive the belt off. I've seen it a couple of times on 3SGTE's. Are you sure you've fitted the washer behind the tensioner? Why wasn't the thread deep enough? Did you fit a stock bolt? Do BC sell the cams like this for a reason, or do you think it was just poor quality control? Hello,When first time it happend the timing belt snaped the tensioner bracket off so we replaced it with brand new one. I'm not sure if we changed the bolt. Do you get a new bolt when you change the tensioner? Sorry for noob question. I'm also thinking the same thing, that something could be bent because this only happend a month later after I got the cams done. This happend on a drag strip, when launching the car off the mark. I heard a loud bang noise, then straight after that I heard the timing belt rubbing against belt cover. I bought the Bc cams from a Group buy on Aussie supra forums. I did ask the guys who bought the cams on Group buy if they had similar problem, and they all said no. So I'm guessing only mine had the shorter bolt thread. I used stock cam bolts. I sent BC a email regading this issue and they said, to send the cams off for inspection. Before I do, I thought I should ask you guys if you think the cams could be faulty The belt is bottom pulley guided, are you sure you have assembled everything on the bottom pulley area correctly, and, as Tony says, have you got the tensioner assembled properly? Yes I'm sure we assembled everything on the bottom pulley area correctly. As I mentioned to TLicense when it happend the first time it snaped off the tensioner bracket, luckily it didn't damage the engine the belt was just hanging on the cam gears, only inch away to slip off completely Aftermarket cam gears........try your stockers, they are very good, and sure to be a good mate with the belt. You may have bent exhaust valves, and if they are not bed the car will still go quite well, as mine did, but better to have it sorted or it may destroy your valve seats. This problem happend when I was still running OEM cam gears. The only reason I changed to aftermarket cam gears to see if that fixes the problem but sadly it didn't. Im not too sure about the exhaust valves, I guess its something i need to look at. Thanks heaps for your help. Did you defo fit the tensioner correctly? the washer on there is special steel and finish, and it wont work properly with any washer. Did you threadlock the bolt also? Yes, Im sure we put every thing back on properly. My mechanic said he has been a mechanic for 35 years fixing performance cars and this is the first time he came across a problem like this. Edited February 6, 2010 by RZtt (see edit history) Quote Link to comment Share on other sites More sharing options...
nevins Posted February 6, 2010 Share Posted February 6, 2010 Yes, Im sure we put every thing back on properly. My mechanic said he has been a mechanic for 35 years fixing performance cars and this is the first time he came across a problem like this. Thats odd as belts running of gears is a common thing, normally down to warn parts, damaged or improper fitment Quote Link to comment Share on other sites More sharing options...
Guest RZtt Posted February 6, 2010 Share Posted February 6, 2010 Yes, Im sure we put every thing back on properly. My mechanic said he has been a mechanic for 35 years fixing performance cars and this is the first time he came across a problem like this. Thats odd as belts running of gears is a common thing, normally down to warn parts, damaged or improper fitment Yes that why we can't figure out what is causing it. We are putting the oem camshafts back in sometimes next week. Will see if that fixes the problem. The car has been off road now nearly 7 months. Very frustrated Quote Link to comment Share on other sites More sharing options...
TLicense Posted February 6, 2010 Share Posted February 6, 2010 I imagine the tensioner bolt will be separate to the bracket. As mentioned there is also a washer that you need to make sure is installed correctly. The fact that something went "bang" is not good. There really shouldn't be anything like enough force going through the cambelt to make anything snap. That sounds like something else is afoot. Quote Link to comment Share on other sites More sharing options...
Guest RZtt Posted February 6, 2010 Share Posted February 6, 2010 (edited) I imagine the tensioner bolt will be separate to the bracket. As mentioned there is also a washer that you need to make sure is installed correctly. The fact that something went "bang" is not good. There really shouldn't be anything like enough force going through the cambelt to make anything snap. That sounds like something else is afoot. went and saw the car today and got a update on the cams. We tested the car with oem cams and sadly it happend again. So now we know that its not the cams. TLicense, i told him about the tensioner bolt. And we going to change the bolt next week. Hopefully it will fix the problem. Thanks mate for the help much appreciated Edited February 6, 2010 by RZtt (see edit history) Quote Link to comment Share on other sites More sharing options...
Chiefgroover Posted February 6, 2010 Share Posted February 6, 2010 Yes, Im sure we put every thing back on properly. My mechanic said he has been a mechanic for 35 years fixing performance cars and this is the first time he came across a problem like this. Even the best can slip on this one, if he follows the book instead of relying on experience he cant go wrong. I fear something is missing. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 6, 2010 Share Posted February 6, 2010 This engine has never overheated and had to have the head skimmed, has it? If a straight six alloy head warps the cam journals will almost certainly be out of line, too. If so the cams may be stiff to turn in the journals and overloading the belt. Try the cams without the tappet buckets in and see if they turn easily by fingers. I'd have thought whoever bolted it together would notice a bent bolt for the tensioner, it wouldn't snug up properly, and the tensioner arm would wobble as it was turned. Quote Link to comment Share on other sites More sharing options...
Guest RZtt Posted February 6, 2010 Share Posted February 6, 2010 This engine has never overheated and had to have the head skimmed, has it? If a straight six alloy head warps the cam journals will almost certainly be out of line, too. If so the cams may be stiff to turn in the journals and overloading the belt. Try the cams without the tappet buckets in and see if they turn easily by fingers. I'd have thought whoever bolted it together would notice a bent bolt for the tensioner, it wouldn't snug up properly, and the tensioner arm would wobble as it was turned. No, the engine has never been overheated. I've just recently fully rebuilt my head due to the engine failing leakdown test. The timing belt problem started way before I did the rebuilt. We had a look at the tensioner bolt and it looks fine. Can't see any kinda of bent. Not sure if you can spot the bent by naked eye. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 7, 2010 Share Posted February 7, 2010 (edited) OK, here's an idea, I am rebuilding an engine at the moment so took a few minutes off to see how you could do something wrong to cause the belt to walk. Tensioner washer the wrong side = seized tensioner. Tensioner on the wrong way round = locked up tensioner. Tensioner washer left out = possibility, the thing will float about. However, my best guess is the shim like belt guide washer with lots of peripheral holes has been put on BEHIND the crankshaft cam drive gear, or left out altogether,instead of put on IN FRONT of it, and the belt is no longer guided and it is walking onto the back part of the damper hub instead of being restrained.Taking the damper off and the covers should reveal all. Edited February 8, 2010 by Chris Wilson (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest RZtt Posted February 7, 2010 Share Posted February 7, 2010 OK, here's an idea, I am rebuilding an engine at the moment so took a few minutes offto see how you could do something wrong to cause the belt to walk. Tensioner washer the wrong side = seized tensioner. Tensioner on the wrong way round = locked up tensioner. Tensioner washer left out = possibility, the thing will float about. However, my best guess is the shim lile belt guide washer with lots of peripheral holes has been put on BEHIND the crankshaft cam drive gear, instead of IN FRONT of it, and the belt is no longer guided and it is walking onto the back part of the damper hub instead of being restrained.Taking the damper off and the covers should reveal all. Chris Thank you very much for all the info. You gave me a lot of ideas there. I will get my mechanic to check it out. Will keep you updated. Thanks heaps mate Quote Link to comment Share on other sites More sharing options...
Guest RZtt Posted February 27, 2010 Share Posted February 27, 2010 Thank you so much guys for helping me out. The problem now slovoed. It was my ebay crank pulley which was causing the problem. Changed to Titan damper and its running sweet now. Quote Link to comment Share on other sites More sharing options...
Suprab1 Posted February 27, 2010 Share Posted February 27, 2010 Glad to here this mate. Quote Link to comment Share on other sites More sharing options...
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