Ian C Posted March 20, 2006 Share Posted March 20, 2006 I'm gonna stick my neck out here and throw some false hope your way... I chucked the audio from the vid into an editor and the frequency of the noise when you rev it up is around 20 knocks per second. When you are doing about 2500rpm, which is about what you are hitting with those throttle blips, the crank does 40 turns a second. The cams, however, turn at half the crank speed... So if you are getting 20 knocks a second I'd start by pulling the cam covers and seeing what's what. If nothing is immediately apparent, turn the engine over manually with a big bar on the crank pulley nut and see if anything isn't right or offer more resistance than the rest of the rotation. Can't help any more than that. It's gonna cost, whatever it is, but a top end rebuild is probably rather less expensive than a bottom end job... -Ian Quote Link to comment Share on other sites More sharing options...
Jake Posted March 20, 2006 Share Posted March 20, 2006 Bearing in mind what Ian has said, it might just be a snapped cambelt idler pulley arm. The same thing as I was on about the other day in this thread. I hope it is that. Pretty easy and cheap to fix. Fingers crossed. Quote Link to comment Share on other sites More sharing options...
how_supra Posted March 20, 2006 Share Posted March 20, 2006 I take it the recovery co got it on the THIRD lorry!. Mate as I said I hope it's not terminal, and I'm sure it'll come back bigger and better than before. Yep, and the best part was that the local base of the recovery company was literally just off the next junction......... Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 20, 2006 Share Posted March 20, 2006 I feel for you buddy. It's an awful sound to hear even if turns out to be something non-critical. A mechanic's stethoscope helps the diagnosis sometimes. If it turns out to be bearings fecked because of inadequate lubrication, I'd investigate seriously why this happened - turbo seals don't allow oil to be lost, not to this extend. You need to be creating smoke-clouds like the batmobile for *many* miles for the oil level to drop a bit. If indeed you lost litres of oil, something else is amiss. Quote Link to comment Share on other sites More sharing options...
SkyJawa Posted March 20, 2006 Share Posted March 20, 2006 Bummer James Quote Link to comment Share on other sites More sharing options...
Ray Posted March 20, 2006 Share Posted March 20, 2006 Daym sorry to hear this... Hope it all gets fixed soon mate, cant wait to see that single in there Quote Link to comment Share on other sites More sharing options...
markssupra Posted March 20, 2006 Share Posted March 20, 2006 Bad news mate. Sorry to hear that. From the sound of it, it seems like a top end prob. It may be one of the camshafts lobes worn or the followers, due to lack of oil. I may be way out on this, hope you get it sorted. Quote Link to comment Share on other sites More sharing options...
monkey76364 Posted March 20, 2006 Share Posted March 20, 2006 Gutting mate and its always just as things are going well and you are about to get ready to spend the cash else where !!! Quote Link to comment Share on other sites More sharing options...
Digsy Posted March 20, 2006 Share Posted March 20, 2006 I'm gonna stick my neck out here and throw some false hope your way... I chucked the audio from the vid into an editor and the frequency of the noise when you rev it up is around 20 knocks per second. When you are doing about 2500rpm, which is about what you are hitting with those throttle blips, the crank does 40 turns a second. The cams, however, turn at half the crank speed... So if you are getting 20 knocks a second I'd start by pulling the cam covers and seeing what's what. If nothing is immediately apparent, turn the engine over manually with a big bar on the crank pulley nut and see if anything isn't right or offer more resistance than the rest of the rotation. Can't help any more than that. It's gonna cost, whatever it is, but a top end rebuild is probably rather less expensive than a bottom end job... -Ian Just in case anyone missed this... Obviously Ian is taking a big flier on what the real engine speed actually was, but maybe if you could post another clip with it revving to a definite RPM he could be more certain about whether this is happening at engine speed or half engine speed or whatever. If it is one knock per two engine revs then it would point to a single valve event rather than a problem with the cam drive system as a whole. If it is a dropped valve or something then it's strange it doesn't do it at idle, but did anyone else think that the valve gear at tickover was unusually noisy? Like I said in my post the knock sounds a little too lightweight to be a big end. Have you tried the extension bar on the camcover bolts trick to see if you can tell where abouts the knock is coming from? Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 20, 2006 Share Posted March 20, 2006 Yeah, it's a big guess but based on all the times I've blipped the engine trying to diagnose stuff you get to about 2500rpm Send me a clip of it held at that rpm and I stand a better chance Indeedy, the valve train sounds noisy, I was thinking sticking valve but it's not sticking open enough to affect the sound of the idle... -Ian Quote Link to comment Share on other sites More sharing options...
wkdtime Posted March 20, 2006 Share Posted March 20, 2006 sorry to hear this mate hope you diagnose whats wrong with it asap, looking forward to your single. Quote Link to comment Share on other sites More sharing options...
Digsy Posted March 20, 2006 Share Posted March 20, 2006 ...actually, just thinking about this a bit more, if it was only one big end gone then you might still only get one knock per two engine revs. Four-stroke engine, you see. However, if it knocked on the power stroke and the compresson stroke then you would one knock per rev. So it's not conclusive yet. Quote Link to comment Share on other sites More sharing options...
terribleturner Posted March 20, 2006 Author Share Posted March 20, 2006 Thanks again guys. Just had Dave S come round so we could have another listen and we pretty sure it's coming from the back on the left. But can't decided if it's high or down the bottom. Gonna go outside in a minute to pull the cam covers to see. I'll take some more video as well. Also not sure if this has anything to do with it but the battery doesn't seem to be hold the charge as well. The engine seems to have a little trouble getting the power together to start up. Quote Link to comment Share on other sites More sharing options...
Dave S Posted March 20, 2006 Share Posted March 20, 2006 Did sound like it came from top end at the back....need to check if a shim has popped out of one of the cams maybe .....long shot ?? Quote Link to comment Share on other sites More sharing options...
chilli Posted March 20, 2006 Share Posted March 20, 2006 well my fingers are crossed for you it's something more trivial like a cam / valve issue I've heard big end failure sound as light as this, and also with similar characterisics, i.e. shows up more under change of engine speed when you rev it, but that certainly doesn't mean that is what it is. if you take one spark plug out at a time and run it on 5, won't that help see if it's a compression related issue (like big end knocking under load) - just a thought Quote Link to comment Share on other sites More sharing options...
piehound Posted March 20, 2006 Share Posted March 20, 2006 droped mine off this morning to be rebuilt and it sounds the same exactly and mines big ends, i tried to record mine but the wanky phone recorder was poo Quote Link to comment Share on other sites More sharing options...
terribleturner Posted March 20, 2006 Author Share Posted March 20, 2006 Did sound like it came from top end at the back....need to check if a shim has popped out of one of the cams maybe .....long shot ?? OK, just got in from taking a look under the left cam cover and although i don't know what to look for 100% im thinking shim. There's loads of oil in there so can't see it being oil starvation. So im right from these pictures you can see the shim under the cam, but on the lug on the right it looks like it's missing. Got more video which i'll put up in a minute. Quote Link to comment Share on other sites More sharing options...
Dave S Posted March 20, 2006 Share Posted March 20, 2006 the shim could be trapped somewhere nasty maybe stopping rotation of the cam which would explain its difficulty turning over....any sign of it.......fingers crossed m8 Quote Link to comment Share on other sites More sharing options...
terribleturner Posted March 20, 2006 Author Share Posted March 20, 2006 Couldn't see it loose in there. I wanted to turn the cam to see if anything moved but wasn't sure how to I used a screw driver to investigate below the cam and there's something flat and smooth there but with so much oil i can't see. Is it worth trying to soak up/remove some oil to see better?? Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 20, 2006 Share Posted March 20, 2006 Can't see from these pics. Did a shim walk away? These shims stick to a magnet, don't they? Prepare the fishing rod! Quote Link to comment Share on other sites More sharing options...
Digsy Posted March 20, 2006 Share Posted March 20, 2006 Valvetrains can run on feck all oil, and the Supra obviously doen't have hydrualic tappets, so it if the problem is in the top end it almost certainly won't be down to oil starvation. Not certain what you are trying to show in the pics. The first one shows what looks like two tappets on the same cylinder, both of which look OK. The second one looks like two tappets from different cylinders, one of which (the right one) looks a bit odd, but it's depressed so you can't see whether there is a shim in there or not. Quote Link to comment Share on other sites More sharing options...
Digsy Posted March 20, 2006 Share Posted March 20, 2006 Couldn't see it loose in there. I wanted to turn the cam to see if anything moved but wasn't sure how to Put the car in top gear and push it forward? Get a long breaker bar on the crank pulley? Quote Link to comment Share on other sites More sharing options...
chilli Posted March 20, 2006 Share Posted March 20, 2006 maybe soak up the oil with some kitchen roll and post up some clearer pics, my fingers are crossed that you are onto something... Quote Link to comment Share on other sites More sharing options...
terribleturner Posted March 20, 2006 Author Share Posted March 20, 2006 What i mean with the shim is to me there looks like an outter holding bit with the shim inside (Picture below. Green outside none moving bit, red is the shim). There's another one that looks pushed down but i can still see it all. It's like this is the only one that doesn't look the same as the others. Can't find anything floating around though Quote Link to comment Share on other sites More sharing options...
Dave S Posted March 20, 2006 Share Posted March 20, 2006 they should all look like that one James,the shim is the thin silver disk directly under the cam lobe Quote Link to comment Share on other sites More sharing options...
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