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Strange noise coming from engine suddenly


Fulcrum2000
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It was making a mild intermittent noise before this though, as per my previous thread. On idle. I posted a video. Looks like the thread has been removed its not in my activity list anyway. I was recommended to have one of the ancillary pulleys changed which I did and it was still there, so I had the oil pump done thinking the cambelt may be slightly loose and it might cure it, but it didnt. the noise was very minor and many on here said it might be a little bit of piston slap. It may have had nothing to do with it but it did make a sound. I also noticed my AC pulley was loud when it went on, not sure if that was indicative. But now the oil pressures are tested and its fine I guess we are looking at pulleys or internals of some kind?

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I could try taking it to a specialist PJJ but the problem when you have a situation like this is the car isnt mobile. I struggled to get it to the local garage so unless there was a massive benefit to starting it and running it onto a trailer, letting it bump about across the countryside and then start again to come off, start again for diagnostics I thought that might be a tad risky? When the big end went in my MR2 it went from the tiniest sound to a massive Japanese machine gun sound in the space of three miles. New engine unfortunately that time so I will stick to this mechanic and if he is stumped it will have to be a specialist like Hartech etc I guess, but thanks for the contact info guys its good to have a backup plan!

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It was making a mild intermittent noise before this though, as per my previous thread. On idle. I posted a video. Looks like the thread has been removed its not in my activity list anyway. I was recommended to have one of the ancillary pulleys changed which I did and it was still there, so I had the oil pump done thinking the cambelt may be slightly loose and it might cure it, but it didnt. the noise was very minor and many on here said it might be a little bit of piston slap. It may have had nothing to do with it but it did make a sound. I also noticed my AC pulley was loud when it went on, not sure if that was indicative. But now the oil pressures are tested and its fine I guess we are looking at pulleys or internals of some kind?

 

 

http://www.mkivsupra.net/vbb/showthread.php?349335-Knocking-sound-after-cambelt-change

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Most people on here said cam wasnt tight enough, had it checked and no issue but no resolution, then I knew I was going to a new mechanic to do the oil pump (so its two mechanics here not one making the same mistake twice or I would be worried) so I bought another new full cambelt kit thinking if its cam then boom, job done. However when I got it back the sound was still there despite all belts coming off and on again. Then I got advice it might be piston slap which can be managed. But clearly something went south quick!

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Most people on here said cam wasnt tight enough, had it checked and no issue but no resolution, then I knew I was going to a new mechanic to do the oil pump (so its two mechanics here not one making the same mistake twice or I would be worried) so I bought another new full cambelt kit thinking if its cam then boom, job done. However when I got it back the sound was still there despite all belts coming off and on again. Then I got advice it might be piston slap which can be managed. But clearly something went south quick!
Piston Slap normally only happens on startup when engine is cold. Once it's up to operating temperature it goes away. It's quite normal for fully forged engines with bigger components. I occasionally have it if extremely cold but it sounds nothing like that or anywhere near as loud.

 

 

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I could try taking it to a specialist PJJ but the problem when you have a situation like this is the car isnt mobile. I struggled to get it to the local garage so unless there was a massive benefit to starting it and running it onto a trailer, letting it bump about across the countryside and then start again to come off, start again for diagnostics I thought that might be a tad risky? When the big end went in my MR2 it went from the tiniest sound to a massive Japanese machine gun sound in the space of three miles. New engine unfortunately that time so I will stick to this mechanic and if he is stumped it will have to be a specialist like Hartech etc I guess, but thanks for the contact info guys its good to have a backup plan!

 

No worries mate just seems like you've had a bad run of issues and a fresh pair of eyes would help maybe.

 

As for getting it there, you could get a tow truck with a winch so you don't need to fire her up. Just push to and from the back of the truck.

 

The other thing to do is try calling James and get his advice over the phone whilst he's listening to your video. It's a longshot i know mate but you never know if he's come across same or similar before.

 

Hope u get sorted soon.

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I think so yes but almost 10 percent different to the other 5

 

Not really enough to worry about, piston slap on a std engine would be unlikely the noise sounds half engine speed to me so if it doesn't prove to be cam or ancillary belt/tensioner, or contact with a cover it may be worth pulling the cam covers and check that it hasn't spat a lifter shim, although again unlikely, and also worth checking that the cam timing is correct after the experienced mechanic had had the crank pulley off he would have needed to ensure the engine was re timed correctly.

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Just been playing your video over and over again on you tube and have you had anything done to clutch at all.

As the noise sounds similar to mine when I thought it was bottom end gone but strip engine only to find flywheel bolts were loose, I know it’s a long shot but comparing your video to my video, they do sound similar.

It’s not letting me post up my video but if you pm me your email I will send my video to you so you can compare yourself.

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Could it be in the valve train sounds like top engine?

 

I agree. I just wrote this post elaborating upon the possible issue and you beat me to it....

 

Hmmm, this sounds very top endy, aluminium/metallic and head/cam related to me, like Tricky just said, though rather than a missing shim, I would guess at an underperforming spring, (causing bad valve float and hammering), which might also account for the lack of static compression. You might even have an exhaust valve seat disintegrating, some of which went through the old oil pump and......... required a new oil pump? Removal of the cam covers would be a very good idea......

 

What was wrong with the old pump and was metallic debris found in the sump?

 

The precise location of the presumably metallic collision causing the noise should be identifiable with a mechanic's stethoscope held against the head and block or at least some idea with your hand on the spark plug and timing cover/s. A longer video would also help but I can understand your reluctance to rev' it for too long. It certainly doesn't sound like any short block issue to me unless it's telegraphing up from the pistons or rods into the head and covers but with an iron block it will be less hollow sounding with a lower pitch. Also, I'm sure it would have been as bad before the service if it was a rod cap coming loose, unless the mechanic thrashed the absolute living bejesus out of it in your absence.......

 

Nah, they never do that.... especially not in a Supra!

 

I'm sure you're only dealing with a rubbing bolt head on a timing cover or something mild, (unlikely actually except in the fan shroud example where centrifugal force increases contact with engine rpm) but if you're really unlucky the crank bearings have been destroyed by a valve seat that fell out, due to a lack of valve lash from an out of spec' shim, (too thick or high), causing an even further worn seat which allowed exhaust gasses to increasingly bypass the valve, overheat and crack the head, (thus allowing the seat to fall out or break apart and go through the engine and pump). Basically, if there's not enough valve lash in an overhead cam engine like this due to worn or eroded exhaust seats, (as the inlets don't experience the much higher temperatures flowing through the open valves and wear anything like as much), the seat will begin to overheat and disintegrate due to ignition and possibly knocking level temperatures exiting the not quite closed valve.

 

Now, I'm not suggesting that this noise is detonation or 'knocking' which is more of a 'pinking' at low rev's and only in an overheated engine but as a potential symptom of knocking which will also be encouraged by a super hot and/or worn thin exhaust valve which is no longer making full contact with the seat upon closure and cooling properly between cycles. Valves spend most of their time closed which allows them to cool in contact with their respective seats which is why race engines are fitted with copper beryllium or the healthier to machine copper non-beryllium seats to aid in wicking away heat from the exhaust valves to reduce wear and failure.

 

Again, hopefully it's nothing serious but a new oil pump speaks volumes to me and fully diagnosing the cause of that failure is your first priority or your crank is potentially being scored by embedded foreign objects, e.g. valve seat material and oil pump compression gear teeth.

 

Sent from my AKG K702 headphones, (which are for your sake, hopefully 'king useless for diagnosing engine problems!)

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I would agree but the pump was replaced as a 'belt and braces' step when the FMS went. To explain the history, I had the valve seals done as the car produced a lot of smoke when starting, and I mean a lot. When they were done it was simply perfect, with the exception that the aircon didnt work. I got my pipes fixed by a specialist company and then went back to the mechanic, had these fitted and the small sound started. Took my car down the bypass on the way home and every time I accelerated got a car wide plume of smoke out the back, went straight back and the FMS had gone. He stripped it all down and fitted a new one and new cambelt but the small sound was still discernible but pretty much only to me. He said I had a slight issue with my AC pulley bearing being loose so I had that changed but again it didnt solve the sound. The mechanic who worked on the Mk III in town then fitted a new oil pump when many on here said it needed it and it made sense to me too but there was no indication it was faulty when it came out. The oil strainer had been clogged up and was cleaned at the same time but the pump was still going strong apparently.

 

When you are next to it, that video doesnt do it justice, it is pretty loud, not big end gone loud, but loud and to me I totally agree it sounds like its coming from the top of engine. Should I have new piston rings etc as a matter of course if it goes that far in?

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Dont agree with the valve seat that Morphus was suggesting, a valve seating that badly would have resulted in a much lower compression reading, and as for any valve or seat debris going through the pump i really don't see how as anything would have passed through the exhaust port.

 

The fact that your now saying that you could hear a slight tapping sound even before the FMS went leads me to think that maybe something was starting to fail, so given that the oil pump pick up was partially blocked i would hazard a guess that oil flow/pressure was restricted to the mains and big ends so perhaps a shell has picked up or spun and failed, i am surprised that the mechanic did not check for crank end float and main and big end play when he replaced the pump, especially since you had mentioned a slight knocking sound, its easy enough to do with the sump off.

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With respect Tricky it's not me now saying it had a sound I always said it and the link to the thread where I thought it was cam pulley is in this thread. I guess until I get an update from the mechanic it's all conjecture at this point but it will get what it needs and perhaps my compression will be radically improved in the process. Got to look for a positive somewhere! I think the respray will have to wait now though for obvious reasons till I'm holding more folding....

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Nothing yet, they're diagnosing it when they can but garages in lincolnshire are really busy, you normally wait a couple of weeks to get a days labour booked at the good ones so when I turned up clacking away I knew it would be a week or more before they did a full check. I'm on my family hols for a while now anyway but if I havent heard anything from them by the time I get back I will start bothering them. I suspect the people on here are right though and its one of the belts or more likely very high up in the engine and it will only be a partial disassembly. I really need some good luc after this as it is getting very hard to justify the near 10 grand I've spent upgrading but mainly repairing the car and only 1500 miles covered! Come on Supe!

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As a quick update all pressures fine engine tested with belts off and noise is from the engine. The mechanic doesn't want to deal with any more invasive issues but suspects the new pump blew away some of the old gunk masking whatever the cause of the problem was and I suspect it's true. I have already found a new mechanic who is happy to strip the engine down from the top and find and fix whatever faults he finds. It sounds high up to me but I will get him to check pistons and bores whilst it's in bits. Obviously I'll keep you all informed and it looks like another big bill coming my way but I'll keep plugging away till my car is strong. I get the impression that most others on here have reliable cars is this the case or are you all periodically suffering the kinds of failures I have had a cluster of? Some reassurance 25 year old Supes actually are reliable when well maintained would help me :)

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As a quick update all pressures fine engine tested with belts off and noise is from the engine. The mechanic doesn't want to deal with any more invasive issues but suspects the new pump blew away some of the old gunk masking whatever the cause of the problem was and I suspect it's true. I have already found a new mechanic who is happy to strip the engine down from the top and find and fix whatever faults he finds. It sounds high up to me but I will get him to check pistons and bores whilst it's in bits. Obviously I'll keep you all informed and it looks like another big bill coming my way but I'll keep plugging away till my car is strong. I get the impression that most others on here have reliable cars is this the case or are you all periodically suffering the kinds of failures I have had a cluster of? Some reassurance 25 year old Supes actually are reliable when well maintained would help me :)

 

Very reliable. I have had spures where something needs replacing one after the other. But over all once the engines maintained properly its trouble free.

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I think unfortunately you've fallen foul of the neglected car that had problems stored up particularly a tired engine. With hindsight a slightly hasty purchase, lot's of questions afterwards suggest the research was not 100% thorough pre purchase? (to be fair when is it)

 

Then this is compounded by having to get any work done by others, and them not being as clued up as perhaps some on here, so you are probably going to end up paying more overall fixing it than buying a better one that was £2-4K more expensive at the time.

 

Amazingly reliable if serviced and kept stock, still very reliable if serviced and bpu, but a 20-25 year old anything is obviously closer to end of life than the great days of when they were 10-12 year old absolute bargains. Not even the Supra can be reliable forever, age and neglect catch up with us all!

 

I hope you get it sorted one way or another.

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