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Desperately Need Help - New Built Engine With Strange Sound.


HI PSI

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  • Member
  • Member For: 17y 10m 3d
  • Gender: Male
  • Location: Central Queensland

Hi all,

a good friend has a rather peculiar sound coming form his freshly built engine. The sounds seems to occur at around 3,000 to 3,300 rpm. He is at his wits end with trying to diagnose and fix the noise. Given this, the owner has gone to extraordinary measures to try and identify the issue, all with no avail. As he has exhausted every idea possible, he requested that I create this thread in the hope that other may assist in its identification and rectification.

History:

The car has been built with quality components, with no expense has been spared. The engine was rebuilt (at great cost) around 7 months ago by a reputable engine builder who is based in South East Queensland. The engine ran for three days, before the intake valves smashed into the pistons and cracked the head casting.

A new cylinder head was built (By the same Engine builder) and has just been fitted to the bottom end. Ever since the car has been making this "Rattling sound". The said engine builder was consulted and his advice constituted of: "It's fine, just run it. But, there is no warranty if it "blows up". As you could well understand (And you will after you view the video posted below), and given the time and money taken to complete the build, the owner is not happy with this advice and lack of support. He has now taken matters into his own hands and has surrounded himself with very experienced and knowledgeable people. That given, the source has not yet been found. He described it as being related to, or affecting the timing chain, as if extra tension os placed on the chain, the sound commences at a higher rev range.

To date, they have:

  • Replaced timing chain, guides, tensioner
  • Replaced cams, vernier gears
  • Removed Jesel rockers and replaced with factory units
  • Removed solid lifters and replaced with hydraulic lifters.
  • Removed cams and checked for straightness and tolerances. timing chain
  • Removed VCT actuators and fabricated a billet relpacements which fed additional oil onto the timing chain. etc

There are no evidence or telltale markings of any kind to suggest rubbing or anything untoward.

Any advice or assistance would be greatly appreciated.

The owner would greatly appreciate it, if the thread could maintain focus on the problem. At this point in time, he would like to keep all emotion out of it, as he just wants to find and fix the issue.

https://youtu.be/kYpgbLsMIQU

MOV_4338_1.mpg

Edited by HI PSI
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  • Member
  • Member For: 17y 10m 3d
  • Gender: Male
  • Location: Central Queensland

Only happens over a 300-400 rpm range, starting at 3,000rpm, then disappears. If he places extra tension on the chain, it moves further up the rev range.

Edited by HI PSI
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  • Dropping a turd
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  • Member For: 16y 5m 1d
  • Gender: Male
  • Location: Perth

Auto or manual

We had a similar noise with our Nizpro engine in exactly the same rev range. There seems to be a resonance at that RPM that amplify noises. For us it ended up being exhaust related , but took ages to diagnoses as it definitely appeared to be coming from the engine. SO this noise may NOT be actually coming from the engine. Noise travels strangely through different components and metals.

Very hard to diagnose from the short video.

Edited by arronm
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  • Member
  • Member For: 17y 10m 3d
  • Gender: Male
  • Location: Central Queensland

Is said engine builder located in toowoomba by any chance?

At this point in time, the owner will not disclose any information regarding the shop involved.

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