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Knocking From Gtr Engine

Dr GTR

By Dr GTR,
in Engines & Forced Induction

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Dr GTR Rookie

Dr GTR

Posted
Posted (edited)

Hi Guys,

I know its my forst post but i need some help.

I am hearing bit of a knocking noise coming from the top of my R33 GTR engine (turbo side) a few seconds after it starts. The noise kinda increases with revs but disappears after 3k rpm but returns when i let go of the gas. The knocking does go when oil get slightly warm after 3 or 4 minutes. I have also taken the oil cap off when the engine is on and i can hear a clicking/tapping kind of noise. The noise has got a bit louder over time but i am hoping its the clearances or lifters and nothing more than that.

Anyone have any suggestion or further dignostic help???

Gerry

Edited by Dr GTR
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RICK-GTR Collaborator

RICK-GTR

Posted
Posted
Hi Guys,

I know its my forst post but i need some help.

I am hearing bit of a knocking noise coming from the top of my R33 GTR engine (turbo side) a few seconds after it starts. The noise kinda increases with revs but disappears after 3k rpm but returns when i let go of the gas. The knocking does go when oil get slightly warm after 3 or 4 minutes. I have also taken the oil cap off when the engine is on and i can hear a clicking/tapping kind of noise. The noise has got a bit louder over time but i am hoping its the clearances or lifters and nothing more than that.

Anyone have any suggestion or further dignostic help???

Gerry

are u sure the noise is comming from the top of the engine? not the middle or bottum?

I thought when my gtr was knocking it was coming from the top but it was actually bottum end bearing

pssiii Collaborator

pssiii

Posted
Posted

Bent valve(s)!!

This happened to a customers GTR, previous owners tried to chase power with boost, leaned out which caused melting of plugs and broken ring-lands. The melting of the plugs caused material to get caught under both exhaust valves at no.6, something else could have gone through engine also?

If the valves dont seat then they have too much clearance and knock at top of engine.

G'luk

Dr GTR Rookie

Dr GTR

Posted
  • Author
Posted (edited)

Thanks for your response guys....The bearings were only done about 3 months ago due to a dodgy filter so i am hoping that they havent gone again. When they did go the noise was not like this and the mechanic seems to think that the noise is my clearances thet need sorting. This time its kind of coming from the top and definately towards the middle of the exahust side cam but as i said the noise does go away after a few minutes.

Gerry

Edited by Dr GTR
Dr GTR Rookie

Dr GTR

Posted
  • Author
Posted
whats the oil presure like? hot/cold? ive never ever heard a big end knock disapear with heat. maybe a dodgy lifter

The oil pressure is great due to the trust oil pump. Im seeing 7bar when the car is stone cold and just over 2 bar on idle when the oil reaches 80 degrees. Pressure whilst driving is also very good. I also have trust sump extension.

Gerry

Dr GTR Rookie

Dr GTR

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  • Author
Posted (edited)

Here is a sound clip io managed to get today when i started her.

Full spec of the car is as follows just in case it could be one of the mods

Apex V-max SPL pistons with cooling channles

Trust rods

R34 crank balanced

Nismo 24 U Block

Apexi 280degree cams with 10.5mm lift

Apexi double springs

Trust greddy Intake plenum

Greddy t517z trubos

Trust oil pump

As i mentioned, this noise does go after the oil starts warming up and there is no loss in performance thats for sure lol

CIMG0895.WAV

Edited by Dr GTR
Dr GTR Rookie

Dr GTR

Posted
  • Author
Posted (edited)
Geez man - I wouldn't be running the engine - take it to a workshop !

Fingers crossed its nothing major man........My tuner is coming over in the morning to have a listen to it. If it was the bearings wouldnt the noise be permanent???

Gez

Edited by Dr GTR

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