Tapping/knocking Noise When Rb26 Cold

[gotenek]

Hey everyone,

My name is Sammy and I bought my first nissan, a 1991 Nissan Skyline GT-R about 5 months ago. I used to own many ae86s after having enough of rust and leaks, i decided to sell them all and move on to something more desirable, which got me here. To briefly describe my technical skills, I'm good at turning a wrench but an amateur at diagnosing.

After driving the vehicle for a few weeks, I noticed that there was a tapping/ knocking noise coming from the engine. The noise is only there when i cold start the engine. After driving the car from about 15 minutes, the noise is COMPLETELY gone.

Here is the video of the sound: https://www.youtube.com/watch?v=TPS5SNXujHc&feature=youtu.be

(sounds exactly how it sounds in the video. I would turn off the bass on the speakers to hear it properly.)

I've had a various tuner shops have a look at the car and noone would give me even a rough estimate of the problem without asking me to rip apart the engine at their shop for $150/hr. So i stopped driving the car and it's been sitting in the driveway for 4 months now.

Although one person told me that my timing belt is too tight and the oil pumps also make that noise sometimes so I have all those parts on order and waiting for them to arrive.

The car is fully stock. No mods whatsoever apart from a quite kakimoto catback.i am using castrol gtx 10w40 conventional engine oil.

Please help

Edited August 26, 2015 by gotenek

[niZmO_Man]

Have you changed the oil?

[gotenek]

Yes, I've changed the oil. The previous owner was running 5w30 and I changed to 10w40 conventional.

[niZmO_Man]

Maybe you have forged pistons

[Ben C34]

Conventional oil? As in not synthetic?

What oil?

Hard to tell from the video, but I would check valve clearances first, as it is relatively easy.

If it's a death knock, go hard. If the engine wants to doe it will Wether you like it or not.

[gotenek]

Conventional oil? As in not synthetic?

What oil?

Hard to tell from the video, but I would check valve clearances first, as it is relatively easy.

If it's a death knock, go hard. If the engine wants to doe it will Wether you like it or not.

Yes, non-synthetic castrol gtx 10w40.

Pretty sure don't have forged pistons lol. I dont think the cam covers were ever removed when i replaced the rubber just a few weeks ago.

[Ben C34]

Wow.

That's some shitty oil to choose for a gtr of all things.

[AngryRB]

I reckon check the valve clearances, sounds like the cam could be hitting the shim?

Edited August 27, 2015 by AngryRB

[breaker1845]

Get some better quality oil in the car. Timing belts don't make that noise, its more high pitched. Definitely sounds like something inside the head causing the problem.

[Missileman]

nothin wrong with the oil put in the car 10-40 dino is absolutely fine

[Hadouken]

I reckon a nice 5/10 40 full syn oil will cover that noise

[gotenek]

I just changed the oil to fully synthetic 5W40 for the hell of it. The noise was still there.

So I grabbed a long screwdriver and started poking around the top of the engine with my ear to the other other of the screwdriver.

The noise was about 10% louder than you can hear without the screwdriver on the whole area of the cam covers.

The noise was about 3X louder when I put the screwdriver on top of the top timing cover. I have a plastic clear timing cover ( just want to mention it)

Thus, I'm assuming the noise is coming from somewhere in the timing belt area. Can tensioners make that kinda knocking/tapping noise? Or perhaps the oil pump?

[scotty nm35]

I would be pulling the cover off and checking before driving any further.

[tridentt150v]

water pump bearing? check with your screwdriver and put it on the water pump - note you may need a longer screwdriver so you don't lose your god given looks to a fan or belt.

[GTRPSI]

Use the screw driver trick to the ear along the top of the cam cover and front cover.

Also do it to your injectors and around the exhaust manifold (in case you have a seriously odd leak making the sound and heat closes the leak).

Take out your coil packs and check to see if your spark plugs are tight.

[doo doo]

Hey Sammy, if you're in Brisbane area send me a pm and I'll be happy come and have a look for you.

[gotenek]

doo doo, Unfortunately I'm located in Canada. Thanks for the offer.

I'm going to be pulling the engine and inspect a few things, especially in the head - the cam cover caps. Thanks for all the help everyone.