Help with Rb20det head noise... Please!!!

[Eikon]

I have a problem that I can't figure out. It's a noise, and now avibration that is driving me crazy!.

It's in the head. I don't get any noise when I first turn the car on. Everything is great when the engine is cold... then as it warms up to operating temp, it develops a pretty loud, strange noise from the head.From the outside, it sounds like a belt noise.. almost like a squeeling noise. But when you open the hood and look closer, it is definitely coming from the head of the engine. The noise isn't constant.. it comes on for a second or two and then goes away for a second. It really seems to come from the intake cam side of the head. I dropped the car off to get the newdownpipe installed, and now it is louder than it was... But I dont' think the downpipe has anything to do with it. I think it is just getting worse. Theother day I could actually start to feel some vibration on the intake side of the cam.. Like if you hold on to the oil cap, you can feel a vibration thatcorresponds with this weird noise.

I took off the valve covers a couple weeks ago... gave them a nice shiny red coat. While they were off, I inspected the insides, and didn't notice any problems that were evident inside the cam area... I didn't notice any metal shards, rubbing areas, etc...

Do you have any idea what is causing this? I just can't figure it out... It bothers me because I have way too much invested in this engine for it to go bad on me.

I did pick up a new head just in case. I got one from a guy in Wisconsin for $250. Figured I wouldn't do any better than that. I also have a gasket kit, so I have a spare head gasket that I can swap on as well. But, I don't want to take on that project if I don't have to.

Any ideas for me? Could it be a blockage in the oil passages? Could it be a funny air leak? Could the cam be loose and rubbing somewhere? Why would it make the sound when hot, but not when cold? Could it be alifter or valve that is bad? I just can't come up with anything..

Sorry for being so long winded. Hope you guys can give me an idea.

Thanks everyone!

[themadscientist]

just spitballing but maybe the timing belt tensioner is fluttering. Are sure the sound is not coming from the crank angle sensor on the front of the exhuast cam?

[Eikon]

I am quite certain that the CAS is good. I replaced it a couple weeks ago.

The sound and vibration come from the intake side of the head.

Keep running ideas past me please! Hopefully someone will find something that makes sense.

Seth

[themadscientist]

what about the timing belt tensioner flutter? There are no bearings in the cams to go bad, it just rides on the head. If it's a constant squeal then it's something that's rotating. I suppose it could be an out of round cam but I would expect that to vibrate constantly. You could run the motor till the noise appears, shut it down, pop the valve cover and feel each cam cap to see if one feels a lot hotter than the others, that may indicate something.

[Eikon]

Madscientist... thanks for your help and attention!

Would a bad timing belt tensioner cause the a vibration across the whole head?

I can feel a vibration that corresponds with the noise when I put my hand on the oil filler cap on the valve cover. I can feel it on the valve cover too until the valve cover gets hot to touch. When I try to pinpoint the sound by moving my ear around the engine bay, it seems like the sound is loudest and most pronouced by the area where the intake manifold attaches to the head. But it's very hard to really pinpoint it. It seems like it is the intake cam... so maybe that cam is out of round or warped or the cam retainer bolts snapped or something like that.

One thing that is strange is that if I unscrew the oil cap and remove it, the noise goes away for a couple seconds. So, I am wondering if it has to do with airflow to the upper valve area. But, I can figure out why airflow would cause such a noticable vibration.

I am going to take off the valve covers this afternoon and take another look at the cams and cam retainers. I am going to check the tightness of all of the retainer bolts and look for any scrapings of any kind.

Anyhow... I will post again after checking the inside of the valve cover again.

[themadscientist]

dam this is weird. I hope you figure it out I would interested to find out what it is. Did someone die tragicly building your engine or something?

[Eikon]

I am tragically going to die working on this engine.

I didn't get time yesterday to pop the valve covers off, but I did swing by a mechanic who is a friend of mine. I asked him to listen to the engine for me to see where he thought the sound was coming from.

He thinks it's more from the front of the engine. His opinion is that it's something with the timing belt... Idler or Tensioner or something like what you said.

I am trying to get both the idler pulley and the tensioner pulley and try replacing both. Maybe that will do the trick.

I was able to find a idler pulley from RBmotoring. They had it in stock and they are shipping it out today. I cannot however find a tensioner pulley. Madscientist... since you are in Japan, would you be able to help me find what I need? I would be happy to give you a little extra to thank you for your time.

I searched on NICO and found the following part numbers... Timing Belt Tensioner - 13072-58S10Timing tension pulley - 13070-73L00Timing idler pulley - 13074-58S00

RB motoring had a timing idler pulley but their part number didn't correspond with mine. I went ahead and had them ship it to me anyhow.

They had the tensoiner pulley part number, but no stock for another 3 weeks.

Can you help me out Madscientist?

Thanks man!

[themadscientist]

I am in the states on vecation right now, sorry. If you still need help in like two weeks let me know, I will be back by then.

[Eikon]

Are you back from Vacation yet?

I have managed to get an idler. But, I cannot seem to come up with a tensioner.

If anyone else on NICO can help me out with this I would greatly appreciate it. Anybody have friends in Japan?

Thanks MadScientist, and everyone!

[Stealth-Z]

Could it possibly be a faulty PCV valve?

[Eikon]

What's a PCV valve? lol... seriously.. I have no clue what that is.

Thanks for the idea!

[Stealth-Z]

It is located on the front corner of the intake manifold. There is about a 3/4 inch hose attached to it. It is about two inches long and will unscrew from the intake manifold.

Here is a link about PCV valves.http://www.vccc.com/pcv_valve.htm

[Joe]

man you guys overlook the simplest troubleshooting steps!

go to autozone/checker, buy the stethiscope (think doctors office one, but for cars). its around 10-20$.warm car up till noise appears. use stethiscope to pinpoint noise. TRUST ME; if its loud enough to hear from outside the stethiscope will find it.

touch it to the timing cover, CAS, every inch on the valve covers, etc. just FIND IT!

every toolbox should have one of these.

[Yellow4g63]

I searched on NICO and found the following part numbers... Timing Belt Tensioner - 13072-58S10Timing tension pulley - 13070-73L00Timing idler pulley - 13074-58S00

Thanks man!

I saw someone on the skyline board with kinda the same problem. Most of the people said tesioner or idler pully I think.

[Eikon]

Timing Belt Tensioner for RB20det

Alright... I found someone in Japan who will be sending me one.

Cost is $53 + 7 for shipping from Nissan to him. Then he will have to get it shipped to me. So I am guessing another $10 or so.

I think I am going to go ahead and get two of them. That way if someone else on NICO needs one, I will be able to sell it to them for what I paid and ship it very quickly.

So I am planning to get 2 of them. Does anyone else want one? As long as I am getting a couple already.. it would be just as easy to get 4 or 10 for that matter.

Let me know if anyone wants me to grab an extra for them just in case they need it.

Thanks
Modified by Eikon at 6:11 PM 7/24/2005

[Yellow4g63]

Alright... I found someone in Japan who will be sending me one.

Cost is $53 + 7 for shipping from Nissan to him. Then he will have to get it shipped to me. So I am guessing another $10 or so.

I think I am going to go ahead and get two of them. That way if someone else on NICO needs one, I will be able to sell it to them for what I paid and ship it very quickly.

So I am planning to get 2 of them. Does anyone else want one? As long as I am getting a couple already.. it would be just as easy to get 4 or 10 for that matter.

Let me know if anyone wants me to grab an extra for them just in case they need it.

Thanks

What are you talking about?

[Eikon]

See posts above... I was looking very hard for a timing belt tensioner.

I had asked themadscientist if he could help.

I found someone else who could help since he wasn't back from his vacation to the US yet.

So I was talking about timing belt tensioners. Sorry, should have been more clear about that. I will edit.