Jump to content
SAU Community

Please help diagnose Cam belt noise?

Eikon

By Eikon,
in General Maintenance

 Share

Recommended Posts

Eikon Explorer

Eikon

Posted
Posted

First off.... i have an RB20det swapped into a USDM 240sx.

It runs very well, and I am very happy with it, but I have found a noise that bothers me. Can you please help me diagnose and repair this.

When the engine idles, I hear a sound from under the timing belt cover. It sounds like the belt it too tight, like it's lugging a little bit.

So, I took off the CAS and then the timing cover and put the CAS back on with spacers and started the engine.

The noise is almost not there at first, but it gets more pronounced within a few more minutes. There are really two different sounds. One just sounds like the belt rubbing a little bit on something.. that doesn't bother me... it's quiet and normal I beleive.

The second noise drives me crazy, worries me infact. It sounds like ballbearings grinding together. It's not completely constant... sounds like it would be at a certain point on the revolution of the exhaust cam gear.

My original thought was that my timing belt was too tight. But with the cover off, the belt seems to be ok by touch... it gives about the width of my finger when I push on it between the Cam Gears.

I listened very closely in a lot of different areas. The sound seems to come from the center of the cam gear or just a little inside the valve cover. Exhaust Cam gear to be specific.

Could it be a bad CAS? Are there bearing in there that go bad? If so, wouldn't the sound seem to come from the outside cap of the CAS?

Could it be the cam gear itself grinding on something? I don't really know much about the internals of the Cam Gears, the CAS, how the cams themselves attach to the cam gears...

Anyone have any ideas?

Thanks

Link to comment
https://www.sau.com.au/forums/topic/70824-please-help-diagnose-cam-belt-noise/
Share on other sites
  • 7 months later...
boomtheroom Community Regular

boomtheroom

Posted
Posted
First off.... i have an RB20det swapped into a USDM 240sx.

It runs very well, and I am very happy with it, but I have found a noise that bothers me.  Can you please help me diagnose and repair this.

When the engine idles, I hear a sound from under the timing belt cover.  It sounds like the belt it too tight, like it's lugging a little bit.

So, I took off the CAS and then the timing cover and put the CAS back on with spacers and started the engine. 

The noise is almost not there at first, but it gets more pronounced within a few more minutes.  There are really two different sounds.  One just sounds like the belt rubbing a little bit on something.. that doesn't bother me... it's quiet and normal I beleive.

The second noise drives me crazy, worries me infact.  It sounds like ballbearings grinding together.  It's not completely constant... sounds like it would be at a certain point on the revolution of the exhaust cam gear. 

My original thought was that my timing belt was too tight.  But with the cover off, the belt seems to be ok by touch... it gives about the width of my finger when I push on it between the Cam Gears. 

I listened very closely in a lot of different areas.  The sound seems to come from the center of the cam gear or just a little inside the valve cover.  Exhaust Cam gear to be specific. 

Could it be a bad CAS?  Are there bearing in there that go bad?  If so, wouldn't the sound seem to come from the outside cap of the CAS? 

Could it be the cam gear itself grinding on something?  I don't really know much about the internals of the Cam Gears, the CAS, how the cams themselves attach to the cam gears...

Anyone have any ideas?

Thanks

did u find out what the problem was?

  • 1 month later...
Hootchy Community Regular

Hootchy

Posted
Posted

I've also got a noise similar to that and it gives me the sh!ts

The best way to describe it would be a grinding rattle It's loudest when the car is cold and only happens at about

1600-1800 rpm It seems to be in the end of exhaust cam / CAS area

can anyone help me ?

  • 1 year later...
Dazzler22 Rookie

Dazzler22

Posted
Posted
I've also got a noise similar to that and it gives me the sh!ts

The best way to describe it would be a grinding rattle It's loudest when the car is cold and only happens at about

1600-1800 rpm It seems to be in the end of exhaust cam / CAS area

can anyone help me ?

Did you find out what this was??

Cheers

Dazzler

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • PranK
      Chris' Toyota Mark ii JZX110

      By PranK · Posted

      This looks great! Awesome to have the 5 speed with an LSD in this. The Recaro's look like SR2's or SR3's. It's a shame they've been retrimmed as they would have looked sweet in their original colours. I think I'd want my agent to be a little more up front and informative too. I've never imported but I reckon it would make me a little nervous, so the more info the better.
    • soviet_merlin
      Duncan's V37.......race car?

      By soviet_merlin · Posted

      Thanks for doing that Duncan! Makes you a good person in my books. We don't get kangaroos or wombats here. But we have bats and it's similar. AFAIK it's often the mums with a baby attached that get hit because they drop lower when starting from a tree. If you hit an animal, check on it. https://www.ifaw.org/au/resources/wildlife-rescue-app An app to get the closest wildlife rescue contact.
    • Murray_Calavera
      Jacks that fit under GTR lips that can reach the subframe?

      By Murray_Calavera · Posted

      My dream is also to have a proper hoist, but I don't think it will ever happen. My quickjack is probably as close as I'll ever get, it really is very good though. 
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      Yeah we keep on in the dailies, it is pretty poor how many animals get hit and the driver leaves without checking....have saved a couple of little ones over the years. Bit of a gruesome job though, pouches generally need to be cut open because they are so tight and often the joey doesn't realise mum is gone so they are still locked onto the teat. I checked the modules in front of the DS wheel where an oil cooler should go.... There is the radar unit - that can go for race use) One of the 2 HX water pumps, the silver cylinder. That needs to be kept but might be able to be relocated But the bad news, the big computer mounted vertically in front of the wheel (blocking any potential air exit) is the electric steering computer. That is required until/unless i do a hydraulic steering conversion, and in CAD based modern car design it is not like I can just pop a big unit like that somewhere else (plus the loom would be too short anywhere else too). So, the passenger side is OK to clear out (just use a smaller washer reservoir, potentially elsewhere), but the DS no beuno
    • Duncan
      Chris' Toyota Mark ii JZX110

      By Duncan · Posted

      Well, all the best with the new camry It was interesting to hear about the UK process, it is generally a lot more streamlined here with a shipping agent looking after all the import side (noting the exact final price can still be a surprise.....) and I've used a few different brokers on the japan (or US) side, and never had any trouble with any of them....luck of the draw I guess. You mentioned you didn't get the auction sheet (understandable since you bought it from a dealer, not auction), but I always try and get hold of that because they are pretty thorough. I've imported 2x R grade vehicles over the years and both were fine, repairs in Japan are pretty thorough compared to here in Oz.
×
×
  • Create New...