I am an owner of a 1990 240SX hatch.I've recently discovered a very odd sound coming from my car.It is a ticking like sound, and coming from the left hand side of the engine bay (drivers side). It only appears as the throttle is depressed during driving, and the more depression there is, the faster the ticking is. When the car is at a certain RPM, the sound is not present, unless I am accelerating at the moment. I.e.: If I'm in gear, and go from 2 to 3k rpm, and hold it at 3, the sound will only be there when I am accelerating. The noise gets a little bit less drastic (but still very noticeable) as the car warms up (when it's cold it's most evident). And as I accelerate, the more gas I press the faster the ticking becomes. After 3k rpm, my exhaust drones out the noise and at that point, when accelerating, it is going so quick that it blends into the normal engine sounds, but I can tell it's still there. The sound is only present under load (when the car is moving), and if I’m idling, I can reproduce it only when quickly revving the car so there is some load on the engine.
Here are my questions/ideas: Could this be an exhaust leak, directly from between the head and the header? I've just welded up a custom exhaust (the noise was there before hand as well), and I know that from the header on (it's a straight pipe) it's leak proof. I can't smell the leak, and I'm not sure if the qualities of the noise I've described above can apply to one, but I'm not a professional, so could they? How can I test for a leak between head and header?
I've replaced my timing chain about 10k miles ago, and the only problems I've had since then are a leaky injector and sometimes an odd idle (goes up and down idles a little high, sometimes a little low). I just checked the timing chain while replacing my valve cover gasket, and it seemed a little loose on the side where the straight guide is (not the curved one), but I'm assuming that's how it's supposed to be when the engine is off, since the tensioner only works on oil pressure, which is not there on a turned off car. The guide is also in fine condition, even the plastic part of it is still in tact (let alone the metal which is behind it). So I doubt it's the chain, also because I know the timing chain rattle and this is not a rattle but more of a ticking (almost chattery but the ticks can easily be heard individually when at low throttle/rpm, so I call it ticking).
I also don't think it's my injectors because the noise is much louder than any injector I've ever heard ticking.
The only other options I can think of are the valves hitting the pistons, or the head (slapping I believe it's called?) and/or my rocker arms doing something weird which would make that noise. I've looked at the top of the head when replacing the valve cover gasket and didn't see anything unusual, but WOULD I be able to notice with the naked eye if there was something wrong with the valve train? Does this sound like a valve train problem?
Any other ideas or suggestions are very welcome, especially if someone could answer at least some of my questions... I'm just hoping this isn't something that would require a lot of downtime, because I need the car to go to school, and even though I can do most of the work myself I wish it'll turn out to be something as simple as an exhaust leak:)
Thanks a lot,
Sil80
Loud ticking/chatter NOT timing related
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sil80drifter
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- Car: 1990 240SX Hatch
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sil80drifter
- Posts: 1313
- Joined: Sun Aug 18, 2002 5:53 am
- Car: 1990 240SX Hatch
A little update to the problem: When I am in 4th and just put it into 2nd (or 3rd) and drop the clutch, the engine revvs up quickly, but the ticking is not present. This makes me wonder about what kind of loads are present when accelerating with the gas pedal versus the wheels making the engine revv up. Why would they affect the ticking/chatter differently? Again any input would be very appreciated.
Sil80
Sil80
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sil80drifter
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sil80drifter
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whoa. stop the madness. patience is a virtue 
valve tap. your lash adjusters aren't working, probably sludged up.
The valve train includes a method to compensate for the changing length of the valve stems as they heat up. With out this adjustment the engine wouldn't right when it was cold. However if the adjusters stop working the result is floppyness each time the cam rolls to press the valve you hear a little "tap" Likely just one adjuster is affected at this point.
You may be able to fix this with oil changes and sludge cleaning stuff, but more likely they'll need to be pulled and cleaned.
To get the best idea of your car's sludge factor, pulling a valve cover is recommended.
My suggestion for working the sludge out of your HLA is:
Start by changing the oil and filter. Use a conventional oil with a high detergency factor. Use one quart of synthetic transmission oil in the change. Drive the car very gently, never excess 3000 RPM for about an hour. Change the oil and filter again.
Add seafoam and drive on the gentle side of normal for a week. Add 1 quart synthetic transmission oil and drive gently for a hour. Change oil and filter again.
valve tap. your lash adjusters aren't working, probably sludged up.
The valve train includes a method to compensate for the changing length of the valve stems as they heat up. With out this adjustment the engine wouldn't right when it was cold. However if the adjusters stop working the result is floppyness each time the cam rolls to press the valve you hear a little "tap" Likely just one adjuster is affected at this point.
You may be able to fix this with oil changes and sludge cleaning stuff, but more likely they'll need to be pulled and cleaned.
To get the best idea of your car's sludge factor, pulling a valve cover is recommended.
My suggestion for working the sludge out of your HLA is:
Start by changing the oil and filter. Use a conventional oil with a high detergency factor. Use one quart of synthetic transmission oil in the change. Drive the car very gently, never excess 3000 RPM for about an hour. Change the oil and filter again.
Add seafoam and drive on the gentle side of normal for a week. Add 1 quart synthetic transmission oil and drive gently for a hour. Change oil and filter again.
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sil80drifter
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I will try that, thanks... But when I put in the synthetic transmission oil (what's the reason for this anyway?), will I still be able to use normal (mineral) oil afterwards? I know that once you've switched to synth, there is no turning back unless you flush the whole engine... Although I don't know if that goes for transmission oil synth additives. I am using Castrol GTX 10W-30 right now.
What exactly would need to be pulled and cleaned? The cam? The rocker arm shafts? The rocker arms? The valve? What are the long term effects of this tapping, if it were not to go away? Will this affect the head or the rest of the valve train?
sil80
What exactly would need to be pulled and cleaned? The cam? The rocker arm shafts? The rocker arms? The valve? What are the long term effects of this tapping, if it were not to go away? Will this affect the head or the rest of the valve train?
sil80
you've mentioned changing timing chain and pulling valve covers so it seems you got some understanding of the mechanics.
The transmission oil is a great detergent. Synthetic is used since it has a higher breakdown temp than normal. (transmission and motor oil are very different, normal transmission oil wouldn't last very long in an engine, synthetic transmission oil will last a tad longer.) You can resume normal conventional oil when this is done. Only the transmission fluid needs to be synthetic for this procedure.
grab your cars service manual and read about how valve lash is controlled. Do this before doing anything else!
I'm pretty certain its done through the use of a device called "Hydrylic valve lash adjuster" (HLA for short). This device is powered by engine oil and keeps the valve rocker tight against both the valve stem and the cam. There is one HLA per valve.
Imagine a lever (the valve rocker) fixed at one end on a pivot point. The other end on the lever presses on the valve stem and mid point on the lever the cam shaft presses on the lever. If the valve stem is a bit short, the sytem gets a bit floppy, the rocker arm slaps up and down between the cam and the valve stem, once per engine cycle. This can be corrected by raising the pivot point, the HLA does this automatically.
Engine varnish and sludge will slowly plug this device's inlet and possibly inner workings.
the risk with this noise are not huge, mostly damage possible to the valve rocker and valve stem.
The transmission oil is a great detergent. Synthetic is used since it has a higher breakdown temp than normal. (transmission and motor oil are very different, normal transmission oil wouldn't last very long in an engine, synthetic transmission oil will last a tad longer.) You can resume normal conventional oil when this is done. Only the transmission fluid needs to be synthetic for this procedure.
grab your cars service manual and read about how valve lash is controlled. Do this before doing anything else!
I'm pretty certain its done through the use of a device called "Hydrylic valve lash adjuster" (HLA for short). This device is powered by engine oil and keeps the valve rocker tight against both the valve stem and the cam. There is one HLA per valve.
Imagine a lever (the valve rocker) fixed at one end on a pivot point. The other end on the lever presses on the valve stem and mid point on the lever the cam shaft presses on the lever. If the valve stem is a bit short, the sytem gets a bit floppy, the rocker arm slaps up and down between the cam and the valve stem, once per engine cycle. This can be corrected by raising the pivot point, the HLA does this automatically.
Engine varnish and sludge will slowly plug this device's inlet and possibly inner workings.
the risk with this noise are not huge, mostly damage possible to the valve rocker and valve stem.
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sil80drifter
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- Car: 1990 240SX Hatch
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sil80drifter
- Posts: 1313
- Joined: Sun Aug 18, 2002 5:53 am
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oh wait a minute, synthetic AUTO transmission oil, or synthetic MANUAL transmission oil?!
I went to the parts store yesterday and they didn't have synthetic AUTO transmission oil, and the only company that makes syntheic MANUAL transmission oil is Redline. IS that what you meant I should get? A quart of synth MANUAL transmission oil?
sil80
I went to the parts store yesterday and they didn't have synthetic AUTO transmission oil, and the only company that makes syntheic MANUAL transmission oil is Redline. IS that what you meant I should get? A quart of synth MANUAL transmission oil?
sil80
did you read in the manual about HLA?
A suggested method for cleaning sludge is to use one quart ATF (Automatic Transmission Fluid) in an oil change and re-changing the crankcase oil again after an hour of driving.
ATF fluid is a good detergent and will help to loosen and remove sludge (but not so much varnish)
ATF fluid breaks down at relatively low temps so, synthetic ATF is really recommended since it has a slightly higher breakdown temp.
Even with synthetic ATF excessive oil temp must be avoided, so during the hour of use, light driving ONLY and exceed 3000RPM only in a true emergency.
This may not fix the defective HLA, it could be seized or plugged, in which case no amount of on-vehicle cleaning will fix it.
A suggested method for cleaning sludge is to use one quart ATF (Automatic Transmission Fluid) in an oil change and re-changing the crankcase oil again after an hour of driving.
ATF fluid is a good detergent and will help to loosen and remove sludge (but not so much varnish)
ATF fluid breaks down at relatively low temps so, synthetic ATF is really recommended since it has a slightly higher breakdown temp.
Even with synthetic ATF excessive oil temp must be avoided, so during the hour of use, light driving ONLY and exceed 3000RPM only in a true emergency.
This may not fix the defective HLA, it could be seized or plugged, in which case no amount of on-vehicle cleaning will fix it.
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sil80drifter
- Posts: 1313
- Joined: Sun Aug 18, 2002 5:53 am
- Car: 1990 240SX Hatch
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sil80drifter
- Posts: 1313
- Joined: Sun Aug 18, 2002 5:53 am
- Car: 1990 240SX Hatch
sorry guys that was my friend, the wacky fool used my name and type silly stuff.
BY THE WAY!
As I was dreadfully unbolting my exhaust heat shield, to see what else could possibly be causing the rattle (in denial of valve problems...) I saw something that caught my eye: ALL FOUR EXHAUST BOLTS/STUDS fromt he 3rd and 4th cylinder exhaust side were GONE. My header flange was being held up by only the 4 bolts/studs that were on the 1st and 2nd cylinder exhaust flange.... This reignited my suspicions of an exhaust leak, and although one of the studs tuned out to be broken off and stuck inside the head (retrievable with a Sears tool to be gotten tomorrow), I bolted up the other 3 bolt holes and now... THE TICKING IS GONE. The nerves I've spent in the last few days hoping my car wasn't all messed up... The price calculations for a new valve train (600 bucks not including the head).... oh boy... Thanks for your help, and I'm still wondering where I could get synthetic auto transmission oil, since I've not seen it in any pep boys/autozone stores but... it seems that this problem has somewhat recessed itself, along with the necessity for such a rare oil
I hope this may help the other guy with a similar problem in this thread. Check your header flange bolts! It's completely baffling to me how all 3 of the bolts/studs could have unlodged themselves out of the holes and just gotten lost, leavign the last stud to break off in loneliness... but I guess that's just one of the weird car problems we run into sometimes...
Thanks for your help,
sil80
BY THE WAY!
As I was dreadfully unbolting my exhaust heat shield, to see what else could possibly be causing the rattle (in denial of valve problems...) I saw something that caught my eye: ALL FOUR EXHAUST BOLTS/STUDS fromt he 3rd and 4th cylinder exhaust side were GONE. My header flange was being held up by only the 4 bolts/studs that were on the 1st and 2nd cylinder exhaust flange.... This reignited my suspicions of an exhaust leak, and although one of the studs tuned out to be broken off and stuck inside the head (retrievable with a Sears tool to be gotten tomorrow), I bolted up the other 3 bolt holes and now... THE TICKING IS GONE. The nerves I've spent in the last few days hoping my car wasn't all messed up... The price calculations for a new valve train (600 bucks not including the head).... oh boy... Thanks for your help, and I'm still wondering where I could get synthetic auto transmission oil, since I've not seen it in any pep boys/autozone stores but... it seems that this problem has somewhat recessed itself, along with the necessity for such a rare oil
I hope this may help the other guy with a similar problem in this thread. Check your header flange bolts! It's completely baffling to me how all 3 of the bolts/studs could have unlodged themselves out of the holes and just gotten lost, leavign the last stud to break off in loneliness... but I guess that's just one of the weird car problems we run into sometimes...Thanks for your help,
sil80
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sil80drifter
- Posts: 1313
- Joined: Sun Aug 18, 2002 5:53 am
- Car: 1990 240SX Hatch
Well the way I described the problem, it wasn't a single answer question, the only thing is that I always suspected that when valves tick, they tick all the time, and if they tick at a certain RPM, the load on the car is not significant, so whether I'm at WOT or not at 3000 rpm, they would tick regardless.
My tick only happened when under load, which is easy to relate to an exhaust leak (in hindsight of course), because as pressure increases, the gasses get out from under the manifold flange at an increased pace.
Still wondering where I can get some of that synth transmission oil tho,because now that the loud noises are gone I can vey fainly hear my valves tapping a little I'll find some online I'm sure. Thanks again,
sil80
My tick only happened when under load, which is easy to relate to an exhaust leak (in hindsight of course), because as pressure increases, the gasses get out from under the manifold flange at an increased pace.
Still wondering where I can get some of that synth transmission oil tho,because now that the loud noises are gone I can vey fainly hear my valves tapping a little
I'll find some online I'm sure. Thanks again,sil80
Hey Guys!
I just wanted to say a HUGE thank you for working your way through this problem and posting it here. :ylsuper
When I read the initial post I found myself thinking I must have wrote this in a sleep walking stupor as the description of the noise and the timing of it is exactly the same as a problem I am having in my car!! Almost Creepy!
So here I've been freaking out over the past week and I've noticed too that bolts are missing from my heat shield and valve cover and who knows where else. Oh the lonely bolts.
With great relief I will look into this further and fix my oh so fun to drive 240sx Lawnmower!
I've already got some Nissan Valve bolts in my collection would anyone happen to know the other bolt part. #s I'll need for the fools at Nissan?
Thank you Thank you Thank you!!
I just wanted to say a HUGE thank you for working your way through this problem and posting it here. :ylsuper
When I read the initial post I found myself thinking I must have wrote this in a sleep walking stupor as the description of the noise and the timing of it is exactly the same as a problem I am having in my car!! Almost Creepy!
So here I've been freaking out over the past week and I've noticed too that bolts are missing from my heat shield and valve cover and who knows where else. Oh the lonely bolts.
With great relief I will look into this further and fix my oh so fun to drive 240sx Lawnmower!
I've already got some Nissan Valve bolts in my collection would anyone happen to know the other bolt part. #s I'll need for the fools at Nissan?
Thank you Thank you Thank you!!