Rough idle and tapping sound after taking out chain guides in sohc - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

acgourley · 11-23-2006, 02:02 AM

Otherwise known as the "respond asap so that I can make the 5 hour drive home for the holiday, and make it before dinner starts"

So i did replaced both guides on the sohc motor today. (Right chain guide gone except for the hex screws and a bit of plastic on each) After putting everything together and crossing my fingers - it started, but very rough and with a very loud tap.

The roughness is almost assuredly retarded timing, and my fault. It just got too dark and I didn't feel like taking out the oil pump to fix that. But then again, maybe its something else as well. Does retarded timing cause the engine to barely hold an idle without dieing?

The tap is what worries me, my engine sounds more like harley and has a loud tapping noise, different than the chain rattle, which seems to be gone. Sounds like its coming from my valve covers.

So, a few questions: Could I have installed the valve covers too tight? Could i only be firing on 3 cyl? How can I check for that? I'm just praying I didn't leave something metal in the engine...

Once again, sorry for the questions before I checked out more of this myself, i'm just desperate to get on the road ASAP so I can make it home in time for turkey.

thanks

Sidewayzzz · 11-23-2006, 10:21 AM

IF your timing is off, it will definantly cause an erratic idle, poor performance, and the motor could barely run depending on how far it is off. If you put the distributor say .. a few teeth off (hypothetical) the motor might not even start.

As far as the loud tapping sound, I doubt you tightened the valve cover bolts too much, did you make sure to check your oil after you put everything back together? Put some oil in it, run it.. see if the noise goes away. If not get a screwdriver or stethoscope and listen for where the noise exactly is (screwdriver is backyard mechanic style, stick it to your ear and the other part where you want to listen).

To check if your mising a cylinder you pull a spark plug wire out, 1 by 1, while the car is running, if you pull it out and the idle pitch changes or performance changes .. plug it back in, that one is firing. Check all of them this way, and if you pull one wire out and it doesn't change the pitch...you know where your problem lies. You can also does this with the injectors in the same fashion.

Let us know if anything changes.

acgourley · 11-23-2006, 10:33 AM

Good advice on the screwdriver and cyl checking.

I fixed the timing, it was way behind. The idle is now normal, but the tapping sound is still present, going back out now...

acgourley · 11-23-2006, 11:02 AM

all four cyl are firing...

I did the 'screwdriver' trick with a ratchet, but could not isolate anything. The worst part is that, the longer that I hear it, the more is sounds 'normal', and I can't tell if maybe thats how it always was, or if I'm just getting used to it. Guess i'll take it off the stands and drive it around town, see if that helps anything, or if I notice power loss.

Sidewayzzz · 11-23-2006, 11:19 AM

All cars have normal valve click / lifter click noises, even brand new cars .. it may be normal, but we really can't tell w/o hearing it

acgourley · 11-23-2006, 12:57 PM

yeah, okay, thanks for the help, i appreciate it.

As of now, the best way to describe how it sounds is like a large truck. Like a certain part of the idle noise is especially loud and sharp. When i get up on the throttle, it still doesn't sound 'right' but its hard to describe.

maybe it just sounds weird because there isn't some loud chain rattle doing on

Anyway, i'll try it on a long drive, and see what happens.

superduner · 11-23-2006, 01:11 PM

Yep tTAPING in the valve cover noise... TYPICAL for nissans..... IT happens on my 71 240z its your VALVE SPRINGS .... theyr a little too loose allowin you valves to hit since their tention is too loose. use the screwdriver SIDEWAYZZ mentioned about and get a near cloes ACCURATE idea of where the loudest tapping is coming from and remove the valve cover. tighthen that indicidual spring LITTLE BY LITTLE. if you over tighten it youl just make things worse the valve will only open half way and your performance will hit rock bottom. just tighten it enough until you BEARLY hear the noice and remember... its better to BEARLY hear the noise than to not hear it and have an engine with no balls :P just some advice " Been there"

Anyways i just bought a 240sx so im new to these cars however i do have a nissan engine on my datsun so i am really familiar with the taping noise on the valvecover :P

anywho hope my advice worked

acgourley · 11-23-2006, 10:23 PM

Well, i took a long ride and made it home in time for dinner. Gas mileage was as good as ever, and power seemed the same. Still, the sound is a bit odd, like part of the stroke is more pronounced. I'm hearing a louder "fuzzy" sound, like something from fuel or air or detonation. And the car smells like it would have trouble passing emissions, although i'm sure what the exact problem is.

Well, i'll take it apart and look for vacuum problems, clean misc. sensors, check the grounds. If I solve the problem i'll post it here.

edit: oh and my idle is irregular. Thats good news to me, because there are a lot of documented things to try to fix that, and one of those will problably solve my problem, i'm guessing.

Sidewayzzz · 11-23-2006, 11:14 PM

egh, idle problem ... every 240 has them lol. As far as taking the timing chain guides out, did you check your tensioner? I know when I took my timing chain guides out my tensioner was stuck, so it's no suprise to me that I can hear the chain smacking the side of my valve cover sometimes. Im gonna fix that one day ... but that might be something to think about.

acgourley · 11-24-2006, 11:09 AM

my tensioner was fine, no gunk or anything. Just a metal block, spring and rod that moved together just fine.

Sort of suprising when you hear about how bad some people's were.

One last stupid question if someone knows, everyone says the 'special' chain link needs to be on the gear tooth with the dot, but in my specific case, I didn't even see the special link. Is that because i didn't rotate the chain to the correct position, or are their mulitple special links so that you should always have one lined up with the dot.

Eric240sx1990 · 11-24-2006, 11:26 AM

i have a new timing chain kit that i just bought. the chain has 2 special links, one for the crank and one for the cam. u gotta line those up with the corresponding marks on the sprockets. Also, many nissan engines have loud tapping in the valvetrain. yours may be from there being slack in the line because of no more chain guides remember metal expands and when you have that chain expanding more and more over time it can get loose. the guides where just keeping the chain from tappin on the valve cover or the side of the timing cover.

superduner · 11-24-2006, 06:28 PM

Like i last posted.. idk if you have tried it... if you chain seems good. and you timing is good... you should maybe try to make shure you valve springs are ok. your valves might be hitting to hard due to springs being too LOOSE.

acgourley · 11-25-2006, 03:17 AM

Well, here's the thing. The tapping noise has subsided, might have been something settling into place. I think the tapping I hear now is pretty normal for high milage nissans. What i'm working on now is the reason why my car sounds like a TRUCK with a rough idle. I'll go down the list in the FSM and forum posts and try to find it. Thanks for the tapping advise though, i'll keep it in mind as I work on this.

superduner · 11-26-2006, 11:42 AM

hmm now that you mention it my 280z did get to a poit sometime where it sounded like a diesel pusher :s.... wounder why that was... i sometimes thought there was some F250 next to me or something when i had my windows down. but the sound whent away i did'nt mess with it or nothing.

acgourley · 11-26-2006, 05:05 PM

quick quesiton i couldn't find in search - how bad is it if my timing chain is 2 teeth counter clockwise from my cam gear mark? I reaaaaly wish I noticed this while I had the front cover off

I don't know if my crank gear is lined up with the chain or not...looks like i'll need to go back in

acgourley · 11-26-2006, 05:10 PM

Quote:

Originally Posted by superduner

hmm now that you mention it my 280z did get to a poit sometime where it sounded like a diesel pusher :s.... wounder why that was... i sometimes thought there was some F250 next to me or something when i had my windows down. but the sound whent away i did'nt mess with it or nothing.

yes yes, thats exactly what seems to be going on. I did some searching on "deisel" in some of the forums, and some people have said its due to their exhaust manifold being loose. The problem is that it really sounds like the sound is coming out of my block. Someone else said that the injects might not all be working, so i'll look into that.

11-23-2006, 02:02 AM	#1
acgourley Join Date: Nov 2006 Location: davis, ca Age: 41 Posts: 35 Trader Rating: (0) Feedback Score: 0 reviews	Rough idle and tapping sound after taking out chain guides in sohc Otherwise known as the "respond asap so that I can make the 5 hour drive home for the holiday, and make it before dinner starts" So i did replaced both guides on the sohc motor today. (Right chain guide gone except for the hex screws and a bit of plastic on each) After putting everything together and crossing my fingers - it started, but very rough and with a very loud tap. The roughness is almost assuredly retarded timing, and my fault. It just got too dark and I didn't feel like taking out the oil pump to fix that. But then again, maybe its something else as well. Does retarded timing cause the engine to barely hold an idle without dieing? The tap is what worries me, my engine sounds more like harley and has a loud tapping noise, different than the chain rattle, which seems to be gone. Sounds like its coming from my valve covers. So, a few questions: Could I have installed the valve covers too tight? Could i only be firing on 3 cyl? How can I check for that? I'm just praying I didn't leave something metal in the engine... Once again, sorry for the questions before I checked out more of this myself, i'm just desperate to get on the road ASAP so I can make it home in time for turkey. thanks

11-24-2006, 11:26 AM	#11
Eric240sx1990 Leaky Injector Join Date: Sep 2006 Location: tx Age: 40 Posts: 69 Trader Rating: (0) Feedback Score: 0 reviews	i have a new timing chain kit that i just bought. the chain has 2 special links, one for the crank and one for the cam. u gotta line those up with the corresponding marks on the sprockets. Also, many nissan engines have loud tapping in the valvetrain. yours may be from there being slack in the line because of no more chain guides remember metal expands and when you have that chain expanding more and more over time it can get loose. the guides where just keeping the chain from tappin on the valve cover or the side of the timing cover. __________________ 1990 240sx s13 ka24e OHHH YA!!! In the process of rebuilding 2002 F.o.r.d. Focus SVT All-Weather package, Steeda STS, Cool flow, borla catback, 3" ss dowmpipe, H&R cup kit, Front upper and rear upper Focus sport strutbars Focussport 9 mm wires, Denso iridium plugs,

11-23-2006, 10:21 AM	#2
Sidewayzzz Zilvia Member Join Date: Mar 2006 Location: Vegas Age: 39 Posts: 221 Trader Rating: (0) Feedback Score: 0 reviews	IF your timing is off, it will definantly cause an erratic idle, poor performance, and the motor could barely run depending on how far it is off. If you put the distributor say .. a few teeth off (hypothetical) the motor might not even start. As far as the loud tapping sound, I doubt you tightened the valve cover bolts too much, did you make sure to check your oil after you put everything back together? Put some oil in it, run it.. see if the noise goes away. If not get a screwdriver or stethoscope and listen for where the noise exactly is (screwdriver is backyard mechanic style, stick it to your ear and the other part where you want to listen). To check if your mising a cylinder you pull a spark plug wire out, 1 by 1, while the car is running, if you pull it out and the idle pitch changes or performance changes .. plug it back in, that one is firing. Check all of them this way, and if you pull one wire out and it doesn't change the pitch...you know where your problem lies. You can also does this with the injectors in the same fashion. Let us know if anything changes.

11-23-2006, 10:33 AM	#3
acgourley Join Date: Nov 2006 Location: davis, ca Age: 41 Posts: 35 Trader Rating: (0) Feedback Score: 0 reviews	Good advice on the screwdriver and cyl checking. I fixed the timing, it was way behind. The idle is now normal, but the tapping sound is still present, going back out now...

11-23-2006, 11:02 AM	#4
acgourley Join Date: Nov 2006 Location: davis, ca Age: 41 Posts: 35 Trader Rating: (0) Feedback Score: 0 reviews	all four cyl are firing... I did the 'screwdriver' trick with a ratchet, but could not isolate anything. The worst part is that, the longer that I hear it, the more is sounds 'normal', and I can't tell if maybe thats how it always was, or if I'm just getting used to it. Guess i'll take it off the stands and drive it around town, see if that helps anything, or if I notice power loss.

11-23-2006, 11:19 AM	#5
Sidewayzzz Zilvia Member Join Date: Mar 2006 Location: Vegas Age: 39 Posts: 221 Trader Rating: (0) Feedback Score: 0 reviews	All cars have normal valve click / lifter click noises, even brand new cars .. it may be normal, but we really can't tell w/o hearing it

11-23-2006, 12:57 PM	#6
acgourley Join Date: Nov 2006 Location: davis, ca Age: 41 Posts: 35 Trader Rating: (0) Feedback Score: 0 reviews	yeah, okay, thanks for the help, i appreciate it. As of now, the best way to describe how it sounds is like a large truck. Like a certain part of the idle noise is especially loud and sharp. When i get up on the throttle, it still doesn't sound 'right' but its hard to describe. maybe it just sounds weird because there isn't some loud chain rattle doing on Anyway, i'll try it on a long drive, and see what happens.

11-23-2006, 01:11 PM	#7
superduner Zilvia Member Join Date: Nov 2006 Location: San Diego Age: 37 Posts: 297 Trader Rating: (1) Feedback Score: 1 reviews	Yep tTAPING in the valve cover noise... TYPICAL for nissans..... IT happens on my 71 240z its your VALVE SPRINGS .... theyr a little too loose allowin you valves to hit since their tention is too loose. use the screwdriver SIDEWAYZZ mentioned about and get a near cloes ACCURATE idea of where the loudest tapping is coming from and remove the valve cover. tighthen that indicidual spring LITTLE BY LITTLE. if you over tighten it youl just make things worse the valve will only open half way and your performance will hit rock bottom. just tighten it enough until you BEARLY hear the noice and remember... its better to BEARLY hear the noise than to not hear it and have an engine with no balls :P just some advice " Been there" Anyways i just bought a 240sx so im new to these cars however i do have a nissan engine on my datsun so i am really familiar with the taping noise on the valvecover :P anywho hope my advice worked

11-23-2006, 10:23 PM	#8
acgourley Join Date: Nov 2006 Location: davis, ca Age: 41 Posts: 35 Trader Rating: (0) Feedback Score: 0 reviews	Well, i took a long ride and made it home in time for dinner. Gas mileage was as good as ever, and power seemed the same. Still, the sound is a bit odd, like part of the stroke is more pronounced. I'm hearing a louder "fuzzy" sound, like something from fuel or air or detonation. And the car smells like it would have trouble passing emissions, although i'm sure what the exact problem is. Well, i'll take it apart and look for vacuum problems, clean misc. sensors, check the grounds. If I solve the problem i'll post it here. edit: oh and my idle is irregular. Thats good news to me, because there are a lot of documented things to try to fix that, and one of those will problably solve my problem, i'm guessing.

11-23-2006, 11:14 PM	#9
Sidewayzzz Zilvia Member Join Date: Mar 2006 Location: Vegas Age: 39 Posts: 221 Trader Rating: (0) Feedback Score: 0 reviews	egh, idle problem ... every 240 has them lol. As far as taking the timing chain guides out, did you check your tensioner? I know when I took my timing chain guides out my tensioner was stuck, so it's no suprise to me that I can hear the chain smacking the side of my valve cover sometimes. Im gonna fix that one day ... but that might be something to think about.

11-24-2006, 11:09 AM	#10
acgourley Join Date: Nov 2006 Location: davis, ca Age: 41 Posts: 35 Trader Rating: (0) Feedback Score: 0 reviews	my tensioner was fine, no gunk or anything. Just a metal block, spring and rod that moved together just fine. Sort of suprising when you hear about how bad some people's were. One last stupid question if someone knows, everyone says the 'special' chain link needs to be on the gear tooth with the dot, but in my specific case, I didn't even see the special link. Is that because i didn't rotate the chain to the correct position, or are their mulitple special links so that you should always have one lined up with the dot.

11-24-2006, 06:28 PM	#12
superduner Zilvia Member Join Date: Nov 2006 Location: San Diego Age: 37 Posts: 297 Trader Rating: (1) Feedback Score: 1 reviews	Like i last posted.. idk if you have tried it... if you chain seems good. and you timing is good... you should maybe try to make shure you valve springs are ok. your valves might be hitting to hard due to springs being too LOOSE.

11-25-2006, 03:17 AM	#13
acgourley Join Date: Nov 2006 Location: davis, ca Age: 41 Posts: 35 Trader Rating: (0) Feedback Score: 0 reviews	Well, here's the thing. The tapping noise has subsided, might have been something settling into place. I think the tapping I hear now is pretty normal for high milage nissans. What i'm working on now is the reason why my car sounds like a TRUCK with a rough idle. I'll go down the list in the FSM and forum posts and try to find it. Thanks for the tapping advise though, i'll keep it in mind as I work on this.

11-26-2006, 11:42 AM	#14
superduner Zilvia Member Join Date: Nov 2006 Location: San Diego Age: 37 Posts: 297 Trader Rating: (1) Feedback Score: 1 reviews	hmm now that you mention it my 280z did get to a poit sometime where it sounded like a diesel pusher :s.... wounder why that was... i sometimes thought there was some F250 next to me or something when i had my windows down. but the sound whent away i did'nt mess with it or nothing.

11-26-2006, 05:05 PM	#15
acgourley Join Date: Nov 2006 Location: davis, ca Age: 41 Posts: 35 Trader Rating: (0) Feedback Score: 0 reviews	quick quesiton i couldn't find in search - how bad is it if my timing chain is 2 teeth counter clockwise from my cam gear mark? I reaaaaly wish I noticed this while I had the front cover off I don't know if my crank gear is lined up with the chain or not...looks like i'll need to go back in