Another FAQ: Timing Chain Tension/Guide
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Another FAQ: Timing Chain Tension/Guide
My KADE needs new timing chain tensioners. How do i replace it? Need to take out timing chain? I heard takes like 3 hrs just to remove the chain. Do i replace the lower or upper tension/guide?
My S14 makes a clicking sound. Friends say its the timing chain hitting sumting. I give them credit for coming close.
My S14 makes a clicking sound. Friends say its the timing chain hitting sumting. I give them credit for coming close.
Last edited by ImportLuv; 04-20-2005 at 05:36 AM.
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I'd start by removing the guides. Here's more info:
"-----Original Message-----
From: 240-chat-bounce@amarok.org [mailto:240-chat-bounce@amarok.org]On
Behalf Of Alex C. Chang
Sent: Wednesday, February 13, 2002 3:13 AM
To: 240s_over_Atlanta@yahoogroups.com; 240-chat@amarok.org
Subject: [240-chat] Re: rattle pulley? chain?
On the DOHC engine, there are two chain guides for the upper timing chain.
The upper timing chain tensioner is the only surface the chain touches (in
addition to the idler gear and the cam gears).
These two chain guides are designed as a failsafe device, in case of
completely loss of oil pressure. Without out them, the timing chain would
simply slack out and start skipping the teeth on the cam gears (if you ever
suddenly lose oil pressure). It could potentially cause you to bend valves,
as the KA is an interference design engine.
A 240SX list member posted this on the tech list last year:
-----Original Message-----
From: 240-tech-bounce@amarok.org [mailto:240-tech-bounce@amarok.org]On
Behalf Of Scott Thomas
Sent: Thursday, July 19, 2001 1:45 PM
To: 240-tech@amarok.org
Subject: [240-tech] DOHC timing chain rattle - important notice
Not sure if this is common knowledge, but I just found out today - I know it
is well known that the upper timing chain guide on TOP of the timing chain
has been removed from service because it is unnecessary and tends to break
(mine did) - but also the LOWEr chain guide on the UPPER chain has also been
abolished by Nissan (You must remove the upper cover to take this off, see
the section under "FAQ - Timing chain Q&A, $5 solution for the procedure).
IMO this is even more important because whereas when the upper one breaks it
tends to just sit on top of the chain and rattle, if the lower one broke it
would probably fall down inside the lower cover and tear things up pretty
badly - bye-bye engine.
IMO, Nissan should recall these - when I pulled my broken upper guide out
after I first bought the car, it was chewed halfway through and if it had
been cut in two, the smaller pieces (as well as metal shavings) could have
wandered around the rockers or down the timing cover and done some serious
damage. Not to mention I doubt it is particularly good for the chain (though
mine didn't show any visible wear).
Scott Thomas Stock 92 Fastback 137K miles
*****************************
I think this is one of the most important pieces of info regarding the DOHC
timing chain. As you may or may not know, the SOHC timing chain is one chain
that directly connects the crank to the cams, and the SOHC engine has an oil
pump that is both easy to replace, and can fail easy. The DOHC engine,
however, has a two stage timing chain assembly. It is difficult to replace
the oil pump (as it is built into the lower chain cover), and often when you
are told to remove the upper top chain guide (above the cams), the timing
chain rattle is still there.
By removing the lower guide on the upper chain, it actually helps protect
the engine. Why?
My engine blew up on me two summers ago. It failed due to a worn oil pump,
and low oil pressure. I drove like that for 3 years, neglecting to fix the
problem. When I took apart that engine, I found out what was the problem. I
had taken off the top guide on the upper timing chain , like everyone else
told me to, but I still had the timing chain rattle. When I pulled the front
cover of my blown engine, I saw that the lower metal guide on the upper
chain completely snapped off (due to too much wear from the upper chain
rubbing against it), and it got wedged where the idler gear was and chopped
the upper timing chain in half.
I have since taken Scott Thomas' advice and removed both upper timing chain
guides when I swapped my stock KA head for a DPR-ported head. I have run 2
track events and logged over 8k miles since then, with no problems or any
sort of timing chain noise.
This is not to say that removing the guides can solve what is causing the
chain to rattle against the guides in the first place. IMO you should make
sure that the tensioner isn't stuck, and you should also have your oil
pressure checked. The rattle is basically caused by two things:
1) Low oil pressure going to tensioner (it is driven by oil pressure,
whether it be from a bad oil pump or blocked oil passages.
2) Stuck/defective tensioner.
I hope you can visualize what I am describing to you. Just wanted to tell
you that by simply removing the guides or trying to dislodge the tensioner
may solve the problem temporarily, but it won't be a permanent fix. The
ultimate permanent fix is to figure out what is causing the tensioner to
slack (and thereby causing it to hit the guides as the engine rotates), and
fix that problem."
"-----Original Message-----
From: 240-chat-bounce@amarok.org [mailto:240-chat-bounce@amarok.org]On
Behalf Of Alex C. Chang
Sent: Wednesday, February 13, 2002 3:13 AM
To: 240s_over_Atlanta@yahoogroups.com; 240-chat@amarok.org
Subject: [240-chat] Re: rattle pulley? chain?
On the DOHC engine, there are two chain guides for the upper timing chain.
The upper timing chain tensioner is the only surface the chain touches (in
addition to the idler gear and the cam gears).
These two chain guides are designed as a failsafe device, in case of
completely loss of oil pressure. Without out them, the timing chain would
simply slack out and start skipping the teeth on the cam gears (if you ever
suddenly lose oil pressure). It could potentially cause you to bend valves,
as the KA is an interference design engine.
A 240SX list member posted this on the tech list last year:
-----Original Message-----
From: 240-tech-bounce@amarok.org [mailto:240-tech-bounce@amarok.org]On
Behalf Of Scott Thomas
Sent: Thursday, July 19, 2001 1:45 PM
To: 240-tech@amarok.org
Subject: [240-tech] DOHC timing chain rattle - important notice
Not sure if this is common knowledge, but I just found out today - I know it
is well known that the upper timing chain guide on TOP of the timing chain
has been removed from service because it is unnecessary and tends to break
(mine did) - but also the LOWEr chain guide on the UPPER chain has also been
abolished by Nissan (You must remove the upper cover to take this off, see
the section under "FAQ - Timing chain Q&A, $5 solution for the procedure).
IMO this is even more important because whereas when the upper one breaks it
tends to just sit on top of the chain and rattle, if the lower one broke it
would probably fall down inside the lower cover and tear things up pretty
badly - bye-bye engine.
IMO, Nissan should recall these - when I pulled my broken upper guide out
after I first bought the car, it was chewed halfway through and if it had
been cut in two, the smaller pieces (as well as metal shavings) could have
wandered around the rockers or down the timing cover and done some serious
damage. Not to mention I doubt it is particularly good for the chain (though
mine didn't show any visible wear).
Scott Thomas Stock 92 Fastback 137K miles
*****************************
I think this is one of the most important pieces of info regarding the DOHC
timing chain. As you may or may not know, the SOHC timing chain is one chain
that directly connects the crank to the cams, and the SOHC engine has an oil
pump that is both easy to replace, and can fail easy. The DOHC engine,
however, has a two stage timing chain assembly. It is difficult to replace
the oil pump (as it is built into the lower chain cover), and often when you
are told to remove the upper top chain guide (above the cams), the timing
chain rattle is still there.
By removing the lower guide on the upper chain, it actually helps protect
the engine. Why?
My engine blew up on me two summers ago. It failed due to a worn oil pump,
and low oil pressure. I drove like that for 3 years, neglecting to fix the
problem. When I took apart that engine, I found out what was the problem. I
had taken off the top guide on the upper timing chain , like everyone else
told me to, but I still had the timing chain rattle. When I pulled the front
cover of my blown engine, I saw that the lower metal guide on the upper
chain completely snapped off (due to too much wear from the upper chain
rubbing against it), and it got wedged where the idler gear was and chopped
the upper timing chain in half.
I have since taken Scott Thomas' advice and removed both upper timing chain
guides when I swapped my stock KA head for a DPR-ported head. I have run 2
track events and logged over 8k miles since then, with no problems or any
sort of timing chain noise.
This is not to say that removing the guides can solve what is causing the
chain to rattle against the guides in the first place. IMO you should make
sure that the tensioner isn't stuck, and you should also have your oil
pressure checked. The rattle is basically caused by two things:
1) Low oil pressure going to tensioner (it is driven by oil pressure,
whether it be from a bad oil pump or blocked oil passages.
2) Stuck/defective tensioner.
I hope you can visualize what I am describing to you. Just wanted to tell
you that by simply removing the guides or trying to dislodge the tensioner
may solve the problem temporarily, but it won't be a permanent fix. The
ultimate permanent fix is to figure out what is causing the tensioner to
slack (and thereby causing it to hit the guides as the engine rotates), and
fix that problem."
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This thread should be linked or stickied somewhere.
I will be doing this tonight as my 95(?) motor (in my 93) has some pretty nice chain slap. I think this was Ranjo's old motor. Either way, awesome slap at low rpms, but fine at around 1500. I'd say that this is a pretty good indication that the tensioner is working right. I'll snap some pics tonight when I yank the guides and inspect the tensioner on the upper chain.
I will be doing this tonight as my 95(?) motor (in my 93) has some pretty nice chain slap. I think this was Ranjo's old motor. Either way, awesome slap at low rpms, but fine at around 1500. I'd say that this is a pretty good indication that the tensioner is working right. I'll snap some pics tonight when I yank the guides and inspect the tensioner on the upper chain.
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AHHH the Tensioner... The Bane of KA owners existance.. mine has a nice slap, but not that bad yet.. will actuaally pull mine in aa few weeks.. Oh BTW This would be a great sticky.
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There are points in life where one looks at his or her situation and says "how the fook did i get here?" ... this is one of those instances....
There are points in life where one looks at his or her situation and says "how the fook did i get here?" ... this is one of those instances....
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Shaun says its most likely tat (that) the timing chain guider is broken. Its nothing serious, and is located right between the pulleys. Anyone have any idea how much they cost? Ill call up AutoWay Nissan tommorowww.
