# 1998 Altima Timing Chain



## omnibaer (Oct 23, 2006)

I just spent the better part of two weeks trying to fix my Altima after my timing chain snapped! I had been noticing considerable valve noise for a few months, and suddenly, after I'd been manually rotating my engine to check my valve clearances, my engine seized!

I began disassembling my engine, and noticed once my valve cover was off again that my lower timing chain was missing...

I took off my oil pan, sump and baffle, and out fell my lower chain. 10 hours of disassembly later and I had my entire timing assembly sitting on my workbench:

My upper chain components were all in perfect condition, but the lower chain had snapped, and was strangely fused to chunks of my lower tensioner and guide. My lower tensioner had been eaten through completely by the chain, and the guide had a chunk broken off. The oil pump housing was smashed, specifically the four "stoppers" that "hold" the chain on the crankshaft sprocket. As for the sprocket, it was missing four teeth...

I could tell that my motor had been going this way for quite some time.

The tensioner had been eaten through at the top around the tensioner piston, suggesting to me that maybe the oil pressure was too high, or that the chain had become rough or eccentric. What I'm curious about is why Nissan chose plastic tensioners rather than a traveling gear tensioner? Surely something that travels at up to 500 miles per hour shouldn't be made to rub against anything alse... just a thought. Not like I'm an angineer...

Anyway, $600 in Nissan parts later (I would never buy discount parts for something like this) which includes 3 new motor mounts and new belts, I have the car fixed.
It still makes the rattling noise, but not as bad as before. I've heard that valve and chain noise is not uncommon in the KA24DE engines, so I'm not too worried.

My poor car. After 3 weeks total of sitting idle, I had to bleed the power steering and thoroughly degrease her to get her going again. I figure in a month or so I'll reinspect my timing chain and make sure it's looking tip top still.

Biggest annoyance: The new lower chain guide that Nissan sold me was the new metal-framed unit, but the bolts for it wouldn't fit under my front cover. I had to take a chunk out of my cover and cut one of the bold heads off to get them to fit. I wasn't about to spend another $300 for a new front cover...

All in all not a lot of fun to do... especially with the engine in the vehicle. I'll keep posted on how everything works out.

Enjoy


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## miss_my_altima (Oct 6, 2006)

Sorry to hear you are having so much trouble. I was wondering how many miles are on the engine/timing chain? I just finished installing a 2001 engine in a 94 Altima due to a broken chain and bent valves. Good luck sorting out the kinks.


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## mech361 (Jul 31, 2006)

The new guide requires different bolts. The dealer should have told you that. The bolts you have in it now should be ok if you got them tight.


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## LONDONDERRY (May 19, 2004)

I'd buy a new engine or a new car instead of all the headaches


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## omnibaer (Oct 23, 2006)

My engine had 120,000 miles on it. However, everything I've been told is that the timing assembly on these engines should last longer than the engine itself.

My Altima's been fixed for a month now, and drives well. I have yet to recheck the timing area for wear, but everything sounds tip top.


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## Remmik (Oct 26, 2010)

I know this is old post but how did your Altima end up?

My girlfriend's Altima just had the same thing happen.She took such great care of this car and always changed the oil on time (or sooner) but supposedly her chain guides fell apart and were making an awful noise. I was out of town and she had towed to a mechanic who found the problem. After quoting her $1400 for the work she decided to buy a new Altima Coupe  This all started "all of a sudden" after she took it to get the oil changed while I was out of town. She took it to a new place where I had taken it to only twice before. Two days after, this happened. When I got back the first thing I did was minor checks (had no tools there) and check the oil. It was way over filled! I took it to different oil change place and had them drain the excess oil. It was 2 quarts over. I can't believe this could be done on accident! Do you (or anyone) know if this could have led to her issue? 

I was hoping the mechanic was wrong and the noise was just from being over filled but the noise was still the same. The strange thing was that the noise went away over 2K RPM (even before draining the oil) and ran fine regardless of the new noise. I had no other means, as money was tight so I drove it to a place where I could work on it. It was a smooth ride and the noise was gone for most of the trip since I was on the highway but it was about 90 miles. I parked it and it seemed fine. When I test drove it one more time, and really wished I hadn't, this is what happened. On the short drive the noise changed sounds but didn't sound worse or louder...just different. I knew this wasn't good. At the next light the idle seemed very rough (always had smooth idle). Got it back to the place, parked it and all seemed OK. Although, when I went out to move it into the work area it would not start. It barely cranked. straining then giving a little then back to straining. I stopped any further attempts.

I know everyone that reads this would flame me for saying I drove this thing but I actually (because of many personal issue) had to..so lets move past that 

I'm finding it hard to get good info on whether or not the valves get bent if the timing chain breaks or jumps a few teeth. You stated that yours broke but did not make any mention of bent valves or head job on yours. I know there are 2 chains and maybe the one that broke, on you, was not the one that affects the timing between the valve train and the crankshaft? Thanks for your time or anyone else that can shed light o this.


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