THAT noise... Help!

[Sandy sx]

From what I've heard if you've got a KA you know what I'm talking about. That noise you hear when you start the car that lasts a few moments and then goes away. Always sounds like it's about to blow up but never actually does. It's because of this noise I ran a whole string of tests on my engine to get a better idea of what the internals were trying to do to themselves or not doing at all. But everything checks out above average for a 90 240sx, excellent compression right across the board, spec vacuum readings, less than 5% cylinder leakage, valves seem to be in good shape, which is what everyone claims to be the cause of the noise,"Oh that thers jest yer valve noise." Well everything seems to be in really good working order EXCEPT a broken timing chain guide. Since everyone is so adamant about "valve noise" has anyone experienced one of these high end industrial plastic engineered timing chain guides breaking /end sarcasm.

If so have you fixed it and was that the source of the KA noise?

[MagikDragon]

umm, yeah Timing chain guides I believe are the most common issues with KA's, from what I've read. I have just started to experience the noise, and I haven't done anything about it yet, I believe that nissan had a huge problem with these and regngineered metal ones to replace the plastic ones. Here is a link to replacing a timing chain, You don't have to replace the chain, but it will guide you in what you need to do.http://www.240sx.org/links/ins....htmlOh btw, I noticed your from CT, IM me sometime (SN in profile) if you need anything. I'll be happy to help ya out. Good Luck

[Red coupe]

your probably just talking about timing chain rattle, you said you had a broken guid? What kind of KA do you have?If its a DE im guessing it was the one on top of the upper chain...on the DE the upper 2 timing chains are not needed and generaly are responsible for making the noise... take the upper timing chain cover off carefuly make sure the chain doesnt have too much slack, then remove the 2 upper chain guides and put it all back together...you should be good to go.

[Sandy sx]

Yes, its the DE, and the source of the noise is the timing chain guide which has snapped in half. The noise is most noticeable whan starting the engine. Its my guess that the guide, broken in half, is being pivoted back and forth as there's much more play on the side of the timing chain without a full guide. So what you're saying, in a nutshell, correct me if I have misinterpereted, is that I should simply remove both timing chain guides? O.o? What is the advantage of removing as opposed to me just replacing the broken guide?Thanks!

[Red coupe]

Nissan no longer makes the guides, they set out a FSB saying that when timing chain work was being done the old upper guides should be removed.That is only the top two, one on top of the cam chain, on on the right side (when viewed from in front of the engine) The lower chain is necissary, and should be left in place/replaced if needed.

The guides are not what put tension on the chain though, there are two tensioners both on the left hand side (again fom in front of the engine) one on the upper chain one on the lower...also check you oil level, they opperate off oil pressure, which is why you hear the chain rattle at start up before there is significant oil pressure. When oil level is lower they tent to make more noise...

[Sandy sx]

Oh, wow. Great. That's exactly what I was looking for, I figured someone would know. So when I pop that timing chain cover I can just remove the top guides, as specified, entirely, as you say they're not required. As far as oil levels, they're fine.

[Red coupe]

yeah search for timing chain rattle, there is a write up by ILikeMy240SX on how to do it that is pretty good....He should have a link in his sig....

Edit:not in the sig any more, but herehttp://forums.nicoclub.com/zerothread?id=105618

[Sandy sx]

Alright, thanks. I've got a pretty good idea on how to go about doing it but I'll take a look at that. In my best interest anyway. Thanks again.

[coolbone28]

Be sure to check the tensioners while you are in there and make sure they are working. Just work them by hand a little. They tend to get gunked up and dont hole pressure as well...hence the chain rattle.

[takaramotors]

i would do like coupe said and replace the tensioner and leave the two guides out it should run like a dream then

[Sandy sx]

Might you be talking about a dual over head? Cuz if I didn't specify before, it's a sohc engine. The right side guide is tensioned BY the tensioner, thus it wouldn't make sense to remove. If at all possible could sohc engines be making that noise due to the tensioner not pumping up with oil quick enough?

[coolbone28]

YOU ARE ON CRACK!!! You did specify...let me refresh...

Yes, its the DE, and the source of the noise is the timing chain guide which has snapped in half.

So you are saying it is the ka24E (sohc) and not the ka24DE (dohc). ok, yes it is probably a tensioner not doing its job like i said. Just try moving it by hand and maybe spray the tensioner with some carb cleaner to get them ungunked. if they still arent causing enough tension then you might have to replace them. as far as the SOHC engine guides...i think they are lined with plastic or something and those MIGHT have to be replaced. not sure...let someone with a sohc chime in. ill try and look it up tho. and i was joking im sure you arent on crack....

[Red coupe]

yeah the D stands for Dual overhead cam...I dont know what the exact procudre for you engine is then...I go back to school next tuesday and can look up any TSB's then....

[Sandy sx]

HAA! Wow, yeah. S'what I meant... right there. *looks around real quick*Yeah I checked it out... and just ordered some new guides through the garage. I figured they need to be replaced, the broken guide is just kind of flapping around like... well something limp and flapping around. Either way the new guides have metal backings that look a lot more sturdy than the old ones, so hopefully this will stop the noise and... *prays to god* well pretty much stop the noise.

Now if you'll excuse me, I'm going to go light my crack pipe.

P.s. red coupe, please do... All the more information the better. Thanks a bunch.

[merc68k]

Guys, is the chain noise a regular, steady tapping on startup? I have that in my 99 Altima, and it's always bugged me wondering if it's a valve out of adjustment or something freaky... Mine is very steady tapping about 4-6 times a second that usually lasts maybe 4 seconds at the most after startup -- does this fit the bill?

I would expect a rattling chain to make a more random rattle sound instead of a regular tapping sound.

PS I thought Nissan had done away with the upper guides on the later KA's? Or maybe they just changed the design?

[Sandy sx]

Uhh, yeah, if it makes that lame tapping noise at start up... I'm willing to bet it's the timing chain guides. Just pull the valve cover off and look for a snapped one. You can't miss it. And as for doing away with the upper timing chain guides... Yes. They did that in later KA's. But mine's a 90 soooo... Yeah.

[merc68k]

Cool, my spark plug hole seals are starting to leak so maybe I'll order new seals and check out the guides if there are any at the same time... thanks

[Red coupe]

Uhh, yeah, if it makes that lame tapping noise at start up... I'm willing to bet it's the timing chain guides. Just pull the valve cover off and look for a snapped one. You can't miss it. And as for doing away with the upper timing chain guides... Yes. They did that in later KA's. But mine's a 90 soooo... Yeah.

Ill check tomorrow Its a good thing this thread got bumped cause I totaly forgot...

[Red coupe]

OK I found some TSB's but nothing that recomends removing the guids, From the picture on the one im looking at now it doesnt look like the E has upper chain guides, it only shows the big one on the right (from the front of the engine) and that one definatly needs to stay in place...

here is one of themQuote »Date: March 22, 1995

Reference: NTB95-027

Classification: EM95-04

KA24E TENSION SIDE TIMING CHAIN GUIDE BROKEN

APPLIED VEHICLES:1990-94 Truck (D21)1989-90 240SX (S13)1990-92 Stanza (U12)1990 Axxess (M11)

SERVICE INFORMATION

If the tension side timing chain guide breaks it usually causes a rattle or knocking noise from the front of the engine. This may also cause poor engine performance or hard/no start. If this incident has occurred, install the countermeasure guide listed.

If servicing the timing chain or replacing a long block, check to see if it has the steel-backed tension side guide. If not, please replace it with the countermeasure guide, including the two bolts listed. Due to the changes made to the guide, new style bolts are required.

For additional information regarding the 1989 countermeasure timing chain guide (slack side), refer to technical bulletin NTB89-028.[/quote]here is the other one I found...Quote »Reference:TECHNICAL BULLETIN NTB90-005Models:

1989 240SX Date:

January 5, 1990TIMING CHAIN GUIDE SERVICE CAMPAIGN

APPLIED MODEL: 1989 240SX (S13) APPLIED VIN: JN1HS36P*KW000001 - JN1HS36P*KW017071 (Hatchback) JN1HS34P*KW000001 - JN1HS34P*KW013885 (Coupe)

Enclosed with this Bulletin is a report detailing all affected 240SX vehicles sold by your dealership that have not had the Timing Chain Guide Service Campaign (EM89-002) performed on them. This report also indicates the owner's name, address and telephone number as reported by your dealership at the time of retail sale.

Nissan believes that it is essential that this campaign be performed on all affected vehicles, and we have made a concentrated effort to reach these customers by both mail and telephone. We are now requesting that you have your service personnel contact each of the customers indicated on the report, and arrange an appointment to complete the campaign as quickly as possible.

Please remind all service personnel that this is not an "inspect and repair if necessary" campaign. All affected vehicles must have the timing chain guide replaced even if it is not presently broken.

Note:

List (Owner Report) not available.[/quote]i just looked up an exploded view on the E, its seems to have a guide on the left that the tensioner operate on, and a guide on the right, which is staight...I wouldn't remove either...

[Sandy sx]

Mmm... I got the replacements for it. Thanks for the information. Pretty much matches up with everything thats going on under the hood. Good stuff. Going to replace the guides Tomorrow or Thursday. Thanks.