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L18 loose timing chain?


Motschrocker

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I have had some other posts regarding timing issues i have been having and i am wondering if it is related to the timing chain. I pulled the valve cover and jiggled the chain and the non slack side seems very loose. I have included pics showing the slack and also a video link showing how loose it is. I watched the l16 rebuild video and my question is if this is the issue what should i replace? Chain guides and tensioner? The chain?

 

20150919_195524_zpsrrwascq0.jpg

 

20150919_195535_zpsrihpvagn.jpg

 

https://youtu.be/pP_UBII2stI

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It does appear to be loose... Have you actually checked the cam timing yet? Does it rattle? Performance / fuel economy concerns?

 

Considering that the engine is at least 35 years old, mileage unknown (let's be honest, your odometer can say xxxxx miles, but c'mon.......) chances are the timing chain is stretched.

 

I know my timing chain is stretched and I adjusted cam timing accordingly.

 

Sure it appears loose, but I'm just looking at pics.

 

Remove your valve cover.

Take your 27mm socket and ratchet and roll the crank over to top dead center.

Take a look at the face of the cam sprocket... You will see a two little notches. one on the cam housing and one on the sprocket.....

 

 

motorLcamtiming.jpg

 

See how the little "U" shaped notch is 'just' right of the "-" notch on the cam housing? This is ideal cam timing.

 

If your little "U" shaped notch is to the LEFT of the cam notch, the chain is stretch and cam timing is retarded.

 

Now, there are 3 "settings" provided on the cam sprocket to compensate for chain stretch. From  my experiences cams come on hole #2. 

You'll need a timing chain wedge to stuff in the timing cover so you don't lose your tensioner.

Remove cam sprocket at rotate to hole #3 to advance cam timing and take up some slack.

Each hole, #1 #2 and #3, equals 4 degrees. Each tooth on the sprocket is 5 deg. 

There are tricks to compensate very stretched chains... but this is at your discretion.

 

My chain was very stretched...... So, I placed my cam on hole #1 from hole #3 which Retarded my cam 8 deg, I then advanced my cam 2 teeth on the chain which equaled 10 deg advance -- 2 deg advance from original hole #3 .... make sense? If not it's ok......

 

Let's start with checking out your two notches first.

pic would be great.

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Turn the engine in the direction of rotation.... clockwise and stop. That slack disappears over to the other side. That slack is just the engine coming to rest in that odd position. When running, the crank pulls down on that side against the resistance of the valve springs and will be tight.

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motor can turn backwards abit an make the chain feel slack

 

you always turn the motor in direction of it running then put it on the timming mark. then feel the slack side and ck the cam timming . if it lines up then your fine time wish but still may have the slack side loose and you have to open the front cover to tighten this. By then you might as well but a new tensioner and slack side guide.( i alwasy have spares of these)

Be honest these chains last a long time the top sprocket will be more worn than the chain in my experience opening up motors. bottom sprocket hardly wears

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I believe i have the engine at TDC. I put my finger on cylinder 1 plug hole and turned the until i felt a puff of air. I wasnt sure it i stop immediately after feeling the air or if i turn until all the air comes out. Either way it looks like my notch it just to the left of the mark. Look at the pics and let me know if anything seems weird.

 

20150921_194016_zpspetfdcxm.jpg

 

20150921_194029_zpsbyunkleu.jpg

 

20150921_194045_zps7uac0zdh.jpg

 

This was the notch when i first felt the puff of air.

 

20150921_195105_zpsawbewjru.jpg

 

This was after i turned it a bit more and all of the air was out.

 

20150921_195027_zps73gqy20p.jpg

 

20150921_194127_zpsctildlyk.jpg

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ok its the 2nd deep notch mark this with white paint  that will be Zero

 

you have the L16 type crank pully.  each notch is 5 deg.. first is 5 deg after then Zero the 5  10 15 20

 

 

the spindal looks correct if it was at Zero on crank.  if not then spndal might be off a tooth.

 

my vid say turn on tite side and go to zero on crank then stop. ck the cam timming mark then ck the spindal for the position as you have photoed

 

 

I think your fine  but ck again as mention.

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Too bad you're way over in Iowa. Over here on the west coat (specifically Oregon an Washington) there are a lot of generous Datsun folks who would be willing to come check it out.......

 

 

Heck, buy me and my girlfriend a plane ticket so we can see the East Coast and I'll gladly verify your timing.  :poke:   :thumbup:

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Too bad you're way over in Iowa. Over here on the west coat (specifically Oregon an Washington) there are a lot of generous Datsun folks who would be willing to come check it out.......

 

 

Heck, buy me and my girlfriend a plane ticket so we can see the East Coast and I'll gladly verify your timing.  :poke:   :thumbup:

Tell me about it. Other than the occasional Z, there are not too many datsuns running around here.

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That's because it is NOT at TDC yet.  Your pointer is at the wrong end of the notches.  Keep rotating it SLOWLY until you have the DEEP notch lined up with the pointer and all should be GOOD!  Really good pictures, they're a big help on this end.

So i think NOW i I am at TDC. Its kind of looking like everything is spot on which is good but also doesnt help me figure out why i cant get the car to run right. On a side note i checked the oil and it is pretty thin and smells like gas. Here are pics. Everything look right?

 

20150923_160307_zps9hjuko0b.jpg

 

20150923_160220_zpsv2mfyh8j.jpg

 

20150923_160541_zps4kxewlr4.jpg

 

20150923_160541_zps4kxewlr4.jpg

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I have been having a really hard time getting it to even idle let alone drive. It misses, backfires, shutters, my spark plugs are black. It just seems way out of time and couldnt get it right. I didnt have mh pointer straight before so i havent used my timing light. I will put it back together and see. Here is a link to my other post talking about the distributor.

 

http://community.ratsun.net/topic/67289-73-610-l18-dizzy-issue-dual-points/?do=findComment&comment=1290775

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The cam is slightly retarded but not enough to make it all that rough as you said it was running ok before( i think you said that)

 

put the timming light on there and it should be the 10degs. 2 after the BIG notch. so get that correct with the idle mixute on the carb and hope if comes out ok.

 

Dizzy bushing maybe be worn. condensor  wrong coil intalled?(you got a 71 say 510 coil and use the ballst resisitor)

 

after that I would look at the carb but yuou know this car better than us

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That's because it is NOT at TDC yet.  Your pointer is at the wrong end of the notches.  Keep rotating it SLOWLY until you have the DEEP notch lined up with the pointer and all should be GOOD!  Really good pictures, they're a big help on this end.

Come on guys, pay attention here.  Get the engine where it belongs, fix the damn pointer and proceed accordingly.  When in doubt, go back to ground ZERO and start over.

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So i put everything back together and went back to a mechanical fuel pump instead of the electric. It took a while to start. Once it started i got it running as good as ever. I beleive my issues has been the electric fuel pump. Possibly too much pressure. The oil smelled like gas so i changed that out. It is running great now. I have one question. Once i got it running well i put it away for a couple of days. Today i started it and it ran really bad for a while. It had no power under load and was backfiring. I floored it a couple of times and eventually it evened out. What would cause it to run so poorly at first?

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So i put everything back together and went back to a mechanical fuel pump instead of the electric. It took a while to start. Once it started i got it running as good as ever. I beleive my issues has been the electric fuel pump. Possibly too much pressure. The oil smelled like gas so i changed that out. It is running great now. I have one question. Once i got it running well i put it away for a couple of days. Today i started it and it ran really bad for a while. It had no power under load and was backfiring. I floored it a couple of times and eventually it evened out. What would cause it to run so poorly at first?

Sounds like spark plugs to me. The fact that it was flooding before only furthers my belief. Try changing the plugs and see if that helps.

 

Once a spark plug gets fouled, it never recovers 100%. Unless you bead blast it.

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Same issue today. Yesterday it idled well and drove great. Lots of power. Put it away. Today it stsrted fine was idling fine and. Let it warm up and when i tried to drive it had no power. Running rough back firing out the carb. Parked it and now it wont idle. I pulled some plugs and they are super black. I changed nothing on the carb from yesterday. Should i just try new plugs? I am thinking this carb just isnt right for this engine. No matter how i have adjusted it, it always runs rich.

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