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Is my timing chain stretched

13K views 19 replies 5 participants last post by  Nismo131 
#1 ·
I have the ga15de, the 1.5l version of the ga and have noisy timing chain
(upper i think) with about 180,000km. I haven't owned many cars so i'm not sure how a car should perform, but when in low gears the throttle very touchy (stick shift), when you release the throttle, the car bounces rough, but doesn't in higher gears with higher load, i had a ford laser that never did this. It also bounces during acceleration specifically between 1800 and 2000 rpm, if i hold it at 1800 it will keep bouncing which makes me think bouncing is more of an electrical or fuel problem.

How would i check for stretch on the upper chain? i've been reluctant to remove valve cover and upper chain cover cause i used the last of my gasket maker to put it back

I replaced upper timing tensioner with one for a ga16de and now it sounds a bit noisier than it use to so i'm gonna try my old tensioner again (not even worn halfway).

Also, which parts of the ga16de timing chain system would fit in the ga15de? i can't find ga15de kits for a good price locally or on ebay so if i need to buy upper chain and sprockets it would cost me over $300 in my expensive country.
 
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#2 ·
can you be a little more specific with the bouncing? is it just rpm fluctuation, or does it feel like a misfire where the engine skips for a second? i recently did the head gasket on my GA16DE and after i finished my upper chain had a horrible chain rattle, i thought my guides and maybe my tensioner were bad. i ended up pulling it back off, shooting air through the oil feed galley in the head and trying to prelube the tensioner. even after that it still had the noise. i ended up just sitting at about 1700 rpm for about 5 minutes because thats where the noise was the quietest. it eventually went away. i think air gets caught in the tensioner and doesn't allow it to fully pump up for a bit. did the chain seem too loose when you had the cover off? can you tell where the chain is contacting? as long as you got a ga16 tensioner from a similar year vehicle the tensioner should be the same. im not sure what else swaps over though.
 
#3 · (Edited)
It's like a bunnyhop when you're learning to drive stick shift, except it's smoother (it's also like the bounce in a rough gear change). It's smooth when revving up to the 1800 mark but the revs fluctuate as they pass 1800-2000 rpm and at a few other points. It also has less power when it's bouncing. The laser i had missed badly from a bad spark plug when it was cold and it felt rough like a truck, yet i only get bounce in this case and i was thinking maybe it was caused by chain slack, or something wrong with throttle and fuel system.

I need to find out how to check for chain stretch because this chain is hitting something in there since the new tensioner (installed dry with locking tab, but probably should have been soaked in oil). On my scooter engine the cam sprocket has alignment marks, and the crank has alignment mark so all i have to do to check for slack is put it into tdc and see if they line up.

Are there marks that will tell me if it's stretched on the car? been having a hard timing finding parts and info on these engines.
 
#4 ·
if the tensioner is doing its job but you're still having chain issues the chain is most likely stretched. i wouldn't worry about the engine surge till after you've got the noise sorted out. it may or may not be related. I don't know of any standard way to check for stretching aside from eyeballing it, or setting the chain next to another new one. you can pull the vc off and eyeball the chain as you rotate the crank back and forth to see how long it takes for the upper chain to move. i just had my tensioner/chain off last week. and it gave me a hell of time trying to get the chain to tension. maybe try pulling it off and priming it with some oil and cleaning up the oil feed galley.

there should be marked links on the chain. 1 gold for the idler gear and 2 silver for the cams. but all you can do with that is check of the chain skipped a tooth or not. i'm not exactly sure how you could check for stretching aside from getting a measurement of link length and measuring in between the 2.... if the chain is stretched the marks should still line up, if the chain SKIPPED they wont. at any rate it wouldn't be a bad idea to just go ahead and do the timing chain. there seems to be a huge lack of info on the GA15. but assuming nissan is like other manufacturers the 15 is most likely identical to the 16 aside from pistons/crank/cams.


http://imgur.com/mlOv5eG

timing for the 1.6 im assuming the 1.5 is the same
 
#5 ·
if the tensioner is doing its job but you're still having chain issues the chain is most likely stretched. i wouldn't worry about the engine surge till after you've got the noise sorted out. it may or may not be related. I don't know of any standard way to check for stretching aside from eyeballing it, or setting the chain next to another new one. you can pull the vc off and eyeball the chain as you rotate the crank back and forth to see how long it takes for the upper chain to move. i just had my tensioner/chain off last week. and it gave me a hell of time trying to get the chain to tension. maybe try pulling it off and priming it with some oil and cleaning up the oil feed galley.

there should be marked links on the chain. 1 gold for the idler gear and 2 silver for the cams. but all you can do with that is check of the chain skipped a tooth or not. i'm not exactly sure how you could check for stretching aside from getting a measurement of link length and measuring in between the 2.... if the chain is stretched the marks should still line up, if the chain SKIPPED they wont. at any rate it wouldn't be a bad idea to just go ahead and do the timing chain. there seems to be a huge lack of info on the GA15. but assuming nissan is like other manufacturers the 15 is most likely identical to the 16 aside from pistons/crank/cams.


Imgur

timing for the 1.6 im assuming the 1.5 is the same
Thanks for the info. I'm gonna take the valve and upper chain covers off and have a better look
 
#6 · (Edited)
I had a read through a manual that covers ga's (it covers all the ga's but goes into specifics for each model including ga15de where there are differences)

Looks like the intake cam knock pin has to be exactly 10-11 degrees below the horizontal mark, and exhaust cam pointing straight up while engine is at tdc

I hope the knock pins are visible with the sprockets on.

 
#8 · (Edited)
I had a look under the covers, without a protractor i couldn't measure the exact angle but the top of the pin aligned with the edge of the valve cover mating surface like in the picture and the exhaust pin was vertical. The chain link rollers weren't worn and sprocket teeth were still squared at the end. I couldn't see any evidence of where the chain was hitting.

The only possible problem i saw was the lower tensioner seems to retract like the upper chain tensioner when i turn the motor. Apparently it's supposed to be a mechanical tensioner but the mechanical tensioner on my scooter can't retract without pressing a button, it can only expand. Are these lower tensioners supposed to retract?

Would it be safe to assume it has not skipped a tooth if the timing is still at 6 btdc like manual says, with distributor bolts centered. I forgot to check for the colored chain links.

The only thing i did was take the new tensioner off and squeezed all the air out in a bath of oil, i'll see if it helped when rtv is dry. oil shooted out when i cranked the motor so passages are good.
 
#10 ·
I have the ga15de, the 1.5l version of the ga and have noisy timing chain

How would i check for stretch on the upper chain? i've been reluctant to remove valve cover and upper chain cover cause i used the last of my gasket maker to put it back

I replaced upper timing tensioner with one for a ga16de and now it sounds a bit noisier than it use to so i'm gonna try my old tensioner again (not even worn halfway).
Generally what causes problems on the GA engines is a failed chain tensioner and possibly a worn out chain guide. When replacing the chain tensioner, it's always best to get a new OEM part from a Nissan dealer. Many aftermarket tensioners are poor quality and can fail in a short amount of time.

The only check that you can do on chain wear is examine the roller links for cracks and excessive wear. If you have the chain off the engine,you can also check the chain for excessive lateral movement. Also inspect the sprocket teeth for excessive wear.
 
#11 ·
I checked the cam sprockets and upper chain and the rollers are still cylindrical and sprocket teeth ends are still square.

Is the mechanical lower tensioner supposed to be able to retract at all? because mine does. I rotated the engine back and forth with my hand to see if the idler sprocket would react instantly, and it did for a while until lower chain started pressing on the lower tensioner. The cams weren't reacting instantly because there was no oil in the tensioner.

I've only looked at the upper chain but can see lower chain and tensioner from inspection panel. I'm going to look up how to drain the coolant so i can get to the tensioner behind the thermostat.


I usually go for good brands with a good reputation like beck and arnley because buying local nissan parts would cost more than the car is worth. They charge $200 for cam sprocket alone.
 
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