i have a 1990 240sx i have a constant clicking sound coming from the motor, it was a loud knock before but when we changed the valve gasket it went back to clicking but when i run the motor hard it comes back, my dad thinks it might be valve lash but its a sohc motor and he says the valves cant be adjusted it doesnt necessarily get louder it gets faster, i mean its loud but it gets faster at higher rpms

 

this would be due to a rod/rod bearing or something to do with timing chain, or the timing parts.

i had the same problems and my knock got loud and even faster when my rpms would go higher then 3,500 and I torn my block apart and it was my rod bearings.

 

well when we had the valve cover off we looked at the chain but nothing seemed loose or missing its a knock that comes and goes

 

check the two upper chain guides?? check the upper tensioner,, did you check the lower tensioner, did you check the lower guide?? you can't just pull off the valve cover look at some top area of the chain and say its okay... you need to take that whole front upper and lower cover off to check it.

 

Yeah dude, Check how loose your timing chain are. Next you want to see how the upper tensioner is doing, you can remove it and inspect it. It can't be that hard at the same time it needs some springing action. INSPECT this parts as well, as my lower chain was making contact with the upper tensioner from the backside of it. Your chain might be scraping too, check for FRESH shaving or grinds (you could usually tell by looking for shiny flat spots.) Hope that helped, good luck!!!

 

yeah what i and ramnailz said and if everything with the timing is fine then its something in the buttom end..

 

what about the valves

 

IF IT WAS IT WOULD BE MORE F'D UP.

 

fuel injectors are to click but not real LOUD.. check them also.

 

I had a clicking/knocking, especially around startup, and i took my valve cover off today and it was the top chain guard/guide, it had broken from the two bolts that hold it, and was just rattling around and hitting the chain. Anyone else had this? It could've been from the front end collision that the previous owner put it through.

 

everyone has had the chain guide rattle and breaking on all the s13's... i think the s14's don't even use them.

 

This is a problem corrected by nissan in 96, just order new timing guides all s13 DE's do this and the 95 s14...............
The guides were reinforced in the later model de's 96-98....
All DE's have the same bolt patterns so just order new timing chain guides from the other model years........
This problem can also cause rough idle or shut off due to the extreme movement in the timing chain......
If this problem isn't corrected it can break the chain and it can bend a valve...........
While you are at it replace the timing chain also just to play it safe...............

 

thank you all for your input but i have more to add on the knocking in my exhaust notes the knocking makes the notes a little more whiny but when there isnt a knock at all the exhaust sounds deep and throaty

 

Could just be the time of detonation.......
New chain and guides....No problems................

 

uhhh did you firgue it out yet????