Well i'm in the middle of my engine rebuild on my 92 240sx with a ka24de engine. I just got thru scraping all the old gasket material off, and was set to start putting things back together when i looked at the lower timing chain and remembered that i did not mark the chain and the idler sprocket so i can align everything again. I feel so stupid!
Well i did a little research in the factory service manual and saw that the lower chain is supposed to have two silver links for mating marks. Well i do not have the front cover off and I have the 1-4 pistons set to top dead center via the crankshaft pulley marks. (I can also see the pistons) For as much of the chain that i can see, I do not see any silver links on my lower chain. I should be seeing atleast one at this point?? Well i also looked at my upper timing chain and i only see one silver link. Aren't there supposed to be two??
Well am i screwed?? Am i missing anything?? Any advice would be greatly appreciated.
Oh and the chains are still the orginals and i am not going to replace them. Car has only ~60,000 miles on it. So i don't see any reason.
Timing Chain Help
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sil80drifter
- Posts: 1313
- Joined: Sun Aug 18, 2002 5:53 am
- Car: 1990 240SX Hatch
it really doesn't matter where the links are, as logn as your crank and cam shafts are aligned properly with respect to one another, and although I don't know what positions they are supposed to be in on a DOHC, I'm sure the FSM covers that. Once they are aligned, you can put the chains on any way u like, since every link has same length, the silver links are really there for reference, not for reasons that the chain has to be put on any in special way.
sil80
sil80
the lower chain has to be lined up with the upper one for the timing to be correct. The cam sprockets should be in a 10 o'clock intake, 2 o'clock exhaust position with 7 (if i remember right) links between them. But they must be lined up correctly with the lower chain. You should be able to see a dot on the upper sprocket of the lower timing chain. there should be 9 links between the dot and the intake mark (again, if my memory serves me right,which it doesn't most of the time). if all else fails, go to an auto parts store and have them show you a new chain. if it has 3 silver links, count the spaces between them and then mark your chain with the same pattern. The new chain set i got from autozone has 3 silver links, one went over the lower sprocket mark and the others went over the cam sprockets. it will only go one way with the cams in the 10 & 2 position. Good luck!
I see what you’re saying. The markings on the chains are not absolute. They can be anywhere on the chain but must have a certain amount of links between them.
Well here's what I plan on doing. I want to run it by some people before I do it (my crazy ideas don't always work). I going to find out how many links difference there is between the exhaust and intake camshaft sprocket markings. Then I’ll count the remaining links on the upper timing chain and divide that by 2. I should then have the third link on which the idler sprocket will line up to. Now I only have to figure out the lower timing chain. I have not taken off the lower front cover or the crankshaft pulley for that matter. So I do not think the chain has ever disengaged. So if I set the 1-4 cylinders to top dead center I should have the crankshaft sprocket in the correct position. Now I just arbitrarily put the lower chain on the idler sprocket. It should be aligned properly because I have the crankshaft in the proper position. When I install the upper timing chain I will keep the third link on the lowest point of the idler sprocket and the other two markings on the stamped marks on the exhaust and intake camshaft sprockets.
Now this should give me the proper alignment of the lower timing chain and the upper timing chain and the alignment between the chains.
So what do you all think?? Does it look like a good plan?? It would great if anyone has any pictures of a proper alignment??
Well here's what I plan on doing. I want to run it by some people before I do it (my crazy ideas don't always work). I going to find out how many links difference there is between the exhaust and intake camshaft sprocket markings. Then I’ll count the remaining links on the upper timing chain and divide that by 2. I should then have the third link on which the idler sprocket will line up to. Now I only have to figure out the lower timing chain. I have not taken off the lower front cover or the crankshaft pulley for that matter. So I do not think the chain has ever disengaged. So if I set the 1-4 cylinders to top dead center I should have the crankshaft sprocket in the correct position. Now I just arbitrarily put the lower chain on the idler sprocket. It should be aligned properly because I have the crankshaft in the proper position. When I install the upper timing chain I will keep the third link on the lowest point of the idler sprocket and the other two markings on the stamped marks on the exhaust and intake camshaft sprockets.
Now this should give me the proper alignment of the lower timing chain and the upper timing chain and the alignment between the chains.
So what do you all think?? Does it look like a good plan?? It would great if anyone has any pictures of a proper alignment??