Hi guys,

long time lurker, first time poster.

I'm installing a new set of timing chains on my vq35de, and I would appreciate it if anyone knows the answer to some queries I have about expected outcomes once the chains are installed.

1/ I have all the relevant chain links sitting on the required timing marks, no worries. However once they are in place one cam on either side is no longer perfectly at the 12oclock position (relevant to its head), the exhaust side is a few degrees ahead of the intake. Is this normal?

2/ If I was to rotate the engine to ensure its all working as expected, how many times would I have to rotate it before the timing marks all lined up again? I did this the first time I installed the chains (50+ rotations) and I seemed to be off by a link on the secondary chains, but I am certain everything was on correctly prior to rotating. Whats going on here? Do they ever line back up? Its freaked me out a bit so I pulled it and reset the chains.

Thanks in advance for any responses, it much appreciated. I dont want to seal this thing and find out I'm off... that would suck!!

 

I think this is normal and once the engine is up and running oil pressure is going to build and put tension on the tensioners and it'll bring it back to where it should be.


I believe this number is 17 times ... I believe you need 17 rotations of the timing chain and then the marks will be on their original marks. I've done this on my car and also did a gallery gasket on an HR and if I remember correctly that's the number. Dont quote me on this but I believe thats the magic number ... try it and report back. I'd make sure they re-align before moving forward.

 

I've done a bit of playing around with the chains to see what is going on.

The old chains had 245000km's (150000mi) on them, and I wanted to see if they had the same number of links and similar length to what I am installing, which comes from Z1. They do appear to have the same number of links, but each chain was roughly 1 extra link in length. The extra length was being taken up by the tensioners and it wasn't an issue. The new chains are tight, especially the secondaries which are tough to get onto the cams, there really is no slack and after seeing other installation videos where the secondaries just seem to slide right on I thought it was weird. But the number of links is the same, so everything will be rotating in correct sync.

However when checking the assembly by rotating the engine I found the following;

The primary chain does go back into the crank timing mark after 17 turns (or maybe 16 I think I lost count), and at the same time the primary marks on the intake cam also line up.

The secondary chain marks do not line up after that amount of turns, however the cams are in the correct position.

I kept turning the engine a bit more to see if they were going to come around, but couldn't find it. However when the primary did get back to the start position again (32-34 turns), the primary was on the intake cam and crank marks again and the cams were in the start position again, but the secondaries were still not on the marks.

At the end of the day it looks right, just that the secondary chains don't want to get back onto the timing marks, however the cams are in the correct positions.

I'm going to roll with it as the cams look right and at the end of the day that is actually whats important. It would have been nice for the FSM to specify # of turns to check it though, if its possible. I can't be bothered counting teeth and gears to mathematically figure out if its in fact even going to happen... anyone ever done that?

 

You'll know right away if timing is off ... if youre one or two teeth off the car will start and will run bad and likely throw camshaft codes. If you're off more than three teeth the engine wont start and/or you will introduce your pistons to your valves ... which I guess means you'll be doing it all over again!

but if you've already cycled the engine 100 times and valves and pistons are not hitting than you're fine.