eric93SE

iTrader: (1)

I rebuilt the VTC's and I have to say that its a peace of cake. It literally takes 1 min. to rebuild each one. As long as you scribe a line to reference the shaft to the body and a line to reference the gear to the body, then there is absolutley no way to put it back together wrong.

I've also replaced the chain tensioners, since the engine would have a low rpm tick (while the VTC's were grounded) so I knew that it was not the vtc's making the noise. It now looks like the left head's tensioner (next to the firewall) was the culprit. Also the nylon guide plate which is on the tensioners has deep channels dug into them from the chain (they needed to be replaced regardless).

I've finished rebuilding both vtc's and the right head is all back together.


NOW THE PROBLEM:

The left and right head are not setup the same way. So after I removed the left head's chain tensioner (next to firewall), the chain dropped off the lower gear. I've marked the intake and exhaust gears with respect to the chain (using a product called Dycan Blue), so that I cannot put them on wrong. The issue is that that I cannot get the chain slack to return to the side of the tensioner.

I plan on removing the exhaust gear, in an attempt to get enough slack in the chain to gain control and get the chain properly re-positioned.

I'm confident that the lower gear has not moved, since that would require enough force to move all the pistons.

Any help would be great (preferably by those of you that have done some actual engine work ).

MrGone

iTrader: (30)

Lemme guess, rear head?

Exact same thing happened to me.

Cliff Clavin

iTrader: (11)

The phrase is "piece of cake."

eric93SE

iTrader: (1)

It really was "A slice of chocolate layer cake" rebuilding the VTC's
But, it was more like eating the cake without a fork.

I wish I had my digi cam to document it for your people. Someone should really make a How-To on this subject because for the most part its pretty easy.


So MrGone, what did you do? buy a new engine?

I'm afraid I'll have to remove the lower timming cover (and unfortunatley take the other timming cover and chain cover back off), in order to access the lower gear. I know that the chain needs to be taught between the two cams and between the VTC and the lower gear.

Cliff Clavin

iTrader: (11)

Actually, I bought the new engine. Technically, it wasn't new, it was a JDM engine with a 1-year, unlimited mile warranty. Jeff installed it and replaced just about everything possible. Now I have new manifold studs, new knock sensor and all new gaskets, hoses and seals, so all-in-all it worked out to my liking.

Shawn went through the same thing you are going through on my engine. He marked the snot out of everything, but somehow the rear side didn't come out timed quite right. One of the cams might have been off by a tooth. I tore the old engine apart the other day, but I didn't really bother checking the upper chains to see if they lined up exactly right. I was on a bit of a time schedule. I don't get much time in the garage because my wife works evenings and I have to watch my son. Shawn will probably give you more info when he gets done working sometime late tonight/early tomorrow morning.

MrGone

iTrader: (30)

yeah, rebuilding the VTC's is a cakewalk, installing them however seems to be more of a PITA than 'we've' anticipated lol. I'm actually not sure quite what happens though, it doesn't make any sense with the way the tension 'switches sides'. The strangest thing is that I marked everything extremely well, white out everywhere, everything was put back in the same place it was removed, except that the tension was different (which is what threw me through loops and drove me insane trying to figure out). The rear bank still showed every symptom of the intake cam being off a tooth.



To be completely safe, I would just retime the whole motor, however IMHO thats a huge job to do with the motor still in the car. Does your car have ABS? if so, hell at the thought of it

blacks92seAuto

how would you be able to tell if the timing on 1 head is off and how can you adjust them???

MrGone

iTrader: (30)

you can hear it in the intake or exhaust as long as the engine is building compression.

eric93SE

iTrader: (1)

No ABS

Damn, I was afraid of that. It seems that the camshafts moves a bit from the valve springs (when the chain is off one sproket), so its required to slightly crank one of the cams in order for the chain to meet the lower gear in the right position (and under tension!). But I still have no guarantee that its the correct spot since I cannot see any timming marks on the lower gear.

I think I'll have to remove the lower timming cover in order to set the timming correctly. I might as well replace the lower chain tensioner

Black92seauto, well the engine also has its own timming marks that need to be lined up.

eric93SE

iTrader: (1)

Ya know, thinking things through my head, and how the two heads are setup a bit differently made me think of how to have removed the chain tensioner and the VTC without loosing the chain position.

If the VTC is removed before the tensioner, the chain will drop down and fall ON TOP of the lower gear, making it very difficult for the chain's position to have changed. While the chain is off the VTC, the tensioner can be removed and replaced without loosing the position in the lower gear since the chain is engaged in its upper half by the excess chain from the VTC. So after the tensioner is replaced, then the VTC can be re-installed.

Its essentially the same as the other head, except in a different order. *******IT.

Cliff Clavin

iTrader: (11)

You want some more bad news?

Compared to the lower chain cover, the upper chain covers are a piece of cake. It took me quite a bit of time and effort to take the lower one off. The upper chain covers I took off in a matter of minutes. Oh, and my engine was sitting on a stand.

PS: If you lose any bolts or anything, let me know. I have boxes of them now...

eric93SE

iTrader: (1)

What was so tuff about it? Did you have the main pulley off?

CandiMan

iTrader: (1)

The whole valve timing in the VE can be a tricky SOB, that's why I removed all three timing chains when I did my VTC rebuild and started from the begining. It all went back together (the valve timing) like a scope of chocolate fudge brownie icecream and I did all this with the motor still in the engine bay. I also pulled the heads to change the exh manifold studs, but that's just me





This pic is when I was going back on, after lining up the timing marks on the lower chain and the two upper chains I used a bungy cord to keep tension on the upper chains while getting the VTC and exhaust sprockets ready


MIKE

eric93SE

iTrader: (1)

Hey Mike, Yeah this is getting real fun now lol.

I'm in the middle of getting to the lower timming cover. I hope I have good access to the lower gear for the left head. Its kinda depressing to be almost finished, then realizing how badly I got s cre wed. Well it looks like the engine will get some fresh antifreeze (red) and a new lower chain tensioner I have to justify this extra work and think positively.

I've done the water pump a couple years ago, and I now rememmber how much fun it was back then. Now its a peace of cake (cheese cake this time).

This engine better purr like a kitten, otherwise I'm going to bring out the big sledge hammer .

mofoaka

hi i'm new to this forum.. but i'm having a problem with my maxima.. when i turn it on.. (cold start) i have this weird grinding noise for like a 3 seconds and then it goes away.. but if i rev a lil it'll come back. once the car is warmed up for about 5 minutes the noise is completely gone. my VTC was rebuild and my upper front bank timing chain tensioner was replace. do you know what it may be? thanks

internetautomar

iTrader: (30)

bad oil flow?

mofoaka

how would i fix it?

internetautomar

iTrader: (30)

start running 5w30 and watch your oil pressure for the first couple of minutes

mofoaka

how do i watch my oilpressure?

internetautomar

iTrader: (30)

add an oil pressure gauge to the car. unforunately we don't get one stock

D-sta

iTrader: (6)

I am hungry with all this cake talk. Hope everything turns out well Eric and e-mail after you're done, I'll pick something up at the cheese cake factory.

eric93SE

iTrader: (1)

Hey Mofaka, No post hijacking allowed!!!
They may have botched your VTC + tensioner install! Get your timming checked! But your could also have a bad lifter or a broken exhaust manifold stud. If the timming is off badly then its not a simple adjustment of the CPS, since the timming on one head is correct and not on the other.

Whats up Diego, this looks like it might take another day or so. I tend to take my time when working in unfamilliar territory, so that I don't mess anything up. So far nothings broken and I have to pick up some parts. I'll be sure to post when she's up and running.

mofoaka

so sorry eric! i didn't mean to jack.. thanks for the response though. how can i found it if one of my exhaust manifold studs are broken? i'm really thinking its the cam shaft and rocker that's messed up. are there any threads or how-to's that show how to do this? thanks

CandiMan

iTrader: (1)

Easiest way is to use your hands and eye. The left bank you can visually check to see if you're missing any nuts that clamp down the manifold. Missing nuts mean broken studs. For the right bank I believe you can reach down and feel around. There's a total of six nuts/studs on each bank. If you feel less than six, you have broken studs.

Also keep in mind, just because you can see and feel nuts/studs doesn't mean the stud hasn't already failed. If you feel up to it, spray some WD40 on the nuts/studs, take your 14mm wrench and see if you can loosen/tighten the nuts, it's a good possibility some might break off in your wrench.

MIKE

eric93SE

iTrader: (1)

Update:

Thanks for all the comments everyone!

1. Seems that the lower gear will not move unless the engine is cranked.
2. The chain cannot slide under the lower gear, either CW or CCW (Nissan Powa )

Therefore, timming was not lost!!! I used my upper timming marks to line the cams up .

MrGone, Your all good! I had slack on the right side, but after cranking the engine around a couple times to get all the OEM timming marks to line up I was able to see how the engine operated and actually see the tensioners pop in and out picking up the slack on that side and switching back and forth. So its completly normal, it just depends what strok the cam is in (picking up the slack or producing it).

And I didn't even take one bolt off the lower timming cover

Michael

iTrader: (21)

Nice...I was a little worried about this because a couple of us (Me, CraigB and Portdave) are doing 2 sets of VTCs and knock sensors this weekend. One engine we are doing it on will be out of the car but the other will be in the car still.

So this was a perfect time for your post .

Thanks for the info.

Mizeree_X

iTrader: (9)

Does anyone else think we should have a more thorough VTC how-to? There is alot of info about why VTCs fail, and how to ground them, but not much about replacing them except "get an FSM" and "read the TSBs". But, from having read about past experiences and this thread, I think it would be very helpful to pool everyone's experiences together and create a VTC install writeup. My $0.02.

D-sta

iTrader: (6)

I'm sure Craig is working on a How-To....very soon!

«§»Craig B«§»

iTrader: (5)

I'm not sure how thorogh it would be since I'll be working and it's hard to keep picking up the camera when you're in the middle of something like this. And my camera is broken right now, but I'll get some pics and see what I can do.

eric93SE

iTrader: (1)

Just thought I'd add that installing the VTC on the left head was a little more difficult than on the right head. I first installed the tensioner, then the exhaust cam gear (but you guys won't have to remove the exhaust gear on either side, I only did this to get all the chain slack I could get to see whether or not the chain can move CW or CCW past the lower gear). When positioning the chain on the exhaust gear I had to crank the cam shaft a little CCW to meet my timming mark, but by cranking it a few teeth the camshaft is then a little 'spring loaded' and is a little like a mouse trap (this is why the chain slack is produced MrGone). So when moving on to installing the VTC if the chain is lifted high enough it will allow the chain to pop out of the exhaust gear and the exhaust cam will rotate to its neutral position (but loose its correct timming position). So I had to use a wood wedge all the way on the left of the exhaust gear placing it between the chain in the gear and the adjacent wall preventing the chain from popping out of the exhaust gear. This must be where RedMax? messed up his timming and was off somehow (360 deg or something) and broke all his rockers and bent valves......

So a word of advice, you can use your own timming marks. But take the extra 5 min's and crank the engine to TDC with the stock timming marks. There are two silver chain links that meet up with dibit in the exhaust gear and VTC gear teeth (its on the side of a tooth and kinda hard to see right away). Realize that it might take a few revolutions of the engine for all the timming marks to line up! The gold tooth is the easiest to locate, the silvers are a little tougher to see. Actaully when the timming marks line up for the silver links on both heads, its almost impossible to see that the lower gold tooth has met its timming mark on the bottom.

eric93SE

iTrader: (1)

Have fun! peace of cake lol.

Aaron92SE

iTrader: (128)

I know I would definitely use this How To if someone creates it. I have my FSM and the TSBs, so that is enough. But a write up will definitely help me a lot.

CandiMan

iTrader: (1)

That's one of the problems about doing a detail write-up. When I did my VTC I intended on doing a write-up from begining to up, but when you're working by yourself and stopping every so often to take a few pics that really adds time to your work. I'm use to working flat-rate (which means time is money) so taking time-out to take pics I'm not use to.

Craig with your upcoming weekend project you're definately going to have enough hands (including mine Friday morning) so hopefully we can write something. BTW my the wife and I narrowed it down to either Cobb or N. Fulton Co. but we'll talk more on Friday.

MIKE

«§»Craig B«§»

iTrader: (5)

Great! Glad you'll be able to lend a hand. Very much appreciated. With all of us there, I should be able to take some good pics. Might have to borrow a camera but I'll figure it out. It'll be nice to have someone there who really knows what he's doing. The rest of us would have probably been allright but it's nice to know for sure

N Fulton is nice but can be pricey, I'll give you more info this weekend.

MrGone

iTrader: (30)

Any VTC info that I have found is extremely vague, it sucks but meh.

MrGone

iTrader: (30)

well that was Nick (gowireless/maxima4DSC). Chris's cam was just advanced, but it didn't do any damage.

yeap, just have to make sure the piston is on the top of the compression stroke, not the top of the exhaust stroke. You can also tell by watching the cam lobes.

eric93SE

iTrader: (1)

thats right gowireless, from NJ, if I rememmber correctly he broke a bank of rockers.

I'm sure you guys will do a good writeup. Its really pretty straight forward, there are no short-cuts. Just time consuming. If you guys want, you can do the right head first, and reassemble that one, since its so easy to access and after reassembling that side there is no chance to get any dirt in that side.

Michael

iTrader: (21)

Craig I will have one of my cameras with me. It may not be my new one since Mandy may need it while I am gone but I will have one at least.

eric93SE

iTrader: (1)

Just to let everyone know, that the car is up and running and there is no more VTC tick or the low rpm tick that was probably from the tensioner. I took my time on this job since I have not done much engine work in the past, and I'm kind of a perfectionist .
The only noise is normal chain noise and normal injector noise. There is a noticiable increase in low rpm torque, and the car hauls ****.
It was nice being able to clean so many parts while they were off the car, my coolant overflow and valve cover look like new .

Hopefully the VTC noise will not reaccure as it has to a few others. I cannot say whether or not those people properly diagnosed the sound that came back, since there is more than one source of a tick sound on the max. But for this reason, courtesy nissan stop selling the rebuild kit. I'll definitly let everyone know if the sound comes back.

Jeff92se

iTrader: (82)

Did you get a chance to clean the oil gallies?