Intake cam sprocket removal on a 1994 N/A 300zx automatic?

[Mikey_ZX]

Hey guys,

I'm in the process of replacing my timing belt and I want to replace my cam seals and also my front seal. My problem is that on my 1994 there is a plate that covers the intake cam sprockets and I'm not sure if I'm able to stick a 10mm socket and extension in place to hold the cam gear from moving while I attempt to break the 98 ft/lb bolt inside of it. I've been following tutorials that are on the net, however the 300zx's are from before 94' and they have holes in the inner sprocket so you can hold the sprocket in place. How can I hold my intake cam sprocket in place so that it doesn't move around so I can break the bolt and gain access to my cam seals? Has anyone worked on a 1994 300zx? I need some help, not trying to mess this up. Also, how can you diagnose a bad cam gear? Thanks!

[marty1mc]

The plate is the cover for the VTC spring. If you pull the 4 bolts (7mm head size, I think) off, there is a spring behind it and an O-Ring. You should have new ones as part of the 60K/120K kit.

To replace the cam seal, you will need to loosen the nut behind that cover and remove the gear first. I usually loosen the nut BEFORE I take the belt off. But, be careful, the gear could slip a tooth. There is also a method where you can wrap the belt around the gear (after removing the belt) to and wrap it around the front of the engine to hold the gear steady while the nut is loosened and re-tightened. I couldn't find that link, though.

Here is a link to the timing belt replacement procedure:
http://www.ttzd.com/tech/timingbelttech.html

[txQ45]

You didn't put how many miles was on the present timing belt setup?
If you're doing the 120K ,, which it sounds like since your doing the cam seals .. You might think about putting the stronger idler bearing studs in too..
We've had three cars in the past two years in which the top idler bearing stud broke.. One was on a NEW engine from a well know builder here in TX.
It was not the builders fault but the fact that the OEM studs do fail and should be replaced with the Ramey studs.. plus many do the bottom sprocket on the 120K timing belt change. The rest was referred to Like marty1mc stated.

[Mikey_ZX]

Thanks for your help guys, I haven't removed the belt yet for my fear of messing up the timing. If I loosen the bolt while the belt is on, and remove the gears, will I have to install the belt in order to get the torque spec on the big bolt inside the intake cam gear? I am installing a 120K timing belt kit from courtesy nissan, it comes with the new idler pulleys, not sure about the studs, I'll look into it, also have the new sprocket with the front seal. Also, I do have the new spring and o-ring that goes behind the intake cam sprocket plate. I'm not sure how many miles were on the present timing belt setup because I bought the car a few months ago, not knowing how much was on the belt, but when I opened the timing belt covers, something is leaking oil, probably the cam seals, or valve covers, not sure but I'm probably going to attempt the plenum job if I can get by this successfully. It's just those plates make this job much more of a harder task, should I a screwdriver into the transmission gear to stop the crankshaft from moving, while I try to break the bolt?

[txQ45]

Loosen underdrive pulley remove pulley and all covers with all covers removed you can align the bottom sproket with the mark on the oil pump
You can align everything before loosening tensioner..you can bump the starter, put the bolt back in the crankshaft and turn it or several other ways.
set mark on crank sproket to the mark on the oil pump then look at the cam sprokets setting them each to the mark on the back plate.. If they are close your ok.
You should have read enough about how to do the rest if your going to do it yourself.

[Mikey_ZX]

Does it take little force for a single sprocket to actually move while your trying to break the bolt? When you mention the belt wrap technique, am I doing this when the belt is off and I'm using the old belt to wrap around the intake cam sprocket using it to pull the opposite direction of when I either tighten or loosen the big bolt? I'm just trying to get an idea of what the belt technique is? Also, when I loosen the bolts to the sprockets will they easily come off or will they need some force, can I just pry them from behind? Right now I'm at TDC with my old belt still on. Sorry for asking so many questions, I am new to doing timing belts, removing gear sprockets and changing cam seals.

[Mikey_ZX]

Well, I loosened all the bolts on the exhaust cam sprockets, I've popped the cover off of the intake cam sprocket that contains the spring and o-ring inside, however still haven't attempted to brake the 18mm bolt on the intake cam sprocket, and sorry for not knowing, but my 120k kit did come with the new studs for the tensioner and the idler pulleys, but I went ahead and ordered the Ramey Z idler studs from import parts pro, since you suggested them and that they are suppose to be a lot stronger. I'm waiting on getting help because I need someone to hold the sprocket in place, also I'm trying to shake my nerves because I need some confidence in trying to approach that big bolt on the intake sprocket. Added, I've done research on what I can do to hold the sprocket in place and some people wrote that they use the timing belt and also use a chain wrench to hold the sprocket in place. Sorry, it's all a learning process for me, just not trying to mess up and I'm trying to take my time.

[Mikey_ZX]

Just broke the intake cam bolts with my father, he helped me out a lot, pretty strong guy too. Umm....sorry for the wrong fact about the bolts being an 18mm socket, it was actually a 19mm, those bolts are kinda tricky to break but having a wiser person around helps alot, just needed to figure out how to break em', me and my dad broke the bolts in 10 minutes. Thanks for your help guys, now I can continue on with this project.

[stebo0728]

Its alot easier with the valve covers off, which if your not pulling the intake collector then you wont be removing the valve covers, but the cam shafts have wrench flats on them inside the engine. I also had a tough time breaking the bolts, I got a 24" pull bar and it went alot smoother, those short socket wrenches suck for leverage.

[Nrook84]

Hi Everyone, I used the search function and now I'm resurrecting this zombie for help with my intake cam sprockets...
I have a 95 NA I'm doing the 120k service on. Everything has been going smoothly until I got down to the intake cam sprockets where I'm trying to get them off to replace the cam seals.

I can't seem to get the belt wrap technique to hold the cam gear well enough to get the torque required to break the bolt loose. (willing to try again but it scares the crap out of me).

I bought a cam gear holder, but the teeth on it don't reach the sprocket due to the protrusion from the cylinder where the bolt is held. So I'm sending that back...

My buddy and I tried holding it with the old timing belt and still couldn't get enough torque on it without moving it. Please help!

Can/should I use PB Blaster on this or is it bad for the motor?
Is there another tool I can use or method to getting it loose? I'm trying to get it done without pulling the plenum and heads.

Any help is appreciated!

[rgregoryb]

I wrapped the old belt around the intake gear put a c clamp on the belt to tighten it against the gear, then c clamped the doubled up belt to the throttle body. It did not move.

[Nrook84]

Thanks! I might give that a shot. Im assuming you mean the opposite side throttle body? So passengers side cam sprocket to drivers side throttle body?

I was given another suggestion of putting the tbelt back on and locking the crank bolt in place with a breaker bar and then trying to break the cam bolts loose that way. I think that was also suggested above but the idea of it slipping a tooth makes me nervous.

[rgregoryb]

You sound like me, I was nervous as hell that the cams would turn. A procedure I followed was to set the timing Mark at 10 degrees and the cams did not move at all.I transferred the markings to the rear timing belt cover. All went well.

[Nrook84]

10 degrees before tdc? Where the sprocket "settles" a little? That's what the ttz walk through says. But I'd have to put the tbelt back on and turn it all together right?

[rgregoryb]

Yes, don't turn them independently

[rgregoryb]

I was replacing the intake cam gears when I changed my belt. My cam gears were leaking oil

[Nrook84]

The throttle body was strong enough to hold without taking any damage?

[NolimitZ32]

FIRST AND FOREMOST: THANK YOU FOR SEARCHING!!!!

If you are scared of the torque required (which I can totally understand) and you have the money I would invest in a VERY GOOD electric or pneumatic impact, it'll take a while but you can hammer it off. Otherwise I've used the timing belt in place and crank locked by breaker bar method, it was still scary but it got the job done.

[Nrook84]

Thanks Nolimit, where did you set the breaker bar to lock the crank? I can't seem to see a spot I'm comfortable with. I'm going to try working through it tonight and see if I can't get these things off, I've lost too much sleep over it already!

[NolimitZ32]

I set the breaker bar with socket on the crank bolt and used a cheater pipe on it and set it against the ground under the car. Be mindful if the engine spins you could end up unbolting the crank pulley (no biggie just watch it), also in addition to all this set the car in gear (if its manual) and apply e-brake to give it as much resistance as possible. Again be very careful because if you start rolling the engine the drive-line will want to move with it. Lastly if you feel the need (or if like yours its an automatic) you can try to use something to lock the flywheel in place, you would need to remove the starter to get at the ring gear. With all this said if you have a couple hundred bucks and work on your own stuff an electric impact is a good investment. Good luck and ALWAYS REMEMBER SAFETY FIRST!

[Nrook84]

I have a 5 speed I think I found a spot for the breaker bar but I was considering dropping it back down off the jack stands so I can us the ground. Hopefully tomorrow I can make some progress.

[Nrook84]

So the crank lock method worked! Thanks guys!

Now the idler studs are giving me hell... Any tips?

[rgregoryb]

Stud puller