Hey Gang, Thought you guys out there with with Z-34s with the 3.4 DOHC might want to take a look at this info. Im currently rebuilding my Z and I had this to share. This is SOOOOOOO Important if you are going to attempt a timing belt on this car! You will need the cam hold down tools. I made my own out of 3/8" thick steel stock cut to fit into the heads with a hole drilled to bolt it in place over the Cam Flats (See Photo #4) you will need 2 one for each head. You will also need to loosen the cam sprockets and will need the sprocket holder ( I made My own) as the cams are not keyed and they need to rotate with the cams locked while setting the belt. I also have diagrams on how to set TDC.( Photo# 2) Not the best copy but its legible. You will need to get the procedure for setting the cams from a reliable source like "All Data" -"Mitchell" & Not from just some dude who posted it on the web. I will not even post the whole procedure here as it's detailed and I wouldn't want to make a posting error that causes someone a problem. Someones typo on the web could be your engine failure.( Also Very Important, DO NOT assume any marks there are correct). In fact just ignore any marks on the sprockets and start from square one. The procedure is Crazy, and I'd like to meet the engineer that designed this. (Id snap his dial caliper in half) Hope this helps if your going to go at it yourself, but I warn you, this is not a job if your not 100% sure you have the know how. If you get it wrong the car will either Not run, run like poop, of even worse, you can crash a valve or two. I am ( And I recommend you do the same) Replacing every Moving Part in The timing Chamber Including, Belt, Tensioner Pulley, Tensioner Actuator, Both Plastic Pulleys, And dressing all the Steel Sprockets to make sure there are no Burrs on the ribs. Also Be sure to clean out the timing chamber well so there is no dirt or grease present. I used a bunch of brake clean in there before i put the new components in place.(See photo#5 Notice how clean the chamber is) Also Clean the inside of the plasitic covers as well. Any dirt or grease on the belt or other parts will ruin the belt. So make sure its all clean and dirt and grease free. If you dont do all this you will just tear up the new belt in no time and the timing will never be 100%. you will have lack of power and a lousy idle as well. Plus while the plenum is off you may as well change the plugs, they have to be removed anyway, wires and the PCV. And Inspect the heater hoses too now that you can see them.(See Photo #3 on Fire Wall at the back of Rear Cylinder Head by The Throttle Body) If you have over 100K just put new hoses in, you will be glad you did. I will keep you all posted as to how the Z runs when Im done Gary. (Updated Info Below)

As A Tech by Trade I am using the best quality parts. The following Part#s are For Car Quest And the Dealer. Car Quest's house brands are "Quality Name Brand" Parts and sometimes even OE. Here is the Parts list for doing this job correctly. (Have Some $$ to spend when you do this). My Z is a 1996, The timing Parts should be the same for 1995-1997 But confirm these #s based on the year your working on.

1ea. Timing Belt (Goodyear) Car Quest PN# T-273 (Made In USA)
1ea. Tensioner Assy. (WPC) Car Quest PN# A5030169675 ( Bearing Japan/ Assembly Korea)
2ea Idler Assembly (WPC) Car Quest PN# A5291169677GMB (Bearing Japan/ Assembly Korea) Comes with With New Bolt
1ea. Tensioner Actuator (GM) GM Dealer PN# 2450-3860 (Made In USA)
1ea. Lower Plenum Gasket Car Quest PN# MS 16317 ( Made In USA / Felpro) This # is for 1996 (confirm this# if you have a different
year)
Locks and Washers may need replacement if Cam Bolts were Over torqued during prior service.

You Will Need The Special Tools for the procedure. If your going to keep your Z and plan on doing your own belts, I recommend getting the Timing belt service kit. The best deal on this kit which has the Cam Holders, Sprocket gear Holder, And Puller is available from sjdiscounttools.com It costs $270.32 and its about the best deal on the kit unless your lucky enough to find a Tech that has givin up on doing these types of jobs and you get it used (Good Luck There) I have the Machines and a welder so I made my own. My home made tools for this aren't pretty but they get the job done. Do Not and I repeat Do Not just throw an Air Rachet on the cam bolts to loosen or tighten them. I have seen guys do this and then came to me to help them fix the mess.

To get the "correct" procedure I recommend using All Data which has really good step by step procedure and torque specs.
Photo #5 shows all the new components in place and ready to activate the actuator and set the cams.
After the belt is set and cams are timed, Especialy if you had belt failure, Be sure to turn the crank through and make sure there is no interference and run a compression test to make sure you dont have any bent valves. If you have interference or low compression in one or more cylinders, Something is wrong either the belt is not set right or there is valve damage, then its time to take it all back apart and pull the heads. Thats the fun of owning one of these cars!

So Take your time, read the procedure, check and double check every step you make. You have only One chance to get it right!

I have not purchased the valve cover gaskets yet, When I do I will post the PN#s. Hope this helps you out. These items are just MY recomendations, There are other options, But I believe the above is the best bang for the buck. Now you can understand why very few shops will even do a belt on this engine and the ones that do charge $800-$1000 to do it right. So if your good with tools and know your stuff, the investment in the tools needed will save you big time down the road.

 

Thanks for sharing! That's great info for all the 5th gen Z34 Monte owners out there.

 

i have a ? im doing my timing belt right now and the manual is not to clear on this motor
i have exp rebuilding motors but not this one. my ? is im looking in the cam chamber and at tdc the 246 cylinders cam's have the flat tool installed , now if i rotate 360 deg
the 135 cylinders cam's will have the flat. is this correct ?? the motor will run but will sometimes back fire when starting but when started it will run just fine . i also ,,, to installed a new crank shaft with new bearings and tested the clearance and all was good. but i need to know about the timing a little more and thanks for the post.
3.4 dohc motor was locked up when i bought it ( owner said it was a starter ) but it only has 70 k miles on it so i thought i could at least use the block , so far starts up but i need to get it right and get it tight thanks for any help on this matter in advance

 

well i found some info on the web and it seems i had the timing correct
and i just needed to get some new vacuum hoses put in the right place
but i still had a miss fire so i pulled up the boot on the spark plugs and found cly no 3 had no fire so i felt the injectors and 3 had no tick to it
so i got a wrench and gave the injector a light tap and boom miss fire gone
now the car runs perfect and now it's time to get a beer and relax from this
head-ace . thanks again for your post.

 

Hey Buddy Im sorry I missed your post. You had the timing right. Its a fun procedure for sure. It will make you second guess yourself. Im glad you got the backfire problem solved. I was thinking you might of had a bent valve causing the compression stroke to leak back into the intake. Im glad it wasnt that. Glad to hear your LQ is running Perrrrfect!

 

i would usually never say this doing the 3.4 timing belt for chevy and doing one for acura. the 3.4 is so much better than the 3.5l motor from acura. its like day and night big difference. when i did my first 3.4 z motor i thought it was going to be a headach but it was straight forward like you posted thank you for posting what you did.

 

Its like anything else. After you get trough it the first time, its not so bad at all. Just attention to procedure and small details make the difference in the outcome of the job. Thanks for your reply! G

 

Hello,

I have a 1996 Monte Carlo Z34 .I saved it from being junked. It had some wires cut out under the dash from where a alarm was hooked up. I got some wiring harness pieces from the local bone yard and it turns over now but will not start..It fires but it seems out of time to me so will start the diagnosis process. I changed the fuel filter already and the fuel pump seems to be working. I will post pictures later! Thanks Roy

 

Thanks for the reply Roy, Start with a good old compression test. That will tell you if you have a Timing belt problem. Good luck with your Z. I just tore the heads off mine and was going to add to my thread here but it got to be a big job.

 

Here is some pictures of the Monte Carlo Z34 that I saved from being scrapped at the local junk yard. Its hard to believe that a clean car like this
was being junked but I guess they are intimidated working on the DOHC. I got the car with a clean title and it has 107K on the car . Not much rust or problems to the body that I can see.

http://s391.photobucket.com/albums/o...20Carlo%20Z34/

Roy
Wisconsin