Timing Belt

[cessna]

I've got 79.000 miles on my  93 z34 now and was wondering how hard it it would be to change the timing belt or would it be better to take to a dealership to have installed also awhile back I noticed a entry on here about the complete timing belt kit ,belt,idlers,and all items the dealer might not otherwise install unless asked to, any help with this .....thanks 

[Galaxie500XL]

_{The first timing belt I ever had to change, I went to the local Chevrolet dealer to see if I could beg/borrow/steal the specialty tools the factory service manual described using.  I was told that they no longer had those tools.  When I asked them what they did in that case if someone came in needing a timing belt replacement, and they told me they sent them "somewhere else".}

 

_{If you're an experienced mechanic, and good at following instructions, and keeping a close eye out for the small details, there's no reason why you can't do the job yourself.  I have--twice.}

[cessna]

Thanks for the response Galaxie500xl,

 

   I here of so many horror stories from people who try to change the belt themselves,from timing issues to bent valves to broken bolts but i've been away from turning wrenchs for sometime now and tools may become a factor along with procedures on this motor, would you know of any good write up about changing this belt and possible tool list .......thanks again ................Cessna

[White93z34]

Moved to Powertrain, you'll likely get more responses here.

 

It's possible, would be easier if it was a 94-97.

 

I'm sure there are other ways of doing this but I've always done it by the book, I used a write up from 60degreev6 and the service manual when I first did it along with the proper tools. I know its possible to make the cam flat hold down tool yourself, but I don't know how I'd go about making a cog puller.

 

In my opinion the idlers, tensioners are MORE important then the belt itself. I've seen wayyy more belt failures caused by component failure then by the belt up and breaking. Hell If you are near Pittsburgh, PA I'd do it for a reasonable cost.

[cessna]

Hey white93z34.thanks for the info, I was looking at a video online about changing the timing belt with using only basic tools and marking the timing belt at each cam and crank posistions then transfering the marks to the new belt and line up, of course replacing the tensioner and idlers also  looks good just a little cautious. I need to check out the info you suggested and do a little more reading up on this so a big mishap wont happen .thanks again and I do have property in Pa near Carlisle about 2 to 3 hours away from you but really app. the offer, who knows I might take you up on it ......thanks again good buddy

[cessna]

Hey just wondering if you guys might have seen this video on quick replacement of timing belt ....what do you all think of this? 

 

www.youtube.com/watch?v=9Xv11NRc5Xg

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[cessna]

Hey just wondering if you guys might have seen this video on quick replacement of timing belt ....what do you all think of this? 

 

www.youtube.com/watch?v=9Xv11NRc5Xg

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[George]

When I did mine about six years ago I just shut the engine off, removed the stuff mounted to the pass front fender, the accessory belt and the covers. With the timing belt exposed I marked the cam sprockets and crank sprocket in relation to the block, loosened the tensioner and removed the belt. I replaced the idler pulleys, tensioner and reinstalled the belt, starting with the crank pulley and working counterclockwise keeping the belt tight and in the cogs until I got to the tensioner. I made sure the belt was tight on the sprockets, the marks made prior were all lined up and pulled the pin out of the tensioner and tightened it to the recommended preload torque and put everything back together. The confusing part for me was figuring how to drain and refill the tensioner with oil and where to put the pin.

Doing it this way still took 4-5 hrs, put I didn't hurry as it was my first time.

All the directions were in the timing belt replacement kit box.

I got a Gates brand kit for about $160

If the timing belt breaks or comes off then you have to go through the cam timing procedure, removing the upper intake manifold and valve covers, using the cam hold down tools, but if the timing is good it's not necessary. I checked and local shops wanted from $700- 1300. Ahh the LQ1, it is a love hate relationship.

 

 

Sent from my iPhone using Tapatalk

[cessna]

Hey George,

 

   Its great to here this works out, sometimes im a little weary about the u-tube videos they seem to leave out some important parts but all in all I guess it all helps in one way or the other ..quick question tho, was it difficult to fill the hyd tensioner and did you reuse your old one? im looking at replacement of belt and hyd.tensioner and idlers hopefully this week if parts come in  .This will be my first go at it and would like to do it right trying to save this car for many years ahead 

[cessna]

Ok guys here's where im at with it now waiting on parts for reinstall ....

[George]

I don't recall how you drain / compress the tensioner but I did reuse the old one and put a new pulley on it.

 

 

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[Psych0matt]

When I did my timing belt job the first time, I reused the tensioner and that failed a few thousand miles later.

[cessna]

Quick question to anyone out there with some knowledge about these motors, will they run if the belt is out of time ? I seem to have developed a mis and was wondering if the tensioner let slack into the belt and cause it to jump time a tooth or so ...any help with this .thanks 

[Galaxie500XL]

Quick question to anyone out there with some knowledge about these motors, will they run if the belt is out of time ? I seem to have developed a mis and was wondering if the tensioner let slack into the belt and cause it to jump time a tooth or so ...any help with this .thanks 

 

If they're not too far out, they should run...but before tearing into that, a more likely culprit are the plug wires.  They're notoriously delicate at the plug end, and I've broken more than one old one by simply pulling them out.  In fact, when I first bought my car, I found 3 of them that were more or less no longer connected at the spark plug terminal.  In fact, I keep a spare set of NOS plug wires just for such a contingency.

 

An "easy" way to check  would be to pull the valve covers, line up at TDC at the crank, and verify that both flats on the cam that the cam tool sits on during an install are parallel to the machined surface of the cam carrier, then rotate the engine two full turns, and check the other set to be pointed in the same way.

 

Of course, you can't pull the rear valve cover with the plenum on, so I'd cheat, and check just the front ones for now.

[Psych0matt]

After my tensioner broke I had to time at about four times and still couldn't get it right, and then I found out is because my timing marks were off. Had had I done it the correct way lining up the flats it would've been fine. It ran and it was drivable, but I got horrible gas mileage and didn't have any power

[cessna]

Great info guys, just wanted to drop in a say I drove the car about 20 miles today runs real good seems to have lost the mis not sure if the computer had to relearn or what but its running very smooth only issue now is when its hot and you shut it down it dos'nt like to restart right away with out sputtering like its starving for fuel at first then it revs up and comes back down,Im thinking that might work out too 

 

 But I must admit changing the belt without removing the plenum or valve covers was a little work, but it worked out great just make sure you mark everything well and keep the belt tight will stay in touch.................  

[Galaxie500XL]

After my tensioner broke I had to time at about four times and still couldn't get it right, and then I found out is because my timing marks were off. Had had I done it the correct way lining up the flats it would've been fine. It ran and it was drivable, but I got horrible gas mileage and didn't have any power

Same here.  I found TDC using a wooden dowel, and discovered on my first belt replacement that the mark on the harmonic balancer was off by at least 6 degrees.

[Psych0matt]

I got the tear down/replacement down to about 45 minutes (without taking off the plenum ), but again that was going by incorrect marks. I think the issue was that at that point the bottom end had been replaced so who knows how close it was between the 94-95 top half and 91-93 bottom

[Heartbeat1991]

I had the same problem on a crate LQ1.  Ran like poo.  Had no power.  I checked the belt, and everything lined up.  Even pulled the valve cover after beating my head against a wall.  Still nothing wrong.  In the end, I pulled the top end apart and got both valve covers off, found TDC using a long screwdriver, and found that none of the timing marks on the thing were correct.  I was not happy.  LOL.

[Schurkey]

when its hot and you shut it down it dos'nt like to restart right away with out sputtering like its starving for fuel at first then it revs up and comes back down,Im thinking that might work out too 

 

 But I must admit changing the belt without removing the plenum or valve covers

First Guess:  You have a typical failed intake gasket.  The symptoms match reasonably well, although I think mine ran a bit worse when cold.

 

Second Guess:  Fuel pump relay or relay control problems.  Engine won't start until it's cranked long enough to build oil pressure.

[cessna]

Hey schurkey,

 

 

 My thoughts too but I replaced intakes about 8k ago it is possible for a failure tho im going to run it awhile and see if it settles ,if not maybe back to intakes again need to seal dist. shaft housing a little better also, still have small leak noticed when I did timing belt ......thanks for the post, also good thinking on fuel relay will check that ...thanks again

[cessna]

Quick question to anyone can someone tell me what this part is or what it dose found a vacumm leak on the other end that was causing the mis  I had earliar it connects  where the pcv valve is by the air cleaner  , and I  traced it back to this valve behind the pass side behind the rear valve cover  but the wire is broken still there but the plug is missing ...any help with this.....thanks  

[55trucker]

^ I can't see it, the pic is toooooo small.....

[cessna]

whoops sorry about that  there is 2 vac lines hooked to it on the right side not shown here but they are the hard plastic lines, and a wired plug that goes into the bottom port  

[55trucker]

That little fellow is the fuel vapor canister solenoid, that tab is supposed to be fastened to the far right rear flange that the upper plenum bolt goes down into.

 

Where's the harness end?...there are two hard lines that go in & out of it that run across the rear of the plenum, one end goes back to the vapor canister at the rear of the car & the other end feeds into a splice that goes to the vacuum port on the rear of the plenum. 

 

The vapor recovery system has an affect on fuel mixture at idle & at speed, the recovery system is designed to open when at off idle to keep a no pressure situation in the fuel tank, you could be getting a stink of gas from the vehicle if any of the lines going to or coming back from the rear are open.