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  • Timing Belt Need replacment?

    Borrowing ShockTherapy's topic idea:

    Attached are pictures of my timing belt. As I got the car 3+ yrs ago w/40k on it, I doubt it's ever been changed. The car has 65k now (95 Z34). I was planning to get the belt/tensioners changed at the dealer as I don't want to screw around with it myself, nor do I want to chance a shop timing it correctly.
    How does the condition of the belt look? Mileage-wise, I'm due. Wear-wise, not sure.

    ***EDIT: Click images for larger hi-res versions***





    Also, on the last pic, are the small yellow lines the timing marks? I assume in the pic that means the cams (at least the front bank) are timed correctly?

    Thanks!
    1995 Monte Carlo Z34 - 3.4L
    1980 Trans Am - 6.6L 400, 428 heads

  • #2
    RE: Timing Belt Need replacment?

    Ignore the yellow lines, they are worthless. Belt looks ok in the pics but that last pic is blurry as well. I don't go by looks alone, as I have seen much worse looking work, and better looking break. The backside could be nice like yours and the teeth could be about ready to shear off. Best to replace it, especially at that milage now and you don't know if it was changed before (doubtful anyway).

    Why not do it yourself? How much does the dealer charge for all of that?

    Hook your PCV setup back up. That is my recommendation from looking at your valve cover. The vacuum will do a better job than open air filter.
    Ben
    60DegreeV6.com
    WOT-Tech.com

    Comment


    • #3
      Ben,

      My PCV setup is still fully functional The vent vac line from the lower intake manifold is still going to the pcv valve, and the valve and 't' are still connected to the upper intake manifold port nearest the EGR valve. I had an issue w/the sh*tty plastic line that vented the front "valve cover" so I put the breather on that vent line - the rest of (and most important portion of) the pcv system is still intact and functional. I also have a breather running right now in place of the plastic line that originally went into the air intake hose....but as mentioned the PCV setup itself is still functioning. Plus my car has been like that for a year + now with no adverse effects ??? Unless someone tells me something is harmful with my current setup...then i'll change it. If not, I'll leave it as is.

      And I don't want to change the belt myself due to the lack of space and lack of experience to do it. I'd rather also just pay the money and do it right once. Unless there's a local experienced MI member willing to help me....
      1995 Monte Carlo Z34 - 3.4L
      1980 Trans Am - 6.6L 400, 428 heads

      Comment


      • #4
        Your belt looks good to me and that breather is not going to help.

        96 Z34 3.4 SC DOHC Getrag, 284 5sd manual transmission, stage 3spec clutch, 97 engine, 97 pcm, S3 intercooler 1 of 1 Roots SC LQ1 in the world 8.5 psi.

        Comment


        • #5
          Originally posted by Dave96z34
          that breather is not going to help.
          Is it actually harming anything though?
          1995 Monte Carlo Z34 - 3.4L
          1980 Trans Am - 6.6L 400, 428 heads

          Comment


          • #6
            You are running a breather where it would hook up to the intake? How are you getting a vacuum on your PCV setup? I noticed a performance loss with mine not hooked up, though im sure after a while I wouldn't notice any more from it. The vacuum helps your piston rings seal and helps keep your other seals from blowing out. While it may not be "vital" its certainly not recommended to not have a vacuum on the system. From your description that is how it sounds, even if everything else is hook up other than the intake to the hose.

            Unless you are near the indiana border, you probably don't wanna drive down here for me to do it.
            Ben
            60DegreeV6.com
            WOT-Tech.com

            Comment


            • #7
              Here's where I'm confused.
              My PCV valve is still connected to the upper and lower intake manifolds. On my car, at least, in that system was a 't' vacuum fitting. The main pcv vacuum supply was, and IS, still hooked up and functioning (at least, pulling my pcv valve vac hose to the plenum just about immediately kills the car). The 2 't'-d lines were vents from A: the front valve cover, and B:...don't know where at present, but wherever would vent air (and, at times, oil) back into the air intake arm/elbow. As both these lines were solely vents and NOT vacuum sources, I put breathers on them. Essentially what I found them to do was take the vented air and re-burn it for better emmissions.
              Tell me why SonyMan's lumina DOHC has the IDENTICAL valve cover breather on his car, among a few other DOHCs I've seen around (not to mention all those 60s/70s muscle cars with valve cover breathers) and none of our cars have imploded, exploded, or anything else yet? Maybe I just don't understand the DOHC's vacuum setup? I assumed though a valve cover breather, whether in the oil-fill cap, or on the side on a vaccum nipple (eg muscle cars, my car, etc), no matter where it is, is still a valve cover breather.
              1995 Monte Carlo Z34 - 3.4L
              1980 Trans Am - 6.6L 400, 428 heads

              Comment


              • #8
                Does it matter what other people do? If so, we can ask why you haven't added a huge wing and a larger tip out the back along with the tornado intake device and a fuel magnet.

                There is no vented air in the PCV system. The tube going to the plenum should be connected to the rear valve cover, the front valve cover, and the block cover under the lower intake. The vacuum, like I said, helps reduce the pressure inside the block from those pistons flying up and down the piston bores, and the crank spinning around like a tornado.

                You could be looking at 10-20 hp between a vacuum pump (more vacuum than the motor makes through the intake even) vs no vacuum hooked up at all. The breathers were better than no ventilation at all but pales in comparison to adding a vacuum source. You should also add a catch can with vacuum pumps, but it is also nice to filter the oil out as well running to the intake vacuum source.

                Ben
                60DegreeV6.com
                WOT-Tech.com

                Comment


                • #9
                  Besides the belt is over center some, but the belt apears good. It may need a few pullys soon, it is just that the belt shouldn't get anymore closer to the face of the cogs, if it does you need some work in there. The tensioner might be a good thing to replace the next belt change.

                  I think you got 10k miles or less.
                  I am back

                  Mechanical/Service Technican

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                  • #10
                    Originally posted by sappyse107
                    Does it matter what other people do? If so, we can ask why you haven't added a huge wing and a larger tip out the back along with the tornado intake device and a fuel magnet.

                    There is no vented air in the PCV system. The tube going to the plenum should be connected to the rear valve cover, the front valve cover, and the block cover under the lower intake. The vacuum, like I said, helps reduce the pressure inside the block from those pistons flying up and down the piston bores, and the crank spinning around like a tornado.

                    You could be looking at 10-20 hp between a vacuum pump (more vacuum than the motor makes through the intake even) vs no vacuum hooked up at all. The breathers were better than no ventilation at all but pales in comparison to adding a vacuum source. You should also add a catch can with vacuum pumps, but it is also nice to filter the oil out as well running to the intake vacuum source.
                    Ben,
                    If you say those lines are as important as they are, then I'll hook them back up. I do for a fact know you know your sh*7 about these motors. But since I've long-since misplaced the OEM lines (as well as broken part of one of them), do you know of either part numbers or official names for the pre-bent plastic lines (OEM)? Specifically the front valvecover one, and the plastic one running back into the air intake arm? I might still have them and be able to use rubber vac line over the breaks, but that just looks sh*tty and is a tacky way of fixing them.
                    1995 Monte Carlo Z34 - 3.4L
                    1980 Trans Am - 6.6L 400, 428 heads

                    Comment


                    • #11
                      They are PCV lines. I don't know part numbers, as I got lucky and used a 95 set on my 91-93 and never had a problem. The dealership should know how to look them up though. Junkyard could be your friend, though the 91-93 setup is probably easier to locate. I hate having the lines ran around the back though, way too cluttered as it is without them.

                      I would definetly go with the hard lines though. The rubber lines might close under WOT. You could use it to patch some sections but there is quite a distance for them to run alone.
                      Ben
                      60DegreeV6.com
                      WOT-Tech.com

                      Comment


                      • #12
                        I've been trying to picture the entire setup in my head (since it's so damn cold outside to look/work on the car).

                        Now, if I have this right,

                        The line running from under the lower intake (the plastic line coming from under the plenum/etc) runs to the PCV valve base connection, the valve then sits there, then the top half runs into the upper intake (plenum). Right? This is the part connected as stock right now.

                        Then by 'T'-ing into the main pcv source lines, the vacuum acts as a pull to the valve cover vent lines (currently running breathers), forcably pulling excess air/pressure out and back into the system to be re-burned?

                        I assume I have that right?

                        Now also Ben, you say
                        You could be looking at 10-20 hp between a vacuum pump (more vacuum than the motor makes through the intake even) vs no vacuum hooked up at all. The breathers were better than no ventilation at all but pales in comparison to adding a vacuum source. You should also add a catch can with vacuum pumps, but it is also nice to filter the oil out as well running to the intake vacuum source.
                        Do you mean to say that I'm actually costing the car 10-20 hp w/o the front/rear valvecover lines hooked up to the main pcv line (and only running breathers)? Or that w/a totally custom catch-can setup, etc, that I can GAIN 10-20 hp?

                        I've only grown up around performance work on classics, hence my little knowledge on common present-day emissions setups (plus MI doesn't have emissions testing, so I don't NEED to know a ton about it).
                        I just figured by venting via a breather, it's still venting nonetheless and the breather setups primarily did their job by relieving pressure, yet prevented some oil from re-entering the air intake arm, etc. I didn't know a pulling vacuum on these sources was required/more beneficial.

                        Or do I have something backwards yet again?
                        1995 Monte Carlo Z34 - 3.4L
                        1980 Trans Am - 6.6L 400, 428 heads

                        Comment


                        • #13
                          Well in that case....

                          I am going to hook up my car vacuum (12v) to that line and I can get 50 hp.

                          Or maybe that electric supercharger hmmmmmm

                          Sorry, I have nothing useful to say
                          95 MC Z34 Black
                          Running strong with new engine, transmission, brakes and suspension.

                          Comment


                          • #14
                            those plastic lines are now discontinued from gm and no warehouses have any, i know this because i was going to buy the whole vaccume harness when i got my new GTP and i found that out, and i am a tech at a Gm dealership so they really looked into it for me, best bet is a local dealer might have one in stock but i doubt it , so go to a junk yard.

                            Jake
                            GM Goodwrench Tech - GM Certified

                            1991 Pontiac Grand Prix GTP - 3.4L DOHC , 5 Speed Manual Transmission , Turbonetics 62mm turbo, Turbonectics Evolution Wastegate , Turbonetics Raptor BOV , Large Front Mount Intercooler , AEM Methanol Injection , Car is running at 11PSI currently with methanol injection.

                            Runs 13.4 In the 1/4 with a 3 second 60 foot

                            Comment


                            • #15
                              I don't know what you are losing with the valve covers only venting. Sounds like you have the block on a vacuum source so you are doing well there at least. If you take no vacuum source to anything vs the intake vacuum source on the block and valve covers vs a vacuum pump hooked up...there could be 10-20 hp in there. I don't know the total, no one has dyno tested it. I know there are large gains on V8s pushing some power, so its most likely a percentage more than a cut and dry hp rating. I do know that I could tell a pretty good difference with mine all on breathers vs hooking it all back up properly.
                              Ben
                              60DegreeV6.com
                              WOT-Tech.com

                              Comment

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