93GTP Posted September 7, 2005 Report Posted September 7, 2005 I'll start by talking about the background of the car. Its a 92 Z34 5-Speed that I bought a few years back with the intention of using it as a parts car in converting my GTP into a 5-Speed. The owner of the car didnt know why it wouldn't start anymore only to say something was jammed up in the ring gear causing the motor not to be able to turn over. Obviously I didn't agree with this assessment but whatever, I didn't care about that because I was just after the gearbox. Out of curiousity, once we got the car home, we popped off the timing belt inspection cover. About a week ago the 5-Speed swap finally began with the removal of the cradle from the Z34. That went about as smoothly as I had anticipated ending with the car slipping off the jack and falling to the floor. So with the engine and transmission out of the car, we started tearing down the motor to further inspect the damage. Our first move was to remove the timing belt cover. The timing belt had wrapped around the intermediate shaft sprocket 4 times and bound up solid, explaining why the motor could not turn over. We pulled, pried and ultimately used a propane torch in a futile attempt to remove the bound up belt. When we determined that this was hopeless, we then attempted to remove the sprocket itself. Upon removing the retaining bolt, we noticed the sprocket was off-center, it wasn't too long after this that we figured out what had actually happened: The final remains of the belt: Anyways I just thought I'd share, this is the first case I know of of a timing belt failure causing an intermediate shaft to shear off. :shock: Quote
digitaloutsider Posted September 7, 2005 Report Posted September 7, 2005 Ho-ly.. shit.. [runs off to change his timing belt] Quote
Guest Anonymous Posted September 7, 2005 Report Posted September 7, 2005 Looks like the old 3.4 in my car :shock: Quote
havikx Posted September 7, 2005 Report Posted September 7, 2005 i'm surprised it wouldnt start. i'm so glad i just had mine changed. very happy. i may need some parts off that 3.4 so dont break anything thats not broken. Quote
JoroCorona Posted September 7, 2005 Report Posted September 7, 2005 Whre are you located and how much do you want for th interior of that thing? Quote
Bandit Posted September 7, 2005 Report Posted September 7, 2005 Seriously, if you are thinking of stripping and/or selling that thing, I got dibs on the intermediate shaft! Quote
5speedz34 Posted September 7, 2005 Report Posted September 7, 2005 Are you swapping that motor into your GTP? I thought your just putting the 5speed into it. I remember when you posted that you picked that up back on EFI-Street. It's nice to see you've come back. Quote
Stevo Posted September 7, 2005 Report Posted September 7, 2005 omfg! Thats nasty. On a positive note. When I installed my water pump I did an inspection of my timing belt and it's like new. Quote
DaveFromColorado Posted September 7, 2005 Report Posted September 7, 2005 ... how much for the hood, bumper cover, grille, signal lights (behind the grille), and the lower skirting on the bumper cover? ... I think I'm gonna change my t-belt here REAL soon. --Dave. Quote
jeremy Posted September 7, 2005 Report Posted September 7, 2005 Moved to the Powertrain Section. Also, If you are going to part out the car please start a thread in the F/S section. Quote
GP1138 Posted September 7, 2005 Report Posted September 7, 2005 Awesome! Sounds like NOHC saved those people at the dealer a lot of headache. Quote
digitaloutsider Posted September 7, 2005 Report Posted September 7, 2005 Awesome! Sounds like NOHC saved those people at the dealer a lot of headache. That thread was great! Quote
bartonmd Posted September 7, 2005 Report Posted September 7, 2005 ... is that a broken crankshaft I see?!?! Mike Quote
93GTP Posted September 7, 2005 Author Report Posted September 7, 2005 No, it is the intermediate shaft that is broken, it is a dummy camshaft that drives the overhead cams. In a pushrod motor it is the camshaft. Quote
Afubar Posted September 8, 2005 Report Posted September 8, 2005 I am so thankful, out of all the dumb things I've done in my life, not changing a timing belt, isn't one of them. That's just plain scarey. :shock: Quote
Canada Posted September 9, 2005 Report Posted September 9, 2005 Just like on your typical pushrod engine......the 3.4 has a timing chain that is driven by the crankshaft that drives the blank camshaft (does it have lobes on it?) which then drives the timing belt. You see, GM is cheap....and they wanted to get this engine out soon. So instead of making an all new one....they bolted DOHC stuff to a pushrod engine. However, you still need to drive an oil pump (which the blank cam drives a blank distributor to drive the oil pump). So all they literally did was bolt a set of DOHC heads down and put a gear on the end of the cam. Nice, eh? What is the recommended interval for changing you timing belt on this engine? 30k? Quote
5speedz34 Posted September 9, 2005 Report Posted September 9, 2005 Just like on your typical pushrod engine......the 3.4 has a timing chain that is driven by the crankshaft that drives the blank camshaft (does it have lobes on it?) which then drives the timing belt. You see, GM is cheap....and they wanted to get this engine out soon. So instead of making an all new one....they bolted DOHC stuff to a pushrod engine. However, you still need to drive an oil pump (which the blank cam drives a blank distributor to drive the oil pump). So all they literally did was bolt a set of DOHC heads down and put a gear on the end of the cam. Nice, eh? What is the recommended interval for changing you timing belt on this engine? 30k? Recommended is 60k but most people don't change them till 80k. About the Intermediate. It is blank except for the bearings on the block that it rides on, which makes me wonder how those even get oiled. Some people have said that they have seen lobes on it and others haven't. Also, 93GTP, do you think it could've broke because because you where so much force onto the intermediate shaft and not taking the bolt out even? Quote
93GTP Posted September 10, 2005 Author Report Posted September 10, 2005 No it definitely broke because of how the timing belt wedged up between the intermediate shaft sproket and the front cover of the engine (timing chain cover). You would not believe how badly it binded up. About the intermediate shaft...it is a blank with no lobes. I have seen the one in my 93 GTP and last night the one in the Z34 motor as well. I have it on a stand and torn down to the block now. Today I'll get the base pan off and check out the bottom end. So far everything looks good aside from the intermediate shaft. Does anyone have parts from a DOHC? I'm trying to find an intermediate shaft because I plan on rebuilding this engine. Quote
Psych0matt Posted September 10, 2005 Report Posted September 10, 2005 once I pul;l my engine out Ill probably part it out. I'll let you know when that happens, though probably not for a couple months Quote
93GTP Posted September 11, 2005 Author Report Posted September 11, 2005 About the Intermediate. It is blank except for the bearings on the block that it rides on, which makes me wonder how those even get oiled. It gets oiled the same way the cam does in pushrod versions: the block has oil galleries machined into it where the bearings are for the Intermediate Shaft. The bearings have holes in them that have to be in line with the galleries (obviously). Quote
88Regal Limited Posted September 13, 2005 Report Posted September 13, 2005 Holy shit! :shock: :shock: :shock: :shock: Besides the lack of power, I now love my pushrod powered 2.8 even more! No shitty ass timing belt! yay! And BTW, before I get flamed, I know the timing belts are prone to snap, and to change them every 60k, and its no all that hard. But I really dont want to get off my lazy ass, so I'll stay with pushrods for the time being. Quote
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