What do I do?

[jthueter]

Hi everyone!
I am a new member and Just joined today and have limited knowledge of these DOHC engines. Here is my problem, I have a stock '96 Monte Carlo Z34 that has been sitting for about 3 years. The reason it was parked is because while driving one day I suddenly lost power and could not figure out what was going on. I was on my (long) driveway leaving so I immediately turned back and shut the car off. I took it to a mechanic to have it checked to see what was wrong. At the time I was 17 and knew very little about cars. The mechanic said that I had shredded the timing belt and needed a new engine. They said that 1 cylinder had no compression, another had very little and the other 4 were fine. (Could this engine be salvageable?) That was that I parked it and got a very cheap beater to drive and would worry about it later. Last summer I really wanted to get the car running again and convinced my dad to get it fixed. He looked around for engines and finally found one for a good deal. Heres the problem the engine is rebuilt but is a pre-96 engine and has multi-port fuel injection instead of what I needed (Sequential port fuel injection). As of now that is where I stand. Can the engine that is (possibly) blown be rebuilt? If so how much would something like that cost? What can I do with the rebuilt one I currently have sitting in my garage?
I live in the Upper Peninsula of Michigan (way in the sticks) but plan on making a few trips towards chicago this summer. Is there anyone in that area Who may be able to help me with engine work or possibly the right engine. My dad warns me that when the car gets a new engine i will have other problems...the tranny has been sitting and he explained that transmittions dont sit well...or something. Anyways this summer I have a bit more money and want to get the car fixed and would love any input you guys could provide for me.
Thanks, Jim.

[1988GTU]

Have you or your dad done a compression test yourselves? I think the mechanic was trying to pull some wool over your eyes because if one valve is crushed, then atleast half of the remaining valves should be crushed too. Never heard of your situation unless a headgasket popped. IF you do have lack of compression after YOU test it yourselves, then it's worth just to pull the heads and have a look see. You might get lucky and only need one head or some replacement valves (With supporting parts) . You dont want to convert to the older design TDC, they have less power and would require some work to get it to run right with your obd2 (tune, sensor, cooling system etc etc) .
Also, how did the guy do a compression check on your car? Did he replace the belt or turn the cogs by hand? Seems fishy.

[jthueter]

My dad and I have NOT done a compression test ourselves. We have some mechanical know how but have never done much with engine rebuilding due to lack of resources (machine shops) and lack of garage space. We do however have an engine stand and cherry picker in hopes of one day performing a rebuild. Anyways being it was 3 years ago when I, not my dad, talked to the mechanic I was dumb (only 16 years old) and didnt pay close attention to what he was sayin. He also didnt think I was the smartest bulb and just plainly told me Ill probably need a new engine. I am not sure weather he tried turning over the engine by hand or not. As for the older gen engine I had no intention of even trying to put that engine in the car. I was hoping I could somehow barter the older engine for a new one but that seems nearly impossible given my location. My dad says there is a great possibility all I would need is new heads but once again...how do I tell? and where would I find them?
Thanks again, Jim

[3100 MPFI]

I would do the compression test yourself first of all.

Next, there is 3 different designs of the 3.4 DOHC. 1991-1993, 1994-1995 and 1996-1997.

You do not want a 1991-1993. You can use a 1994-1995, but you will have to swap out some minor parts. A lot of people install the 1996-1997 intakes onto the older ones to get the more power.

You can take a 1991-1993 and make it into a 1996-1997, but it is a lot of work.

If the replacment engine is at least a 1994-1995, then I would say to get it, and swap the intakes and the EGR. There is a lot of people that are converting their 1994-1995 ones to OBD2 which is basically the 1996-1997 one anyways.

[jthueter]

Ok, So the rebuilt motor I actually bought may be able to fit. Of the three motors I am not sure weather I purchased a 91-93 or a 94-95. I know it is not a 96-97 because when we went to swap motors the rebuilt one we purchased did not have a cam sensor hole drilled on the front of the heads. Did the 94-95 series have places for a cam sensor? If not the motor I have may work right?

[3100 MPFI]

yes, the 1994-1995 has the cam hole. The 1994-1995 is SFI. The only difference is the upper intake, and EGR and minor things to the fuel rail, etc. If it does not have the cam sensor, then it is a 1991-1993. You could probably swap out the front cam carrier to get the right one, but I think there were some changes so you would have to swap in the back cams as well.

This is the 1994 3.4 DOHC that is in my 1995 Cutlass Supreme. You can see how it has the sensor.

[walterdude]

Nobody has suggested finding out what is wrong with the engine that's already in the car??? I AM surprised!!
Most mechanics are scared of these engines, they don't understand them so, they don't want to get involved with fixing them and they tell you the worst case. Your mechanic sounds like just such a case. If a belt shredded, broke or jumped timing I don't see how it is possible to even check the compression. You NEED to have the valves in the correct phase (or at least closed) to be sure of an accurate reading. I can't picture him pulling it apart enough to turn the cogs by hand, for each and every cylinder,,, could be wrong, of course.... You don't mention any BAD noises as this was happening,,, I imagine pistons whacking valves would make considerable noise.... Not sure if this year is an interference engine or not. It doesn't sound as if you were abusing the car when it happened... I'd say your probably safe if RPMs were low,,,, most reports of valves hitting seem to have abuse and HIGH RPMs involved......
The first thing I'd do is pull one of the little covers from around the cam cogs and look in there with a flashlight. If the belt is shredded or broken you WILL be able to tell... If the belt IS shredded it might be worth it to take it step by step and figure out if you want to try to save it... I WOULD, but, what do I know?!?! You just might be able to get it going for just a couple hundred bucks, possibly less....

If you really want to spend some money check this: http://www.car-part.com/
There are a few near you that look pretty good, with low miles and a good price... I'd stay away from the 100,000+ mile engines tho....

It's your call, but, if it was me I'd HAVE to find out just what failed or I'd NEVER be able to sleep!!! Especially if it's as easy as pulling a cover and looking!!! As far as actually fixing it,,,, well,,,, you're the one that knows what kind of shape the car is in, how many miles it has and what else it will take to fix it...
Look at the timing belt and post what you find, someone will be able to help....
Try posting the pre 96 engine in the buy/sell/trade section if you don't use it.... I'm sure someone could tell you just what you'd have to do to use that engine, all 3 mount the same and you have the engine that's in the car for the parts you might need,, I'm sure it's possible, but I really don't know what is involved....
Tom.......

[3100 MPFI]

several people have said to run a compression test to be sure.

As for me, when I hear only 1 cylinder has compression, this is what runs through my mind.





This is the reason that I have swapped a 1994 engine into my 1995.

We have said for him to test the compression, and that will let us know if it is worth looking into. If 1 cylinder is dead, it might not be WORTH fixing. If all 3 are dead, then I would say check the timing belt.

[1994KlrWhaleOlds]

This is the reason that I have swapped a 1994 engine into my 1995.

That and the '94 engine was free...

[jthueter]

I am definitely gonna tear into this engine to look for any damage. Here is my recollection of what happened. I was Exiting my driveway and started down the road very mildly (low RPMS) and then...Loss of power "what the hell is going on?" I turned around and limped down my driveway and up a small hill to the pad in front of the garage. There was almost no power and I could definitely tell it was missing... Kind of like chugging. There was no loud clinking or knocking...no sound of metal on metal contact. 2 hours later to try to decipher the problem my moms boyfriend...(not my dad) tells me to try to start it. I ask are you sure it will be ok? He sais well we have to figure out the problem dont we. I tried starting it and after about 3 tries turning it over it starts and runs for about 10 seconds before dying. Thats it. Took it to the shop and they said new engine because of shredded timing belt. The timing belt was removed by them and was no good. They gave me the car back with the timing belt cover off and the head cover off.
Now having sat for 3+ years(out of sight, out of mind) I see a bit of surface rust on the cams and dont know enough to tell weather this is drastic or manageable. I am going to remove the engine from the car and check for wear on the heads, valves, seats, block and pistons to see how bad it is. Hopefully I can get to this by the end of next week. I am super busy...but I also have found a used engine with 55k for around 700 that I could pick up. Im thinking Ill pick that one up and look at the one I have and if it is ok, keep it for the future.
Jim.[/I]

[SappySE107]

http://realfierotech.com/phpBB/viewtopic.php?t=13695

[jthueter]

Well guys I have found a 97 engine and trans (the 4t65e trans is beefier right?) that are used with just under 60k. It will cost me about $1100 for the set but I would add a new timing kit, and maybe gasket set, before putting it in the car. Will I be able to replace the transmission and engine as it sits now (without replacing transaxles or reprogramming the computer)?

Sorry for repeat questions I know I have read thousands of posts between here and mymonte.com and I am sure the questions have been answered but I would like the reassurance. After putting in the 97 setup, I plan on rebuilding the engine currently in my car, possibly with more power in mind, pending how much damage there is. If there is a cracked block then i guess that idea is gonzo, but if there are bent valves and I need new heads or head work done Im sure I can find someone on here to help me

Thanks guys for all your help. Hopefuly, someday I will be able to rank higher than NooB and maybe help some people on this forum.

Thanks, Jim

[bszopi]

Can't run a 4T65-E without a standalone controller. It is a fully electronic tranny, which AFAIK was never offered with the 3.4DOHC, so the PCM doesn't have any provisions to run it.

[SappySE107]

97 3.4 DOHC has it so you need that computer and add the wiring it needs.

[bszopi]

I guess he did say he found the engine/trans as a combo, so that would mean it was available. I knew it came out in 97, I just wasn't sure it was ever mated from the factory with the DOHC. And now I know...