Would a 3400 out of a 05 rendezvous go in a 96 grand prix with a 3100 are they still pretty much the same or would the 05 be too new?
please help i have a month to get this car running

 

A 3400 is the second-worst V6 engine GM ever made, the first being the 3.4 DOHC. Back away from the Rendezvous, very slowly, so no flying bearings hit you.

it has to be at least as easy to find another 3.1, and easier to find a 3.8, to put in your car. Both of them are bulletproof engines. Do that.

 

X-2

 

Stupid question as I don't know much about GM 60 degree engines, but what makes the 3400 so much worse than the 3100? I had always assumed the two engines were virtually identical save from a few minor part differences to account for the increased displacement. That's why I found it strange you'd say a 3100 is bulletproof but a 3400 is the second worst gm v6 ever.

 

Im curious also. Im under the assumption they have the same head gasket/intake issues as one another..

I loved my 3400..

 

Well, it started with the clouds of white smoke generated by my 93 Camaro. Never had that diagnosed or repaired, because I traded it in a month after the nonsense started.

Then, in the wife's Trans Sport, the top end came apart. That was about $1200 and a week's worth of labor. While the top end was still under warranty, it threw a rod. The rod is in the bottom end, so another $2000. (Add that to the 4T60-E replacement, and the powertrain repairs equaled the cost of the vehicle.)

I had none of these repairs with the 3100 in my Beretta. The 3800 isn't even close to the same engine. They are bulletproof. The 3400 is metal garbage.

 

96z34man's commentary does not help the OP's question. I do understand why he holds his opinions based on bad personal experiences with a couple 3400 powered cars.
On the flip side, my family and friends have had a ton of good experiences with the 3100 and 3400 v6 engines. I have a friend who did nothing but oil changes to his 3400 and neglected most other maintenance. The car never had a failed intake or head gasket and he traded it in, still running fine with 257K miles on it.

But to be of some help to the OP, I believe in '05 GM may have changed the 3400. You will want to do some research on that.

You may also want to look at the PDF in this thread for some help with the swap:
https://montecarloforum.com/forum/fw...ne-swap-46706/

 

Unfortunately this engine doesn't really apply to your argument. Although the 3.4L in the camaro is the same displacement as the newer 3400 that you claim is garbage, its a rather different gen 1 engine and arguably is just as similar to the 3100 as it is the newer gen 3 3400.

I get that you had engine issues with your 3400 and a good experience with your 3100. What I'm trying to figure out is if that was just the luck of your one off experience or if there is a design difference between the two that created the issues you had (ie are there lots and lots more of the same failure mode in the 3400).

I just want to make sure we don't mislead the OP without some solid design reasons as to why it's worse. I just honestly don't think the 3100 and 3400 are all that different, at least not enough to cause them to be drastically different in reliability.

 

I can say personally that I loved the 3400. I raced it daily. I never "abused" it but I beat on it hard. I had it for years without a single problem other than the alternator.. Given after a while I upgraded parts that would have otherwise probably went bad but I put a good 100k miles on it in the harshest of conditions while it was stock and not a problem during that time..

 

Well, that right there explains the discontinuity between everyone else's experience and mine.

So you guys really, REALLY think it's okay to only get 100K out of a motor? Seriously? Do you think it's still the 80's? Hadn't you noticed your odometers had six digits?

I freely admit my problems with the 3.4 started after 100k on both vehicles. So what? I had 239 on my GTP when I killed her, and she'd be running today if I hadn't. Those are MY expectations for a piece of machinery that costs more than my parents' house.