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Guys....first, a MAJOR thanks to this list and all the advice I got from it. Hopefully I have been able to help others (or will) as much as I have been. Sappy, 3100MPFI, Chris GP, etc.....all are called out for special thanks!
Anyhow, here are the final (hopefully) results from my 3400 DOHC swap. A quick refresher....
I have a 1995 Lumina that had a 3100/4T60E combo. At 285K miles, the cam snapped in half due to trashed cam bearings. I used Mobil1 since I got the car, and other than the cam bearings.....she was immaculate. WHile I could have easily replaced this engine with a 3400 I had laying around, the 3.4 DOHC was a much more intrigueing choice. The engine/harness/PCM I had was for a 1996, so I assumed I would be able to reuse my current trans and such. I could have....but.....I could not find a tuner package for a 96 computer, but I could for the 97. So, I changed the year to a 97
New harness and PCM took care of that issue....but now I had to swap a 4T65E in, as that is the trans in the 3.4 DOHC cars of that year.
For the engine, I replaced all the timing components hoses, belts, accesories, plugs, wires, etc..... I used Mobil1 in the engine, synthetic PS fluid, and Dexron VI inthe trans. I also installed a spacer shift kit in the trans.
My first attempt to fire it up resulted in it running.....like a big turd. Major miss, running rich, etc. After a bit, it wouldn't even run. It would always start fine, run for about 2seconds, start stumbling....and die. I checnged out the fuel rail/injectors for a brand new set....no luck. After going through all the diagnostics.....I narrowed it down to a bad PCM. Popped in the 96 I had laying around, and it ran great. Sooo.....I ordred a new 97 computer, which took 2 weeks to show up (grrr....). HOWEVER, in the meantime.....I also found that the front cover had a crack inthe coolant passage. Off came the timing belt (in the car!) and I JB Welded it up. So far.....so good... I am running some stop leak in the coolant as well, so hopefully this is good enough. I did have to shim one of the idler puleys in the timing setup though to clear the repair.....so far so good there too. Timing belt is running about 1/8" from the end of the cam pulley....so I'm good. I now have a replacement cover which I recently beadblasted and clearcoated......so when I get inspired, I am going to put it on. What a PAIN!
Anyhow, once the new PCM showed up (last Friday), I plugged it in, started it up...and brought it up to temperature. Wow! That thing sounds nice! I checked all the fluids, for leaks, and all that.....and it was good. Drove it in and out of the driveway/garage, around the block, around the city a bit more, then around a loop that included highway. ALL is good!! WooHoo!!! So, this Sunday, I took my first long drive....to my P's for mothers day. Made it there no problem, but I popped the hood to make sure everything was looking good....and I noticed the main harness off the C100 connector had moved and was rubbing against the P/S pulley! Doh! The loom was worn through, and a couple of wires had copper showing as the insulation had worn down. I don't know how it didn't short out....but it didn't. I moved the harness over, and repaired it when I got home last night. All is good....
Now, I just need to figure out a way to get the damn rear O2 to start sending usable data to the PCM to put the MIL ight to rest once and for all. I tried the doubled up anti-foul thing, and now am down to one anti-fouler and I am still getting a non-repsonsive O2 reading P code. I am going to ditch the antifoul thing tonight and see about running it right in the exhaust stream.....but I think that may be too much and I'll get it TOO responsive. Once I get the tuner software, I am just going to shut the damn thing off....unless I pop for a new converter
Drove it to work today with no issues at all. Runs nice and smooth....
My comments on this motor are:
- Idles smooth as silk. I could almost balance a house of cards on this thing while it is running and have no problems.
- Top end....pulls like a bat out of hell! Seriously, from 60-90 goes by fast!
- Conversely, bottom end feels marginally better than my old 3100. I can spin the tires from a 5mph roll though....so it defainitely has more power.
- TBD as far as mileage goes. I have been on the throttle a lot more than I normally would be, so I tend to think this tank willbe my worst case scenario. Has to be better than the 17mpg avg in my Trailblazer though
- My stock downpipe is 2 1/2" and I have it neck down to 2.25" and then 2" to mate to the stock rear exhaust system (seriously.....2") I think this may be a bit restrictive (even with no Cat) as I hear a "wooshing" sound over say 4000rpm. Sounds like a restricted exhaust
So, so far initial (200miles or so) reaction is good. I like this motor.....but it was a LOT more work than I thought it would be. Granted, I wanted to do this all factory....and not rig antyhing, so I had a lot of changeover to do. Simple things like even heater hoses, trans dipsticks, etc all needed to be changed, in addition to things like a unique driver side halfshaft, rewire, and of course the engine/trans.
Any suggestions as to a decent, inexpensive (ie not Borla) exhaust for this car that is halfway decent? I think a full 2.5" system would work best.....
Again, if anyone has any questions about any part of this, let me know. MUCH thanks to everyone again!!!
Larry
Anyhow, here are the final (hopefully) results from my 3400 DOHC swap. A quick refresher....
I have a 1995 Lumina that had a 3100/4T60E combo. At 285K miles, the cam snapped in half due to trashed cam bearings. I used Mobil1 since I got the car, and other than the cam bearings.....she was immaculate. WHile I could have easily replaced this engine with a 3400 I had laying around, the 3.4 DOHC was a much more intrigueing choice. The engine/harness/PCM I had was for a 1996, so I assumed I would be able to reuse my current trans and such. I could have....but.....I could not find a tuner package for a 96 computer, but I could for the 97. So, I changed the year to a 97
New harness and PCM took care of that issue....but now I had to swap a 4T65E in, as that is the trans in the 3.4 DOHC cars of that year. For the engine, I replaced all the timing components hoses, belts, accesories, plugs, wires, etc..... I used Mobil1 in the engine, synthetic PS fluid, and Dexron VI inthe trans. I also installed a spacer shift kit in the trans.
My first attempt to fire it up resulted in it running.....like a big turd. Major miss, running rich, etc. After a bit, it wouldn't even run. It would always start fine, run for about 2seconds, start stumbling....and die. I checnged out the fuel rail/injectors for a brand new set....no luck. After going through all the diagnostics.....I narrowed it down to a bad PCM. Popped in the 96 I had laying around, and it ran great. Sooo.....I ordred a new 97 computer, which took 2 weeks to show up (grrr....). HOWEVER, in the meantime.....I also found that the front cover had a crack inthe coolant passage. Off came the timing belt (in the car!) and I JB Welded it up. So far.....so good... I am running some stop leak in the coolant as well, so hopefully this is good enough. I did have to shim one of the idler puleys in the timing setup though to clear the repair.....so far so good there too. Timing belt is running about 1/8" from the end of the cam pulley....so I'm good. I now have a replacement cover which I recently beadblasted and clearcoated......so when I get inspired, I am going to put it on. What a PAIN!
Anyhow, once the new PCM showed up (last Friday), I plugged it in, started it up...and brought it up to temperature. Wow! That thing sounds nice! I checked all the fluids, for leaks, and all that.....and it was good. Drove it in and out of the driveway/garage, around the block, around the city a bit more, then around a loop that included highway. ALL is good!! WooHoo!!! So, this Sunday, I took my first long drive....to my P's for mothers day. Made it there no problem, but I popped the hood to make sure everything was looking good....and I noticed the main harness off the C100 connector had moved and was rubbing against the P/S pulley! Doh! The loom was worn through, and a couple of wires had copper showing as the insulation had worn down. I don't know how it didn't short out....but it didn't. I moved the harness over, and repaired it when I got home last night. All is good....
Now, I just need to figure out a way to get the damn rear O2 to start sending usable data to the PCM to put the MIL ight to rest once and for all. I tried the doubled up anti-foul thing, and now am down to one anti-fouler and I am still getting a non-repsonsive O2 reading P code. I am going to ditch the antifoul thing tonight and see about running it right in the exhaust stream.....but I think that may be too much and I'll get it TOO responsive. Once I get the tuner software, I am just going to shut the damn thing off....unless I pop for a new converter
Drove it to work today with no issues at all. Runs nice and smooth....
My comments on this motor are:
- Idles smooth as silk. I could almost balance a house of cards on this thing while it is running and have no problems.
- Top end....pulls like a bat out of hell! Seriously, from 60-90 goes by fast!
- Conversely, bottom end feels marginally better than my old 3100. I can spin the tires from a 5mph roll though....so it defainitely has more power.
- TBD as far as mileage goes. I have been on the throttle a lot more than I normally would be, so I tend to think this tank willbe my worst case scenario. Has to be better than the 17mpg avg in my Trailblazer though
- My stock downpipe is 2 1/2" and I have it neck down to 2.25" and then 2" to mate to the stock rear exhaust system (seriously.....2") I think this may be a bit restrictive (even with no Cat) as I hear a "wooshing" sound over say 4000rpm. Sounds like a restricted exhaust
So, so far initial (200miles or so) reaction is good. I like this motor.....but it was a LOT more work than I thought it would be. Granted, I wanted to do this all factory....and not rig antyhing, so I had a lot of changeover to do. Simple things like even heater hoses, trans dipsticks, etc all needed to be changed, in addition to things like a unique driver side halfshaft, rewire, and of course the engine/trans.
Any suggestions as to a decent, inexpensive (ie not Borla) exhaust for this car that is halfway decent? I think a full 2.5" system would work best.....
Again, if anyone has any questions about any part of this, let me know. MUCH thanks to everyone again!!!
Larry
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