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341 Posts
Fist I want to thank all those who have posted various advise.
So I'm just about done with my 2001 AWD Astro LT swap to 5.7 Vortec. It's not a trivial amount of work but the other day I started it up and it purrs like a kitten :0) I had a bit of trouble that I initially attributed to not getting the distributor installed properly at tdc. Problem really was that after installing the v8 programmed computer, I had to have it "learn" the passlock code from the steering column. Who woulda thunk?
I'm going to elaborate over the next few days but wanted to point out a couple of things I had not read on previous posts. I was able to get a $200 Canton Racing 8qt pan to fit by beating it to submission to clear the front diff and cross tube with a reasonably heavy hammer. I don't have the part number on hand but I ordered it from Summit Racing and made sure it had a passenger side dipstick provision and was "4 x4". Again, beating it with a hammer a bit and packing three washers behind the tops of the JTR mounts to raise the motor just a tad gives me enough clearance (just). Also prevents the need for clearancing the frame around the RHS manifold (just).
I did all the work solo with no assistance really needed, just be VERY careful lifting the van up to pull the subframe. I could not get jackstands anywhere close to helping out and I ordered 12 Tonners just for the job. They would barely reach the running boards and were only really there for redundancy should my rigged-up supports fail. I ended up using two steel bars with the subframe mounting bolts to key 'em into the chassis and relied on biasing the load to the rear wheel chocks to support the van as I wheeled out the subframe. Kinda like an A-frame i s'pose.
Bleedin' transmission electrical connectors - arg. the primary one is glued- in, don;t try and pry it off the PRNDL switch like I did, the wsitch housing will break before the connector comes out. As I learned. doing it again, I'd either heat the connector and/ or lube it up with something non corrosive to plastic of course.
Wasn't expecting the oil filter housing to be such a pita. I wound up sourcing and pulling a oil filter adapter from a 96 impalla SS which fits like a glove and allows the re-use of the 4,3;s oil cooler lines just by removing the stud from the SS oil filter housing. V6 oil filter adapter will not work.
The motor I used was allegedly from a 30k mile 2002 Express 5.7 but I'm pretty sure it's a 96-98 L31 from a pickup. I replaced the intake gaskets which were already bad and the motor other wise seems fine. I put in the SEFI update (get the newer spider assy from amazon btw) and put in the newes GM intake gaskets which will outlast the rest of the van I'm sure. new plugs dist cap /rotor of course, orig ht leads seem fine so I am using them.
So how does it drive I hear you ask? Well it doesn't, well not yet. See, I was so focused on the mods, wiring, mounts, pan etc that when I pulled the V6 off the trans, I left the torque converter attached to the flexplate. Being an idiot, I assumed it would line up with the new trans if I lined up the dog-ears on the TC in the same orientation on the 5.7 as from the 4.3. Well let's say that wasn't my best idea ever. :banghead: Take a few mins and watch a torque convert installation procedure vid on you tube… 5 mins will save you a couple of days.
So after finishing up and getting the van running, installing my new 1" core radiator and dual flex-a-lite fans, routing the dipsticks etc, I dropped the van off the stands and fired 'er up for a ride. Alas no gears were to be had. I spent yesterday pulling the trans and am facing a $1,700 rebuild to fix the buggered up pump and various other worn-out bits. Turns out if I had not fluffed up the tc installation, it would have worked, but not for long. There are several components that were on their way out so there's that. Hopefully I'll get the trans back in the next couple of days and get it back in. Good Grief. Se word to the wise: I though I had taken grat care of my trans and after having it torn down I was close to losing reverse, and had various other worn parts. Do yourself a favor and at minimum have your transmission inspected while it's easy to pull from the subframe. Going through all the work to do the swap right and then to have to R&R the xmission is regrettable. Also, I was told it's best to use a V8 TC as they differ from the V6. My drivetrain has/ had 108K on it and maybe another 6 mos optimistically looking at the transmission parts this morning.
I could not unload my torsion bars by using the keys so had to pop the front ball joints etc to get enough travel from th lower control arms to unload the bars and slide em forward to drop the crossmember. Still, droping the trans is a lot less work than pulling the subframe agian....
Couple of other things, upper radiator hose needs a coupler to relieve some twist necessary to clear the brake reservoir, cruise control "clip" from the 4.3 will not fit the 5.7 so I'll need to rig something up for that. If anyone has a solution pls advise, my cruise control cable has the black plastic screw on it but the nub on the 5.7 lever/ cam thing on for cc on th throttle body is bigger than that on the 4.3, I tried drilling the plastic clip/ adapter thing out a bit but no-go.
I ordered A/C hose barbed couplers from eBay and got a few inches of A/C hose to extend my rear A/C hose to the compressor. I need to figure out an air leaner and will likely just chuck together something from the auto-parts store for now.
I had to extend the knock wire (singular -used the one from the V8) extend the water temp sensor wires (used the water temp and oil pressure sensors from the 4.3) other than that and the inevitable harness rework for the extra injector wires, wiring was pretty uneventful. I did pick up a relevant section of harness from a 4.3 blazer to avoid extra crimping etc. Also ordered a new v8 injector connector thing. BTW there are a lot of useful links on the S10 V8 sites to help with pinounts etc...
I used my stock y-pipe, and exhaust and got an o'rieley/ kragen passenger side manifold and the alignment is fine. If you are doing this swap on a newer AWD, get all Moog stuff ang replace anything that moves in the steering assembly while you have the subframe out. Also spring for new motor mount-mounts (the bits that bolt to the subframe with the rubber inserts), this will likely help with keeping your pan clear of the diff and cross tube.
So I'm just about done with my 2001 AWD Astro LT swap to 5.7 Vortec. It's not a trivial amount of work but the other day I started it up and it purrs like a kitten :0) I had a bit of trouble that I initially attributed to not getting the distributor installed properly at tdc. Problem really was that after installing the v8 programmed computer, I had to have it "learn" the passlock code from the steering column. Who woulda thunk?
I'm going to elaborate over the next few days but wanted to point out a couple of things I had not read on previous posts. I was able to get a $200 Canton Racing 8qt pan to fit by beating it to submission to clear the front diff and cross tube with a reasonably heavy hammer. I don't have the part number on hand but I ordered it from Summit Racing and made sure it had a passenger side dipstick provision and was "4 x4". Again, beating it with a hammer a bit and packing three washers behind the tops of the JTR mounts to raise the motor just a tad gives me enough clearance (just). Also prevents the need for clearancing the frame around the RHS manifold (just).
I did all the work solo with no assistance really needed, just be VERY careful lifting the van up to pull the subframe. I could not get jackstands anywhere close to helping out and I ordered 12 Tonners just for the job. They would barely reach the running boards and were only really there for redundancy should my rigged-up supports fail. I ended up using two steel bars with the subframe mounting bolts to key 'em into the chassis and relied on biasing the load to the rear wheel chocks to support the van as I wheeled out the subframe. Kinda like an A-frame i s'pose.
Bleedin' transmission electrical connectors - arg. the primary one is glued- in, don;t try and pry it off the PRNDL switch like I did, the wsitch housing will break before the connector comes out. As I learned. doing it again, I'd either heat the connector and/ or lube it up with something non corrosive to plastic of course.
Wasn't expecting the oil filter housing to be such a pita. I wound up sourcing and pulling a oil filter adapter from a 96 impalla SS which fits like a glove and allows the re-use of the 4,3;s oil cooler lines just by removing the stud from the SS oil filter housing. V6 oil filter adapter will not work.
The motor I used was allegedly from a 30k mile 2002 Express 5.7 but I'm pretty sure it's a 96-98 L31 from a pickup. I replaced the intake gaskets which were already bad and the motor other wise seems fine. I put in the SEFI update (get the newer spider assy from amazon btw) and put in the newes GM intake gaskets which will outlast the rest of the van I'm sure. new plugs dist cap /rotor of course, orig ht leads seem fine so I am using them.
So how does it drive I hear you ask? Well it doesn't, well not yet. See, I was so focused on the mods, wiring, mounts, pan etc that when I pulled the V6 off the trans, I left the torque converter attached to the flexplate. Being an idiot, I assumed it would line up with the new trans if I lined up the dog-ears on the TC in the same orientation on the 5.7 as from the 4.3. Well let's say that wasn't my best idea ever. :banghead: Take a few mins and watch a torque convert installation procedure vid on you tube… 5 mins will save you a couple of days.
So after finishing up and getting the van running, installing my new 1" core radiator and dual flex-a-lite fans, routing the dipsticks etc, I dropped the van off the stands and fired 'er up for a ride. Alas no gears were to be had. I spent yesterday pulling the trans and am facing a $1,700 rebuild to fix the buggered up pump and various other worn-out bits. Turns out if I had not fluffed up the tc installation, it would have worked, but not for long. There are several components that were on their way out so there's that. Hopefully I'll get the trans back in the next couple of days and get it back in. Good Grief. Se word to the wise: I though I had taken grat care of my trans and after having it torn down I was close to losing reverse, and had various other worn parts. Do yourself a favor and at minimum have your transmission inspected while it's easy to pull from the subframe. Going through all the work to do the swap right and then to have to R&R the xmission is regrettable. Also, I was told it's best to use a V8 TC as they differ from the V6. My drivetrain has/ had 108K on it and maybe another 6 mos optimistically looking at the transmission parts this morning.
I could not unload my torsion bars by using the keys so had to pop the front ball joints etc to get enough travel from th lower control arms to unload the bars and slide em forward to drop the crossmember. Still, droping the trans is a lot less work than pulling the subframe agian....
Couple of other things, upper radiator hose needs a coupler to relieve some twist necessary to clear the brake reservoir, cruise control "clip" from the 4.3 will not fit the 5.7 so I'll need to rig something up for that. If anyone has a solution pls advise, my cruise control cable has the black plastic screw on it but the nub on the 5.7 lever/ cam thing on for cc on th throttle body is bigger than that on the 4.3, I tried drilling the plastic clip/ adapter thing out a bit but no-go.
I ordered A/C hose barbed couplers from eBay and got a few inches of A/C hose to extend my rear A/C hose to the compressor. I need to figure out an air leaner and will likely just chuck together something from the auto-parts store for now.
I had to extend the knock wire (singular -used the one from the V8) extend the water temp sensor wires (used the water temp and oil pressure sensors from the 4.3) other than that and the inevitable harness rework for the extra injector wires, wiring was pretty uneventful. I did pick up a relevant section of harness from a 4.3 blazer to avoid extra crimping etc. Also ordered a new v8 injector connector thing. BTW there are a lot of useful links on the S10 V8 sites to help with pinounts etc...
I used my stock y-pipe, and exhaust and got an o'rieley/ kragen passenger side manifold and the alignment is fine. If you are doing this swap on a newer AWD, get all Moog stuff ang replace anything that moves in the steering assembly while you have the subframe out. Also spring for new motor mount-mounts (the bits that bolt to the subframe with the rubber inserts), this will likely help with keeping your pan clear of the diff and cross tube.
