3.6L LY7/ 6spd auto swap

[SexyG6]

sooooooooo ive been looking into swaping in the 3.6 and 6spd auto into my 6er around christmas..... and im getting ready to start buying parts for the swap soon and have only a few questions left......... so far i have the cost at right around $4k

the first question has to do with the engine wireing harness......i took the split loom tubing off of the wires that go to the ECM to see if one connector on the ECM went to the car and one to the engine harness.......i found that to not be the case...but rather it seems the entire cable with the big white tag (in the second pic) goes to its own "conector" in the fuse block which is the white piece in the first pic..........

my question is when i buy the wireing harness for the 3.6L will it just plug right into the place the 3.5 does and get held in by the nut on top of the fuse block, as i would assume all the wireing in the fuse block of most models of 6ers are the same and just have dif engine harnesses for the diff engines but interchangeble........can andy or anyone confirm that





my second question is if the engine cradle are the same for the 3.5/3.9 and the 3.6? when looking at both setups it appears they are the same but does anyone know for sure?

i know that the ECM/ TCM (appropriate for the 3.6) will have to be programmed to my vin which i will be getting a tune right from the get-go..........BUT will the BCM need re programed for the new engine/trans? also i will need a new instrument cluster appropriate for the 3.6 powertrain so does anything in that area need reprogramed?

it seems to be a pretty strait forward swap and pretty easy considering its not tearing the current engine apart and fixing something........

so far on the list of thing i will need for the swap i have:

3.6L LY7 engine and all engine acc. alternator, ac compressor, PS pump........
3.6L engine wireing harness and ECM/TCM
6spd auto 6T70 transmission
new radiator the match the new setup
new axles to mate up to the new trans
New guage clust with the appropriate RPM redline
fuel lines and PS lines and transmission line will more than likely just be custom by me with some good rubber tubeing aproppriate for the application.. and the AC lines look to bolt right up

if everything works out and i get the GXP i want soon i will just take the exhaust manifoldsand cat off and put them on this 6er and hopefully have a set of headers fabbed for the GXP

at the time i do the swap i will also be replaceing all the wheel bearings since i will have the front ones off anyways to install the new axles.....also i will be installing coilover since my suspension is pretty much shot now after 118k k miles, and ill be replaceing the sway bar bushings while i am at it...........
now i havent had any problems with the powersteering but i am wondering if i should replace the steering rack while it is easy to get to?

not includeing the bearings coilovers or the tune ive got the cost figured at about $4300 and i also am planning on putting some stock leather heated seats in too

so i have it figured at just under $6k for everything with me doing all the work and i would almost bet i could get all the powertrain parts for a bit less if i get them all from the same place and just tell them i want the entire 3.6l 6spd auto powertrain

im really planing on going thru with this being that in the year and a half i have owned my 6er i have put almost 100k miles on her........it just doesnt make sense at all to only get 5k out of my car on trade in and put 100k on the next car and lose all the value on it too.........

BUT what does make sense is to buy one of the few new GXPs left and have that as my toy and only have like 20k miles on it in 10-15 years as that one i would keep forever.....(want headers a cam set and turbo on that in addition to all the reg. mods)
and just put a new engine and trans in mine and keep using it for work..........ive also looked into geting the 3.9 and 6spd manual as well and it would be considerable less, but as much as i would love to make my 6er a manual i just dont know about haveing to have the 3.9.........i really dont wanna have to change head gaskets every 20-30k miles..........

speaking of which my 3.5 has caused the 6th radiator now since 78k miles to fail from excessicive pressure so i'm thinking about haveing a custom radiator fabbed up that is 100% aluminum rather than haveing the stupid plastic tanks that now on this 6th radiator has actually started to crack and buldge where the outlet hose is......which leads me to beleive that the coolant passaged may be partially blocked in the block or there is excessive preassure from something else wrong in the engine which causes too much pressure on the radiator causeing them to fail on me like every 6-7k miles

any thoughts, opinions or answers to questions welcome......

[SexyG6]

Re: 3.6L LY7/ 6spd auto swap

BTW i will update this with pics as i order parts and they come in and again when i actually do the swap.....

not quite ready to order parts yet tho as my first priority is working a deal on a new GXP as i need to put $4k down on it in order to get a loan for the remainder without needing a cosigner........ but parts will be orderd as soon as everything is sorted out and ive got enough $$ back in the bank to be spending that kinda cash again....... i wont be able to do the swap until my 2 weeks off for chritsmas/new years anyways

also one more question..... does anyone know if the shift control cable from the trans on my 3.5 will bolt up to the 6spd auto?

[CrimsonGTP]

Re: 3.6L LY7/ 6spd auto swap

wait...ur buying a GXP...AND swapping a motor into ur current 6? or ur swapping the motor out of the GXP into ur car and parting the other...im confused.

[CrimsonGTP]

Re: 3.6L LY7/ 6spd auto swap

sidenote. im going to say regardless of which, you need to pick a bigger motor to swap in. say.......ls1... go big or go home!

[BORN2SKI]

Re: 3.6L LY7/ 6spd auto swap

[SexyG6]

Re: 3.6L LY7/ 6spd auto swap

wait...ur buying a GXP...AND swapping a motor into ur current 6? or ur swapping the motor out of the GXP into ur car and parting the other...im confused.

ya, im getting a GXP and at some point in time (probably soon) im going to need a new engine and trans in the one i have now........its got 118k on it now and something is def screwed up in the trans or engine and not balenced anymore.........that and my engine keeps makein radiators fail like every 6-7k miles and i really dont want to put the 3.5 and 4spd auto back in it........its gotta be either the 3.9 6spd manual (not the best quality engine for what ive read/seen) or the 3.6 6spd auto which seems to be a good quality engine with decent power...........

the GXP will be my weekend toy so no need to go swapping huge engines into whats gonna stay as my DD.........LOL i just have those last few things to figure out before i start ordering parts.........that and ive gotta make it back home smetime soon to sign papers on the GXP lol.........

[CrimsonGTP]

Re: 3.6L LY7/ 6spd auto swap

put the 5.3 in from the GP GXP's. if you are doing an engine swap IMO it has to be worth it. if u dont go V8 or boosted 4, you might as well buy another car. swapping a motor into a car with 118k miles on it that isn't a bigger engine (not just another G6 motor ) is silly IMO

[LoJac963]

Re: 3.6L LY7/ 6spd auto swap

^I have to agree, it will cost a little more but the end result will blow people away. I think the GP GXP motor would be easier I'd imagine

[dre256]

Re: 3.6L LY7/ 6spd auto swap

put the 5.3 in from the GP GXP's. if you are doing an engine swap IMO it has to be worth it. if u dont go V8 or boosted 4, you might as well buy another car. swapping a motor into a car with 118k miles on it that isn't a bigger engine (not just another G6 motor ) is silly IMO

I have read before, and no cant find it for a link anymore, GM was going to put the 5.3L in the G6 GXP for 09 after the GP GXP and the Monte Carlo SS eairlier then expeceted GM had a surplus of the 5.3Ls. GM only stopped the project because to much R&D money had to be put in to re design the layout of the engine bay such as relocate the battery to trunk or under the back seat. So I would def belive the 5.3L will fit under the hood.

2nd just my oppinon, but I think your CRAZY swapping in the 3.6L. I would sell the G6 first and buy a used LS1 Camaro or Pontaic Trans AM or even a Mustang GT with the 3V 4.6L. Then take rest of the money for repairs on the car. I cant belive all said and done 4K will do a full swap over. I would also some how find out if the BCM will even comunicate with the 3.6L from the 3.5L.

[SexyG6]

Re: 3.6L LY7/ 6spd auto swap

2nd just my oppinon, but I think your CRAZY swapping in the 3.6L. I would sell the G6 first and buy a used LS1 Camaro or Pontaic Trans AM or even a Mustang GT with the 3V 4.6L. Then take rest of the money for repairs on the car. I cant belive all said and done 4K will do a full swap over. I would also some how find out if the BCM will even comunicate with the 3.6L from the 3.5L.

im not swapping it to make it faster, yes it prob will be but thats not the reason........all i need is for it to be a reliable daily driver for probably about 150-175k miles more.........obviously the 3.5 thats in their now isnt gonna make it that long, seing as the crank bearings, camshaft and lifters and head gaskets have already been replaced once and it causes radiators to fail consistantly about every 6 k miles since 78k.....

i have no interest in the camaro transam or mustang.............i dont like the looks of them at all with the exception of the transam and even then its not practicle to get one of those to have as a DD for 150k mile or however much driving work takes me till my apprenticeship is finished, especially with the nasty winters out here..............

IMO the 3.6l and 6spd auto is the best engine to put in quality wise, i have not heard of any issue with them other than steelgrays whereas the 3.9's have major HG failure, and my 3.5 has been full of problems as well............ and its really not all that expensive........i have sourced an engine with 12 miles on it for $1400 and a trans for $600 the rest is just axles ECM/TCM and tune and such which doesnt add up to more than 4300 or soo..............considering i bought my 6er for 12k which turned into 17k after interest and such only a year and a half ago and now on a good day get 5k for it its not worth getting rid of.........

especially when i am already in the proccess of buying a NEW carbon black metalic G6 GXP coupe.......THAT will stay home and be hardly drive as i am only home mabey 20 days out of a year.........now THAT car i want to do all the bolt on mods include headers if they will still make another set, and i would like to put a cam set and turbo on that thing a ways down the road...........

and im gonna have to say no to the 5.3.............its only gonna be a DD and i dont want the headache of haveing to figure out what GM didnt..........mabey down the road (like when im donw with the apprenticeship) when it again might need another motor it its up to like 300k miles by then....mabey i wil put the 5.3 in it but not now........i only have 2 weeks to get the swap done in, and its easy enough to figure how the 3.6 would go in seeing it was optional on the G6........5.3..Not so much LOL

[dre256]

Re: 3.6L LY7/ 6spd auto swap

I really wish you the best of luck, but 2 weeks is alot. I dont know what your mechanical skills are but I think that is a large load. I can understand where you are coming from. My 3900 at 32K miles has gone through 2 head gaskets (same side) and that last head gasket is sepping a bit of oil but atleast it isnt coolent. I have the 3.6L in my Torrent GXP and that is a great engine and transmition overall.

I understand better from your last post your looking for a car that can do high mileage and get decent MPG. I really do wish you the best of luck and look foward on reading on your progress!

[SexyG6]

Re: 3.6L LY7/ 6spd auto swap

ya i really love my 6er and couldnt give it up lol, and im actually planning on getting a gxp (which is what i wanted from the get go and before i even graduated HS........getting that is a bit higher priority than the engine swap, as i will really be able to figure things out with it haveing the same setup i want to put in the one i have now and if worse comes to worse i could always use the GXP if my engine goes before i get a chance to put a new one in........a lot of people say why not just get rid of mine and get the GXP but letting mine go for 5k just isnt worth it to me....that and i DONT want to be putting massive amount of miles on the GXP like i have on mine.........i hope to only have like 20k miles on the GXP in 10-15 years......

im not "new" to working on my car but im no pro..........however it seems fairly strait forward being that im not tearing down the engine and rebuilding it, just simply swaping the entire powertrain...........one of my cousins is a mechanic at a private shop that can help me if needed, now being i havent done something quite like this before i cant know for sure but i cant see this takeing more than 4-5 days if that once i have all the parts sitting at home...... gonna have my cousin drain the AC system on this one before i take it out and have him check everything and refill it when the swap is complete... i assume the new engine and trans may have to be primed with oil or somethin from the sounds of so of steelgrays post about his engine work which my cousin will have to probably help me with that.... i dont forsee any major problems other than possible the BCM needing reprogrammed or something and anything to do with the instrument cluster which i asked in the first post in the thread but have yet to get ans answer................

this is all still a ways away but i def want to know everything about it before i dive into it haha

once i actually have my GXP i think i will be able to answer a lot of the questions on my own... by compairing them side by side

[SexyG6]

Re: 3.6L LY7/ 6spd auto swap

just reread your post again dre and it seems that your under the impression i only have 2 weeks from now to finish? to clear things up, im not going to be doing ANYTHING till around christmas, at which point i will be home for 2 weeks strait.....just tryin to find out everything i need to know so i can have all the parts on hand for when i actually do it but other than that nothing is happening till the end of the year....

[CrimsonGTP]

Re: 3.6L LY7/ 6spd auto swap

another motor i was day dreaming about fitting into a six the other day was a 3800 SC out of a GTP GP.....anyone think itll fit? then its still a v6 that can make big power.....just throwin ideas i know u have ur heart set but if i had ur budget with ur situation and HAD to motor swap i would make it a bit quicker because you might as well. i know its not supposed to be a race car but if u are already dropping coin on the motor, make it worth the effort/time/money

[Tupperware SC2]

Re: 3.6L LY7/ 6spd auto swap

I think that the money that you are going to spend to do this swap you could use, in combo with your dd, and just trade it in for another g6. I read wher you are ging to get a second g6 already but it is going to be speasier to just ditch the car and get one with a good motor

However.... If you are going to do the swap i like this idea

another motor i was day dreaming about fitting into a six the other day was a 3800 SC out of a GTP GP.....anyone think itll fit? then its still a v6 that can make big power.....just throwin ideas i know u have ur heart set but if i had ur budget with ur situation and HAD to motor swap i would make it a bit quicker because you might as well. i know its not supposed to be a race car but if u are already dropping coin on the motor, make it worth the effort/time/money

This motor can be super potent and the parts are everywhere. It is not without its downfalls but the parts are outthere and cheaper than custom fabrication