3500 Swap Finally Underway, a few questions

[jmgtp]

After a year of delays I am finally getting started.

I collected most of the parts over a year ago. I believe I have all the major items to make this work in my 91 Grand Prix:

LX9 engine
3x00 alternator and 3x00 alternator bracket
3x00 power steering pump
3x00 ICM and coils
3400 balancer
3400 injectors and rail
lower engine mount and bracket from a 3100 w car
a/c bracket from a 3x00
TCE crank trigger setup
new gasket set (metal lowers)
spare getrag 284 that shifts perfectly and a new clutch set
I'm sure there is more I am forgetting

I think I want to get a set of 3400 exhaust manifold. I was initially going to use the LX9 manifolds and weld up a crossover to make it work but I think I want to go for simplicity here.

Before I pull the 3.4dohc out I want the LX9 basically ready to go right in. This means replacing the lower intake gaskets, installing the crank trigger, balancer, and the necessary brackets.

This evening I removed the 3500 wire harness and began to mock up some of the parts. One thing that bothers me a lot is the a/c bracket. This thing doesn't want to line up at all. It even seems like it will hit the exhaust manifold. What needs to be done here? I think the bracket I have is from a 3x00 w car but its been so long since I got it that I can't remember. What is the solution here? I want this to work with the a/c compressor from my 91 3.4dohc.

There is an oil filter adapter on the LX9 that drops the filter lower. This won't work on a w car, it wont clear the subframe. What can I expect to find under there when I pull the adapter off? I need to be able to mount an oil filter without that drop down adapter.

Left Side Pic- the 3100 lower mount bracket. Not exactly sure how this mount without interfering with the crank pulley, am I holding it wrong?

Middle Pic- the a/c bracket against the LX9, not even close? wrong part? oriented incorrectly?

Right Side Pic-, will the bearing mount for my getrag 284 intermediate shaft bolt up correctly to the side of the block?

[bszopi]

For that left pic, I don't know what to say. I've never even seen a mount that looks anything close to that. But for a couple other questions, I did a search through the 3500 sticky in the Performance section and found the following...

oil filter adapter : http://60degreev6.com/forum/showthre...unt#post332360

strut mount : http://60degreev6.com/forum/showthre...unt#post330896

Hopefully that will help, or the threads around will will give you some direction. Glad to see its finally happening!

[Jonpro03]

If you want an easy fit, get a 1stgen w-body 3100 rear exhaust manifold to put the down pipe in the right spot. Then you can use a 3400 front and crossover.

Oil filter adapter - you can remove the threaded adapter (?don't know what its called) on the end of the extension, remove the extension and screw the threaded adapter straight into the block and attach your oil filter straight to the block.

1st pic - That looks like the automatic trans mount on the drivers side of a W body.
2nd pic - I can't help you with the A/C but I think that the only A/C you can use is the one that came on the 3500. I never installed the a/c compressor or the passenger side upper mount. I just have one upper mount on the driver side.
3rd pic - the holes are in slightly different positions. You will have to open up the holes your bracket to make it fit.

About the passenger side lower motor mount. The engine mount bolts right on to the oil pan. Go find a 1stgen 3100 W in a junkyard and have a look at the mount and you'll see what I mean. There are two bolts on the side and one on the front right under the crank pulley. Looking at your oil pan, it looks like you have a different one than what I had. Can you take more pictures of it right below the crank pulley?

[jmgtp]

Fellas, thank you for your replies.
I've officially gone through all 49 pages of the 3500 swap thread (pcguys thread). Lots of info. Also found the LX9 torque spec pdf.

It looks like my car, being a 91, leaves me in a tricky spot for the a/c compressor. I'd like to retain the original r12 compressor since it works great. Not sure what to do for this bracket.

Bszopi, thanks for the link to the oil filter adapter, that is one problem solved. And Jonpro03, it seems you identified the mount I had as an auto trans mount, which will likely be no use to me. The LX9 has a bracket for a lower mount beneath the crank pulley. I heard automatic 3x00 W cars use a similar bracket and mount. My 5 speed has a mount that is offset towards the back of the car. From what I remember I was told I could use a 3x00 lower mount/bracket as well as my 3.4 rear mount. I have the gasket set for the 3500 to replace the lowers. Is there a procedure somewhere? I will start gasket replacement work tomorrow evening.

thanks again

[Jonpro03]

Fellas, thank you for your replies.
I've officially gone through all 49 pages of the 3500 swap thread (pcguys thread). Lots of info. Also found the LX9 torque spec pdf.

It looks like my car, being a 91, leaves me in a tricky spot for the a/c compressor. I'd like to retain the original r12 compressor since it works great. Not sure what to do for this bracket.

Bszopi, thanks for the link to the oil filter adapter, that is one problem solved. And Jonpro03, it seems you identified the mount I had as an auto trans mount, which will likely be no use to me. The LX9 has a bracket for a lower mount beneath the crank pulley. I heard automatic 3x00 W cars use a similar bracket and mount. My 5 speed has a mount that is offset towards the back of the car. From what I remember I was told I could use a 3x00 lower mount/bracket as well as my 3.4 rear mount. I have the gasket set for the 3500 to replace the lowers. Is there a procedure somewhere? I will start gasket replacement work tomorrow evening.

thanks again

Do you have another picture of your oil pan? It doesn't look like what I got.

[jmgtp]

I'll take a few pics tonight. I know the 3x00 oil pan is much more rigid than the stamped steel LQ1 pan, does the 3x00 have a bracket for a mount bolt to the pan? Wonder if my different looking pan is going to be another issue.

I'm still not 100% clear on the lower engine mounts for the LX9. I've heard that my LQ1 mounts will bolt up but I'm not so sure

Edit: when I picked the engine up at the scrap yard it was already out of the car (which I never saw) it was supposedly from an 05 Malibu.

After reading the massive 3500 swap thread I believe I recall reading about the mounting bosses for the motor mounting being slightly different and the need to elong the bolt holes on the brackets. And I re-read your post and see that you wrote the engine mount bolts right to the oil pan. I know you said my oil pan looks different than yours but for sake of arguement, lets say they are the same, then would all I need be a 3100 lower mount? Does a 3x00 w car only use ONE lower mount on the passenger side? Problem is that I have never owned or seen the underside of a stock 3100, I'm only familiar with how the 3.4 dohc mounts. Do you have any pictures that I can use as a reference just to see how a 3x00 mounts?

[Jonpro03]

I'll take a few pics tonight. I know the 3x00 oil pan is much more rigid than the stamped steel LQ1 pan, does the 3x00 have a bracket for a mount bolt to the pan? Wonder if my different looking pan is going to be another issue.

I'm still not 100% clear on the lower engine mounts for the LX9. I've heard that my LQ1 mounts will bolt up but I'm not so sure

Edit: when I picked the engine up at the scrap yard it was already out of the car (which I never saw) it was supposedly from an 05 Malibu.

After reading the massive 3500 swap thread I believe I recall reading about the mounting bosses for the motor mounting being slightly different and the need to elong the bolt holes on the brackets. And I re-read your post and see that you wrote the engine mount bolts right to the oil pan. I know you said my oil pan looks different than yours but for sake of arguement, lets say they are the same, then would all I need be a 3100 lower mount? Does a 3x00 w car only use ONE lower mount on the passenger side? Problem is that I have never owned or seen the underside of a stock 3100, I'm only familiar with how the 3.4 dohc mounts. Do you have any pictures that I can use as a reference just to see how a 3x00 mounts?

These are the best I have





I've never had a 3.4dohc. Do you have that motor mount?

[jmgtp]

Thanks for the pics, I think I see. On your setup it looks like directly beneath the balancer there is a bracket bolted to the oil pan and a mount to the bracket.

My LX9 has a bracket beneath the balancer but a long time back someone indicated that this bracket would not work in a W car. So, they may still be correct, but in your setup it looks like a similar bracket. Did your LX9 come with the right bracket/mount on it or is that something you had to transfer over from a 3x00 equipped W car?

The 3.4 dohc uses two lower mounts (the motor is still in the car so I don't have pics) Rather than a single one in the middle, like you have pictured above, it uses one on each side. And again, a long time back, someone said that I could use my 3.4dohc rear mount along with the 3x00 mount and have a pretty solid setup. Possibly negating the real need for the dogbones or at least getting away with only 1, after all the 3.4 dohc only uses a single dogbone.

I'll take some pics of my oil pan tonight and hopefully we will be able to figure out whether or not the 3x00 lower mount will workout for me. Now, I'm REALLY hoping that my subframe has a provision for the 3x00 lower mount!

So I think I have 3 real issues to work out:
1) do I have the right oil pan to support the 3x00 lower mount? If not will a 3400 oil pan bolt-up?
2) Can I use my 3.4 dohc rear motor mount and get away with using only 1 dogbone up top
3) The a/c bracket looks like it is going to be a pain. I can cut/weld and fabricate to an extent and I may end up hacking up that bracket that I have to make it work
4) exhaust manifolds: find a cheap set from a 3x00 w car (prefer to at this point), or weld up/fabricate a crossover for the LX9 shorty style manifolds

Part of my wishes I went with a 3400 for simplicity. But at least the 3500 will be a bit more unique and hopefully have a little more grunt over a 3400.

thanks again, I really appreciate you sharing your knowledge and experience with this swap

[Jonpro03]

The pictures I posted are just pictures of my oil pan. I don't have any pictures of the mount bolted to the pan. I would like to see some more pictures of your oil pan right below your balancer. From the one picture you posted earlier, it looks like your oil pan is different than mine.

[jmgtp]

I looked at it on my phone so I guess I couldnt really see that well - I will have pics of my oil pan tonight.

I ventured over to w-body.com and found a writeup on changing a 3100 motor mount (http://www.w-body.com/content.php/19...ement-Write-Up). I now have a much better idea of what the 3100 mount looks like. In the pics of the writeup I can see the 2 bolts that secure the lower motor mount to the oil pan. My LX9 has a bracket bolted to the oil pan under the harmonic balancer. I am hoping that if I remove the bracket the bolts securing it to the oil pan are where the 3100 motor mount would bolt up. That would be really good news! I'll take the pics tonight and some measurements. The more I think of it the more I am sure that my subframe has the "pocket" for the 3100 lower mount to bolt up.

Once I get the motor mount figured out that will be a weight off my shoulders! I'm probably going to go with a single dogbone mount on the drivers side, I believe I need the motor side bracket for that, but thats is more like a detail down the road than an immediate issue.

What year motor mount should I get? Will one from any 3x00 W car be the right one? I know that I should get the solid mount rather than the hydraulic.

[jmgtp]

Here we go... I think this all is good news right now:
The oil pan, I removed the bracket from the Malibu and it looks like it will accept a 3x00 bracket/mount. The distance between the two bolts is about 8", does this look right? I'll have to get the bracket for the 3100 since the motor mounts seem not to come with them.



Now the other good news, I got the a/c bracket to bolt up. I had to cut out a spot from it where it hit a mounting boss on the block meant for the stock 3500 a/c compressor. Also had to bend up the heat shield on the manifold. 3 bolts hold it (circled in red), one into the head, and two into the block. This will be sufficiently strong to hold the a/c compressor but will it be strong enough to use the dogbone mount? I also need to consult my factory service manuals for the 91 to make sure that this bracket is correct for my a/c compressor. The last pic shows the "C" shaped part of the bracket where the compressor would bolt up.



Thoughts, comments and suggestion are welcome!

[Jonpro03]

Yeah, that (oil pan) looks like it'll work. The real test will be bolting the mount to it.

As far as the A/C, it also looks like it will work. I would say that those 3 bolts should suffice for the dogbone mount.

[jmgtp]

Will any 3100 w car motor mount work? Did they change at all over the years?

Tomorrow should be gasket and crank trigger day. I'm hoping it goes quickly, this thing is so easy to work on while on the engine stand.

[Jonpro03]

Yes. I found a picture with a quick google search that shows the bracket

[jmgtp]

Thanks for the pics. I happened across those same pics via google, they're from the w-body site writeup for the mount replacement.

I bought the bracket this morning to bolt to the oil pan from a 2000 3100 Grand Prix, I will buy a new (solid) motor mount for the same vehicle to assure a direct fit though it looks as if any 3100 w-car mount will work. I'm hoping that I can still use my 3.4 dohc rear mount in conjuction, that should allow for a pretty solid setup and will be good to handle hard shifts from the getrag.

Now that it is really coming together I'm excited to get the engine prepped and pull the old one out. The only thing I'm not looking forward to is welding up a crossover pipe using the LX9 manifolds or swapping on a 3400 set. And either way my downpipe will likely not be in the correct spot so I'll prolly be cutting, welding and fabricating there too. Not a big deal, just time consuming.

Thanks again for your replies, I really appreciate them and I am sure I will have more questions in the coming days/weeks.

edit: Almost forgot to ask! I removed the LX9 balancer last night. I'm going to be installing the external crank trigger and a 3400 balancer. Is it recommended to coat the crank snout with silicone before installing the balancer? I noticed that there was some gray color RTV on it but not much. Do I coat just the key way or the whole thing? Or not at all? I'm not sure why I need to since there is a seal there. BTW the crank is a 7484 which I believe is the better steel crankshaft.