LZ9 and LZ4 Fiero Swap Parts

[ericjon262]

I'm slowly working towards a few LZx swap parts that should make putting one in a Fiero a bit easier.

As most of you know, I have made a prototype engine mount bracket that bolts to the stock Fiero engine mount.





I'm also working on a low mount alternator brackets here, using a LS V8 style alternator used in a very wide array of applications.





and here, using the stock 3900, alternator, coincidentally, a ~2003 Grand Am Alternator also fits, and is a little bit simpler from a swap standpoint.



Hopefully I can get these test fit this week, and can validate their use on other engines like LX9's, and 3400's.

Next project will be belt tensioners, and dog bone mounts.

[Shaun41178(2)]

Do you have an LS style alt laying about. If not I have an ls4 one here

[ericjon262]

I'm fairly certain the LS4 uses a different style alternator than most other LS engines, but I could be wrong. Either way, I have one here, and used it to validate the model shown in one of the above pictures.

I cut prototypes yesterday morning when I got off work, the parts fitup looked good initially, but I found a few issues.



This plate that bolts to the side of the block, I measured slightly wrong, I had the holes to close together by about 2mm, so the bolts would not go in. I used the back bolts for the rest of the test fitting.



The pulley offset was WAY wrong, this was not unexpected, I quickly took the measurements, dropped them into CAD, unfortunately I didn't adequately label everything, and later when I was working on it couldn't remember which mark was the right offset, I should have measured before cutting, but you know, if you're gonna be wrong, be confidently wrong. unfortunately, this offset error will also make other parts of the mounts more difficult.



other than the above mentioned pulley offset, the LS alternator mount fit the alternator almost perfect, and the fitup of the 60v6 alternator mount also looked very promising, however, some of my measurements were not quite right. as you can see in the above picture, with the mounting plate bolted to the alternator, it's not meeting the rest of the assembly square. between this, and the pulley offset issue, I'm probably going to completely redraw this mount.

[neophile_17]

There are two different 3X00 alternators that are almost imperceptivity different. I broke an alternator bracket by blindly mixing and matching before I discovered this. If you measured one alternator and test fit with another you may have discovered the same thing.

These mounts look great! Hoping I'm at a place to buy a set sometime in 2024.

Sam

[The Dark Side of Will]

Most people just modify one of the stock 2.8 brackets, however, I did test fit parts on a LX9 oil pan, and they do fit the same as they do on the LZ4 pan I have, with the exception of the taller vertical part, the LZx version is too short for the older engines.

Would a dual use version be as simple as slotting the bolt hole on the long vertical piece?

[ericjon262]

Most people just modify one of the stock 2.8 brackets, however, I did test fit parts on a LX9 oil pan, and they do fit the same as they do on the LZ4 pan I have, with the exception of the taller vertical part, the LZx version is too short for the older engines.

Would a dual use version be as simple as slotting the bolt hole on the long vertical piece?

Most likely, yes, although it wouldn't be hard to make the long vertical piece slightly longer and and have a slight stickout for one mount that gets ground after welding. I'm also debating adding an additional brace to further support the vertical piece. Howard and Shaun have prototype #1 in hand now, hopefully they can share the results of the mount shortly.

[ericjon262]

on the subject of alternator mounting, it's worth mentioning that 3.9's installed in buick Lucernes have a different alternator and water manifold, GM parts Giant list this manifold as available, however, if you order they cancel and say it's not available. this mount fits LS truck alternators, which from a swap standpoint can be a big bonus because they are a little easier to swap in as a more "one wire" setup.

[Shaun41178(2)]

Trimming of hinge bracket necessary for the Lucerne mount? Isn't that the water manifold already employed by a member here?

[ericjon262]

Trimming of hinge bracket necessary for the Lucerne mount? Isn't that the water manifold already employed by a member here?

not 100% sure, I know someone on Facebook is running one, but I haven't seen pictures.

[eHoward]

Some shots below. Couple thoughts:

1. Nice welds.
2. Real clean cuts.
3. Paint looks pretty nice not even considering how fast you made it.
4. We were thinking it might be helpful to incorporate one more bolt hole from below.
5. A gusset would be reassuring.
6. A thicker gauge would be nice

Would be interested to hear what other ideas we could crowdsource.

[Shaun41178(2)]

I would like to see an additional mount location at the pan circled.

And a gusset on the backside of the vertical section. There seems to be plenty of room.

IMG_8165~2.jpeg (2.23 MiB) Viewed 4240 times

[ericjon262]

Some shots below. Couple thoughts:

1. Nice welds.
2. Real clean cuts.
3. Paint looks pretty nice not even considering how fast you made it.
4. We were thinking it might be helpful to incorporate one more bolt hole from below.
5. A gusset would be reassuring.
6. A thicker gauge would be nice

Would be interested to hear what other ideas we could crowdsource.

#1-3, Thanks!

#4, I'll address below.

#5, I've gone back and forth on this alot, and will most likely be adding one.

#6, the idea of this mount was to bolt the engine into the stock fiero location as closely as possible, this gauge is almost spot on with that thickness, going thicker will lift the crankshaft nose higher, and position the engine out of the stock location slightly. the design was developed with the mindset that the oil pan carries the load, and the vertical piece adds stability. With the factory fiero parts, the load was carried further from the mounting points, requiring the bracket to be thicker. While I haven't done any real world testing, I suspect adding a brace to the vertical portion will more than make up for the thickness.

I would like to see an additional mount location at the pan circled.

IMG_8165~2.jpeg

Factory LZ9 mounts that use that bolting provision have the rubber cushion centered between them, you may remember my original prototype catching that bolt hole as well. in out application, the mount is offset significantly further from that bolt location and any other additional structure/support. I'm not an engineer (maybe one of the resident engineers will chime in) but I didn't feel like the added material was worth the minimal increase in strength.

it should also be noted, that this mount should be used in conjunction with a dog bone, I am working on a mount for that as well.

[ericjon262]

I found this noteworthy while working on a "gen 2" alternator bracket, the bolt pattern on the end of the head is the same on an LZ as it it on the earlier engines, while this isn't massively significant, it is potentially useful depending on how a mount is developed.

[ericjon262]

I've been working towards a new design alternator mount, which should allow for the use of intermediate shafts, and hopefully, automatic transmissions. My old design used the bosses on the side of the block that both of those bolted to, this one, while possibly looking simpler, is a bit more complicated, and unfortunately, will require more processes to be put into production. on the plus side, I should be able to make this mount also work on the earlier LX9, and 3400 engines, with some small modifications.




it's built around Bosch 60V6 alternators, some of which need the PCM to operate as GM designed, some can be wired to the lamp on the dash like an older style alternator, I may, or may not build a mount for the Delphi/Delco alternators. they're extremely similar, but not interchangeable.

[pmbrunelle]

I was checking out Onshape, and it looks like it has some sort of FEA built into it. However, that looks to be a $$$ paid option.

For comparing the strength of different engine mount designs (which can be hard to analyse by intuition with their funky shape), I think that doing sort of basic static FEA could help guide you.

The free Calculix looks interesting:
http://www.calculix.de/

I haven't tried it yet. On the downloads page there are Windows executables.

[Series8217]

I was checking out Onshape, and it looks like it has some sort of FEA built into it. However, that looks to be a $$$ paid option.

For comparing the strength of different engine mount designs (which can be hard to analyse by intuition with their funky shape), I think that doing sort of basic static FEA could help guide you.

The free Calculix looks interesting:
http://www.calculix.de/

I haven't tried it yet. On the downloads page there are Windows executables.

You can use CAEPlex for free in Onshape.

[ericjon262]

I'll have to look into the element analysis, I'm not sure how well it would work with the way I design my parts, but that's a great reason to change the way I design parts. I'm on design 3 of the alternator mount, I'm onto a design that I believe to be viable, but I would like to integrate a dog bone mount into it still.



the new design is significantly more rigid, and although it is made of more parts. the most difficult issue I currently need to overcome, is finding a very close measurement for where the dogbone mount is, relative to the block face, and crankshaft centerline, once I have that, I should be able to model the mount with minimal fuss.