LZ4/Fiero Swap

[neophile_17]

Hey guys,

I was going to hold off on letting the cat out of the proverbial bag but things seem kinda slow so here we go.

I've been looking at the LZ* series motors for a couple years and finally snagged an LZ4 on half off day at the junkyard. This will be my third swap following an LA1 and LX9 all into Fieros. Timeline is 9 months since I have a racecar to maintain/improve and an LX9 powered Fiero to enjoy.

My impression is that people shy away from swapping LZ* motors into older cars because of limited control options. Aftermarket ECMs aren't common and VVT hasn't been implemented to my knowledge. The OEM computer requires most/all of the original subsystems making a retrofit difficult. My goal with this project is to keep as much of the LZ* motor stock and run it with a MS3X (Megasquirt 3 w/ Expansion Board). In the spirit of MegaSquirt this will be openly available to make future swaps easier.

I feel some need to justify the MS3X since I'll be spending almost 4 times as much on the computer as the engine. While I love my 7730 powered projects chip swapping is tedious and finding information is cumbersome. I understand that I could probably do this with a MS2 but I'm trying to keep this as straight forward as possible. This philosophy helps me and anyone following a similar path get it running faster.

I expect the first incarnation to be as follows:
Batch Fire
VVT mechanically limited to +3 or -2 On/Off operation
Stock Coils with Wasted Spark
Stock Crank and Cam Wheels/Sensors
Early 3X00 Alternator
Fixed Fuel Pressure (58psi) and Stock LZ* Rails/Injectors
75mm Truck Thottlebody (might go to 4.3L 70mm for the LZ4)

I'm interested in pursuing these features once the above is reasonably stable:
Knock Sensing with the stock LZ* Broadband Sensors
Sequential Injection
VVT operation in variable mode with mechanical limits
VVT operation in variable mode without mechanical limits
LZ* computer controlled Alternator

I'm hoping to get the engine cleaned up this weekend. Then there's likely to be pictures.

The Haynes manual for the Malibu has no wiring diagrams for the engine. Anyone have a good/inexpensive source for these. My biggest concern is the CMP sensor which I gather is a Hall type but I don't know if it is 5V or 12V and which wire is power, ground, and signal.

Thanks for reading this far.

Sam

[neophile_17]

So here are my first impressions of the LZ* series motor.

My initial plan was not to dig into this motor too much. However, GM downgraded to exhaust manifold bolts instead of studs and I had 4 that were broken. So it was off with the heads so I could weld nuts on at work. It's nice to get MLS head gaskets for $20 each. I have to say that apart from the aforementioned bolts GM made some nice upgrades. The stock intake gaskets are metal even though coolant no longer passes through them. Compared to the LX9 the ports and valves look significantly bigger as seen in the pictures. Getting oil squirters for all cylinders was a nice bonus too. I didn't quite get the timing cover off to look at the phaser as I can't seem to find my 3 jaw puller.

What is everyone's experience with AlldataDIY? Are they going to have the wiring diagrams I need? Ideally there would be component information like expected injector resistance as well.

[Guest]

I see exhaust bolts as an upgrade from studs. I always replace the studs on my 660s when I'm doing anything more than just repair, as in custom turbo set-ups or installing headers.

[neophile_17]

I'm curious why you say this. My experience on the four 660s I've worked with is bolts snap and studs don't. I've always read that studs were superior in terms of strength and consistency of clamping force.

[Guest]

Normally I say the same thing, except when it comes to exhaust fasteners. The extreme heat cycling in my experience causes studs to fail much sooner than bolts. I can't recall any bolts ever breaking on me when used on exhaust except for the rear exhaust bolts on my 2000 Yukon, that were broken when I got it and it's a known problem for those engines (LS), at least in the trucks anyway. I've had more than a few exhaust studs break on me over the years. Using bolts has bot been an issue. *shrug*

[ericjon262]

So here are my first impressions of the LZ* series motor.

My initial plan was not to dig into this motor too much. However, GM downgraded to exhaust manifold bolts instead of studs and I had 4 that were broken. So it was off with the heads so I could weld nuts on at work. It's nice to get MLS head gaskets for $20 each. I have to say that apart from the aforementioned bolts GM made some nice upgrades. The stock intake gaskets are metal even though coolant no longer passes through them. Compared to the LX9 the ports and valves look significantly bigger as seen in the pictures. Getting oil squirters for all cylinders was a nice bonus too. I didn't quite get the timing cover off to look at the phaser as I can't seem to find my 3 jaw puller.

What is everyone's experience with AlldataDIY? Are they going to have the wiring diagrams I need? Ideally there would be component information like expected injector resistance as well.

[ATTACH=CONFIG]8462[/ATTACH]
[ATTACH=CONFIG]8463[/ATTACH]
[ATTACH=CONFIG]8464[/ATTACH]
[ATTACH=CONFIG]8465[/ATTACH]
[ATTACH=CONFIG]8466[/ATTACH]

I have access to diagrams, let me know what you need, and I will see what I can do.

[neophile_17]

Raven- That's interesting. Are the studs you've seen break applications where water/salt was a major factor, or just load like extreme heat or the weight of a turbo?

Ericjon- That would be great but I'm looking for basically all the wires that connect to engine components. There are certain things that are probably the same like CLT and IAC. However cam phaser polarity, CMP, CKP, and ignition module power/signal(s) all come to mind.

I got the cam phaser off last night so I'll be looking at how to limit it's motion soon.

The LZ4 intake diameter is 75mm so that makes the truck TB seem like a reasonable size- maybe. I'm probably half way through machining an adaptor- smallish chunks of time make custom pieces take forever.

[Guest]

Well, I do live in an area where salt is used, so that may be a factor, but again, bolts in the same application seem to be a non-issue. Also many times where I see the breakage turbos are not applicable, mostly N/A applications. In my custom turbo builds I always support the turbo by other means than using the headers to support it. The only exception has been when using a stock turbo manifold on my Nissan I6, but that's a different animal completely.

[ericjon262]

Raven- That's interesting. Are the studs you've seen break applications where water/salt was a major factor, or just load like extreme heat or the weight of a turbo?

Ericjon- That would be great but I'm looking for basically all the wires that connect to engine components. There are certain things that are probably the same like CLT and IAC. However cam phaser polarity, CMP, CKP, and ignition module power/signal(s) all come to mind.

I got the cam phaser off last night so I'll be looking at how to limit it's motion soon.

The LZ4 intake diameter is 75mm so that makes the truck TB seem like a reasonable size- maybe. I'm probably half way through machining an adaptor- smallish chunks of time make custom pieces take forever.

I can get it for you, I'll try to do it this weekend.

[neophile_17]

Raven- I was trying to figure out what the difference could be. One thought was that a stud/nut allows salt water to wick behind the nut. From what you said this seems like a possibility. I'll probably just get a bag of SHCS and HD washers anyhow.

Ericjon- That would be a huge help! Greatly appreciate anything you can get me.

[ericjon262]

Looks like they're 5 volt. working on more for you.

[neophile_17]

Thanks! That's a great start.

So the first step is done on the TB adapter. It all bolts together nicely. I'm waiting to trim it down in case I want to use the extra material as a mounting point. I probably would have forgotten to open up a passage for the IAC if I hadn't just read about it in Ericjon's thread. Hopefully that notch is enough. If not, it's easy to change later. And after getting it all done I discovered that I could have bought one at http://www.killerbv6.com/shop/all/tb...r-lz-lx-detail. It certainly looks a lot better than mine.




I also took apart the the cam phaser. It's an interesting piece. My plan to limit it's travel wouldn't have worked and I may abandon that approach altogether. I did some more reading while trying to find the thread where phaser travel was limited. Basically I didn't realize that the VVT cam is ground quite differently. As a result, operation of the phaser is important to making the most power not just the lowest emissions as I originally thought. So fully operational VVT has become a higher priority.

[ericjon262]

Thanks! That's a great start.

So the first step is done on the TB adapter. It all bolts together nicely. I'm waiting to trim it down in case I want to use the extra material as a mounting point. I probably would have forgotten to open up a passage for the IAC if I hadn't just read about it in Ericjon's thread. Hopefully that notch is enough. If not, it's easy to change later. And after getting it all done I discovered that I could have bought one at http://www.killerbv6.com/shop/all/tb...r-lz-lx-detail. It certainly looks a lot better than mine.

[ATTACH=CONFIG]8467[/ATTACH][ATTACH=CONFIG]8468[/ATTACH]
[ATTACH=CONFIG]8469[/ATTACH][ATTACH=CONFIG]8470[/ATTACH]

I also took apart the the cam phaser. It's an interesting piece. My plan to limit it's travel wouldn't have worked and I may abandon that approach altogether. I did some more reading while trying to find the thread where phaser travel was limited. Basically I didn't realize that the VVT cam is ground quite differently. As a result, operation of the phaser is important to making the most power not just the lowest emissions as I originally thought. So fully operational VVT has become a higher priority.

any thoughts on obd2? I have some ideas floating around that could make this a very interesting swap... you are sticking with a 5 speed right?

[neophile_17]

I haven't really played with OBD2 at all. It makes me very nervous that it's not completely hacked. It'll be a manual but probably a 4 speed. They've been really good to me.

[ericjon262]

that's understandable. I've been thinking about LZ4's and LZ9's alot lately, and ways to control the VVT. a couple of ways might work, been looking at mechanical and electrical.