LZ4/Fiero Swap

[caffeine]

The gen III timing cover *looks* like it could fit on a gen IV, assuming there wasn't a cam actuator in the way. The water crossover would probably have to be custom to fit with a FWD gen III timing cover.

[ericjon262]

I have been in talks with Crane cams and have dropped off a 3900 cam to see what they can do for reproduction and custom specs for the larger cam journals of the lz4/9. they would be based off of the earlier style timing chain so the vvt would be eliminated. This would allow for obd1 and obd 2 setups. I am waiting to hear back for pricing, so not sure if anyone would be interested in this option or not.

OBD2 would still require a custom timing cover with provisions for the 24x CKP, and possibly a special balancer to fit, I'm not sure if the spacing would work between gen 3 and gen 4.

I have been in talks with Crane cams and have dropped off a 3900 cam to see what they can do for reproduction and custom specs for the larger cam journals of the lz4/9. they would be based off of the earlier style timing chain so the vvt would be eliminated. This would allow for obd1 and obd 2 setups. I am waiting to hear back for pricing, so not sure if anyone would be interested in this option or not.

Hmmm, that sounds like a great option, and far better than finding or getting bearing spacers made.

If this comes to fruition, I may go to an LZ9 sooner than I would have thought.

Of course, I still want to put a good cam in my LX9 and play with it for a while before any drastic changes are made.

I have been in talks with Crane cams and have dropped off a 3900 cam to see what they can do for reproduction and custom specs for the larger cam journals of the lz4/9. they would be based off of the earlier style timing chain so the vvt would be eliminated. This would allow for obd1 and obd 2 setups. I am waiting to hear back for pricing, so not sure if anyone would be interested in this option or not.

[ericjon262]

The project is on hold but I've got the 3.5 with F40 in the car. Axles are figured out. Exhaust was in process before I had to move. Wiring isn't terrible. I have all the colors and gauges figured out. And was in the process of drawing the new diagram.

My build is unusual as it is a 3.5 for initial fitment and debug followed by a fully built 3.9L with DOD, VVT and a VGT all run off a C6 ZR1 computer controlled fuel pump.

I'm using stock coolant tubes and cross over pipe welded to fit. It's quite a bit of fab work.

There are several computers capable of running this engine. Though a modified ZR1 computer is probably the best choice given the complexity of my build.

The trouble is getting software figured out

I didn't think the ZR1 had VVT?

I feel like the hardest part of running a non stock computer, esp obd1, will be the fact that you basically will need all of the same tables you would use for spark control replicated to control the cam, which then leads to the tuning nightmare of having another big variable to have to dial in. it's the part of swapping to a VVT engine that I dread the most.

[NateD4]

The project is on hold but I've got the 3.5 with F40 in the car. Axles are figured out. Exhaust was in process before I had to move. Wiring isn't terrible. I have all the colors and gauges figured out. And was in the process of drawing the new diagram.

My build is unusual as it is a 3.5 for initial fitment and debug followed by a fully built 3.9L with DOD, VVT and a VGT all run off a C6 ZR1 computer controlled fuel pump.

I'm using stock coolant tubes and cross over pipe welded to fit. It's quite a bit of fab work.

There are several computers capable of running this engine. Though a modified ZR1 computer is probably the best choice given the complexity of my build.

The trouble is getting software figured out

[neophile_17]

Nate,

That's interesting. I didn't know that had been done. Do you have a build thread somewhere? I'm sure I'll be running into similar problems soon enough.

I'm assuming that you're talking about the radiator hose and not the heater core lines. I had an initial thought about re-purposing the stock Fiero pipe that crosses to the drivers side but I'm a long way from that point.

[NateD4]

Use of the stock computer for an LZ is possible. Just have to get EFI live and turn off the vehicle anti theft check.

I'm half way through this swap with both 3.5 and 3.9. The snag I had to figure out is plumbing the coolant system. Wiring isn't too bad as the engines are simpler than the LX in many ways...

[neophile_17]

My initial thought was that there is no way this could be done mechanically but after a little more consideration I think something along the lines of the advance mechanism in an old school distributor could work. The oil control system would have to be bypassed in this scheme and it's not something I'd probably take on but it's fascinating nonetheless. Going the electrical route will be tricky unless you have feedback on the angle difference between the cam and the crank. I like that all the hardware is in place for this on the MS3X- I just have interpret the signals and tune the control loop. That's the hope anyway.

I'll take pictures of the cam phaser before I put it all back together. Anything in particular that you want more detail of?

[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.

[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]

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]

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.

TB_Adaptor_75mm.jpgTB_Adaptor_Assembled.jpg
TB_Adaptor_On_Manifold.jpgTB_IAC_Passage.jpg

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]

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

[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.