LZ4 3500 V6 Swap

[neophile_17]

Hello guys,

I started working on an LZ4 swap some time in the past. It might even be as much as 8 years ago. I wasn't originally going to do a build thread but WTH. Hopefully it will finally run this spring. The motor is already together and in the car, but many of the details have yet to be ironed out.

The picture folders below have some details from the motor build. I measured everything, and refreshed the bottom end. Some port cleanup was done on the top end and the valvetrain was upgraded. The cam is a WOT street/strip grind riding on teflon lined bearings (I made a jig to narrow SBC bearings). Cam bearing spacers adapt the small journal cam to the LZ* block. The valve springs were changed to duals with titanium retainers.

Teardown
https://drive.google.com/drive/folders/ ... sp=sharing
Buildup
https://drive.google.com/drive/folders/ ... sp=sharing

The remaining items that I'll be documenting are motor mounts, plumbing, and microsquirt wiring.

Lower Motor Mount Bracket
https://drive.google.com/drive/folders/ ... sp=sharing

I built this bracket to use the stock fiero lower mount and also incorporate an idler pulley. The basic idea is that the routing and belt length is the same as the LZ4. However I didn't account for the bump in the subframe. I thought about lifting the passenger side of the motor. This got crazy and now I'm leaning toward welding in a straight tube where the bump was. Thanks for the idea Zok15! I think this mount could be made so that the idler is higher and further out. This modified configuration would maintain the subframe bump, routing, and belt length. If I ever do another one I'll look into it, but with 3/16" stock instead of 1/4".

Does anyone have a line on a new C500 connector that PhoneDawgz or FieroX from OE offered? I'd like to get one on order if they are available but neither responded to my inquiry.

Thanks for reading.

Sam

[Shaun41178(2)]

Nice. I like your idea on the front mount.

[ericjon262]

Will has also been looking for the C500's as well.

I'm guessing you're not going to try and retain AC?

I look forward to seeing your progress!

[neophile_17]

No plans for AC in the near term. The 20-something version of me didn't need AC and took out the lines going to the front of the car. AC would be nice, but it isn't a life or death feature in New England. I do have a plot to rewind a Prius compressor. This would allow me to keep all the AC stuff in the front trunk which would be engine agnostic.

I modified the subframe this past weekend. It came out about as good as I could have hoped considering I had to work around the engine. The tube is 1.75" square and 0.083" or 0.109" wall. I had some 2" 0.065" wall but the width wasn't as good a match. If keeping the subframe stock, there won't be much if any clearance for the oil filter. Running an oil cooler from an Uplander in the vertical orientation won't be possible with this subframe. I will do it differently on the racecar to accomodate the cooler. Alternatively, I could tap the block to eliminate the angle adaptor but I'd lose the oil pressure port.

Neo17_LZ4_01_Sub_Mod.jpg (371.62 KiB) Viewed 2051 times

Neo17_LZ4_02_Sub_Mod.jpg (291.71 KiB) Viewed 2051 times

Neo17_LZ4_03_Sub_Mod.jpg (321.61 KiB) Viewed 2051 times

Neo17_LZ4_04_Sub_Mod.jpg (319.98 KiB) Viewed 2051 times

Neo17_LZ4_05_Sub_Mod.jpg (392.65 KiB) Viewed 2051 times

I finally got to check out the laser cutter at work and had some block off plates made to cover the old passthrough. I should be able to remove the new harness similar to stock.

Neo17_LZ4_01_Bulkhead.jpg (339.84 KiB) Viewed 2051 times

Neo17_LZ4_02_Bulkhead.jpg (287.47 KiB) Viewed 2051 times

Neo17_LZ4_03_Bulkhead.jpg (282.03 KiB) Viewed 2051 times

I ordered a muffler, flowmaster 80 series in 2.5". I think it's going to be too loud but I have a couple resonator tip options in mind depending on how much additional damping I want.

[zok15]

Very cool, you could definitely design the front mount to locate that idler above the hump which would be a great solution to prevent the need of crossmember modification. You could make a little mount off that front mount for the oil filter relocation also required to avoid crossmember modification (assuming you want to keep the stock oil heater/cooler).

If this was ever going to be a kit, you could redesign the front mount to mount a tensioner instead of idler, and maybe build a low mount alternator bracket off the other side of it to put the alt where the stock tensioner goes. Then this could truly be a "bolt in" swap.

I look forward to seeing your progress!

Edit: your last post just went through, cradle mod looks good. Also you are somewhat close to my friend's place (he lives in Suffield CT), it would be cool to come check out your racecar and swap sometime, maybe when I can drive my Fiero down. I go down there often.

[Shaun41178(2)]

I was able to use the factory oil filter adapter with my factory 88 subframe without making mods

I made a video about it

I did have to use a smaller oil filter however. I think it was a pf47????? Not sure off the top of my head. But it fit

https://youtu.be/cJTRupRXSt8

[The Dark Side of Will]

Does anyone have a line on a new C500 connector that PhoneDawgz or FieroX from OE offered? I'd like to get one on order if they are available but neither responded to my inquiry.

Will has also been looking for the C500's as well.

Yeah, as much trouble and expense as it must have been to have those parts reproduced, and the number of swappers who could buy one, they sure are lying low about selling them.

[zok15]

I too would like a new C500 connector, was going to leave my wires a little long and splice for now, then if I get ahold of one I can chop the spliced connector off and crimp new pins on the wires.

[The Dark Side of Will]

I too would like a new C500 connector, was going to leave my wires a little long and splice for now, then if I get ahold of one I can chop the spliced connector off and crimp new pins on the wires.

All the terminals are available, so you can repopulate your original housing with new terminals. That's my plan if I can't source a new C500 housing. IIRC, the terminal position assurance (TPA) forks are NOT part of the new connector housings, so you still have to either salvage old ones or improvise new ones.

[neophile_17]

Very cool, you could definitely design the front mount to locate that idler above the hump which would be a great solution to prevent the need of crossmember modification. You could make a little mount off that front mount for the oil filter relocation also required to avoid crossmember modification (assuming you want to keep the stock oil heater/cooler).

If this was ever going to be a kit, you could redesign the front mount to mount a tensioner instead of idler, and maybe build a low mount alternator bracket off the other side of it to put the alt where the stock tensioner goes. Then this could truly be a "bolt in" swap.

I look forward to seeing your progress!

Edit: your last post just went through, cradle mod looks good. Also you are somewhat close to my friend's place (he lives in Suffield CT), it would be cool to come check out your racecar and swap sometime, maybe when I can drive my Fiero down. I go down there often.

I really like that accessory solution. If I was to start over I'd probably go that way. It would be cool to be able to buy a bracket kit to swap these motors. I'd buy one but I don't know how big the market is.

I'd definitely be down to meet up some time, hopefully with running cars to show. The racecar lives at my buddy's place in Methuen, MA so I'm up that way several times a year.

https://youtu.be/cJTRupRXSt8

Thanks for the video Shuan, several interesting things there. It's good to know the PF46 is an option to get an extra inch. That may be enough that I can get the oil cooler on this setup. The oil cooler you have is different. The only coolers I've seen are coolant to oil, not air to oil. What car did you find that one on? I still have PTSD from a leaky coolant to oil cooler. Given that, eliminating this coolant/oil interface is interesting option.

I looked up the pushrods I used and they are within a couple thou of what you measured. If anyone else wants to risk using OEM pushrods the picture below has the part numbers I used highlighted and interchange as well.

LZ_Pushrod.jpg (104.17 KiB) Viewed 2006 times

All the terminals are available, so you can repopulate your original housing with new terminals. That's my plan if I can't source a new C500 housing. IIRC, the terminal position assurance (TPA) forks are NOT part of the new connector housings, so you still have to either salvage old ones or improvise new ones.

This is what I'll end up doing unless I can get a spare connector at the JY. I was hoping to keep that harness complete but it wouldn't be that much work to swap the connector back.

[Shaun41178(2)]

I think that oil cooler housing came off of an Impala but it was a police car Impala.

Not sure if that makes a difference or not.

I didn't specifically search outthe police car, it just happened to have a low mile 3900 in the wrecking yard

[zok15]

I think that oil cooler housing came off of an Impala but it was a police car Impala.

Not sure if that makes a difference or not.

I didn't specifically search outthe police car, it just happened to have a low mile 3900 in the wrecking yard

I have seen that they make modifications to cop cars cooling systems to allow them to idle for extended periods of time, maybe that oil cooler is part of that package for the police Impalas.

[neophile_17]

I think that oil cooler housing came off of an Impala but it was a police car Impala.

I took a look online and GM option KD1 for an 08 Impala has the oil to air cooler. I'll keep an eye out for these in the JY.

You could label this post- "wouldn't you make a lot more progress if you didn't get caught up in nit-pick fab projects".

First up is the finest LZ dog-bone made out of scrap/old Mazda control arms. This took about 4 times as long as I planned so no exhaust work got done this past weekend.

LZ4_neo17_1_Upper_MM.jpg (969.35 KiB) Viewed 1867 times

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LZ4_neo17_3_Upper_MM.jpg (621.56 KiB) Viewed 1867 times

Next we have an unnecessary but convenient bracket to hold the microsquirt to the ecm bracket that held the 7730.

LZ4_neo17_1_uS_Bracket.jpg (551.02 KiB) Viewed 1867 times

LZ4_neo17_2_uS_Bracket.jpg (540.74 KiB) Viewed 1867 times

Thanks to Shaun for pointing out that the crank sensor needs a pull-up resistor on Zok15's thread. I was debating between using terminal blocks for the pull-up resistors and soldering them in-line. I'm leaning towards soldering them in. I have a buddy that is morally against soldering automotive wiring. I understand the fatigue complaint, but with proper soldering and heat shrink I've never had or seen a problem. I have seen solid wires break so resistors are a concern. Fiberglass rod under the heat shrink will eliminate flex in the solid/soldered area and heat shrink will fade out the strain as well as any other connection method. That's how I see it anyway. Next up is to order more wire and C500 terminals.

[ericjon262]

I must have missed it, what are your plans for engine managment? Megasquirt?

[zok15]

Believe he is using Microsquirt as well.

I bought a bunch of 1K 1/2W resistors, they will work for pulling WLED up from 5Vref to use as the 3rd spark trigger, and I am hoping it will work for the crank position sensor pullup as well. In the manual they always use a 1K resistor for any CPS that needs a pullup in all their examples, but I have seen people install a potentiometer to figure out a fine tuned value.

I think soldering is fine if properly strain relieved to take stress off any tinned wires. I am going to solder the resistor leads to some short sections of wire and double heat shrink tube it. Then I will use crimps when bridging 5Vref and Signal. I am going to try and stick with all crimps but I don't want to crimp the resistor leads.

[neophile_17]

I must have missed it, what are your plans for engine managment? Megasquirt?

I am using a Microsquirt.

I bought a bunch of 1K 1/2W resistors, they will work for pulling WLED up from 5Vref to use as the 3rd spark trigger, and I am hoping it will work for the crank position sensor pullup as well.

For the resistor, I see 1K mentioned in several posts about the 58X sensor. This is what I will be using.

These are my notes from doing testing with a MS3 on the crank and cam sensors. This was done on the bench and that was awhile ago so take it as a starting point rather than etched in stone. The 24X colors were closer than the 58X colors which is why used that part of the manual to edit.

LZ4-CKP-Sensor_MOD.jpg (2.1 MiB) Viewed 1830 times

[zok15]

Just don't forget the 58x sensors take 5Vref instead of 12V

[neophile_17]

Good call I revised the photo.

LZ4-CKP-Sensor_MOD.jpg (2.1 MiB) Viewed 1819 times

[zok15]

Was talking with my coworker/friend's dad (experienced electrical engineer with lots of hall effect sensor experience) about pull up resistors for the CPS, he is a car guy too, has a 2007 911 manual with less than 2K miles on it (bought it recently). But anyways he was basically informing me that the pullup resistor value is going to affect how fast the voltage is pulled back up to 5V. When the sensor is triggered it pulls the signal wire down to ground, and then it goes back up to 5V ref at a rate determined by the pull up resistor value. He was saying 1K might be a little low depending on how many RPMs this will be turning because the voltage on the signal wire may not be pulled up to 5V fast enough to create a square wave profile. Just some good info on what to do if CPS signal is breaking up at higher RPMs, a higher pull up value can increase pull up speed to create a cleaner signal.

[Shaun41178(2)]

I've had mine up to 6900 rpm before and it was good with the recommended resistor