LZ4/Fiero Swap

[ericjon262]

the buckets also probably allow oil to pool around the spring, which should help keep it cool. you driving this thing yet?

[neophile_17]

my 2009 lz9 has the buckets on the springs too. Not sure why they did this...

I actually think I've figured out the answer while I was researching springs. The buckets are actually dampers that reduce harmonics that increase spring fatigue. This is accomplished by the inner spring in a multi spring setup but it has the downside of adding heat and friction to the most highly stressed part of the spring- the inside. Because the cup dampens on the outside harmonics are reduced without adding additional stress to the inside of the spring. Pretty clever actually.

[1QUICKHATCH]

So I've been thinking about a couple problems and ca7n't seem to make up my mind.

Valve spring seats - Why did GM turn them into cups for the LZ4 and presumably LZ9? These are shown in the picture below. Is there any clocking required? I'll probably end up going to LS seats but I'm curious what made GM spend the extra $ on these.

Cam bearing holes - I opened up the cam bearing holes to match the spacers or 3/16". This started because I installed SBC bearings and I had to open up the second hole in the first bearing. But then I figured I should make all the holes line up. Now I'm concerned that I might have upset the oil flow balance and I'm considering a new set of bearings. Anyone care to chime in?

Thanks!

my 2009 lz9 has the buckets on the springs too. Not sure why they did this...

[neophile_17]

Just an FYI. This motor is getting pushed back into the corner so I can build a high compression 3400 for the race car. See you next year ;P

[neophile_17]

So I've been thinking about a couple problems and can't seem to make up my mind.

Valve spring seats - Why did GM turn them into cups for the LZ4 and presumably LZ9? These are shown in the picture below. Is there any clocking required? I'll probably end up going to LS seats but I'm curious what made GM spend the extra $ on these.

Cam bearing holes - I opened up the cam bearing holes to match the spacers or 3/16". This started because I installed SBC bearings and I had to open up the second hole in the first bearing. But then I figured I should make all the holes line up. Now I'm concerned that I might have upset the oil flow balance and I'm considering a new set of bearings. Anyone care to chime in?

Thanks!

[neophile_17]

I decided to go with the VR circuit for the crank sensor and the opto circuit for cam which seems to be the current recommendation for an LS1. I built the MS3 over the last week and did a little bench testing today. I can see the inputs in the log for both sensors which is promising. Now I need to get the motor cleaned up and back together.

[neophile_17]

I did some testing on the crank and cam sensors last night to verify that I was on the right path with the input setup. They appear to be identical internally with only the physical housing being different to mount at the correct angle and bolt clocking.

Looking at the MS3Base documentation (clip below) for an LS motor the wire color lined up better with the LS1 than the LS2 even though the LZ4 has a 58X wheel like the LS2. I applied power to the sensor and looked at the voltage on the signal wire. What I got was 0V with the tip in open air, and 1.75V when next to an iron flag. This was the same with both sensors and input voltages at 4V, 5v, and 12V. I'm wondering if I should follow the current recommendations and attach the crank sensor to the VR circuit instead of the Opto In, or go to a smaller cap than originally speced.

[neophile_17]

That's a good plan. I had planned to make the injectors easy to split for sequential but hadn't thought to go so far as to make an adapter harness.

Anyone run a cam sensor with cam spacers on an LZ*? I was looking at the old VVT cam and a stock LA1 cam side by side on the bench and I'm a little concerned that sensor was offset inboard and the sensor won't see the tooth. Not sure it's a problem but it's a concern.

Ti[: Wire it for the MS3, then make an adapter that combines the two plugs into the single no X MS3. I have done this with my Datsun, and plan to swap to my MS3X at some point soon.

[neophile_17]

Thanks!

New soldering iron and opto-isolator are arriving tomorrow so hopefully I can make some good progress this Sunday on the MS3. I'm going to be wiring the MS3 similar to what Jonpro03 did for his MS2 in this thread:

http://www.60degreev6.com/vb5/forum/pushrod-engines/pushrod-general/23648-lx9-crank-relcutor-megasquirt-coil-near-plug

With crank sensor, cam senor, ignition triggers, electric fan and the Evap solenoid I'll be out of I/O but I can upgrade to the X part of the MS3X at any time.

Yes you can do it that way. That's how my machinist did it I think

[neophile_17]

Is there a recommended sequence to install the cam spacers into the block. It would be nice to line up and install the bearing into the spacers and then install the assembly into the block. I can't think of a reason not to do it this way but I figure it's worth asking.

Thanks!

[neophile_17]

Wow! It's been more than two and a half years since the last update on this thread. Other life things have gotten in the way like new job, new house (much better garage!) but I'm looking to get back to this guy. The engine did get torn down to the block in that time and some cleaning got done, but the big news is that I ordered and received the MS3. So I will be moving forward this winter with a running this spring plan.

Alright, just thought I'd offer in case you hadn't found one yet.

[neophile_17]

Unfortunately this is my only car project with no deadline so progress is slow. Realistically it will July before I can spare time for it, unless my LX9 isn't salvageable.

The VVT part doesn't really scare me nearly as much as getting all the sensors reading reliably.

I picked up that bolt a couple weeks ago. Thanks though!