this is probably a dumb question, but is it possible to test run the engine while it is still attached to a stand? Meaning, does it need to be in the vehicle and hooked up to the gauges and other things to function properly, or can the ECU be hooked up to the vital engine controls (cam sensor, crank sensor, injectors, IAC and so on) while it is still out of the vehicle to test before installing? Is this something you will be doing to yours prior to install? Also, in your experience, do you know if the starter from the 2.8L will fit the LZ9?
the 2.8 starter should work, but the 3.9 starter is about 1/3 of the size/weight of the 2.8 starter, it's generally used as an upgrade for the 2.8 part as it's lighter, and significantly easier to change.
as far as running the engine on the stand, it's possible, but frequently not practical.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.
the 2.8 starter should work, but the 3.9 starter is about 1/3 of the size/weight of the 2.8 starter, it's generally used as an upgrade for the 2.8 part as it's lighter, and significantly easier to change.
as far as running the engine on the stand, it's possible, but frequently not practical.
The reason I ask about the starter is about 7 months ago I bought a gear reduction Denso style starter when my OE starter went out. Its only 8 pounds and is made for high compression engines, but I got it for a great price and I really like the way it sounds lol. If it fits the LZ9 that will save some money for other things .
You mentioned in your opening post that when you changed out your cam, you also replaced the timing set from a 3.4L. Did you change out both the cam and crank sprockets? I ordered a new LZ9 tensioner like you have, but the only one I could find also came with a new cam & crank sprocket and chain. I had also ordered a 3.4L timing set, and it came with the chain and crank sprocket. I noticed the LZ9 chain and sprockets are much thicker than the 3.4L chain and crank sprocket, and the tooth count from the LZ9 crank sprocket is less than the tooth count of the 3.4L crank sprocket (20 teeth on the LZ9, 25 teeth on the 3.4). Did you change out both the cam and crank sprockets from a 3.4L? I the attached pictures, the smaller/thinner parts (chain and crank sprocket) came with the 3.4 timing set, and the thicker parts (chain, cam and crank sprockets) came with the LZ9 kit. I am assuming that since you replaced the LZ9 VVT cam with the Equinox 3.4L cam, you needed to change the camshaft sprocket to fit, and also the crankshaft sprocket as well(?)
t
[This message has been edited by Murcie-Me (edited 02-14-2025).]
You mentioned in your opening post that when you changed out your cam, you also replaced the timing set from a 3.4L. Did you change out both the cam and crank sprockets? I ordered a new LZ9 tensioner like you have, but the only one I could find also came with a new cam & crank sprocket and chain. I had also ordered a 3.4L timing set, and it came with the chain and crank sprocket. I noticed the LZ9 chain and sprockets are much thicker than the 3.4L chain and crank sprocket, and the tooth count from the LZ9 crank sprocket is less than the tooth count of the 3.4L crank sprocket (20 teeth on the LZ9, 25 teeth on the 3.4). Did you change out both the cam and crank sprockets from a 3.4L? I the attached pictures, the smaller/thinner parts (chain and crank sprocket) came with the 3.4 timing set, and the thicker parts (chain, cam and crank sprockets) came with the LZ9 kit. I am assuming that since you replaced the LZ9 VVT cam with the Equinox 3.4L cam, you needed to change the camshaft sprocket to fit, and also the crankshaft sprocket as well(?)
t
I used the 3.4 timing set. sprockets for cam and crank and chain.
I couldnt find an LNJ cam for the 2007 Equinox, everything said it was unavailable. I bought a stock camshaft from GM for the 2007-2009 3.4L equinox, Should it be the same (other than sprocket mounting)? You mentioned you were reusing the lifters from the LZ9 engine, which are roller lifters. Is the Equinox camshaft compatible with roller lifters, or does that matter? For some reason parts are becoming very difficult to find for this swap.
I couldnt find an LNJ cam for the 2007 Equinox, everything said it was unavailable. I bought a stock camshaft from GM for the 2007-2009 3.4L equinox, Should it be the same (other than sprocket mounting)? You mentioned you were reusing the lifters from the LZ9 engine, which are roller lifters. Is the Equinox camshaft compatible with roller lifters, or does that matter? For some reason parts are becoming very difficult to find for this swap.
That camshaft would be for the LNJ. It should be a roller camshaft either way so yes it will be compatible.
That camshaft would be for the LNJ. It should be a roller camshaft either way so yes it will be compatible.
OK thank you! I was beginning to worry I ordered the wrong cam. Have you started back on your build yet or are you still busy with your work training? Im really anxious to see how you tackle the electrical on this engine, it seems like it's going to be far less than all the connections on the stock 2.8L, and I assume no smog connections? How did you get your engine parts so clean, especially the LIM and oil pan?
I bought one a couple months ago. They are discontinued from GM, and I was only able to find them at Vintage Parts. They had around 70 of them at the time....I assume they bought up all the remaining ones.
Edit: I just checked their website, they show 43 in stock. So they might be completely gone soon-ish.
[This message has been edited by I Lean (edited 02-19-2025).]
I bought one a couple months ago. They are discontinued from GM, and I was only able to find them at Vintage Parts. They had around 70 of them at the time....I assume they bought up all the remaining ones.
Edit: I just checked their website, they show 43 in stock. So they might be completely gone soon-ish.
Could you post a link to the website you're talking about? Do you know the part number of the cam? The one I ordered from GM is 12596567
[This message has been edited by Murcie-Me (edited 02-19-2025).]
Originally posted by Murcie-Me: Could you post a link to the website you're talking about? Do you know the part number of the cam? The one I ordered from GM is 12596567
The cam I got was 12596567....which I found zero dealers had in inventory at the time. So if that's the one you got, you should be good to go!
There is now! I realized that the flywheel that I used from the old 2.8 was an externally balanced flywheel. so there is a weight on one end that would have make the internally balanced lz9 vibrate. so I got a new flywheel for an 88 fiero that will work. apparently late 87 and all 88 fieros had internally balanced engines and those flywheels will work.
Good catch! I have a question for you. I was installing my new cam the other day in the LZ9, so i lined up the mark on the crank sprocket with the mark on the cam sprocket and bolted it all in (to the camshaft). When the #1 cylinder is TDC on the compression stroke, should these marks line back up (facing each other)? it seems when mine is TDC #1 on compression, both marks are at 12 o'clock (attached picture). I know its hard to see in the picture, but the crank sprocket mark is straight up at 12 o'clock, and the mark highlighted on the cam sprocket is as well. If I crank it to where they line up, im no longer at TDC on compression. The crank sprocket has an index so it only fits one way, and the cam sprocket has a pin so it fits in only 1 position as well. Am I missing something?
Also, did you use the harmonic balancer from an '87-'88 Fiero? I have been reading that since the LZ9 is an internally balanced engine (like you mentioned in your previous post), that you cannot use a harmonic balancer from a pre '87 2.8l engine since those had a weighted harmonic balancer. I notice the LZ9 I bought did not have a balancer on it, just a crank pulley for the belt. If this is correct I guess I will have to track down a 1988 Fiero harmonic balancer.
[This message has been edited by Murcie-Me (edited 03-24-2025).]
Good catch! I have a question for you. I was installing my new cam the other day in the LZ9, so i lined up the mark on the crank sprocket with the mark on the cam sprocket and bolted it all in (to the camshaft). When the #1 cylinder is TDC on the compression stroke, should these marks line back up (facing each other)? it seems when mine is TDC #1 on compression, both marks are at 12 o'clock (attached picture). I know its hard to see in the picture, but the crank sprocket mark is straight up at 12 o'clock, and the mark highlighted on the cam sprocket is as well. If I crank it to where they line up, im no longer at TDC on compression. The crank sprocket has an index so it only fits one way, and the cam sprocket has a pin so it fits in only 1 position as well. Am I missing something?
Also, did you use the harmonic balancer from an '87-'88 Fiero? I have been reading that since the LZ9 is an internally balanced engine (like you mentioned in your previous post), that you cannot use a harmonic balancer from a pre '87 2.8l engine since those had a weighted harmonic balancer. I notice the LZ9 I bought did not have a balancer on it, just a crank pulley for the belt. If this is correct I guess I will have to track down a 1988 Fiero harmonic balancer.
Ultimately if the marks line up, that's what it is, the cam spins at half crank speed, so if both sprockets are in the correct position, it will be cyl 1 TDC at both the 12 o'clock and 6 o'clock positions, compression and exhaust, all you need to make sure when you're putting it on is that it is exactly 12/6 o'clock and not 11:30, 6:10, etc. Ultimately the crank has the pistons at the correct position in relation to the valves.
The harmonic dampener can be used from any 2.8, they are not a balancer, only work to dampen the pulses from individual combustion events to prevent resonance in the crankshaft that can build up and cause damage,
Everything I've read says that the Fiero changed from externally balanced to internal balance in 1988, as well as all other 60 degree V6 GM engines. The external balance was achieved through both the flywheel and harmonic balancer, while the 88 and later were balanced internally with the disc on the crank and had a neutrally balanced flywheel and a neutral balancer in front. There is a difference between a pre-88 balancer/pulley arrangement and an 88+ There is also a thread about this already on this forum, read the opening paragraph here:
Doesn't matter to me either way, just thought I would share this info in case there really is something to it. I dropped my '86 balancer off at a machine shop for them to remove the extra weighted area and check to make sure its neutrally balanced afterwards.
[This message has been edited by Murcie-Me (edited 03-25-2025).]
I have done a few 3500/3900 vvt swaps with MicroSquirt and will hopefully be helping a local with the ms3 mini like you are planning on using. Currently my personal fiero is a turbo VR6 running on MicroSquirt and I just got the ms3 mini in the mail for it to get proper vvt control along with the sequential
I have yet to keep the fiero timing cover on a build I usually keep the 3900 set up, but I respect the direction
If you need any files for tuner studio I would be more than happy to send you some of the different builds I have done base files
I am very excited to see how your exhaust sounds. I have done the modified rear manifold with stock crossover on routing on two cars, the other car is now turbo using a similar design and then was redone to have equal length using a g6 rear manifold to join to the factory crossover that was then modified to be the turbo inlet manifold. I am hoping to convert one of the cars to a dual non collected manifolds routed to equal length manifold similar to your crossover. I love hearing how each different set up sounds
You look more than capable of crossing all the bridges but if you need any help I would love to lend any assistance I can
Everything I've read says that the Fiero changed from externally balanced to internal balance in 1988, as well as all other 60 degree V6 GM engines. The external balance was achieved through both the flywheel and harmonic balancer, while the 88 and later were balanced internally with the disc on the crank and had a neutrally balanced flywheel and a neutral balancer in front. There is a difference between a pre-88 balancer/pulley arrangement and an 88+ There is also a thread about this already on this forum, read the opening paragraph here:
Doesn't matter to me either way, just thought I would share this info in case there really is something to it. I dropped my '86 balancer off at a machine shop for them to remove the extra weighted area and check to make sure its neutrally balanced afterwards.
There are several threads, read that whole thread you posted, especially the 3rd last post, the GM manuals list different numbers between 85-86 and 87-88, that doesn't coincide with the internal balancing. From all the threads I've read, it seems the aftermarket thinks they are different parts (maybe confusing the seperate part numbers with the internal balancing changes even though they were done in different years), but all gm information and manuals list them as fully backwards compatible. It is interesting that some have the weighted area (although that is small compared to the flywheel balancer), although that to doesn't seem to correspond to specific years, there was an 86 GT and another 86 without that bump in that thread you posted, and the documentation in the 3rd last post pictures one with the bump and specifically calls it neutral balanced. There may be balancing/a balancing tab to be machined away as needed at the factory to achieve a neutral balanced dampener, that may be what the bump on some is for, in that case, before machining it away, make sure that it isn't balanced already with that tab. Every thread I've read have the "experts" on this forum saying they're all neutral balanced, as well as gm documentation, Fiero Sound, JazzMan, Blacktree, all with over 15,000 posts each, and much more experience than me haha. Example
Every thread has people saying what you're saying, but every thread also has more people, with more experience, and sometimes gm documentation saying that they are all neutral balanced. The flywheel balances the rotational weight imbalance, the dampener balances the torsional resonance on the crank caused by the pulses of the pistons firing, hence why it's called a "harmonic" balancer/dampener, it doesn't balance a weight imbalance, it balances resonant frequency and harmonics in the crank, which occurs whether your engine is internally or externally balanced.
[This message has been edited by 1985 Fiero GT (edited 03-25-2025).]
I've been working on this thing the whole week. Working on wiring evertlything right now. I 3D printed a mount for the MegaSquirt to be put in the factory ECU spot. Made a throttle cable bracket that mounts to the top of the intake manifold. Got the fuel pressure regulator mounted and lines running to it and to the fuel rail. relocated the evap canister to where the old cruise control stuff was. got the intake largely routed where it will be other than the filter at the end. got a IAC valve from a 1995 vw golf mounted with its own little filter.
Excellent work! I love seeing all the custom parts made for this installation also. I am going to do my throttle cable much the same way as you, I also need to hook up the TV cable as well for my 4T60. Did you end up staying with the stock Fiero fuel pump, and which pressure regulator did you use?
Excellent work! I love seeing all the custom parts made for this installation also. I am going to do my throttle cable much the same way as you, I also need to hook up the TV cable as well for my 4T60. Did you end up staying with the stock Fiero fuel pump, and which pressure regulator did you use?
im using some cheap regulator off Amazon. i think it was yeshma or something. right now I am using the stock fuel pump, but when testing the fuel pressure, it won't go past about 40psi. I dont know if its the fuel pump or regulators fault. the regulator is supposed to go all the way to 100 psi and the stock fuel rail pressure sounds like it was about 40.... the lz9 fuel rail sounds like it wants 60psi so something needs to change
[This message has been edited by TheMoist1 (edited 04-23-2025).]
