3900 versions and configurations for swap use

[ericjon262]

If, as with the LS4 the E67 needs the BCM in order to operate AFM/DOD, then it might not be feasible to implement.

Can't the 58x wheel be swapped for a 24x?
I wonder if the cylinder select in the E40 from the early LS4's could be switched from 8 down to 6 to run the 3900. The 3900 is just 100cc's shy of being 3/4 of a 5.3... That would allow running the AFM/DOD (and cruise control!) with 24x DBW engine management.

is there a cylinder select option in the LS4 programming? I haven't seen one in the later PCM's that I've looked at (doesn't mean it's not there though...)

I like the idea of the LNJ trigger sounds like the best option to me, I would bet it could be installed as long as the 58x trigger isn't machined into the crank like the earlier triggers. even then a quick trip to the lathe could fix that.

[caffeine]

I don't know of any available 24x internal reluctors that will fit a 3900. The equinox 3400 one MAY be useable but IMO it'd be easier to fab an external trigger and then you can run it on whatever you want.

As for the coolant crossover, it would be pretty simple to fab one up. I was gonna start doing that but haven't had time.

[Will'sFiero]

thought on the coolant crossover, why not make one? it's not a complicated part, 2 plates, one bolted to each cylinder head, a little hose, done.

Or even weld up some tube in between and save the potential leak points; Yes, it could be built. I'll have to investigate how the original is plumbed internally before I decide how easy or not that might be.

yes, all are 58x, and AFAIK, they all use the E67 ecm as well...

If, as with the LS4 the E67 needs the BCM in order to operate AFM/DOD, then it might not be feasible to implement.

Can't the 58x wheel be swapped for a 24x?
I wonder if the cylinder select in the E40 from the early LS4's could be switched from 8 down to 6 to run the 3900. The 3900 is just 100cc's shy of being 3/4 of a 5.3... That would allow running the AFM/DOD (and cruise control!) with 24x DBW engine management.

[ericjon262]

http://www.fiero.nl/forum/Forum3/HTM...-26.html#p1011


That's why... I asked on that thread if he meant using the 24x PCM for his next swap in order to try getting AFM/DOD working.

All 3900's are 58x, right?

yes, all are 58x, and AFAIK, they all use the E67 ecm as well...

[ericjon262]

thought on the coolant crossover, why not make one? it's not a complicated part, 2 plates, one bolted to each cylinder head, a little hose, done.

[caffeine]

3900 versions and configurations for swap use

Nvm

[ericjon262]

here's a list of tunable parameters for the 3900 using tunercat obd2. not sure what HP tuners or EFI live offers, not too interested either, as I have TCobd2 and not the others.

OBD2_56.pdf

[caffeine]

It might be a t-stat bypass you're looking at on the crossover. As for the head gaskets, I don't actually know what the difference is just that they are different. I'm thinking they may have differently sized coolant passages to work with the crossover on the front of the engine.

[Will'sFiero]

The 3900 water crossover could be moved to the other side of the heads. Since the 3900 has different head gaskets left and right, however, you might need to also swap the heads/head gaskets to get proper cooling. For a RWD conversion this is almost essential in order to make room for accessories with a flipped upper intake.

I did notice in the photobucket above that there's a loop of hose from a heater connection on the waterpump casting to a connection on the coolant crossover... What does that do?
Also, with the coolant crossover on the back of the engine, the main coolant outlet points to the trunk in a Fiero, instead of forward to the firewall. This isn't the end of the world, but makes plumbing more complicated. If used on the back of the engine, the coolant crossover might also interfere with the minivan exhaust crossover

What's the difference between the head gaskets? Different size coolant passages?

[caffeine]

And yes the oil filter can be moved directly to the block. However some 3900s come with an oil cooler that would be nice to keep.

Also a note on the oil pan. I do now remember that it is different from a 3500 oil pan, as it has a 'notch' in it for oil filter clearance. With the oil filter moved closer to the engine on the 3900 there's a chance it could clear the Fiero cradle with some more minor notching compared to, say, the stock 3500 oil filter location.

[caffeine]

The 3900 water crossover could be moved to the other side of the heads. Since the 3900 has different head gaskets left and right, however, you might need to also swap the heads/head gaskets to get proper cooling. For a RWD conversion this is almost essential in order to make room for accessories with a flipped upper intake.

[Will'sFiero]

http://60degreev6.com/forum/showthread.php/50665-V6-curiosity?p=459520&viewfull=1#post459520

I'm guessing the piston pin is located differently and it too is a different diameter (.9055 for a 3.4 and .9447 for a 3.5).

Did Upson have to do anything about wrist pins to install his LS1 pistons?

Edit: https://www.gmheritagecenter.com/doc...let-Impala.pdf
Pages labeled 35 and 42 have LZ4 and LZ9 rod lengths... both listed at 150mm; We know this is incorrect, because the engines have the same pistons but different strokes.

Upson measured 3900 rods at 5.827" long... Just to make up for the difference in stroke, LZ4 rods would have to be 5.984" long. They're probably a little longer than that to put the piston higher in the bore to keep the compression up.

[ericjon262]

None at all... just getting a handle on the different configurations.
I haven't looked at Upson's thread in a while...
Are the wrist pin diameters the same? LS1 ring pack or 3900?

Edit: Upson says 3900 rods are 5.827" long. Have you seen any info on LZ4 3500 rod length?

sorry, I don't have any rod info. pin diameter for the LZ9 is listed as .943" LS1 is listed as .945" little machine work and that's not a problem.

Edit:I wonder how accurate upsons rod measurements were. all the published specs I've seen say the LZ9 got 5.9" rods, maybe the 3500 got them though. stroke is .3"less, .3"/2+5.827"= 5.977" maybe the rods stretched a bit?

Edit2:
The LX9 has the water outlet manifold on the back of the cylinder heads, as I thought the LZ9 did.

nope, it's part of the lower intake manifold. the LX9 doesn't use a separate water manifold

[Will'sFiero]

any reason LS1 pistons couldn't be used?

None at all... just getting a handle on the different configurations.
I haven't looked at Upson's thread in a while...
Are the wrist pin diameters the same? LS1 ring pack or 3900?

Edit: Upson says 3900 rods are 5.827" long. Have you seen any info on LZ4 3500 rod length?

Edit2:
The LX9 has the water outlet manifold on the back of the cylinder heads, as I thought the LZ9 did.

[ericjon262]

any reason LS1 pistons couldn't be used?