LS4 / F40 swap - fieroguru (Page 213/216)
Rickady88GT OCT 14, 11:21 PM

quote
Originally posted by fieroguru:

I need to take the front wheels off the Fiero for some new tires. While I have it up in the air, I will likely remove the two rear bolts for the front crossmember and see where the chassis side holes are.

From some preliminary measurements, the wheel flange face to the lower a-arm cross bolts were off slightly, but close. I think the a-arm to crossmember brackets are longer on the PS than on the DS.

It it wasn't "designed in", then the bolt on the chasiss would be off to the side of the hole.The rear holes are large enough for M14 bolts, but that is much too larger for some stamped steel brackets. They are likely M12 to M8 which would give them some sloppiness to accomodate this issue.

The real question is can I fix this as I design my new crossmember. At a minimum, I could add a slot to the passenger side that would allow the current hole as well as the hole that matches the drivers side.



Doesn't the front member have a large pin on each side to locate the member exactly the same position every time it is removed and reinstalled? I don't remember if that was just pre88 or all Fieros? But the bolts wouldn't have any affect at all on locating the member if the pins are there. I seem to remember them being but the spring towers.
fieroguru OCT 15, 07:09 AM

quote
Originally posted by Rickady88GT:
Doesn't the front member have a large pin on each side to locate the member exactly the same position every time it is removed and reinstalled? I don't remember if that was just pre88 or all Fieros? But the bolts wouldn't have any affect at all on locating the member if the pins are there. I seem to remember them being but the spring towers.



There is a single pin on the DS in between the two crossemember to frame bolt holes by the upper a-arms.
Will OCT 16, 07:02 PM

quote
Originally posted by fieroguru:

The real question is can I fix this as I design my new crossmember. At a minimum, I could add a slot to the passenger side that would allow the current hole as well as the hole that matches the drivers side.



Even BMW slots holes to deal with production tolerances. One corner of a crossmember will be the "anchor" with a round hole. The other hole on the same side will be slotted slightly fore/aft, while both holes on the other side will be slotted left/right.
Will OCT 16, 07:09 PM

quote
Originally posted by fieroguru:

Spent a few hours detailing the stock cradle in AutoCAD. All the suspension points are within about 0.005", but some of the crossmember shapes are appoximates. This crossmember I modified to remove the bump stop pad and trimmed the area around the spring perch. The main reason for this is to document the stock suspension setup for comparison to the new setup once I design it.



I have to be out of town Monday night to Tuesday night and have some orders to process, so it will be a few more days until I can get back to this.




Did you make a 3D model? Are you willing to share?
fieroguru OCT 16, 08:19 PM

quote
Originally posted by Will:
Did you make a 3D model? Are you willing to share?



Just a 2D version. Have the drivers side view, but haven't finished the front, rear, or passenger side views. Once I came across the significant variation, I wanted to figure that out and determine how I proceed with the drawing (detail as fabricated or as designed).

If we were talking 0.030" it wouldn't be a big deal and I would just make everything symetrical in the drawing and account for the variation with hole slots in the appropriate direction.
When things are off 0.125+" then I need to have a better understanding of why.
fieroguru OCT 18, 06:08 PM
Got the new front tires mounted today that match the new rear ones I purchased on the HRPT. Bridgestone RE-11 tires were discontinued so I went with Bridgestone RE-71.
While the front of the car was up, I tried to check out the rear bolts, bt they are covered with the coolant tubes. So I didn't go much further with that.

Started playing around with the hole issue on the rear stands in AutoCAD. I went ahead and mirrored the hole from the left to the right. From there, I added a centered M12 bolt to the right and then mirrored it back to the left. It fits both sides. So I decided to use the Left hole in the cradle and slot the old on the right. It is hidden from view by the bolt, but the right cap has the centerline for the right hole and the mirrored left hole cut into the leading edge.


Once I was good with that, then I made the caps, welded them in place and smoothed out the welds.

Finsihed rear stands and removed the two rear jack bolt supports:


[This message has been edited by fieroguru (edited 10-18-2025).]

fieroguru OCT 19, 08:06 PM
Should have had the front cradle attachment stands completed today, but I think either the power supply or the motion controller went out on my plasma table. I have a note into Langmuir and will call them in the morning. Of coarse it happened right as I was getting ready to cut the top plates out. The table has worked near flawlessly for the last 5 years, so I can't complain.

Here are the front stands with the tabs welded to them and the 5/8 bolts welded to the tabs:






Here is the drawing for the top plates. The right side was treated the same way as the rears with slotting.

[This message has been edited by fieroguru (edited 10-19-2025).]

ericjon262 OCT 19, 09:33 PM
You've had way better luck with your langmuir than I have. I'm on my third torch fire relay board and my second THC module.... One of the fire control relay boards failed on my second or third cut.

------------------
"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.

fieroguru OCT 23, 06:21 PM

quote
Originally posted by ericjon262:
You've had way better luck with your langmuir than I have. I'm on my third torch fire relay board and my second THC module.... One of the fire control relay boards failed on my second or third cut.




Getting my plasma table back up and running is becoming spendy...

I purchased mine in May 2020 and it used Mach 3 for the table control software. I also upgraded to the XL version of the table at the same time to maximize the cut area, which was an early upgrade.
My table has a bad motion control board and it was proprietary to Langmuir and unique for Mach 3 control. Langmuir has obsoleted everything with Mach 3, so I can't purchase a $50-$100 control board.

I have to upgrade to FireControl software, which also means I have to get an entire new power panel enclosure. Basically everything electrical on my table except the actual X &Y servo motors will be new. However, these are now only available with the THC for the Z-axis, which my early table did not have (nor really need). So I also have to upgrade to the THC. What complicates that is my XL upgrade predated the THC upgrade and they eventually switched to a thicker tube to support the additional cantilevered weight of the Z-axis servo, brackets, and lead screw... so I also have to purchase and swap out one of the Y axis tubes...

It will cost $817 and a few hours of work to get my table back up and running... Parts are currently in transit with a Saturday delivery, so I will likely do all this work this coming weekend.

I really like this CNC plasma table, so it will be $$$ well spent, but I would have preferred to swap out the board and be back running in minutes vs. hours.
ericjon262 OCT 24, 01:44 AM
Thats a bummer that it will cost you that much to get it running again... I will say, back during the 'vid, I got a chance to try and play with a MACH 3 langmiur, it was kinda a nightmare compared to the firecontrol software. I think you will like that aspect of the "upgrace"

------------------
"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.