Real tech discussion on design, fabrication, testing, development of custom or adapted parts for Pontiac Fieros. Not questions about the power a CAI will give.
CaptainHindsight wrote: ↑Sat May 22, 2021 12:04 am
I build all sorts of custom robots and 5+ axis machines as well as additive manufacturing tech. I could print sand molds and cast aluminum rockers or cam blanks and grind them. It just more of a project than I planned.
@ericjon262 What ratio are the comp "Magnum" roller rockers? If they were to magically shrink and fit on the pedestals, how would they ride on the valve stems?
Do you know who makes the header flanges? I might pick some up vs plasma cut them.
They're 1.8:1, I honestly don't remember how well they rode the valve stem, I didn't give them much more thought after seeing they had interference issues. if you wanted to get fancy, you could machine shouldered shafts that only have a snap ring on one side, and then they would probably fit. Hopefully, later this month I'll be able to access my mock up cylinder head and I can put them back on and provide better information.
I have a DXF file for the flange, I haven't cut any yet myself, but a guy on Old Europe did, and they look like they fit ok.
"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."
No aftermarkwt vvt cams for the lz. I enquired years ago. Not enough demand which makes sense. The engine came in 4 door family cars.
You can swap to a non vvt cam from GM made for the lnj engine but it shares the same lift as the stock vvt cam.
You can have a custom cam made but its gonna be costly. Maybe 1k bucks for a billet cam with vvt. The problem is the blanks. From what I understand the cam companies dont have the blanks to be machined with the larger LZ cam journals.
You cant talk to sales people at these cam companies. They just look at the catalog. You gotta talk to the machinists. Since you are one, maybe you can get or already know more details about cam production
Mark the welding rod V12 guy used his own mill with a live fourth axis (probably better on a lathe...) to machine blanks from round bar, then sent them to Comp or Crane to be ground to spec from round... for ~$100/lobe
I wonder if they meant a blank already machined to length with some rough work already done.
In the spirit of GM's assembled cams, take a piece of whatever ground round bar suits you, then cut some keyways in it where the lobe center will end up. Have some rough lobes wire EDM'd from 8620 with keyways under the peak. Heat shrink them onto the ground bar. With the pushrod engine, you'd have to do the journals too, but that's doable with the same technique.
I imagine most cams are cut on cnc today. A program has to be written. There is no program for a LZ vvt cam so thats a hurdle cam companies arent going to invest time into either without demand.
Comp makes the roller cams for the 3x00 third gen motors because those cams share the journal diameter of a sbc which they have a program for. The roller lobes are cut using the programs setup for those same sbc cams. So cutting the cam for the 3x00 cam is easy and cheap.
Comp has nothing for the larger journals and base lobes of the lz, not to mention the drilling for vvt actuation in the front. I dont see them doing so either.
The easiest/cheapest would be to have them build a program for a bolt in LZ cam based off the LNJ cam sans vvt but for larger lift and duration.
Lnj cam is a direct bolt in with the same cam sensor ring, same 3 bolt drilled in front for the gear, and new is 200 from GM. Maybe sending off an lnj cam to a cam company to build profiles off of would be the way to go.
I just plan to use spacers but I'd prefer the correct journal cam if a choice was avail. Unfortunately right now there isnt
Shaun41178(2) wrote: ↑Sun May 23, 2021 11:25 pm
I imagine most cams are cut on cnc today. A program has to be written. There is no program for a LZ vvt cam so thats a hurdle cam companies arent going to invest time into either without demand.
Comp makes the roller cams for the 3x00 third gen motors because those cams share the journal diameter of a sbc which they have a program for. The roller lobes are cut using the programs setup for those same sbc cams. So cutting the cam for the 3x00 cam is easy and cheap.
Comp has nothing for the larger journals and base lobes of the lz, not to mention the drilling for vvt actuation in the front. I dont see them doing so either.
The easiest/cheapest would be to have them build a program for a bolt in LZ cam based off the LNJ cam sans vvt but for larger lift and duration.
Lnj cam is a direct bolt in with the same cam sensor ring, same 3 bolt drilled in front for the gear, and new is 200 from GM. Maybe sending off an lnj cam to a cam company to build profiles off of would be the way to go.
I just plan to use spacers but I'd prefer the correct journal cam if a choice was avail. Unfortunately right now there isnt
"The Community" could help a little bit by modeling the cam first. That's maybe as much as a day to reverse engineer, though. The bigger time sink would be in doing the CAM and optimizing the program.
Not sure why you'd want to lock the community into a non-VVT cam as the first option. I'd think that would actually limit the market because it's something that's only realistically available to swappers.
Nice work on the spring compressor, simple, and effective. If everything goes according to plan, in a few weeks I'll be able to start working on mine again somewhat regularly. I may even pick up an LZ9 to start working on mounts for. When I get around to it, I would like to make a bolt in LZ9 kit, some tool purchases I have planned for later this year should help facilitate that.
"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'll see how my summer goes for time on the CAM grinder. If I go ahead we can make custom cams for the LZ9/LZ4 and keep the VVT or any engine up to 36" long.
The engine is almost fully apart and is being cleaned up. I'll likely start on the body and frame next. Somebody lifted it in the wrong spots so the SS tubing leaks near the back of the doors. Then brakes and suspension before putting the engine and trans back together. Right now there are no brakes at all (the lines are all decrepit) and there is surface rust on every suspension component. I still have to see what the frame rails look like above the rear shock towers. From what I can already see from the engine bay a bit of new frame will be fabricated.
That is also a set of 8. May be able to save money ordering direct... which will leave $$ in the couch cushions for skirt coatings and gapless top rings.
ouch, the cancer looks rough! looks fixable though.
"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."
CaptainHindsight wrote: ↑Sun Jun 20, 2021 5:17 pm
The bodywork begins. A bit of cancer to fix first.
This area of a Fiero seems to get hit hard. Are those auto trans cooler lines?
Now is your opportunity to weld in the plinth boxes for a roll cage, since that's exactly where they have to be and you already have free exchange of volume into the cabin
Edit: i will be adding some box tube around the area where the SS coolant lines run to the radiator just in case it ever ends up in some not know it alls shop and they try to crush them again by the jack or lift.
