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924RACR
Joined: 29 Jul 2001
Posts: 8877
Location: Royal Oak, MI, USA
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 Posted: Tue Dec 10, 2024 5:41 am Post subject: Resurrection - head flange scan/STL file? |
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Digging back into the past... I think I've pretty well given up on finding the old data on stepped header. Gonna see if I can re-start the engine sim effort into next year.
At the other end... I do have a local laser cutter I've used with success in the past, thinking of getting them to pop out a few flanges to start a fresh build.
I have an old broken MSDS header we can use to scan a template, but seems to me that probably someone on here has already gone through the effort and might have an STL file for the flange?
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Vaughan Scott
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'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
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Mike9311
Joined: 14 Dec 2004
Posts: 1761
Location: Chicago-ish
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| Posted: Tue Dec 10, 2024 6:04 am Post subject: Re: Resurrection - head flange scan/STL file? |
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| 924RACR wrote: | Digging back into the past... I think I've pretty well given up on finding the old data on stepped header. Gonna see if I can re-start the engine sim effort into next year.
At the other end... I do have a local laser cutter I've used with success in the past, thinking of getting them to pop out a few flanges to start a fresh build.
I have an old broken MSDS header we can use to scan a template, but seems to me that probably someone on here has already gone through the effort and might have an STL file for the flange? |
I am checking if I have anything and If we don't, then I'll get it for you
I do have individual flanges designed since I am slowly making a stainless header for my 80NA
Anyway let me check
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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924RACR
Joined: 29 Jul 2001
Posts: 8877
Location: Royal Oak, MI, USA
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| Posted: Tue Dec 10, 2024 7:05 am Post subject: |
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Thanks!
Yeah, individual flanges is an interesting thought... pros/cons of one vs. the other?
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Vaughan Scott
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'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype |
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Mike9311
Joined: 14 Dec 2004
Posts: 1761
Location: Chicago-ish
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| Posted: Tue Dec 10, 2024 7:54 am Post subject: |
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| 924RACR wrote: | Thanks!
Yeah, individual flanges is an interesting thought... pros/cons of one vs. the other? |
My thought was twofold. Weight savings and allowing for more ability to move or flex, thermally or otherwise. I always felt like they did one big plate for ease of fabrication
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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Fifty50Plus
Joined: 28 Feb 2008
Posts: 1398
Location: Washington DC area
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| Posted: Tue Dec 10, 2024 9:34 am Post subject: |
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Vaughan,
Y'know, Dan bought the rights to another famous header Mfr some years back. He came by my house and showed me what he got. Looked good and there was some stepped work. I can't remember if there was a single header plate or individual runners in the batch. Maybe he sold it all off when he downsized.
BTW, I texted him a couple days ago saying there was a thread about him. He said he tried to get on the board recently but couldn't get authenticated. Said he'd try again.
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1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car |
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Mike9311
Joined: 14 Dec 2004
Posts: 1761
Location: Chicago-ish
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| Posted: Tue Dec 10, 2024 10:47 am Post subject: |
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I think Vaughn has all that of which you speak 
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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924RACR
Joined: 29 Jul 2001
Posts: 8877
Location: Royal Oak, MI, USA
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| Posted: Tue Dec 10, 2024 11:39 pm Post subject: |
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Yeah, we have the Stahl header jig (pictured in the thread); planning to use it as the core of a build, but going back through some of the details and considering possibilities for optimization...
Ideally, I even get a chance to do some dyno runs next summer with a few of the different options; currently I have a rather high-mileage MSDS style header on the car, would be nice to have that as a baseline, then maybe the original Stahl design, hopefully leading to a stepped version and data to prove those out...
Talked to my fabricator last night, he's gonna bring me the existing ones over the Xmas break when he visits, I can start with that as a baseline for design...
Thanks for getting Dan back online!!
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Vaughan Scott
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'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype |
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Mike9311
Joined: 14 Dec 2004
Posts: 1761
Location: Chicago-ish
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| Posted: Wed Dec 11, 2024 7:25 am Post subject: |
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This is an old pic by now and I am unsure if I can get the thin wall tubing I was using. Nobody would do what I was trying....the thin wall part anyway. Wanted a long tube header combined with larger pipe. Hopes were to raise torque peak as well as raising torque below that peak.
I also have the ICE engineering kit for the same tubing size. These are like lego's (snap and spin) and while using 3d printed flanges (this instance) and the kit you can assemble a header in place while trying all sorts of placement ideas. Stepped designs are also possible. Drawback is price and each tube size is its own kit. I actually put it on a Christmas list for fun and was surprised when I got it 
ICE kit is in blue for 1 5/8 pipe below (41.275mm)
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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morghen
Joined: 21 Jan 2005
Posts: 8982
Location: Romania
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| Posted: Wed Dec 11, 2024 8:24 am Post subject: |
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Whoah whoah, wait..whats the story behind that cam gear?
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Mike9311
Joined: 14 Dec 2004
Posts: 1761
Location: Chicago-ish
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| Posted: Thu Dec 12, 2024 1:25 am Post subject: |
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| morghen wrote: | | Whoah whoah, wait..whats the story behind that cam gear? |
I knew someone would ask  Apologies in advance for topic drift
This was done many years ago. Asymmetrically lightened cam gear. At the time an attempt was made to have it offset the camshaft unbalance. Something done much easier today with scanning and much improved modeling. Certainly could be done more "cleanly" today. The process helped on a work project afterward for a 15000 rpm spindle design and build. Even that would be easier today. Looking at the gear I was so wrong with my guessing lol
The camshaft and cam gear are balanced. I mentioned it before but sometimes my madness goes unnoticed. Two plane balancing on outer cam journals with gear installed. The holes are actually drill dimples (not through the gear) to correct the remaining imbalance in the design attempt of the gear lightening. Did something related to this previously on a Ducati
Also, if you look really close at the cam lobes on the right side, they have holes. Everything on this particular NA is extra balanced. Engine, clutch, flywheel etc.
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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Raize
Joined: 18 Sep 2013
Posts: 258
Location: Scotland
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| Posted: Thu Dec 12, 2024 6:41 am Post subject: |
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The stuff you guys make is wild.
Wonder if we could finally have the technology to remake the Franco VVT gear in 2024? |
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morghen
Joined: 21 Jan 2005
Posts: 8982
Location: Romania
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| Posted: Thu Dec 12, 2024 9:45 pm Post subject: |
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Oh the technology is here...thats good point actually.
Hmmm..do i need to buy another scrappy 924 to use as a mule now? 
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Cedric
Joined: 27 Aug 2004
Posts: 2699
Location: Sweden
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| Posted: Thu Dec 12, 2024 11:42 pm Post subject: |
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| Raize wrote: | The stuff you guys make is wild.
Wonder if we could finally have the technology to remake the Franco VVT gear in 2024? |
The idea behind the Franco gear is brilliant, though the durability was maybe questionable. But oscillations is a difficult thing when it comes to cam transmissions, its a challenge for normal VVT designs aswell, an something OEMs will put alot of effort on handling.
But it would only work reasonable if you have crank triggered ignition like EFI or like on the s2, or else your ignition will slide around with the cam timing
I did a cam shaft sweep in my 924 simulation model i used back when I worked with these things, would be interesting to see if it had even more possibility if the cam was swept even more back and forth.
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Mike9311
Joined: 14 Dec 2004
Posts: 1761
Location: Chicago-ish
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| Posted: Fri Dec 13, 2024 12:41 am Post subject: |
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I love this forum. An unrelated mod sets us off on a new journey
We should probably start another thread for this one. It would be interesting to see how we would approach a remake
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car |
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| Back to top |
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morghen
Joined: 21 Jan 2005
Posts: 8982
Location: Romania
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| Posted: Fri Dec 13, 2024 2:59 am Post subject: |
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So the holes in the cam lobes are for rotational balancing?
Mike, I think you should start the Franco gear thread
| Mike9311 wrote: | | morghen wrote: | | Whoah whoah, wait..whats the story behind that cam gear? |
I knew someone would ask Apologies in advance for topic drift
This was done many years ago. Asymmetrically lightened cam gear. At the time an attempt was made to have it offset the camshaft unbalance. Something done much easier today with scanning and much improved modeling. Certainly could be done more "cleanly" today. The process helped on a work project afterward for a 15000 rpm spindle design and build. Even that would be easier today. Looking at the gear I was so wrong with my guessing lol
The camshaft and cam gear are balanced. I mentioned it before but sometimes my madness goes unnoticed. Two plane balancing on outer cam journals with gear installed. The holes are actually drill dimples (not through the gear) to correct the remaining imbalance in the design attempt of the gear lightening. Did something related to this previously on a Ducati
Also, if you look really close at the cam lobes on the right side, they have holes. Everything on this particular NA is extra balanced. Engine, clutch, flywheel etc.
|
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Supercharger and EFI kits
https://www.the924.com |
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