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morghen
Joined: 21 Jan 2005 Posts: 8884 Location: Romania
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Posted: Thu Sep 07, 2017 4:37 pm Post subject: |
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custom cams can be made, is that head cutting feasible? do the spacing and bores work? how about the stuts? _________________ https://www.the924.com |
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Paulyy
Joined: 05 May 2014 Posts: 87 Location: Melbourne
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Posted: Mon Sep 11, 2017 6:37 pm Post subject: |
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morghen wrote: | custom cams can be made, is that head cutting feasible? do the spacing and bores work? how about the stuts? |
Im actually not sure which 20v head we're talking about. The 5 cylinder or the 4 cylinder??
I can't find info in either.
Cutting and welding a 5 cylinder head into 4? i dont think it's really feasible if everything lined it. maybe, depends on head design. _________________ 924 - Race car project in the works.
http://www.924board.org/viewtopic.php?p=384410#384410
951 - 400whp. |
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morghen
Joined: 21 Jan 2005 Posts: 8884 Location: Romania
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Posted: Mon Sep 11, 2017 7:47 pm Post subject: |
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I was talking about taking a 5cyl audi head and cutting it to fit the 924 if the spacing is ok and the head studs position are an advantage. _________________ https://www.the924.com |
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Paulyy
Joined: 05 May 2014 Posts: 87 Location: Melbourne
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Posted: Mon Sep 11, 2017 7:54 pm Post subject: |
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The 07K head? i dont think so. it'll require to much work to even consider it. Give it a google search to see how it looks. _________________ 924 - Race car project in the works.
http://www.924board.org/viewtopic.php?p=384410#384410
951 - 400whp. |
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morghen
Joined: 21 Jan 2005 Posts: 8884 Location: Romania
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Posted: Mon Sep 11, 2017 8:32 pm Post subject: |
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meh, I believe you, I was just talking out of my ass
One could CNC one I guess....or CNC a head and block in one piece and run 10bar of boost making 5000hp _________________ https://www.the924.com |
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Paulyy
Joined: 05 May 2014 Posts: 87 Location: Melbourne
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Posted: Mon Sep 11, 2017 8:43 pm Post subject: |
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hahaha!
Trust me, if i had a 5 axis, i would be drawing up a head by now.
I only have a small 3 axis cnc router.
Im looking at combustion chambers, if its worth cutting into a n/a head. even if it's 5mm deep. i did make a thread about it just before.
I know the 931 head has it, and i did see someone modify it to some extent. _________________ 924 - Race car project in the works.
http://www.924board.org/viewtopic.php?p=384410#384410
951 - 400whp. |
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v2rocket_aka944
Joined: 05 Jan 2009 Posts: 43 Location: Nashville, TN
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Posted: Tue Sep 12, 2017 6:50 am Post subject: |
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Paulyy wrote: | The 07K head? i dont think so. it'll require to much work to even consider it. Give it a google search to see how it looks. |
not the o7K...
i meant the old 20V "AAN" 5 cylinder of the 1980s rally cars...
2.2 or 2.3L usually, found in the audi Quattro coupes, some sedans, etc.
the 924 I-4 shares a bellhousing pattern with that 5 cylinder which is how the 5 cylinder bolts up easily enough.
could the 924 engine be derived/related to the Audi 5?
or just coincidence of bolt pattern? |
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Paul
Joined: 02 Nov 2002 Posts: 9491 Location: Southeast Wisconsin
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Posted: Wed Sep 13, 2017 1:09 pm Post subject: |
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Porsche Audi and VW were the same company in years past, so they were just using what was in their supply chain. _________________ White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy. |
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nickthompson
Joined: 26 Mar 2013 Posts: 873 Location: Central Georgia
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Posted: Wed Sep 13, 2017 5:47 pm Post subject: |
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v2rocket_aka944 wrote: | Paulyy wrote: | The 07K head? i dont think so. it'll require to much work to even consider it. Give it a google search to see how it looks. |
not the o7K...
i meant the old 20V "AAN" 5 cylinder of the 1980s rally cars...
2.2 or 2.3L usually, found in the audi Quattro coupes, some sedans, etc.
the 924 I-4 shares a bellhousing pattern with that 5 cylinder which is how the 5 cylinder bolts up easily enough.
could the 924 engine be derived/related to the Audi 5?
or just coincidence of bolt pattern? |
The old Audi i5s have a much smaller bore spacing than the original 2.0 |
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Euro924S2
Joined: 06 Mar 2008 Posts: 215 Location: UK
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Posted: Thu Dec 05, 2019 7:32 am Post subject: |
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An old thread to resurrect but I’m in the process of trying to build a 2.0L 16v engine. Block is standard 924, pistons are Vw flat tops to bring the compression up and the head is from a Ford Duratec engine. The cylinder spacing is 95.5mm compared to 95mm on the 924 but hopefully that’s not an issue. There are LOTS of issues including head bolt location, it’s a lubricated cam chain instead of belt and the oil supply/return and water galleries area all wrong, but importantly it has 16valves and massive ports so if I can get it to work it should be a worthwhile upgrade....
Full details here on the UK site but you need to sign up to be a forum member to view I think.
https://porsche924.co.uk/forum/viewtopic.php?f=122&t=33648 _________________ UK spec '83 N/A with 931 motor with Eaton MP62 'charger @ 15psi. EFI - 565cc inj. Standalone Adaptronic ECU. 951 FMIC. Ally rad. Twin throttle. Recirc valve. Custom manifolds and CAI. 232bhp |
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Mike9311
Joined: 14 Dec 2004 Posts: 1678 Location: Chicago-ish
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Posted: Thu Feb 27, 2020 4:14 am Post subject: |
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The hardest part with this project is identifying cylinder spacing for any cylinder head. I'll have to register for the other forum to keep up with your progress
I'm still too busy working on the 2 valve head project before moving to the 16 _________________ 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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Euro924S2
Joined: 06 Mar 2008 Posts: 215 Location: UK
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Posted: Thu Feb 27, 2020 7:42 am Post subject: |
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True, I was lucky Rich H did the hard work for me there. The head is now bolted to the block and cylinder spacing isn’t an issue. The oil and water galleries are in theory sorted (although not tested I don’t imagine any major issues). Oil feed to the head is just a case of threading a union into the block. The remaining jobs are the cam sprockets. I hoped to use 2 x 924 pulleys so the crank could remain stock, but they are too large to clear each other with the Duratec cam shaft spacing. Mx5 (Miata) pulleys will work nicely though (I had a pair of verniers for that engine on the shelf!) so I’ve bought a Mazda crank pulley to keep the 2:1 ratio and will machine that to fit the 924 crank. I can hen attempt a start by running it with all the Ford wiring harness, injectors, eCU etc on the engine stand and check there are no glaring errors before spending the cash having the block machined and head rebuild properly. _________________ UK spec '83 N/A with 931 motor with Eaton MP62 'charger @ 15psi. EFI - 565cc inj. Standalone Adaptronic ECU. 951 FMIC. Ally rad. Twin throttle. Recirc valve. Custom manifolds and CAI. 232bhp |
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Mike9311
Joined: 14 Dec 2004 Posts: 1678 Location: Chicago-ish
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Posted: Thu Feb 27, 2020 7:48 am Post subject: |
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Wow, its finally going to be done by someone. Very cool
I keep looking for a Volvo twin cam head since it is rumored to be Porsche
or Cosworth designed but they are hard to come by
Your path may just be the path! _________________ 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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Euro924S2
Joined: 06 Mar 2008 Posts: 215 Location: UK
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Posted: Thu Feb 27, 2020 7:56 am Post subject: |
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It’s been both simple and a nightmare! The actual conversion is not that hard, but I’ve spent probably 100 hours welding and machining the new head bolt holes. The HG side is easy because access isn’t a problem. The cam shaft side is a major challenge. It’s not helped because the cast ally has been bathed in oil for years so contamination is a major problem. Pressure testing the water jacket reveals the porous welds which needed grinding out and re-welding over and over and over. They then have to have a final grind flat to seat the nuts - that exposes porosity and the cycle of weld and grind starts again. I’ve learned a lot about welding, machining and how much access I should have created from day one instead of gradually improving. I’ve now done so much work on the galleries etc I’m loathed to start again, although had I have done that 50 hours ago it might well have been much quicker (and cheaper in Argon!) - oh yeah, I also bought a new, more powerful Tig which helped!!
The rest of the machine work is more straightforward and helped even more by having a CCN mill and lathe at home. Time is the biggest problem so I fear this engine won’t get in my car until this coming winter. _________________ UK spec '83 N/A with 931 motor with Eaton MP62 'charger @ 15psi. EFI - 565cc inj. Standalone Adaptronic ECU. 951 FMIC. Ally rad. Twin throttle. Recirc valve. Custom manifolds and CAI. 232bhp |
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Euro924S2
Joined: 06 Mar 2008 Posts: 215 Location: UK
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Posted: Thu Feb 27, 2020 7:58 am Post subject: |
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The major benefit on the Duratec is the head was £75 because they are so common and no-one wants them. The bottom ends are not really rebuildable apparently so an engine issue is just a swap for a used one or buy new I’d flush with cash. So lots of heads are available cheaply. _________________ UK spec '83 N/A with 931 motor with Eaton MP62 'charger @ 15psi. EFI - 565cc inj. Standalone Adaptronic ECU. 951 FMIC. Ally rad. Twin throttle. Recirc valve. Custom manifolds and CAI. 232bhp |
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