Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

Has anyone done 2.0na high cr?
Goto page Previous  1, 2, 3
 
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades
View previous topic :: View next topic  
Author Message
ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Fri Jun 26, 2020 11:42 pm    Post subject: Reply with quote

I think it was Augidog who had a high CR NA made with S2 pistons + NA head.
Digging thru some of his old posts might be interesting:
http://www.924board.org/search.php?search_author=augidog
_________________
88 924S SE | 82 931 Holbert | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition
Back to top
View user's profile Send private message
ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Fri Jun 26, 2020 11:48 pm    Post subject: Reply with quote

safe wrote:
Note that you need "spacers" to center the rods on the crank with those bmw rods.

I'd be intereseted in how one would implement this solution.
_________________
88 924S SE | 82 931 Holbert | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition
Back to top
View user's profile Send private message
safe  



Joined: 18 Mar 2017
Posts: 166
Location: Sweden

PostPosted: Sat Jun 27, 2020 12:00 am    Post subject: Reply with quote

ideola wrote:
safe wrote:
Note that you need "spacers" to center the rods on the crank with those bmw rods.

I'd be intereseted in how one would implement this solution.

Me too, probably making spacers on the small end centering in the piston.
Back to top
View user's profile Send private message
gegge  



Joined: 27 Jul 2007
Posts: 1075
Location: Sweden

PostPosted: Sat Jun 27, 2020 12:09 am    Post subject: Reply with quote

I made thick 22mm washers in aluminium in order to center the rod, nothing fancy. It is mportant that they are a tight fit to the wrist pin and doesn´t move. The inside of the piston was wedge shaped, two parallell surfaces to would be better thogh. But there are no horizontal forces on the rod so I guess it worked...
_________________
Carl Fredrik Torkildsen

924 turbo -81 Carrera GT RESTOMOD
924 turbo -80 Dolomite De Luxe
924 -85 DP kit, BBS RS, M030 and tuned engine
924s -86 Black on black turbo with Fuchs
Back to top
View user's profile Send private message
TJC  



Joined: 04 Apr 2010
Posts: 751
Location: Central-ish Arizona, USA

PostPosted: Sat Jun 27, 2020 12:21 am    Post subject: Reply with quote

ideola wrote:
safe wrote:
Note that you need "spacers" to center the rods on the crank with those bmw rods.

I'd be intereseted in how one would implement this solution.


Many moons ago I did my time at a high performance/race engine machine shop in Phoenix, Az. I don't remember the application right off the top of my head, (probably a open wheel sprint car Chevy V8 or midget 4 cylinder engine), but we took rods that were too narrow at the big end and machined spacers from chrome moly tubing and then tack welded them onto the rods. we split them at the parting line of course, resized the rods and made sure they had the proper chamfer on them to facilitate proper clearance and oiling. I think we were using Carillo rods at the time. It was over 30 years ago and actually may have been for the all aluminum Chevy V4 engines we built for midgets...a designed first conceived by my late friend Ron Trainor.
_________________
'95 BMW 318i/5 ..."Pearl"
'80 Porsche 924 Turbo..."Pogo"
'81 Porsche 924 Turbo...Parting!
'87 Porsche 944 NA... "Liebchen"
'02 Porsche Boxster..."Sunbeam"

Still on the Prowl!

www.ttrs1.com
Back to top
View user's profile Send private message Visit poster's website
ideola  



Joined: 01 Oct 2004
Posts: 15501
Location: Woodstock IL

PostPosted: Sat Jun 27, 2020 12:24 am    Post subject: Reply with quote

Cool, thanks for that. Follow up questions:
1. So these washers are at the little end, placed over the pin bushing?
2. Rough estimate of the thickness of the washers?
3. Any thoughts on specific flavor of alu?
4. Why alu vs steel?
5. Any concerns about the alu deforming over time due to the harder metal of the rods and pin?
_________________
88 924S SE | 82 931 Holbert | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades All times are GMT + 10 Hours
Goto page Previous  1, 2, 3
Page 3 of 3

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group