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

Overhaul Porsche 931 S1 engine
Goto page Previous  1, 2, 3  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Tech.
View previous topic :: View next topic  
Author Message
MOTANUL  



Joined: 19 Nov 2018
Posts: 143
Location: ROMANIA BUCHAREST

PostPosted: Wed Dec 02, 2020 9:06 pm    Post subject: Reply with quote

Both are valid for S2. (8.0 and 8.5)
S1 7.5


_________________
1980 Porsche 924 Turbo (931) diamond silver metallic/helios blue metallic
sold Porsche 924 NA 1979
Back to top
View user's profile Send private message
MOTANUL  



Joined: 19 Nov 2018
Posts: 143
Location: ROMANIA BUCHAREST

PostPosted: Wed Dec 02, 2020 9:13 pm    Post subject: Reply with quote

[quote="Carrera RSR"]
MOTANUL wrote:

S2 piston would be my preferred design, but with a slightly thicker Cometic MLS headgasket to bring CR below 8.5:1 for sub 1bar boost. Closer to 8 - 8.2:1CR if wanting over 1bar boost. Big boost would need to be closer to 7.5:1


I would like to keep the car as stocky as possible. I only want to raise the boost pressure from 0.67 to 7.3 bar.
My S1 pistons are very good (deviations are within permissible tolerances - can be reused).

The question is whether to use S1 or S2 piston rings. First of all:S2 piston rings fit on S1 pistons? Secondly, what would be the advantages and disadvantages for each?
_________________
1980 Porsche 924 Turbo (931) diamond silver metallic/helios blue metallic
sold Porsche 924 NA 1979
Back to top
View user's profile Send private message
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2104
Location: Somerset, UK

PostPosted: Thu Dec 03, 2020 1:47 am    Post subject: Reply with quote

MikeDanger wrote:
are you sure s2 is 8.5:1?? thought it was 8.0

944 turbo is 8.5


Full power Row 924 turbos, absolutely 8.5:1CR
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
MOTANUL  



Joined: 19 Nov 2018
Posts: 143
Location: ROMANIA BUCHAREST

PostPosted: Sat Dec 12, 2020 9:10 am    Post subject: Reply with quote

Going deeper
The turbo is out. Next step Cylinder block.


_________________
1980 Porsche 924 Turbo (931) diamond silver metallic/helios blue metallic
sold Porsche 924 NA 1979
Back to top
View user's profile Send private message
MOTANUL  



Joined: 19 Nov 2018
Posts: 143
Location: ROMANIA BUCHAREST

PostPosted: Fri Dec 18, 2020 10:27 pm    Post subject: Reply with quote

I have been looking for piston rings, Connecting-rod bearing, Crankshaft bearing for 924 turbo for some time. Very few options.

ref. to: https://www.mespiecesauto.com/en/produit/coussinet-porsche-924-046105501-0406105561-046105591-046198451/

Someone used these bearings? Does anyone have an opinion on how good they are? Did anyone use them?

I ask my Porsche local dealer - NLA.
I send a email to Total seal for piston rings - I am waiting for their answer
I send a email to mittelmotor.de for bearings - I am waiting for their answer

A lot of NLA in rest. These engines are doomed to die ...
_________________
1980 Porsche 924 Turbo (931) diamond silver metallic/helios blue metallic
sold Porsche 924 NA 1979
Back to top
View user's profile Send private message
morghen  



Joined: 21 Jan 2005
Posts: 8274
Location: Romania

PostPosted: Fri Dec 18, 2020 10:55 pm    Post subject: Reply with quote

This is precisely the reason why if your car is running without any major issues, you should enjoy driving it.
I hope you get it back in one piece very soon.
_________________
SUPERCHARGED Ruby-sh 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
TJC  



Joined: 04 Apr 2010
Posts: 777
Location: Central-ish Arizona, USA

PostPosted: Sat Dec 19, 2020 1:58 am    Post subject: Reply with quote

MOTANUL wrote:
I have been looking for piston rings, Connecting-rod bearing, Crankshaft bearing for 924 turbo for some time. Very few options.

ref. to: https://www.mespiecesauto.com/en/produit/coussinet-porsche-924-046105501-0406105561-046105591-046198451/

Someone used these bearings? Does anyone have an opinion on how good they are? Did anyone use them?

I ask my Porsche local dealer - NLA.
I send a email to Total seal for piston rings - I am waiting for their answer
I send a email to mittelmotor.de for bearings - I am waiting for their answer

A lot of NLA in rest. These engines are doomed to die ...


Interesting that you have done so much research and have come up empty handed for the most part it seems. I may have thought that the availability of parts in Europe would not be so bad and it makes me think that it may be much worse here in the US. Either that or the cost far, far outweighs the benefit as one could choose to go another route.
I have been following this and many other threads for the past year just to get some valid information regarding parts availability now and in the future, and I must admit it looks a bit bleak to say the least. I myself may need to reconsider my own plans for the '80 924 Turbo I planned on tearing into next year...hmmmm.
_________________
'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
CÚdric  



Joined: 27 Aug 2004
Posts: 2077
Location: Sweden

PostPosted: Sat Dec 19, 2020 2:18 am    Post subject: Reply with quote

It's mostly about preparation, gathering parts over time when they are available. The same goes for used parts if you want them for reasonable prices.
_________________
1980 924 Turbo
Back to top
View user's profile Send private message MSN Messenger
MOTANUL  



Joined: 19 Nov 2018
Posts: 143
Location: ROMANIA BUCHAREST

PostPosted: Sat Dec 19, 2020 3:17 am    Post subject: Reply with quote

I found in US some genuine bearings (not all of them): https://www.ecstuning.com/Porsche-1979-924-924-Base-Coupe-L4_2.0L/Search/SiteSearch/46105501/

If we put both continents together, we get some 924 turbo parts.
_________________
1980 Porsche 924 Turbo (931) diamond silver metallic/helios blue metallic
sold Porsche 924 NA 1979
Back to top
View user's profile Send private message
CÚdric  



Joined: 27 Aug 2004
Posts: 2077
Location: Sweden

PostPosted: Sat Dec 19, 2020 3:40 am    Post subject: Reply with quote

The French bearings seems to be very good and thought through design. Probably the way to go. They are about to do the rod bearings aswell, i will try to buy those
_________________
1980 924 Turbo
Back to top
View user's profile Send private message MSN Messenger
MOTANUL  



Joined: 19 Nov 2018
Posts: 143
Location: ROMANIA BUCHAREST

PostPosted: Sat Dec 19, 2020 7:42 am    Post subject: Reply with quote

You ref. to mespiecesauto bearings? Yes - they look very good.
Somobody order from them anything? I know nothing about this company. They are fresh on the market (at list I don't know them).
_________________
1980 Porsche 924 Turbo (931) diamond silver metallic/helios blue metallic
sold Porsche 924 NA 1979
Back to top
View user's profile Send private message
CÚdric  



Joined: 27 Aug 2004
Posts: 2077
Location: Sweden

PostPosted: Sat Dec 19, 2020 8:02 am    Post subject: Reply with quote

Have you checked the thread i guess?

http://www.924board.org/viewtopic.php?t=44582
_________________
1980 924 Turbo
Back to top
View user's profile Send private message MSN Messenger
MOTANUL  



Joined: 19 Nov 2018
Posts: 143
Location: ROMANIA BUCHAREST

PostPosted: Sun Dec 20, 2020 11:03 am    Post subject: Reply with quote

You guessed right. Now I read the thread.
_________________
1980 Porsche 924 Turbo (931) diamond silver metallic/helios blue metallic
sold Porsche 924 NA 1979
Back to top
View user's profile Send private message
chuck21401  



Joined: 20 Feb 2005
Posts: 322
Location: Annapolis, MD

PostPosted: Tue Dec 22, 2020 11:20 am    Post subject: Reply with quote

MOTANUL wrote:
I have been looking for piston rings,


I don't have too much to add here...but the previous owner (Ian84c4) that rebuilt the 931 engine (S1) in my car apparently used rings from a Peugeot turbo motor.

See this thread:
http://www.924board.org/viewtopic.php?p=388463&highlight=#388463

No specs are mentioned. That thread mentions some other part numbers...perhaps worth investigation.

Oh, and did you see these on Ebay? A little pricey.
https://www.ebay.com/itm/Set-of-piston-rings-NOS-Porsche-924-Turbo-original-in-box-93110390175-/324038546921

No sure if these are for S1 or S2 pistons...YMMV.
_________________
1981 Porsche 931
Back to top
View user's profile Send private message
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2104
Location: Somerset, UK

PostPosted: Tue Dec 22, 2020 7:00 pm    Post subject: Reply with quote

Use Total Seal piston rings.

Try 'Karlio' on here and known as 'the colonel' on 924OC for any NLA engine parts. Being a racer he has his ear to the ground for hard to find engine parts

As Morghen & Cedric say, never pull a running engine apart on a whim unless its absolutely dead already. Accumulate parts over time. Buy them even if you don't need them right now or can afford them sometimes. I'm already accumulating for another turbo engine build in next 12-24 months. Bearings, rod bolts and ARP head studs, Cometic HG are on my shopping list next in the New Year. I know where I can find most of that when the wallet is ready.
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Tech. All times are GMT + 11 Hours
Goto page Previous  1, 2, 3  Next
Page 2 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