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Forged conrods manufacturing
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gegge  



Joined: 27 Jul 2007
Posts: 1084
Location: Sweden

PostPosted: Fri Jul 10, 2020 4:31 pm    Post subject: Reply with quote

The forged rods, are they a direct OEM replament for stock pistons with the HUGE (diesel) wrist pin?

The reason for asking is that aftermarket pistons seldom use 24mm and a light strong rod to match a heavy marchmallow piston doesn´t make sense to me.

Would it be possible to make the same rod with different sizes of the small end bushing? Im am looking for 22mm for exemple.
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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
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Coco_Lev  



Joined: 04 May 2020
Posts: 21
Location: France

PostPosted: Sat Jul 18, 2020 1:42 am    Post subject: Reply with quote

safe wrote:
Coco, valves looks hard to find, for the NA 924 (I need exhaust valves right now).

You don't have connections that can make some nice stainless inlet and exhaust valves, maybe even 1 or 2 mm oversize?
I would by at least 2 sets.


Sorry guys I'm late.
Yes don't worry it's on the track yet.
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Coco_Lev  



Joined: 04 May 2020
Posts: 21
Location: France

PostPosted: Sat Jul 18, 2020 1:44 am    Post subject: Reply with quote

Cédric wrote:
How have you done with the piston cooling oil squirter hole? Are there any sets extra available?


It's drilled on the CNC. With two different tools in order to respect different holes diameters. This is necessary to obtain a low oil emerging section in order to get a powerful oil flow to sufficiently cool the piston.
Yes there are some sets still available


Last edited by Coco_Lev on Sun Jul 19, 2020 5:38 pm; edited 1 time in total
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Coco_Lev  



Joined: 04 May 2020
Posts: 21
Location: France

PostPosted: Sun Jul 19, 2020 5:16 pm    Post subject: Reply with quote

gegge wrote:
The forged rods, are they a direct OEM replament for stock pistons with the HUGE (diesel) wrist pin?

The reason for asking is that aftermarket pistons seldom use 24mm and a light strong rod to match a heavy marchmallow piston doesn´t make sense to me.

Would it be possible to make the same rod with different sizes of the small end bushing? Im am looking for 22mm for exemple.


Only one size will be available as it requires to build another special forging matrix, which is very expensive.
The piston pin diameter is maybe a bit consequent. However you have to know that the piston pin is very long. As a consequence, its bending deformation has to be as fewer as possible because the consequences can be dramatic.
Exemple of a rod foot fatigue failure on a peugeot 505 turbo, due to the high pressure contacts and then the knocks of the piston pin after 100kms:

That's why a big diameter is highly recommended for this part. It will be direct OEM replacement with 24mm piston pin. You have to know that the stiffness depends on the diameter power 4, as the weight only depends on the squared diameter.

What is possible to do, is asking a machinist to reduce the length of your piston pin in order to reduce its deformation and lower the weight of the part. You have to adapt a new fitting in the piston boss. The deformation depends on the cube diameter (without considering the piston boss deformation that is also linked).
However this is a high risqued operation, as this shouldn't be done anyhow, by anyone.


Last edited by Coco_Lev on Fri Jul 24, 2020 9:24 pm; edited 7 times in total
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gegge  



Joined: 27 Jul 2007
Posts: 1084
Location: Sweden

PostPosted: Sun Jul 19, 2020 5:26 pm    Post subject: Reply with quote

Then I have to withdraw my interest in this then.
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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
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