Reducing compress ratio with shorter con.rods!
#47
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you can't rely on PET to source you the exact rod Porsche used for initial production because Porsche sometimes discontinues parts and replaces with others to lower manufacturing costs, and maybe other reasons. For example, N/A 944's built before 3/84 came with forged rods, but I can gaurantee you wont recieve forged rods today if you order brand new ones from Porsche for your '83 944.
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If I get a minute tomorrow I will shoot some pics of the 968 rods/pistons I have sitting around the shop.
I don’t like the rod design (forged or not) the ‘neck’ at the little end is to narrow.
I don’t like the rod design (forged or not) the ‘neck’ at the little end is to narrow.
#49
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Originally Posted by pete95zhn
Oh well, here we go...
I just did a search with " forged connecting rods" and found this and that, also a claim about 968's rods being forged. While I don't say anything about those, I do have something to say about 944 con rods.
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I just did a search with " forged connecting rods" and found this and that, also a claim about 968's rods being forged. While I don't say anything about those, I do have something to say about 944 con rods.
![Wink](https://rennlist.com/forums/images/smilies/wink.gif)
I asked at Porsche, they checked and said both pistons and rods are forged on the 968, But then they also claimed the bores on the
951 to be nicasil
![Roll Eyes (Sarcastic)](https://rennlist.com/forums/images/smilies/rolleyes.gif)
So as far as I know ............
#50
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Originally Posted by 944CS
you can't rely on PET to source you the exact rod Porsche used for initial production because Porsche sometimes discontinues parts and replaces with others to lower manufacturing costs, and maybe other reasons. For example, N/A 944's built before 3/84 came with forged rods, but I can gaurantee you wont recieve forged rods today if you order brand new ones from Porsche for your '83 944.
To be precise, PET gives only one number for early 944 ( including all MY's ) :
944 103 001 01 ... which apparently was forged.
Then it also says that "it's been dropped, use 944 103 008 00 as replacement". Which is again that very same replacement rod for almost all 944's.
#51
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Originally Posted by blodstrupmoen
As far as I know 968 Pistons and Rods are forged ..
the first rods had problems.
to weak even for a NA 968
Konstantin
#52
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Originally Posted by pete95zhn
To be precise, PET gives only one number for early 944 ( including all MY's ) :
944 103 001 01 ... which apparently was forged.
Then it also says that "it's been dropped, use 944 103 008 00 as replacement". Which is again that very same replacement rod for almost all 944's.
944 103 001 01 ... which apparently was forged.
Then it also says that "it's been dropped, use 944 103 008 00 as replacement". Which is again that very same replacement rod for almost all 944's.
#53
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From 944 Workshop Manuel 13-34a
Old - Sintered connecting rod, Part No. 944 103 001 00 (rough part number on inside of conrod shaft)
New - Cast connecting rod, Part No. 944 103 001 01 (rough part number reduced on both sides on conrod base and conrod cap).
From 951 Workshop Supplement
944 103 008 00 Sinter-Forged
From 968 Workshop Manuel
Rods Forged
Reinforced connecting rod adopted from Oct 1, 1993 as of the following engine numbers.
42R00598 M44/43
42R50621 M44/44
Reinforced transision are from stem to bolt head seating surface.
From 1999 Water Cooled Parts & Technical Catalog
924S 1987-88 Part 944 103 008 02
944/S/T 1983-88 Part 944 103 008 02
From PET
968 (Both Rods Shown For 92-95) M44.43/44
u944 103 008 01
944 103 008 04
944
944 103 001 01 M44.02, M44.04
944/2
944 103 001 00 M44.50/51, M44.52
944 103 008 00 M44.05-10, M44.40
Old - Sintered connecting rod, Part No. 944 103 001 00 (rough part number on inside of conrod shaft)
New - Cast connecting rod, Part No. 944 103 001 01 (rough part number reduced on both sides on conrod base and conrod cap).
From 951 Workshop Supplement
944 103 008 00 Sinter-Forged
From 968 Workshop Manuel
Rods Forged
Reinforced connecting rod adopted from Oct 1, 1993 as of the following engine numbers.
42R00598 M44/43
42R50621 M44/44
Reinforced transision are from stem to bolt head seating surface.
From 1999 Water Cooled Parts & Technical Catalog
924S 1987-88 Part 944 103 008 02
944/S/T 1983-88 Part 944 103 008 02
From PET
968 (Both Rods Shown For 92-95) M44.43/44
u944 103 008 01
944 103 008 04
944
944 103 001 01 M44.02, M44.04
944/2
944 103 001 00 M44.50/51, M44.52
944 103 008 00 M44.05-10, M44.40
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Hey
To those who have 968 pistons in their position..Can you please measure the thickness of the pistons top. I did cut one 951 piston into 2 halfs and you can see that the thinnes area in the dome is somethig 8mm - but we all know how deep is the dome in 951 pistons..
I need to know can stock 968 pistons dome area can be machined for that extra chamber volume to bring down the compress ratio? I could put them into CNC machine and remove some material from top of piston, dome without touching the quench. Lets say I need to bring down the comp ratio from 11:1 to 9:1.
By shortering the rod for lower comp.ratio it would mean 2mm shorter rod to bring it on the same kind level. in teh piston I need to go deeper because dome volume is not equal to chamber volume.
markus
To those who have 968 pistons in their position..Can you please measure the thickness of the pistons top. I did cut one 951 piston into 2 halfs and you can see that the thinnes area in the dome is somethig 8mm - but we all know how deep is the dome in 951 pistons..
I need to know can stock 968 pistons dome area can be machined for that extra chamber volume to bring down the compress ratio? I could put them into CNC machine and remove some material from top of piston, dome without touching the quench. Lets say I need to bring down the comp ratio from 11:1 to 9:1.
By shortering the rod for lower comp.ratio it would mean 2mm shorter rod to bring it on the same kind level. in teh piston I need to go deeper because dome volume is not equal to chamber volume.
markus
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Well I am looking for other options at the moment then to spend 1750 USD + transportation+ 10% customs + 18% VAT = 2400 USD just for PISTONS. I think there are other options and if you ask me 8,0:1 is way to low for modern 16 valve turbocharged engine. There are some other areas in my car where that money should be througed
Markus
Markus
#59
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Originally Posted by Markus951
Well I am looking for other options at the moment then to spend 1750 USD + transportation+ 10% customs + 18% VAT = 2400 USD just for PISTONS. I think there are other options and if you ask me 8,0:1 is way to low for modern 16 valve turbocharged engine. There are some other areas in my car where that money should be througed
Markus
Markus
If you're willing to try them out that is.