 103 mm bore x 71 mm stroke engine., Anyone tried this? |
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| Charles Deutsch |
 Sep 12 2003, 08:57 PM
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#1
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Unregistered  |
The Scat (what a name!) catalog has a 103 mm big bore kit for the 914. Could I use these pistons & cylinders with my 2.0 case without any machining? What kind of hp and torque curves would this combination produce with a street cam optimized for mid-range power and torque? If it's well balanced, it should be a free-revver considering the stock stroke is retained, no? Btw, what are some of the bore/stroke numbers for the flat-six motors?
Thanks |
 
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| Jake Raby |
Sep 13 2003, 12:02 PM
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#2
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Engine Surgeon  Group: Members Posts: 9,398 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Going with a bore that big and a cast iron cylinder is asking for trouble....Some of this trouble is:
Head leaks- those darn out of round non square cylinders leak like a sieve and need 5-6 studs to keep from it... Oil temperatures- The bore size is increased 9mm over stock thats a whopping .360 about 3/8 of an inch!! Cooling that oil takes alot of work.. Head studs- the TIV has a non square stud pattern, it does not like a huge bore......Also the studs are 2 different lengths from top to bottom, and that makes for uneven expansion rates...uneven expansion warps the cylinder and even the heads and starts head leaks! heads- After you get them sealed off, you have to flow the air that a piston that big can move....not happening cheaply or easily! I felt so strongly and had so many problems with those pistons (actually anything over 100mm) that I REFUSE to use them any further. Every 100mm+ bored engine I build gets LN Engineering Nickies, or I won't put my serial # on it...simply too risky! alot of guys disagree with this, and thats fine....I can make 180 ponies from a 96mm bored engine with some stroke and correct cam and head selection and do so for 80-100K miles....I have seen 103s last 10% of that time before they have a head leak or worse. They are simply not needed, and until we correct some issues with cylinder heads and borespacing, they are a simple waste of money.(in my opinion) As for my software, I use Engine Analyzer Pro, coupled with old fashioned trial and error... |
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Posts in this topic
Charles Deutsch 103 mm bore x 71 mm stroke engine. Sep 12 2003, 08:57 PM
URY914 That is a lot of questions!
1. 103's requi... Sep 12 2003, 09:02 PM Charles Deutsch I wonder what kind of engine dyno simulation softw... Sep 12 2003, 09:17 PM tat2dphreak here's the answer to the last Q:
http://www.p... Sep 12 2003, 10:06 PM Charles Deutsch Thanks for the great information, Jake. I've d... Sep 13 2003, 01:48 PM
Charles Deutsch For anyone who's interested, you can download ... Sep 13 2003, 02:34 PM |
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