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Mag cases, What kills them exactly?

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Craig Torrens 6 times Australian, 7 times State Hillclimb Class Champion

8,040 posts · joined Jan 2003 ·

#599010
pete wood wrote:wow bix, you know the regs better than me. thanx

dave, I was hoping you comment at some stage. One question, are ally cases available for 85.5-87 mm bore size or do they start larger than that?
you can buy them for a standard bore size.


Jeza Officially Full-On Dubber

353 posts · joined Jan 2003 ·

#599032
What ally cases do people recommend?

Or have they all sorted out their teething problems??
......random gibberish for today.......

hellbugged 48's and straight cuts

5,080 posts · joined Apr 2003 ·

#599041
what stroke and bore are you thinking of to come in just under 1600cc Pete?

pete wood 23 Windows of Awesome

6,828 posts · joined Jan 2004 ·

#599159
The motor has to be standard stroke. So 69mm. Basically 1600, but bore wise things get interesting. If I go historic I can put 87mm pots on a 1600 and still be counted within the class as it's within the 1.5mm overbore allowed. This is to allow people to use old engine blocks. VWs get a loophole here.

In group 3c-PRC I have to stay within 0.6mm window and I can't exceed the capacity limit of the class. I'm aiming an updated replica of this...http://www.rallybugs.com/engtrans.htm. They had 85.9mm bores. Could I just machine some 87s down?

[ Edited on 27-6-07 by pete wood ]
"stoopid is stronger than axles"
http://drivingnotpolishing.blogspot.com.au/

BiX Veteran Volks Folk

2,499 posts · joined Sep 2002 ·

#599166
You can change the capacity of the engine in regular PRC as its a pre 86 car... you jsut change classes..... Stroke and Bore are free..... as long as it fits in the homoglated engine block... eg a std mag case....

Mite be worth fully reading the regs front to back and taking notes on them. Almost like studying for an exam. Cross out old regs and add new as you read through.
I have no sympathy for my car, only the wallet that pays for it!
Go hard or go home!!!!

pete wood 23 Windows of Awesome

6,828 posts · joined Jan 2004 ·

#599172
either way, I'll be sticking with the 69mm crank. They're cheap, you can't go wrong with them and pistons aren't that hard.

might be right about reading the regs, I'm not a good detail person so it's gonna mean spending lots of time getting it right.

BTW, just had a quick look at the 4ag bore vs stroke; 81mm vs 77mm. So the stocker 1600 has a better ratio than the 4ag in terms of revving from my understanding of racing engines.

[ Edited on 27-6-07 by pete wood ]
"stoopid is stronger than axles"
http://drivingnotpolishing.blogspot.com.au/

dangerous 23 Windows of Awesome

5,901 posts · joined Jan 2005 ·

#599305
pete wood wrote:BTW, just had a quick look at the 4ag bore vs stroke; 81mm vs 77mm. So the stocker 1600 has a better ratio than the 4ag in terms of revving from my understanding of racing engines.

[ Edited on 27-6-07 by pete wood ]
The 4A series engines, particularly the 5 valve one, will out flow a VW by heaps (or more in standard form).

The bore stroke ratio and rod length discussions are very little in the scheme of things when it comes to reving,
so long as you are within some basic real guidelines.

Airflow and valve control is king when it comes to rpm potential and power.
westi wrote:That's mad Alan.

Craig Torrens 6 times Australian, 7 times State Hillclimb Class Champion

8,040 posts · joined Jan 2003 ·

#599379
pete wood wrote:just found this on the Gene Berg site.

http://www.geneberg.com/cat.php?cPath=22_503_2984

very interesting reading. The engine will be getting a new case. 🥷
Good propaganda for selling new cases! :thumb

or for admitting the fact that machining a case accurately can only be performed by a small minority of engine builders.


hellbugged 48's and straight cuts

5,080 posts · joined Apr 2003 ·

#599428
.........fancy someone writing down and publishing, for all to see, their findings after 30 years of research, testing and development..........pfffffffft🙄

Craig Torrens 6 times Australian, 7 times State Hillclimb Class Champion

8,040 posts · joined Jan 2003 ·

#599494
there's plenty of documented incorrect information out there.