TECHNICAL ESSAYS...
01-02-2005, 10:53 AM
#1
TECHNICAL ESSAYS...
I want more for the technical essay forum, so please nominate any posts you found interesting as this way, they can be saved forever in their own forum allowing us to cut and paste from them as we feel to help newcomers asking the same questions 
Here's a taster of what is in there already
Any suggestions for new material to be moved across?
Here's a taster of what is in there already
Any suggestions for new material to be moved across?
Trending Topics
01-02-2005, 11:16 AM
#9
Originally Posted by st3v3
Taking a RST gearbox apart by blackRS (with pictures) thats my nomination
Im not talking about future topics folks, im talking about toics that have already been done that should be saved as reference info
EG:
Do you remember anyone doing an interesting essay in the past that would be usefull in teh future and deserves entrance into the Tech Essays forum?
01-02-2005, 11:41 AM
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01-02-2005, 11:49 AM
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0-60 in 17 seconds (eek)
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Stu, not much of an essay, but this https://passionford.com/forum/viewtopic.php?t=83046 is all about repairing a front bumper on a cossie. Took me ages to find the parts, etc... I think the post and pictures were helpful to some folks.
It could do with some tidying up I suppose, but is it "technical" enough ?
It could do with some tidying up I suppose, but is it "technical" enough ?
01-02-2005, 12:18 PM
#17
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Originally Posted by Stu @ M Developments
Originally Posted by st3v3
Taking a RST gearbox apart by blackRS (with pictures) thats my nomination
01-02-2005, 12:46 PM
#18
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Originally Posted by Mercury_Magic_S2
ZVH converion step by step guide
Mfi to Efi conversion step by step guide.............
Mfi to Efi conversion step by step guide.............
My personal fav is by blackRS with his gearbox,a qaulity read is that
01-02-2005, 09:00 PM
#20
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Stu,
What about the little gem below ?
Excessive cylinder pressure will encourage engine destroying detonation with no piston immune to its effects. The goal of performance engine builders should be to build their products with as much detonation resistance as possible. An important first step is to set the assembled quench distance to .035". The quench distance is the compressed thickness of the head gasket plus the deck height, (the distance your piston is down in the bore). If your piston height, (not dome height), is above the block deck, subtract the overage from the gasket thickness to get a true assembled quench distance. The quench area is the flat part of the piston that would contact a similar flat area on the cylinder head if you had .000" assembled quench height. In a running engine, the .035" quench decreases to a close collision between the piston and cylinder head. The shock wave from the close collision drives air at high velocity through the combustion chamber. This movement tends to cool hot spots, average the chamber temperature, reduce detonation and increase power. Take note, on the exhaust cycle, some cooling of the piston occurs due to the closeness to the water cooled head.
If you are building an engine with steel rods, tight bearings, tight pistons, modest RPM and automatic transmission, a .035" quench is the minimum practical to run without engine damage. The closer the piston comes to the cylinder head at operating speed, the more turbulence is generated. Turbulence is the main means of reducing detonation. Unfortunately, the operating quench height varies in an engine as RPM and temperature change. If aluminum rods, loose pistons, (they rock and hit the head), and over 6000 RPM operation is anticipated, a static clearance of .055" could be required. A running quench height in excess of .060" will forfeit the benefits of the quench head design and can cause severe detonation. The suggested .035" static quench height is recommended as a good usable dimension for stock rod engines up to 6500 RPM. Above 6500 RPM rod selection becomes important. Since it is the close collision between the piston and the cylinder head that reduces the prospect of detonation, never add a shim or head gasket to lower compression on a quench head engine. If you have 10:1 with a proper quench and then add an extra .040" gasket to give 9.5:1 and .080" quench, you will create more ping at 9.5:1 than you had at 10:1. The suitable way to lower the compression is to use a dish piston. Dish (reverse combustion chamber), pistons are designed for maximum quench, (sometimes called squish), area. Having part of the combustion chamber in the piston improves the shape of the chamber and flame travel. High performance motors will see some detonation, which leads to preignition. Detonation occurs at five to ten degrees after top-dead-center. Preignition occurs before top-dead-center. Detonation damages your engine with impact loads and excessive heat. The excessive heat part of detonation is what causes preignition. Overheated combustion chamber parts start acting as glow plugs. Preignition induces extremely rapid combustion and welding temperatures melt down is only seconds away!
Absolutely correct in many cases, yes.
This is EXACTLY why, these peeps who lop the top off a piston to lower the compression ratio dont know what the fook they are doing
_________________
Best Regards,
Stu
What about the little gem below ?
Excessive cylinder pressure will encourage engine destroying detonation with no piston immune to its effects. The goal of performance engine builders should be to build their products with as much detonation resistance as possible. An important first step is to set the assembled quench distance to .035". The quench distance is the compressed thickness of the head gasket plus the deck height, (the distance your piston is down in the bore). If your piston height, (not dome height), is above the block deck, subtract the overage from the gasket thickness to get a true assembled quench distance. The quench area is the flat part of the piston that would contact a similar flat area on the cylinder head if you had .000" assembled quench height. In a running engine, the .035" quench decreases to a close collision between the piston and cylinder head. The shock wave from the close collision drives air at high velocity through the combustion chamber. This movement tends to cool hot spots, average the chamber temperature, reduce detonation and increase power. Take note, on the exhaust cycle, some cooling of the piston occurs due to the closeness to the water cooled head.
If you are building an engine with steel rods, tight bearings, tight pistons, modest RPM and automatic transmission, a .035" quench is the minimum practical to run without engine damage. The closer the piston comes to the cylinder head at operating speed, the more turbulence is generated. Turbulence is the main means of reducing detonation. Unfortunately, the operating quench height varies in an engine as RPM and temperature change. If aluminum rods, loose pistons, (they rock and hit the head), and over 6000 RPM operation is anticipated, a static clearance of .055" could be required. A running quench height in excess of .060" will forfeit the benefits of the quench head design and can cause severe detonation. The suggested .035" static quench height is recommended as a good usable dimension for stock rod engines up to 6500 RPM. Above 6500 RPM rod selection becomes important. Since it is the close collision between the piston and the cylinder head that reduces the prospect of detonation, never add a shim or head gasket to lower compression on a quench head engine. If you have 10:1 with a proper quench and then add an extra .040" gasket to give 9.5:1 and .080" quench, you will create more ping at 9.5:1 than you had at 10:1. The suitable way to lower the compression is to use a dish piston. Dish (reverse combustion chamber), pistons are designed for maximum quench, (sometimes called squish), area. Having part of the combustion chamber in the piston improves the shape of the chamber and flame travel. High performance motors will see some detonation, which leads to preignition. Detonation occurs at five to ten degrees after top-dead-center. Preignition occurs before top-dead-center. Detonation damages your engine with impact loads and excessive heat. The excessive heat part of detonation is what causes preignition. Overheated combustion chamber parts start acting as glow plugs. Preignition induces extremely rapid combustion and welding temperatures melt down is only seconds away!
Absolutely correct in many cases, yes.
This is EXACTLY why, these peeps who lop the top off a piston to lower the compression ratio dont know what the fook they are doing
_________________
Best Regards,
Stu
02-02-2005, 03:08 PM
#21
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This is EXACTLY why, these peeps who lop the top off a piston to lower the compression ratio dont know what the fook they are doing
thats excatly what i did to get 7.2cr. mind you the pistons pa1079 (i think) 2wd cosworth pistons are virtually flat top anyway. only have a raised area 4mm wide and 1mm high. am i gunago BANG ?
10-02-2005, 09:39 PM
#25
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Originally Posted by capri-rs
you can have mine cosworth manuals online if you want (in pdf format now)
wbr
Geir
wbr
Geir
http://www.siipicossu.com/manuaaleja/manuaalit.htm
10-02-2005, 09:41 PM
#26
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Originally Posted by wimwerf
nice....for the gold members... 
don't worry mate, it's just another stunt from Stu to become more Gold members
10-02-2005, 10:21 PM
#31
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Originally Posted by Stu @ M Developments
Actually its just another stunt from Stu to ensure the valuable Gold members are rewarded properly with masses of usefull technical information at their fingertips in exchange for their 5.4pence per day.
11-02-2005, 12:05 PM
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Stu,
I think your closed loop thread is a good one as it is something i think that everybody is interested in and i certainly enjoy reading about it
Pugo
I think your closed loop thread is a good one as it is something i think that everybody is interested in and i certainly enjoy reading about it
Pugo
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