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Old 12th May 2006, 10:50   #16
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Quote:
Originally Posted by bhogalrajnish
Well the compression can be increased in a number of ways as discused.
Another way is to shave the head and then veld it to the cylender block (remove the packing).
Hade done it on my Suzuki Shogun a couple of years back. I did get the block re-bored after that never had to remove the head. Doing the same will be difficult on a car as a 4 stroke engine has valves and a car has 3-4 cylenders unless you beleave in replacine the cylender kit itself instead of reboaring or even changing the valves.

i dont think thats possible on a watercooled engine.... if we remove the head gasket... what about the water n the oil lines...?? n this is rather unusual.... welding the head to the block.... ???? u rather get a thinner head gasket n shav the head.. if at all u want to increase comp so much..... frankly ive never heard of n e one doin it on a 4 cylinder or rather n e engine.... sound impossible to me....
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Old 12th May 2006, 20:24   #17
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Wow,

Welding the head on !! Ive never ever heard of or even thought of that!! Dont know if it sounds like the best idea....

ZenGT, sounds like it can generally only work on air cooled single cylinders....

cya
R
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Old 13th May 2006, 08:19   #18
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Cool

Quote:
Originally Posted by Rehaan
ZenGT, sounds like it can generally only work on air cooled single cylinders....

R

yeah rehaan.. even if it can be done only on a air cooled engine... i dont c the point here... what if after welding....... yr piston breaks o conrod bends o whatever ... then wt.. throw the engine away????? mayb there s another way to it n he cant explain it right... but i wud really like to know....
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Old 13th May 2006, 10:59   #19
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Are we super engineering brains or are we letting our "Harry-Potter" imaginations run wild here?

How do you propose to "weld"
an aluminium-alloy head to a cast iron cylinder block?

Of course, you can consider metalock, metalace, etc. But unless you're fond of throwing away good money, give me good old torqued cylinder head bolts anyday.
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Old 13th May 2006, 11:34   #20
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Default what is shaving of head

plz... tell me in detail what does shaving of head means ( to increase compression ratio)......plz.......
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Old 13th May 2006, 13:09   #21
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Quote:
Originally Posted by ram
There are several ways to increase the compression ratio of an engine
  1. domed pistons,
  2. increased stroke,
  3. changing to a head with a smaller combustion chamber,
  4. Shaving the head or block of an engine,
Shaving beyond a limit, can get the valves bent if they violently collide with the pistons. That said, higher compression ratio generally puts more stress on pistons, connecting rods and bearings. We can't just assume that they will take the extra load, but must be very careful to build up the rest of the engine as needed.

Sometimes, just going with a thinner head gasket (if available) is a poor man's way to increase compression.
Are shaving the head of an engine and changint the head to a smaller combustion chamber similar to each other?

Also, does just shaving a cylinder head increase so much pressure on the engine tht it needs to be monitored?
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Old 13th May 2006, 13:11   #22
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Quote:
Originally Posted by devsus
plz... tell me in detail what does shaving of head means ( to increase compression ratio)......plz.......
Shaving a head means shaving the cylinder head you have mounted on the cylinder (which houses the piston). When shaved, the compression chamber size decreases, thus increasing the compresion ratio.

But the air/fuel mixture have to be spot on when this is done, else it can have unwanted effects on the engine.
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Old 15th May 2006, 13:33   #23
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I have found that simply increasing compression rstio in a stock car without doing any mods will affect the performance.............higher compression ratio CR.....means more power performance.....but it then requires higher octane fuels which doesnt preignites easily in high compression.....we dont get higher octane fuel everywhere.............in my esteem I increased the compression ratio from 9:1 to 10:1 by shaving the head.............but then I made grooves on the surface of head.......this combination working so gr8.........my power increased so much......FE too increased nearly 10%.....this is the patented innovation of Mr Somender Singh.....I advise u all to read it first........by grooving the head.....we are helping engine burning fuel totally......the squish area.....area between top of piston and head surface is called squish area.....in normal engine designs this area is of importance bcz when piston reaches TDC....Top dead center......with air fuel mixture being compressed ...the mixture squish out of this region to cylinder walls when piston reaches TDC.......if we made grooves....then heat energy will be given a path in this area whr till now no flame has been reached bcz of the design aspect....this heat energy ignites fuel .... flame propagates in multiple ways resulting in most efficient combustion in any IC engine..........this effect burns every drop of fuel hence giving increased FE .....performance is also increased with increased compression and grooving..........now with such setup there is no knocking with high octane fuels......infact purpose of high octane fuel is better utilised............

members do study this innovation.............its so simple yet so effective.Mr Somender Singh had been recently awarded Best Innovator Of the Year by National Geography....

Enjoy.........
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Old 15th May 2006, 14:28   #24
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Doesn't the addition of a turbocharger or a supercharger also increase the compression ratio of an engine?
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Old 16th May 2006, 13:51   #25
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Default Shaving head vs. changing to different/smaller combustion chamber

Quote:
Originally Posted by turbo_v12
Aren't shaving the head of an engine and changing the head to a smaller combustion chamber similar to each other?
Yes, they are similar, but can have vastly different results.
Let me try to explain.

Imagine a 80 cc hemispherical compression chamber in the head.
As you shave away material of the head surface (green area),
the volume of the compression chamber reduces and compression ratio increases.

For a given reduction in height of the head, the compression volume reduces
much faster if we had a conical chamber and
much slower if we had a cylindrical head.

See diagram below.
<picture unavailable>

Here I've computed the relevant curves showing impact of shaving the head on compression chamber volume.
<picture unavailable>

So, shaving the head has a varying impact on compression ratio, depending on the shape of the head.

Hope your question is answered.

Quote:
Originally Posted by turbo_v12
Also, does just shaving a cylinder head increase so much pressure on the engine tht it needs to be monitored?
Absolutely! high compression engines must have
heavier duty pistons, rods, bearings and other stressed items.

Last edited by Rehaan : 10th April 2010 at 17:54. Reason: Removed 2 picture links as they were showing some error. If you still have the pics please re-upload + report post. Thanks.
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Old 16th May 2006, 17:10   #26
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Thumbs up very informative

Quote:
Originally Posted by ram
No. Compression ratio is a hard quantity, beyond the control of software in the ECU.

.....
This was very informative, Yes, go in step by step from the poor man's way to the rich man's way :-)
and also let us know how it is doing time to time *peace*
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Old 16th May 2006, 23:28   #27
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Default How much to shave a head?

I have a Maruti Zen Mpfi, I want to know by how much can i shave the head without changing the pistons , rods, bearings or anything else,
How does shaving the head affect the FE?
I am also planning to make the grooves as per mr somender singh,
So am open to suggestions

Last edited by Kaizer Sozay : 16th May 2006 at 23:29.
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Old 17th May 2006, 09:07   #28
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Quote:
Originally Posted by sujaylahiri
Doesn't the addition of a turbocharger or a supercharger also increase the compression ratio of an engine?
Even though forced induction does have the effect of increased compression, I dont think it affect the "compression ratio".

Superb explaination Ram!
And i never ever thought about the curves for different shaped chambers as your graph showed! Thanks.

>> Q - When heads are shaved, are they flycut? milled? surface ground?

cya
R
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Old 1st August 2008, 21:34   #29
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In a carburetted engine after increasing the compression ratio the jetting and the ignition timing is generally altered to suit the increase in compression ratio.

But when we increase the compression ratio in a fuel injected engine how does ECU recalculate right amount of fuel to be fed in. Is it necessary to remap the ecu to deliver the correct amount of fuel? Or is the ECU self adjusting and what if it's a open loop system?
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Old 9th April 2010, 14:39   #30
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Quote:
Originally Posted by finetuning View Post
I have found that simply increasing compression rstio in a stock car without doing any mods will affect the performance.............higher compression ratio CR.....means more power performance.....but it then requires higher octane fuels which doesnt preignites easily in high compression.....we dont get higher octane fuel everywhere.............in my esteem I increased the compression ratio from 9:1 to 10:1 by shaving the head.............but then I made grooves on the surface of head.......this combination working so gr8.........my power increased so much......FE too increased nearly 10%.....this is the patented innovation of Mr Somender Singh.....I advise u all to read it first........by grooving the head.....we are helping engine burning fuel totally......the squish area.....area between top of piston and head surface is called squish area.....in normal engine designs this area is of importance bcz when piston reaches TDC....Top dead center......with air fuel mixture being compressed ...the mixture squish out of this region to cylinder walls when piston reaches TDC.......if we made grooves....then heat energy will be given a path in this area whr till now no flame has been reached bcz of the design aspect....this heat energy ignites fuel .... flame propagates in multiple ways resulting in most efficient combustion in any IC engine..........this effect burns every drop of fuel hence giving increased FE .....performance is also increased with increased compression and grooving..........now with such setup there is no knocking with high octane fuels......infact purpose of high octane fuel is better utilised............

members do study this innovation.............its so simple yet so effective.Mr Somender Singh had been recently awarded Best Innovator Of the Year by National Geography....

Enjoy.........
have any resident experts here on the forum explored Somender Singh's technique ? There is quite a bit of reading available online and also a youtube video showing how its done.

on first read it seems sound. any expert opinions ??
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