Head shim versus low compression pistons ?

[ak]

Which one is better? I know a few thing about each I would like to know your opinon of which one is better and why, And which one would have better throttle response. Thanks,

 

[mulot30th]

Low compression have good quench... head shim... no quench....

Pstons... eare forged while head shim runs stock cast pistons.

 

[zross1]

Exactly, low compression is low compression but with lc pistons they are forged vs cast stock pistons.

 

[racinstation]

The only thing better about the head shim is the easier of the two to install.

 

[mulot30th]

The only thing better about the head shim is the easier of the two to install.

I did the shim on my rx1 mountain with 12# of boost supercharger.

Should not be a problem for throttle response because its a lysholm blower...

But for turbo, much better LC pistons.

 

[Jamie Gelting]

The only thing better about the head shim is the easier of the two to install.

For most people the head shim will work great. If you really want the best then the pistons would be the way to go. Much more work but better.

Jamie

 

[tko47]

do pistons JE are the most reliable

 

[MEAT]

Low compression have good quench... head shim... no quench....

Pstons... eare forged while head shim runs stock cast pistons.

Can someone explain this ? I understand the wiescos are forged but what is quenched ?

 

[mulot30th]

Juste like squish on a 2 stroke.

 

[fullthrottle800]

I have never really heard of stock pistons failing.Mabye at extremely high boost levels.

 

[Brent_P]

The only thing better about the head shim is the easier of the two to install.

ummm, and cost!!!

 

[Srxspec]

"Quench" or "squish area" is typically the flat area on the top of the piston that's almost level with the top of the block deck. It must have a corresponding flat area on the deck surface of the head to qualify as quench (so in this case it is the outside edge of the piston).

If you look at a combustion chamber, you will usually see these flat areas, and they will have the volume of the actual combustion chamber between them. When the piston is compressing the mixture, as the piston nears the head, the flat areas on the head and piston come together and force the mixture from those areas to "squish" into the chamber, where the spark plug and burning mixture reside, so you achieve a more complete burn.

Running a head shim or stacked gaskets you eliminate the "quench" area and loose that area to "squish" the fuel mixture into the center of the chamger.

If you look at a Wiseco or JE low compression piston it still has the "quench" area around the outside edge but is "dished" in the center. That is the proper way to decompress a motor, but also the more expensive and time taking way.

 

[mulot30th]

"Quench" or "squish area" is typically the flat area on the top of the piston that's almost level with the top of the block deck. It must have a corresponding flat area on the deck surface of the head to qualify as quench (so in this case it is the outside edge of the piston).

If you look at a combustion chamber, you will usually see these flat areas, and they will have the volume of the actual combustion chamber between them. When the piston is compressing the mixture, as the piston nears the head, the flat areas on the head and piston come together and force the mixture from those areas to "squish" into the chamber, where the spark plug and burning mixture reside, so you achieve a more complete burn.

Running a head shim or stacked gaskets you eliminate the "quench" area and loose that area to "squish" the fuel mixture into the center of the chamger.

If you look at a Wiseco or JE low compression piston it still has the "quench" area around the outside edge but is "dished" in the center. That is the proper way to decompress a motor, but also the more expensive and time taking way.

Exactly what I would have wrote haven't I been so lazy

 

[MEAT]

"Quench" or "squish area" is typically the flat area on the top of the piston that's almost level with the top of the block deck. It must have a corresponding flat area on the deck surface of the head to qualify as quench (so in this case it is the outside edge of the piston).

If you look at a combustion chamber, you will usually see these flat areas, and they will have the volume of the actual combustion chamber between them. When the piston is compressing the mixture, as the piston nears the head, the flat areas on the head and piston come together and force the mixture from those areas to "squish" into the chamber, where the spark plug and burning mixture reside, so you achieve a more complete burn.

Running a head shim or stacked gaskets you eliminate the "quench" area and loose that area to "squish" the fuel mixture into the center of the chamger. ?

If you look at a Wiseco or JE low compression piston it still has the "quench" area around the outside edge but is "dished" in the center. That is the proper way to decompress a motor, but also the more expensive and time taking way.

So how much of a benefit is this over a headshim ?

 

[ak]

"Quench" or "squish area" is typically the flat area on the top of the piston that's almost level with the top of the block deck. It must have a corresponding flat area on the deck surface of the head to qualify as quench (so in this case it is the outside edge of the piston).

If you look at a combustion chamber, you will usually see these flat areas, and they will have the volume of the actual combustion chamber between them. When the piston is compressing the mixture, as the piston nears the head, the flat areas on the head and piston come together and force the mixture from those areas to "squish" into the chamber, where the spark plug and burning mixture reside, so you achieve a more complete burn.

Running a head shim or stacked gaskets you eliminate the "quench" area and loose that area to "squish" the fuel mixture into the center of the chamger. ?

If you look at a Wiseco or JE low compression piston it still has the "quench" area around the outside edge but is "dished" in the center. That is the proper way to decompress a motor, but also the more expensive and time taking way.

So how much of a benefit is this over a headshim ?

Im guessing you wont have the lag that the headshim brings ?