Radial Anti Detonation Grooves

General engine tech -- Drag Racing to Circle Track

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andrew1
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Radial Anti Detonation Grooves

Post by andrew1 »

This wiseco piston has radial grooves around the piston top above the top ring land.


What is the purpose of these grooves and how do they work?


Image
Ed-vancedEngines

Post by Ed-vancedEngines »

Looks like someone went crazy and started cutting grooves everywhere they could to me.

Obviusly they know more than I do about what a piston needs. I am not a piston company. I am a lowly engine designer and builder.

I see no reason or benefit for any purpose I can think of for a groove to be above the top ring land.

To make it easier to lift the land maybe? It looks to me that all structial strength near the ring lands have been destroyed.

Ed
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Post by panic »

H-D used to cut a single groove above the top compression ring to reduce heat flow from the dome to the skirt.
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Post by SteveS »

This topic recently appeared on another forum.................and very little arose from the discussion with the exception of one post that quoted the claimed benefits of "anti-detonation" grooves found in material appearing on a Subaru site.

What are the anti-detonation grooves on the top ring land for?

The Anti-detonation grooves prevent carbon-buildup from locking up the top ring. They also help keep the air and fuel in suspension. These grooves knock the peaks off shock waves within the cylinder, reducing the propensity to detonate. They also temper pressure spikes and enhance piston ring life. The presence of this feature depends on your piston manufacturer as some have them, some don’t.
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Re: Radial Anti Detonation Grooves

Post by N/A Power »

andrew1 wrote:This wiseco piston has radial grooves around the piston top above the top ring land.


What is the purpose of these grooves and how do they work?


Image
These grooves would also function to minimize contact area and friction between upper sides of piston and cylinder wall. This contact happens when piston rocks on direction changes. It also appears that these grooves would increase available piston area to be exposed to combustion heat, taking some of this heat away from top ring.
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Anti-detonation marketing

Post by WATT'S SHOP »

Wiseco is primarily a dirt bike piston. Those grooves help reduce welding of the piston to the cylinder wall when you don't have enough sense to reduce the crown diameter so contact doesn't occur with the cylinder wall. JE calls them contact reduction grooves. Most all serious race pistons don't use this tactic. It is a hold over from 2 stroke racing, it works best with oil in the fuel and a chrome cylinder wall. If you like it, use it. BTW check out the relief at the top of the piston creating the reqired crown clearance, a recent update, proof even wiseco doesn't believe there own BS! I've seen this cause needless damage in several engines. If your crown rides the wall your clearance is too large or your piston is too big for the application or getting too hot. Either way crown contact deposits aluminum and wears away iron, so it is always bad. Dirt bikes get a new piston every race and a new sleeve pretty often. I don't race dirt bikes so I don't use wiseco pistons, neither should you.
Crutch

Post by Crutch »

Hummmm

I thought that Wiseco made all the blanks at one time for Larry Widmers Roller Wave Piston.

Oh, that's right, they are for Hondas.
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Post by andrew1 »

I noticed Larry Widmer's Super Squish Enhanced-Combustion Pistons on this thread have a very similar Radial Anti Detonation Grooves

viewtopic.php?t=5264&postdays=0&postorder=asc&start=15
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Post by Unkl Ian »

"Anti Detonation" grooves ?

I doubt these grooves actually prevent detonation.

My understanding was the were to help isolate the top ring
from pressure spikes caused by detonation.
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Post by Cheapstreetduster »

is that a high silicone piston?
i know they reflect alot of heat off the top...
wich actually causes the very top of a piston to see higher temps..
and it expands differently then the lower or cooler mass of the piston farther down the skirts area..
seems like it goes along with the two stroke and anti sieze issues..
high silicone pistons need different ring gaps..
and they have been known to have the tops pulled off when ring gap butts against its self
cheapst.
mechanical engineer, carpenter by trade,love racing engines in general, drag race in the NMCA fastest street car cheapstreet class. i am a doit yourselfer
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Re: Anti-detonation marketing

Post by Racer7088 »

WATT'S SHOP wrote:Wiseco is primarily a dirt bike piston. Those grooves help reduce welding of the piston to the cylinder wall when you don't have enough sense to reduce the crown diameter so contact doesn't occur with the cylinder wall. JE calls them contact reduction grooves. Most all serious race pistons don't use this tactic. It is a hold over from 2 stroke racing, it works best with oil in the fuel and a chrome cylinder wall. If you like it, use it. BTW check out the relief at the top of the piston creating the reqired crown clearance, a recent update, proof even wiseco doesn't believe there own BS! I've seen this cause needless damage in several engines. If your crown rides the wall your clearance is too large or your piston is too big for the application or getting too hot. Either way crown contact deposits aluminum and wears away iron, so it is always bad. Dirt bikes get a new piston every race and a new sleeve pretty often. I don't race dirt bikes so I don't use wiseco pistons, neither should you.
:roll:

Wiseco has been and is being used in many NHRA Pro-Stock winning engine programs and have won PS championships and also in many NASCAR Winston and Nextel Cup championship winning engine programs as well as winning two championships lately. They and Mahle make their own forgings which almost none of these other companies do. I have used hundreds of sets of their pistons and never had "the crown ride the wall" but I have had several JEs do that including some at SAM that were made wrong.
Erik Koenig

Houston, TX

http://samracing.com

http://HKRacingEngines.com
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Re: Radial Anti Detonation Grooves

Post by beth »

andrew1 wrote:This wiseco piston has radial grooves around the piston top above the top ring land.


What is the purpose of these grooves and how do they work?


Image

The groove could very well give a place for liquid mixtures that cannot be expelled by the squish action to occupy rather than being excessively compressed into detonation.



beth
Ed-vancedEngines

Post by Ed-vancedEngines »

Erik,
Do you know that you are talking about the same company? Wiseco JE
Wiseco has been and is being used in many NHRA Pro-Stock winning engine programs and have won PS championships and also in many NASCAR Winston and Nextel Cup championship winning engine programs as well as winning two championships lately. They and Mahle make their own forgings which almost none of these other companies do. I have used hundreds of sets of their pistons and never had "the crown ride the wall" but I have had several JEs do that including some at SAM that were made wrong.
Maybe they do make their own forgings, I don't know. Most Piston companies I know of buy the forging blanks from aluminum companies.

Ed
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Post by Scott Smith »

Just because they have a sticker on the side of their car don't mean they run the product. :lol:

Do you think Warren Johnson really runs a Fluid Damper? :lol:
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Post by Vengeance »

Ed-vancedEngines wrote:Erik,
Do you know that you are talking about the same company? Wiseco JE
That's like saying Dodge and Jeep are the same company.
Wiseco and JE might be owned by Performance Motorsports Inc., but they still operate completely independent of each other.
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