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Arouse the DAMPFHAMMER!
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6,624 Posts
Discussion Starter #1 (Edited)
BNIB Pro 156 head *$old*

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$old

Thanks for your interest!

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This is a brand new 4Piston Pro 156 CNC head with the product no. 430 (s. picture below) for sale. It consists of:
  • PRB-1 casting
  • Ferrea 6000 36/30 mm valves
  • Ferrea S10100 valve springs
  • Ferrea retainers E11066
  • Pro156 port and valve seat job
  • Viton valve sealing rings
Every part is new or at least unused and of course it is a product fabed by 4Pistonracing.com. According 4Piston it flows at intake 346 [email protected]" and 245 [email protected]" at exhaust port. I want to see $2650.- obo plus boxing and shipping incl. valve cover as shown. I will ship international, but only to long term members of K20a.org I know or confirmation of identity. PM me for information or placing a offer.

Product confirmation zoom:


Product confirmation:


Valves and sealing ring:


Intake side view:


Intake port view:


Exhaust port view:


Fire deck side view:


Intake valve size:


Top view:


Retainer confirmation:


Exhaust side incl. valve cover:


Intake side incl. valve cover:


Thanks

Markus
 

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Arouse the DAMPFHAMMER!
Joined
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6,624 Posts
Discussion Starter #2
Some better pics - all for you

Some better pictures, done with the support of my mountainbike photons gun "Hope Vision Four" on the first of five power levels...LOL :D

Incl. valve cover:


Valve cover top:


More precise valve diameter measurement (mobile cam handling and measuring :facepalm:)


Exhaust port:


Exhaust side:


Intake port:


Intake side:
 

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Arouse the DAMPFHAMMER!
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6,624 Posts
Discussion Starter #3
Some addtional information from 4Piston website:

4pistonracing.com said:
Recommended Use
  • All Motor Street/Race
  • Outlaw Turbo
  • Turbo Street
  • Road Race
  • USAC Midget
  • Suitable for 2.0-2.4L Road Race engines with a broad powerband in mind
  • Suitable for 2.4-2.7L Drag Race engines as an alternative to our large valve 163 heads
 

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Arouse the DAMPFHAMMER!
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6,624 Posts
Discussion Starter #8
Right sized port velocity profile

What is going on instead?
My 86.5x86 engine project needs smaller intake and exhaust ports cross sectional area for a higher gas velocity. This high flowing CNC head is better installed on a NA'd 87x99 (endurance, drag) or a FI'd 86x86 short block (endurance, drag) to utilize it's value. I will switch to my RSP casting and let work in some nice features to reach a bit less flow, around 315 [email protected]" but due to a smaller port cross sectional area higher gas velocity. The right velocity and velocity profile over port length is the key for a high VE level...this head is for bigger guys :D
 

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Arouse the DAMPFHAMMER!
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6,624 Posts
Discussion Starter #11
Man this is awesome. Good luck with sale and bump for a cool guy!
Thanks Mixwell :eek:.

Some additional info Luke of 4Piston did post some days ago...was in 2012 :D:
DRAG said:
BELOW - Here is the PRO TSX vs our Pro 156 CNC head. The flow chart only shows so much. They are very different port designs and the air moves through each port in a totally different manner, and at very different air speed. There are applications where one will be better than the other, and vice versa...so contact us for a recommendation
While the Pro TSX CNC head support higher gas velocity due to it's smaller cross section, it will support smaller displacement engines, the Pro 156 CNC head need a higher displacement to reach the same gas velocity which is ideal for very high VE support because of it's bigger cross section.

One can see that just on the diagrammatic flow over valve lift lines of both, the Pro 156 CNC head get awake "later". A typical technique to improve low lift flow could be done by 36 mm intake valves, this specific head has integrated.
This is a great improvement over the 35 mm intake valve!

Some further information Luke of 4Piston did post years ago:
4piston said:
For what its worth, I had a guy comment on K20 that he just did a back to back of a Stock Type S vs our Pro 156 on his 12.5:1 2.4L and he picked up 21hp from the stock head on pump gas.
Found on http://honda-tech.com/all-motor-nat...ead-test-true-back-back-3143775/#post48752032
 
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