CNC'd UZ Heads

[XR8tt]

Very similar to CNC heads I have coming..

 

[JustenGT8]

You stumped up for a pair of Ben's heads XR? They look good but out of my budget

Plenty of flow figures around for stock heads Rod so no problem getting something to compare to, as long as the same pressures are used.

 

[XR8tt]

You stumped up for a pair of Ben's heads XR? They look good but out of my budget

Plenty of flow figures around for stock heads Rod so no problem getting something to compare to, as long as the same pressures are used.

Yep...Getting assembled with shimless buckets now..

 

[cribbj]

Moved the CNC head posts to a new thread from Zuffen's.

XR8TT, about how much are these heads?

 

[XR8tt]

Moved the CNC head posts to a new thread from Zuffen's.

XR8TT, about how much are these heads?

$3600 AU ...
Plus any facing, oversize valves etc..
I inquired other places like Kelford,Kostecki etc
These are good value..
Repeatable port & chambers produce repeatable power and torque curves.

 

[Zuffen]

If I was starting agaain I would jump at them at that price.

I guess I have twice that invested in my heads and I know each port is an individual, hence flows different amounts of air.

I would have been tempted to do away with the excess valve guide length and the flat area around the exhaust valve's guide.

 

[cribbj]

If I was starting agaain I would jump at them at that price.

I guess I have twice that invested in my heads and I know each port is an individual, hence flows different amounts of air.

Me too....

XR8TT, have those heads been flowed on a bench, alongside a stock head, and if so, can you post up the numbers?

 

[XR8tt]

From "memory" 286 cfm at 13mm with std sized valves .. I'll find out for sure..
I would say close to 300cfm with bigger valves ??

 

[XR8tt]

Std
2mm=52.2cfm 2mm=31.3cfm
7mm=203.8 cfm 7mm=125.2cfm
13mm=230.1 cfm 13mm=149.9cfm

max new port
2mm=74.0cfm 2mm=54.0cfm
7mm=208 cfm 7mm=144.3cfm
13mm=274.7 cfm 13mm=180.4cfm

and with new intake valve (stock diameter)
2mm=79.9cfm
7mm=222.2 cfm
13mm=286.2 cfm

 

[Zuffen]

13mm is huge lift on a shim over engine.

I would think 9-10mm would be the go without a lot of $ going into the valve train.

 

[XR8tt]

Yea it's more can base circle that keeps shims in there..
As with any heads flow .. They always advertise over or to when flow starts slowing down on pushrod engines anyway..
Mine is shimless buckets from Prius NZ FE engine..

 

[cribbj]

With that lift, I would think you're going to be bottoming against the guides too, or have you already machined them down as well?

We (Scotturnot and I) also had some issues with our higher lift Kelford's fouling the lifter bores, and the cam lobes required chamfering.

 

[ed_ma61]

head flows are rated to 13mm & 1/2" lift almost as standard. whether someone runs that lift or not, its hardly the point. it makes ports flows comparable...

heres the maths id did earlier on cam lift to impact: http://www.v-eight.com/tech_forum/viewtopic.php?f=4&t=1019

 

[XR8tt]

With that lift, I would think you're going to be bottoming against the guides too, or have you already machined them down as well?

We (Scotturnot and I) also had some issues with our higher lift Kelfords fouling the lifter bores, and the cam lobes required chamfering.

YEP as with all modded engines its just not a bolt on part.. Once you get into serious power levels.. Its not like your swapping carbs...
All these issues have to be checked.. Including bigger or another dowel pin, coil bind, guide clearance etc etc.. Check check check..
All these things lead into good bullet proof engine building...
I have assembled a few Subaru WRX & STI engines.. There are various slight changes between the two.. Stronger cam locating bolts, stronger dowel location pins, heads are chamfered for extra base circle cam etc etc.. No different to these engines..
I'm hoping using these CNC heads that power will be much easier without excessive boost [heat] and give higher detonation threshold..
It has worked with previous pushrod engines I have turbo'd so I cannot see any reason this would be any different !!