# Cylinder heads/porting



## nailsgtr600 (Aug 2, 2007)

I just thought people would like to see what goes into porting a Rb Head, 
The Rb25/26 heads really struggle to make power on the standard ports,
This is for a customer in Greece, its going to be running a V-cam system, with standard valves, the head is good for around a 1000bhp on standard valves with the port sizing/spec.. (obviously depending on turbo specs and cams etc)


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## FRRACER (Jun 23, 2013)

Impressive work and looks very well done. Not many around who know what they are doing these days.


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## Gojira-R32 (Jun 22, 2012)

this looks really nice and clean, would like to know what it would cost for my RB20 head in the future when i go forged


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## tarmac terror (Jul 16, 2003)

Always believed a good cylinder head is the key to a good engine...

Do you guys have a menu or fixed cost approach to head work? Probably wouldn't go for an all-singing, all-dancing head from the outset but would be interested in some aspects....

I know a head from CNC Heads costs between 1350-1850 depending on valve sizes and would be interested to gat an indication of what sort of costs you guys charge...


TT


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## FRRACER (Jun 23, 2013)

I am a big fan of head work, if done right you can make some impressive torque right across the rev range and helps reduce dynamic cr.

I would love to get mine done at some point when I start to focus my efforts on the engine.


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## BenR (Jan 28, 2013)

What do you guys use to cut valve seats?


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## BenR (Jan 28, 2013)

FRRACER said:


> I am a big fan of head work, if done right you can make some impressive torque right across the rev range and helps reduce dynamic cr.
> 
> I would love to get mine done at some point when I start to focus my efforts on the engine.


Increase dynamic CR. 

Increasing the discharge coefficient of any cylinder head will increase the dynamic CR, hence the cylinder pressure increase and torque/power increase.


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## Saifskyline (May 19, 2013)

Headgasket down is just a pump, headgasket up is where horsepower is made. That looks like a very good job what sort of prices do you charge for this service?


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## Corsa1 (Sep 8, 2003)

BenR said:


> What do you guys use to cut valve seats?


A rottler SG8


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## BenR (Jan 28, 2013)

Does that use a live or dead pilot?

I looked at rottlers years ago and seem to remember they had some joint system on the spindle, but cant remember if the pilot was live or dead. 

Looked at the sunnen vgs20 as well, but didnt like it.


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## BenR (Jan 28, 2013)

Oh, nice work BTW!

I like how you dont go mad on finish and concentrate on the important areas. You always know when someone is wasting time and money if the finish is anally smooth or over a 120 grit finish.....woe betide mirror polished lol.


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## Corsa1 (Sep 8, 2003)

BenR said:


> Does that use a live or dead pilot?
> 
> I looked at rottlers years ago and seem to remember they had some joint system on the spindle, but cant remember if the pilot was live or dead.
> 
> Looked at the sunnen vgs20 as well, but didnt like it.


Lol ever body to there own


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## nailsgtr600 (Aug 2, 2007)

tarmac terror said:


> Always believed a good cylinder head is the key to a good engine...
> 
> Do you guys have a menu or fixed cost approach to head work? Probably wouldn't go for an all-singing, all-dancing head from the outset but would be interested in some aspects....
> 
> ...


This Head spec costs £900 which includes supertech bronze guides, stem seals supplied and fitted, all shimmed up using customers existing shims,cams,valves, if you need any more info PM Andy or myself.

Rich


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## tarmac terror (Jul 16, 2003)

[email protected] said:


> This Head spec costs £900 which includes supertech bronze guides, stem seals supplied and fitted, all shimmed up using customers existing shims,cams,valves, if you need any more info PM Andy or myself.
> 
> Rich


Bloody hell Rich, thats excellent VFM!!!!

Could see me getting some head work done sooner rather than later!!!


TT


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## nailsgtr600 (Aug 2, 2007)

tarmac terror said:


> Bloody hell Rich, thats excellent VFM!!!!
> 
> Could see me getting some head work done sooner rather than later!!!
> 
> ...


No probs anytime, It was the best mod I ever did to my Rb26, it really came alive after this! 

Rich


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## Calibrat (Jan 22, 2013)

looks great rich, think ive gone abit over kill on mine looking at your BHP figures on standard valve size


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## jdmchrist (Apr 27, 2009)

Calibrat said:


> looks great rich, think ive gone abit over kill on mine looking at your BHP figures on standard valve size


Is there any downside going 1mm oversized valve when building a +/- 700whp rb30?


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## bigmikespec (Sep 5, 2008)

jdmchrist said:


> Is there any downside going 1mm oversized valve when building a +/- 700whp rb30?


Get your head porter to flow test around the head of the valve at various valve lifts, there is a risk of poor flow profile if the head of the valve is too close to the cylinder bore. Something to watch out for.


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## jdmchrist (Apr 27, 2009)

bigmikespec said:


> Get your head porter to flow test around the head of the valve at various valve lifts, there is a risk of poor flow profile if the head of the valve is too close to the cylinder bore. Something to watch out for.


I'm gonna get my head buid and ported by one of these 3 compagny which i think they know what they are doing

-cncheads

-rips

-amt 

But by my question i meant, on a well built and ported head, is there any disavantage of going with 1mm oversized valve on a 700whp rb30?


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## bigmikespec (Sep 5, 2008)

I would go with AMT.

To answer your question, NO.


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## jdmchrist (Apr 27, 2009)

ok thanks, and great work btw rich!


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