Super stock iron heads - work in progress

General engine tech -- Drag Racing to Circle Track

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KnightEngines
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Super stock iron heads - work in progress

Post by KnightEngines » Wed Aug 02, 2017 1:22 am

Thought you lot may like to see this, doing a set of Holden iron heads for a super stock racer - can't share all the details, but can share pics & non-specifics.
Class requires factory head & block castings, flat tappet cam & cast single carb intake, it's a lb/ci class so this will be a smaller capacity engine turning real hard.
Castings chosen are 'VT' heads - smaller chambers with a better shape than the earlier 'VN' type heads, some say there is not as much metal for porting, but from what I've seen that's not the case.
I started with a set of clean core heads, minimal core shift & clean water jackets, not previously touched & with no cracks in the chambers (hard to find!)
Valves will be 7mm stem Ti, so I've fitted .502/7mm CHE bronze guides.
Seats are 50 deg (both intake & exhaust) & sunk into the chambers a bit.

Started grinding on them today, I've done a couple of R&D ports on junk heads previously, so I got a pretty good idea where I'm headed, but I haven't had access to any junk VT castings, so I'm doing 1 cylinder 1st for testing to confirm the different chamber is going to do what I think & to trial a slightly different short turn before I commit to it.

I've got 1x intake port roughed out at the moment, here's the process:

As cast with seats guides fitted & seats cut:
ImageDSC00692 by tony knight, on Flickr

Stock runner, guide boss hacked a bit to get the bulk out the way:
ImageDSC00693 by tony knight, on Flickr

Rough sizing the walls:
ImageDSC00694 by tony knight, on Flickr

ImageDSC00695 by tony knight, on Flickr

Calipers set to stock pinch width:
ImageDSC00696 by tony knight, on Flickr

Roughing in the roof height:
ImageDSC00698 by tony knight, on Flickr

Roughing out the bowl:
ImageDSC00701 by tony knight, on Flickr

ImageDSC00703 by tony knight, on Flickr

Knocking back the short turn, not gonna be this shape, just moving metal to get the width roughly right:
ImageDSC00704 by tony knight, on Flickr

ImageDSC00705 by tony knight, on Flickr

Sizing the window over the turn & the pinch:
ImageDSC00706 by tony knight, on Flickr

Knocking the roof into shape:
ImageDSC00709 by tony knight, on Flickr

ImageDSC00710 by tony knight, on Flickr

KnightEngines
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Re: Super stock iron heads - work in progress

Post by KnightEngines » Wed Aug 02, 2017 1:26 am

Shaping & sizing the bowl:
ImageDSC00711 by tony knight, on Flickr

ImageDSC00712 by tony knight, on Flickr

ImageDSC00715 by tony knight, on Flickr

Shaping the turn:
ImageDSC00717 by tony knight, on Flickr

ImageDSC00718 by tony knight, on Flickr

Shaping & finalising the floor & back of turn:
ImageDSC00719 by tony knight, on Flickr

ImageDSC00720 by tony knight, on Flickr

Finalising the roof, walls & bowl roof:
ImageDSC00721 by tony knight, on Flickr

Just needs sanding, 1 done:
ImageDSC00723 by tony knight, on Flickr

desoto30
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Re: Super stock iron heads - work in progress

Post by desoto30 » Wed Aug 02, 2017 3:17 am

looks nice Tony.

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Re: Super stock iron heads - work in progress

Post by desoto30 » Wed Aug 02, 2017 3:18 am

What class?

KnightEngines
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Re: Super stock iron heads - work in progress

Post by KnightEngines » Wed Aug 02, 2017 3:45 am

Class? - can't really say.

Ran out of day, here's a couple of quick snaps of the 1 finished cylinder:

ImageDSC00739 by tony knight, on Flickr

ImageDSC00740 by tony knight, on Flickr

ImageDSC00742 by tony knight, on Flickr

ImageDSC00744 by tony knight, on Flickr

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Re: Super stock iron heads - work in progress

Post by cgarb » Wed Aug 02, 2017 5:00 am

You know you do very nice work. Have you ever thought about making a career out of porting?...lol

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Re: Super stock iron heads - work in progress

Post by Carnut1 » Wed Aug 02, 2017 6:10 am

Things I like, how you design a port for high rpm, your cutter work, how much metal you can remove to get desired shape, even the photography is top notch. Tony, maybe you can add to the texture threads and flow one cluttered and then your 60 grit finish? I know time is money but at your level it may bring some good info. Thanks for sharing, Charlie
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Re: Super stock iron heads - work in progress

Post by mag2555 » Wed Aug 02, 2017 8:53 am

It really really surprises me that a performance Head would have been designed with a Intake port on such a bias away from feeding the center of the cylinder, very nice work non the less!
It likely makes some big swirl numbers though?

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Re: Super stock iron heads - work in progress

Post by gvx » Wed Aug 02, 2017 9:32 am

Are these the same heads used in 400 CI super-stock making north of 1100 HP NA?
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Re: Super stock iron heads - work in progress

Post by Carnut1 » Wed Aug 02, 2017 12:24 pm

mag2555 wrote:It really really surprises me that a performance Head would have been designed with a Intake port on such a bias away from feeding the center of the cylinder, very nice work non the less!
It likely makes some big swirl numbers though?
Mag, I bet the swirl is actually on the low side which for a high rpm mill is actually a benefit. I like how Tony shaped the guide to aim some flow towards the center of the bore away from the cylinder wall. Tony, please explain why you are twisting the air towards the center. Is that costing you some cfm? Thanks, Charlie
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Re: Super stock iron heads - work in progress

Post by paulzig » Wed Aug 02, 2017 5:02 pm

mag2555 wrote:It really really surprises me that a performance Head would have been designed with a Intake port on such a bias away from feeding the center of the cylinder, very nice work non the less!
It likely makes some big swirl numbers though?
Its not a performance head its an OEM passenger car head....

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Re: Super stock iron heads - work in progress

Post by CGT » Wed Aug 02, 2017 5:37 pm

mag2555 wrote:It really really surprises me that a performance Head would have been designed with a Intake port on such a bias away from feeding the center of the cylinder, very nice work non the less!
It likely makes some big swirl numbers though?
Ever looked at a LS?

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Re: Super stock iron heads - work in progress

Post by KnightEngines » Wed Aug 02, 2017 7:10 pm

Its not a performance head its an OEM passenger car head....
Yup, everything from mum & dad sedans to work utes to taxi's got these heads, not designed as a performance head.
Mag, I bet the swirl is actually on the low side which for a high rpm mill is actually a benefit. I like how Tony shaped the guide to aim some flow towards the center of the bore away from the cylinder wall. Tony, please explain why you are twisting the air towards the center. Is that costing you some cfm? Thanks, Charlie
These swirl a bunch, too much, a bit less swirl is good. On my R&D junkers I used a smaller guide boss vane, this one is a little bigger but will still have pretty minimal effect, likely won't affect flow. May get a chance to do some flow bench testing late today, not sure, a bunch of bits for a couple of urgent jobs showed up yesterday arvo so I gotta crack on with them today.
Will probably end up with some rough cuttered sections, but I have to sand it to get it all blended in before hand anyway.
Are these the same heads used in 400 CI super-stock making north of 1100 HP NA?
No, you'd be thinking of aussie pro stock.

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Re: Super stock iron heads - work in progress

Post by MELWAY » Wed Aug 02, 2017 7:50 pm

Tony did you move the intake guide position when u installed those brass guides?
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Re: Super stock iron heads - work in progress

Post by KnightEngines » Wed Aug 02, 2017 8:12 pm

I wanted too, but rules say no & we wanna be 100% legal. Valve positions gotta be stock, no material to be added by any method (other than for repairs - won't fly 'repairing' all 8 cylinders LOL).

I'm doing a similar set with both guides shifted for Mondo.

If you want some shifted guide heads I invested in the tooling to do it, happy enough to do you a set with guides done & seats cut ready for porting if you wanna grind yourself.

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