Hey all
Has anyone got any tips or know how on cuttin the support bit on the ports where the head bolt goes thru? If i was to remove this can i just run a shorter bolt or a stud and nuts? My other head has small tubes in place but the head im currently doin was thinkin we could take this out and not replace ive heard its been done? Any one got pixs or know how?
Cheer
Stedz
Cuttin out the Support on Red heads
Started by
Stedz_lc
, Jun 27 2006 07:45 PM
14 replies to this topic
#2
_draglc_
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Posted 27 June 2006 - 08:45 PM
I had a head that had that done... ive heard it makes no improvement, but does make airflow worse, as that posts sort of directs airflow to the valves.
Also having a shorter bolt, ie not having it come through the top of the head is bad for it.. causes cracking or warping. Its supposed to be bolted from the top.
A1
Also having a shorter bolt, ie not having it come through the top of the head is bad for it.. causes cracking or warping. Its supposed to be bolted from the top.
A1
#3
rodomo
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Posted 28 June 2006 - 01:24 AM
The boss is removed and the base milled and recessed to the size of the (shallow)head of an allen screw. The bolt hole on top of the head is drilled to allow the allen screw to pass through and is then blanked off with a welch plug after tensioning. As mentioned above this may lead to different "true" tensions as long bolts stretch more than short bolts. I have also seen the boss ground back to a sharp point at the leading edge and relieved to almost nothing where the bolt passes through. Option 3 is to remove the boss and fit cast alloy bosses that turn them into 12 port. Option 4 is to remove the boss, drill the head from the bottom and fit tubular sleeves from the bottom. This is probably the max for flow with still retaining original head bolt
Edited by rodomo, 28 June 2006 - 01:30 AM.
#4
makka
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Posted 28 June 2006 - 09:27 PM
but what he wants to know how to get it out, and I would suggest a power hacksaw, yeehaar!
#5
rodomo
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Posted 28 June 2006 - 11:42 PM
^ Bloody country bumpkins! 
Probably bore the bolt hole (to predetermined depth) to the welch plug size, then use die grinder to remove the boss and finish with mill and die grinder.
Probably bore the bolt hole (to predetermined depth) to the welch plug size, then use die grinder to remove the boss and finish with mill and die grinder.
#6
makka
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Posted 29 June 2006 - 11:40 AM
hey Rob, I manage to survive up here in the bush!
#7
rodomo
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Posted 29 June 2006 - 11:54 PM
Sorry mate, but your post lost all credibility with the "Yee hah" at the end.
#8
_Toranamuk_
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Posted 01 July 2006 - 10:49 AM
Cut or die grind the post out & smooth/port the inlet tract to the shape you desire.
Don't lower the port floor too much though when porting.
I drill the top of hole to 19/32" & tap it to take a 3/8npt gallery plug (just makes for easier removal when you need to tension or remove the bolt).
With the bottom of the hole it needs to have a counter sunk flat surface machined into it for a 7/16 socket head cap screw to be fitted. I've got a 19/32 drill bit that I've machined to give a flat "seat" cut & has a pilot on the bottom of it that fits in the existing head bolt hole to keep it all true & square.
The outer diameter of the bolt head will have to be machined down to fit through the top bolt hole, & also can have the head trimmed down so it doesn't protrude much into the port.
The short head bolt only gets tensioned to 65ft/lb (still use a thread sealer).
Its a worthy conversion when the rest of the head is well ported.
Hope this helps.
Craig.
Don't lower the port floor too much though when porting.
I drill the top of hole to 19/32" & tap it to take a 3/8npt gallery plug (just makes for easier removal when you need to tension or remove the bolt).
With the bottom of the hole it needs to have a counter sunk flat surface machined into it for a 7/16 socket head cap screw to be fitted. I've got a 19/32 drill bit that I've machined to give a flat "seat" cut & has a pilot on the bottom of it that fits in the existing head bolt hole to keep it all true & square.
The outer diameter of the bolt head will have to be machined down to fit through the top bolt hole, & also can have the head trimmed down so it doesn't protrude much into the port.
The short head bolt only gets tensioned to 65ft/lb (still use a thread sealer).
Its a worthy conversion when the rest of the head is well ported.
Hope this helps.
Craig.
#9
makka
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Posted 01 July 2006 - 01:53 PM
have you got any pictures of this setup Craig?
#10
_Toranamuk_
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Posted 01 July 2006 - 07:34 PM
I've got 2 heads partially completed at the moment & will try & post some photo's tomorrow night.
I'll also include a pic of the modified drill bit i use for cutting the new seat for the head bolt.
If i don't get the pics up tomorrow evening, i wont be able to do it till next weekend (8/7/06)
I'll also include a pic of the modified drill bit i use for cutting the new seat for the head bolt.
If i don't get the pics up tomorrow evening, i wont be able to do it till next weekend (8/7/06)
#11
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Posted 02 July 2006 - 09:26 PM
I've tried uploading some pics, it took so long i've only put 1 on.
Very sorry for the size of the pic, i thought i'd shrunk it to 20% ?????
In the next week & a bit i'll post some more when our broadband is connected.
PS, this head is far from finished.
http://home.iprimus....on pics 152.jpg
EDIT: Please reduce the size of this pic.
Very sorry for the size of the pic, i thought i'd shrunk it to 20% ?????
In the next week & a bit i'll post some more when our broadband is connected.
PS, this head is far from finished.
http://home.iprimus....on pics 152.jpg
EDIT: Please reduce the size of this pic.
Edited by enderwigginau, 03 July 2006 - 03:23 PM.
#12
_Toranamuk_
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Posted 11 July 2006 - 11:22 PM
Finally some more pics of the Holden 6 red 9 port head with the support cut out.
The pics are grainy & the head is still a long way from finished, but you'll get the general idea I hope.
Any queries, just ask.
The pics are grainy & the head is still a long way from finished, but you'll get the general idea I hope.
Any queries, just ask.
Edited by Toranamuk, 11 July 2006 - 11:23 PM.
#13
_draglc_
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Posted 12 July 2006 - 12:47 PM
Like i said before, ive heard it makes no improvement, but does make airflow worse, as that posts sort of directs airflow to the valves, but i guess im interested to know how it goes.
Good luck!
Andrew
Good luck!
Andrew
#14
_Toranamuk_
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Posted 12 July 2006 - 11:06 PM
From my flow figures & air speed results there's definitely a huge improvement in results.
It did make the air coming through the inlet tract "pulse" at low lift, but that settled down from .250" valve lift & was clean to 550" lift.
It really depends on the final cam choice & inlet system, if it was a small/mild cam with low lift (low airspeed), then the "pulsing in the head would affect the incoming air speed & disrupt it, but when used with a high lift, fast ramp cam the results are great.
It also appears to dampen the pulsing affects from one inlet valve to the other, my theory is there is more of a plenum chamber type of effect happening in the inlet port with minimal changes in air direction between the valves, hence less disruption to the flow path.
In the photo with the head bolt sitting in it, the final product sits approx .200" lower. The counter sink is lower & the bolt head is turned down into more of a dome shape.
It did make the air coming through the inlet tract "pulse" at low lift, but that settled down from .250" valve lift & was clean to 550" lift.
It really depends on the final cam choice & inlet system, if it was a small/mild cam with low lift (low airspeed), then the "pulsing in the head would affect the incoming air speed & disrupt it, but when used with a high lift, fast ramp cam the results are great.
It also appears to dampen the pulsing affects from one inlet valve to the other, my theory is there is more of a plenum chamber type of effect happening in the inlet port with minimal changes in air direction between the valves, hence less disruption to the flow path.
In the photo with the head bolt sitting in it, the final product sits approx .200" lower. The counter sink is lower & the bolt head is turned down into more of a dome shape.
#15
LX2DR
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Posted 13 July 2006 - 12:18 AM
Suppose it depends on the red head! would she like to have a leg removed?
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