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Porting 12 port heads

Started by _rb3torana_ , Nov 10 2012 04:22 PM

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27 replies to this topic

#1 _rb3torana_

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Posted 10 November 2012 - 04:22 PM

I am thinking of pulling the head of my turbo 202 and porting it. It is currently stock and has run a best of 13.1@ 113.5mph at 15psi with my setup. Its got an aussiespeed manifold on it which are an open design at the port face. I was wondering if I should taper the head face where the head bolt goes through or will it hinder flow? Obviously going to tidy up the short turn etc. Thanks

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#2 rodomo

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Posted 10 November 2012 - 07:44 PM

Just screw the boost up a tad. :spoton:

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#3 _STRAIGHTLINEMICK_

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Posted 10 November 2012 - 09:33 PM

G'day mate,I am using an open manifold and a ported 12 port head which is tapered to a point at manifold face where tthe head bolt is.It seems to work well it does a 13.1 @100 N/A.It would be best to start with a black motor head as they have a good short turn as cast.

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#4 _rb3torana_

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Posted 11 November 2012 - 08:16 AM

So have you have made it complete point? I already have been using the blue motor head. Im going to grind out those stupid air nozzles bosses in the exhaust ports also lol. I would screw the boost but its already been to 20psi but have to back the timing back to 16 deg to stop detonation, I'll probably open the chamber up a little also to drop some comp

.

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#5 _stretchlc_

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Posted 11 November 2012 - 08:45 AM

13.1 @ 113mph??.................not much traction it would seem?.....thats a decent top end.

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#6 _rb3torana_

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Posted 11 November 2012 - 09:01 AM

Yeah 175 13 inch tyres dont help, nor does the manual and open centre diff lol. But it is surprising how much traction it does actually get lol. On the 13.1 run I half missed 4th gear and it only ran 110mph, going off the half track times it would have ran a 12.93 lol. You have to sort of squeeze it in first gear. It will eventually get a powerglide big stall etc.

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#7 _stretchlc_

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Posted 11 November 2012 - 09:06 AM

A man after my own heart......Glide!

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#8 _rb3torana_

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Posted 11 November 2012 - 03:19 PM

G'day mate,I am using an open manifold and a ported 12 port head which is tapered to a point at manifold face where tthe head bolt is.It seems to work well it does a 13.1 @100 N/A.It would be best to start with a black motor head as they have a good short turn as cast.

Are you using a aussiespeed manifold on your car? If so have you noticed that no6 runs richer than the rest? Well on my car it does, no5 is fine just no6 is richer. Still alot better across the cylinders than any other 6 cyl manifold Ive used.

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#9 _ljxu1torana_

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Posted 11 November 2012 - 04:08 PM

Yeah 175 13 inch tyres dont help, nor does the manual and open centre diff lol. But it is surprising how much traction it does actually get lol. On the 13.1 run I half missed 4th gear and it only ran 110mph, going off the half track times it would have ran a 12.93 lol. You have to sort of squeeze it in first gear. It will eventually get a powerglide big stall etc.

dont put a stall in it.i would put a done up trimatic than a done up glide.

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#10 _Bomber Watson_

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Posted 11 November 2012 - 04:10 PM

No stall? WTF Jason?

Cheers.

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#11 _rb3torana_

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Posted 11 November 2012 - 07:52 PM

Well the heads off, does this look like a little bit of reversion in the chamber? It also had a bit of a blown gasket on a couple of cylinders, even though it had no symptoms.

Posted Image

Thanks

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#12 _STRAIGHTLINEMICK_

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Posted 11 November 2012 - 09:01 PM

Are you using a aussiespeed manifold on your car? If so have you noticed that no6 runs richer than the rest? Well on my car it does, no5 is fine just no6 is richer. Still alot better across the cylinders than any other 6 cyl manifold Ive used.

I did have an Aussiespeed manifold and 450 holley, some cyls were richer than others but definatley better than other 6cyl 4bbl manifolds.At the moment i'm running 2" su's on an armours manifold.

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#13 _ljxu1torana_

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Posted 11 November 2012 - 09:21 PM

No stall? WTF Jason?

Cheers.

i should have said not to use a big stall.that is what i ment to say.personally i would stick to using the manual because turbo holden 6s,use tall diff gears because they work on load.using low diff gears is a no no.it is like taking a knife to a gun fight.thanks jason.

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#14 _Bomber Watson_

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Posted 11 November 2012 - 09:42 PM

The last turbo'd holden six i had had a 2500rpm stalll, it was far to small.

Cheers.

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#15 _rb3torana_

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Posted 12 November 2012 - 07:20 AM

Yeah in the last auto turbo car I had (rb30 torana) it had a 4500rpm stall and I didnt want to go any smaller, admittedly it had a big turbo on it. At least with a big stall it keeps it in the powerband on shift point, which in my case is around 4500rpm and upwards. Has anyone got any cutaways of 12 port heads? Ive seen the ones on oldjohnno's site, just after more if possible. How much meat is in the chamber right out to the gasket edge? Thanks

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#16 _stretchlc_

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Posted 12 November 2012 - 01:48 PM

I know from EXPERIENCE that turbo'd Holden 6's like a higher stall speed.......I'm on Bombers side on that arguement!!..............Are you talking theoretically here Jason or from hands on experience?

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#17 _rb3torana_

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Posted 12 November 2012 - 06:46 PM

Bomber how much did you open the chamber in the grenade engine? How far have you got till water on the squish/quench side, Im hoping to go about 2mm deep right out to the gasket. Thanks

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#18 _Bomber Watson_

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Posted 12 November 2012 - 07:17 PM

I hogged a fair bit out, i've got a cutaway here somewhere i'll try to find.

Had a much better cutaway, i gave them to Heath, perhaps PM him for some photo's, forgot to take picks before i gave them to him.

Cheers.

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#19 _rb3torana_

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Posted 12 November 2012 - 07:19 PM

That would be awesome, thanks mate.

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#20 _oldjohnno_

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Posted 12 November 2012 - 07:36 PM

These might help, this head has been lightly skimmed already but not by much. General rule of thumb is that there'll be 3/8" thickness in the deck and wall areas. I could probably sonic an untouched head if you wanted a thickness for a specific spot. But generally you can take quite a bit from the deck without problems and you can lay back the edge of the chamber into the pad quite a long way.

Posted Image

Edited by oldjohnno, 12 November 2012 - 07:37 PM.

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#21 _rb3torana_

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Posted 12 November 2012 - 08:45 PM

Thats awesome, thanks mate. Is that the same cutaway as this one? In this picture, does the water jacket on the short turn side of the chamber run virtually parallel with the length of the head? Did this port have a 1.73 ish seat fitted? You wouldnt happen to have any pics looking virtually straight at the chamber? Thanks

Posted Image

Edited by rb3torana, 12 November 2012 - 08:54 PM.

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#22 _rb3torana_

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Posted 13 November 2012 - 08:19 PM

Well this is what Ive come up with so far lol. Theres officially no quench.

Posted Image

Thanks

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#23 _Bomber Watson_

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Posted 14 November 2012 - 08:06 PM

I left some of the quench near the plug to try to push push the air fuel over the plug, but that might work?

What chamberr size did you end up with?

Cheers.

Edited by Bomber Watson, 14 November 2012 - 08:07 PM.

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#24 Stinga

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Posted 14 November 2012 - 08:34 PM

looks better than this...

Posted Image

Edited by Stinga, 14 November 2012 - 08:37 PM.

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#25 _rb3torana_

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Posted 15 November 2012 - 07:26 AM

It ended up going from 56cc to 62cc, 8.2 to 7.6:1. I had about 75" quench before this so I figures I'd try loosen it up some. I could only run 20-22 deg on 15psi or it would ping, hopefully this should help. Stinga that head does look similar to how mine looked after polishing except yours looks like a nine port? BTW yours are polished alot more than mine ended up lol.