Holden six cylinder head 101.
#151
Posted 07 February 2015 - 09:33 PM
#152 _Bomber Watson_
Posted 07 February 2015 - 09:46 PM
The new alloy 9 port that wasnt done by YT had the four bolt holes around #1 as well for ancillary mounting, good call to as thats a prime spot to mount a vac pump or similar on a high effort engine.
THat said looking at the pick closer i dont think the head im thinking about had the second set of holes in the head infront of the dizzy the same as the coil mount ones to the back of the dizzy, so yeah probably YT 12 port.
Cheers.
#153
Posted 07 February 2015 - 09:58 PM
#154 _Bomber Watson_
Posted 07 February 2015 - 10:18 PM
Actually im on my ass with a schooner glass in my hand, but same same
#155 _Skapinad_
Posted 07 February 2015 - 10:22 PM
#156
Posted 08 February 2015 - 07:10 AM
Ta guys....don't think I'd ever seen one before....all those threaded holes on the plug side had me wondering..ta
#157
Posted 10 February 2015 - 10:25 AM
Heres my take on it... yer just showin' off! (got any spares???)
#158 _RedKobra_
Posted 19 July 2015 - 05:10 PM
How much of a performance gain is there from a 12 port over a 9 port when comparing the same chamber volume?
#159
Posted 19 July 2015 - 05:26 PM
Nice read here Scott, from Oldjohnno's book:-
twelve port heads
How much of a performance gain is there from a 12 port over a 9 port when comparing the same chamber volume?
#160 _RedKobra_
Posted 19 July 2015 - 05:48 PM
Looks like a good read. Cheers.
#161 _oldjohnno_
Posted 19 July 2015 - 08:48 PM
How much of a performance gain is there from a 12 port over a 9 port when comparing the same chamber volume?
When absolute maximum peak power is the goal the 9 port is still the one to beat. The advantage of the 12 port is in applications where a strong, flat torque curve is more important than peak power as it allows better use of well tuned manifolding.
#162 _Bomber Watson_
Posted 19 July 2015 - 08:56 PM
Stock for stock and same chamber for same chamber, pretty big improvement.
#163
Posted 12 October 2015 - 08:08 PM
The picture has been posted in this thread before,a closer look at the efi head as stolen from the for sale section of the forum.
3300EFIresize.jpg 255.25K 11 downloads
#164 _Muzzy_
Posted 11 February 2016 - 05:39 PM
Attached Files
#165 _Bomber Watson_
Posted 11 February 2016 - 06:27 PM
Super cool, thanks Muzzy!
#166 _Agent 34_
Posted 03 October 2016 - 05:36 PM
bomber - john and Mick - was there a change or a change over of design in the 173 heads - 9 ports. If so what was the difference. I vaguely remembering that it was the next gen head change.
I't just I gave rams a small sort of YT 161 head and a standard 173 - they took the 173.
I was also speaking on the weekend to an engine builder and the 173 was the head to use as well.
g
#167
Posted 04 October 2016 - 05:50 AM
They may not have taken the YT161 because the ports have already had metal removed.
#168
Posted 24 November 2016 - 03:47 PM
Hello DJ,
Question:-
How would a Yella Terra head exhaust promote exhaust savaging with shared exhaust ports 2/3 and 4/5, as I would of thought the ports would need to be separate using extractors?
s-l1600 (3).jpg 101.31K 7 downloads
http://www.ebay.com....sd=201675600955
So are these heads only designed for XU1 Headers or the likes?
#169 _Bomber Watson_
Posted 24 November 2016 - 04:01 PM
Its only the very end of the port that you can see that joins, most people put a bit of aluminium or something there to seperate them.
#170
Posted 24 November 2016 - 04:06 PM
Ah, OK mate,
thanks for your extraordinary knowledge.
#171
Posted 16 July 2017 - 08:24 PM
Can you tell me what the differing exhaust valve colouring is caused by here.
The head is off an engine with triple 175 strombergs.
P.S.
If no one definately knows. Dont bomb in on this post assuming to know.
I am after a definite answer.
I see it all too often... people trying to get genuine answers to topics. And threads being screwed up by ASS u mers. Then NEK MINIT off topic.
Attached Files
#172
Posted 18 July 2017 - 08:28 PM
Charge robbing due to siamesed intake ports with 1x carb per port. Port with the valve that opens 1st gets more fuel, firing order is 1 5 3 6 2 4 - 1&2 share a port, #2 has just closed it's valve when #1 opens - #2 has already nicked fuel droplets clinging to port walls etc leaving less residual for #1 so #1 is leaner than #2.
Not much you can do, that's siamesed intake ports with multiple carbs for you.
Just tune it by the lean cylinders & put up with the others being a bit fat.
#173
Posted 05 August 2017 - 06:42 PM
Charge robbing due to siamesed intake ports with 1x carb per port. Port with the valve that opens 1st gets more fuel, firing order is 1 5 3 6 2 4 - 1&2 share a port, #2 has just closed it's valve when #1 opens - #2 has already nicked fuel droplets clinging to port walls etc leaving less residual for #1 so #1 is leaner than #2.
Not much you can do, that's siamesed intake ports with multiple carbs for you.
Just tune it by the lean cylinders & put up with the others being a bit fat.
Thanx TK383.
I'LL give your above advice a whirl.
#174
Posted 06 August 2017 - 08:06 AM
Bomber.
Can you tell me what the differing exhaust valve colouring is caused by here.
The head is off an engine with triple 175 strombergs.
P.S.
If no one definately knows. Dont bomb in on this post assuming to know.
I am after a definite answer.
I see it all too often... people trying to get genuine answers to topics. And threads being screwed up by ASS u mers. Then NEK MINIT off topic.
Hi Sunburst
Re your question and very good answer by TK383
the PS asking only for qualified answers is a point well taken, but rather than the problem being people chiming in with wild and erroneous ideas, i see the problem as that they don't specifically warn the OP that they are merely guessing or are not an expert, so in the example you give, it would be appropriate for people to add something like,,,, WARNING take this advice at your own risk, it is just my 2cents worth.
The reason i see it differently is that i see a forum as all comers, not just the experts.. If in doubt, in other forums i have started a public thread but also private messaged one or two players for their specific recommendations..... and again i see you specifically asked the question to bomber so i cant argue against that, except that because it went public it allowed an excellent response by someone else as well.
the other interesting thing about forums that is both irritating and enjoyable to me at the same time, is that quite often the OP is actually asking the wrong question and so often the off topic stuff is actually pertinent. You will note in your case there is more relevance in the intake valve /chamber richness differences as the 'tell tale' not withstanding your question is still very valid if the answer is something like the exhaust valves go that colour after running cherry red from being too lean.
But again i do get your frustration at people not answering the actual question.. ( i see questions like should i dial this cam in a couple of degrees early to help responsiveness often being answered by that cams sucks my cam rules...) so not helpful at all
PPS sorry if i have taken this off track, please continue on track again. Cheers Darryl
Bomber.
Can you tell me what the differing exhaust valve colouring is caused by here.
The head is off an engine with triple 175 strombergs.
P.S.
If no one definately knows. Dont bomb in on this post assuming to know.
I am after a definite answer.
I see it all too often... people trying to get genuine answers to topics. And threads being screwed up by ASS u mers. Then NEK MINIT off topic.
#175
Posted 06 August 2017 - 08:53 AM
Has the engine this head came off ever run on ULP?
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