86 replies to this topic

[Bruiser]

Been carrying on around the place here about 202 heads and cams for a couple of years
I’ve finally got off my arse and took my troubles to tony from knight engines - tk383 you might
know him as
I liked some of his advice given here on this forum and only went to see him for a cam upgrade suggestion.
I have put that spec and story up here somewhere, but that’s turned out a bit different now.
I took the head down to him to flowbench so his cam recipe would be as optimal as possible,
but the head flow wasn’t as good as I was told it was, and a bit of port work was all it needed
(and for his special valve seat job) (and a bit of deshrouding)
Shit, this was only to be a well informed slight cam upgrade,
and find some more power after 17ish years hahaha
I am sure I won’tbe racing any of you for anything more than a laugh,
so I would like to share the freakish flowbench results of my head
Oops, exhaust numbers first



And intake numbers next
 68372C52-0891-4FEE-8EAE-4463E0F89AAC.jpeg   286.72K   14 downloads

I’d seen his figures on the web before, but never thought I needed that much!

The thing I am most stoked about is this



This came about from one of those unfortunate problems that come up
The previous guy who did my head (mildly) must have drilled out the existing yellaterra
posts right through to the head face so he could get to the short turns
He told me he had tested the head bolt crush with a dial indicator and found no movement
so tubes weren’t necessary at all. The bolts aren’t much smaller than a tube, so not really even a gain.
There were small cracks in mine, So don’t let anyone tell you this is a good idea!

I had always wondered if those tubes could be streamlined in some way, so when tony gave me the bad news
I smartarsedly suggested could he make them like his port vanes somehow.
That is the result. He bored them out to 700thou I think, enough to shape them into what you can see.
He even seemed surprised at the results and reckons they could be worth 10 cfm, and is thinking he might offer per it as an option to the full semi 12 port vane thing he can do
Like this other one below (not mine)

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He’s a clever bloke and knows Holden 6’s pretty bloody well
Anyhow, lucky me, can come back again to go on about the cam spec
he’s ordered to match the head. Quite a bit bigger than I thought I wanted too.
I think it’s arrived, have to go fetch it and get cracking on putting it in

Something went wrong there exhaust numbers again

[Bruiser]

Oh what is going on this computer is reaming me
: exhaust

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And the thing I am most stoked about would be these port dividing posts

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[claysummers]

Very cool Bruce


Sent from my iPad using Tapatalk

[LXCHEV]

Looks very trick, great job!

 

For those of us who don't live and breathe 6 cylinder flow numbers - how do your figures compare to a normal head, mild head etc?

 

How much actual valve lift will you see with chosen cam? Impressive numbers climbing at 0.750"!!

[Bruiser]

Cheers Clay, I am rapt, it’s been off the road since late October
He’s an in - demand feller alright

Typically 200cfm equates roughly to 300 hp potential, and that’s pretty bloody good.
Tony can get up to 240cfm from memory, he’s pretty savvy.
Although the flow numbers at .750 aren’t much use to me, they do indicate that the port
has a very stable non - turbulent flow characteristic and that’s as valuable as big flow numbers
My cam is going to have .598 and .510 lifts. I freaked when he told me, but he assures me it will
be ok, and not shit itself or wear out any faster than usual. I had the block lifter bores trued up
years ago and taken out to .875 fjord size so it’s fine with a faster ramp higher lift cam.
The head turned out to flow a lot more than I (and I think him as well) expected it to
so the story is a bigger cam than I originally was after will be reasonably easy to live with,
and make the most of the head
His pipemax simulation says 298hp @ 6500rpm, 280hp maybe in the real world!
That’s also assuming I take it home and get the exhaust, carbs, manifold, timing etc all perfect perfect perfect
He’s brilliant at matching cams to heads, and reckons the head will make a big cam behave itself somewhat in
the normal driving rev ranges
I am trusting he is right

[N/A-PWR]

Congrats on your new improved 9 Port Bruce,

 here is a read:

 

https://www.speed-ta...=815288#p815288

 

https://www.gmh-tora...ort-flow-chart/

 

http://www.bur.st/~o...nno/page13.html

Edited by N/A-PWR, 01 March 2023 - 03:32 AM.

[N/A-PWR]

Another thing I think of is Head flow C.F.M vs Cubic Inch of Motor,

 

Now N/A is just atmosphere, and is equal to Piston area inlet valve down stroke x R.P.M

where as forced induction is a % increased pressure flow that a high Head CFM would be an advantage.

 

R.P.M is where C.F.M starts to work well in great flowing Heads.

 

The Motor is a Four stroke, which is two R.P.M, and to work out what a Motor C.I is vs C.F.M is, is by doing a calculation:

 

6000 R.P.M divided by 2 = 3000 inlet valve down strokes a minute.

202 c.i divided by 6 = 34 cubic inch.

3000 x 34 = 102000 cubic inches.

120000 divided by 1728 cubic inch to a cubic foot = 69.4 C.F.M

 

You can see that we only need 70 odd C.F.M per port for 6000 R.P.M

 

You can also use this to work out Carby C.F.M to suit

70 x 6 = 420 C.F.M Carby

So a 500 Holley is perfect.

 

So when we increase R.P.M is when all these figures increase for the great ole 9 port six. 

Edited by N/A-PWR, 01 March 2023 - 05:14 AM.

[Bigfella237]

~ the flow numbers at .750 aren’t much use to me, ~ My cam is going to have .598 and .510 lifts. ~

Don't forget to multiply the cam lift by the rocker ratio?

[Bruiser]

.374 and .319 lifts on the lobes, chosen to match the 1.6 rockers I was already using.
Still need to find out which actual lobes they are, probably out of the crow master list again.
Intake is ford specific, 252 @50, exhaust 254 @50. Ground on 106 lsa

[Bruiser]

Thanks Dave, those are all good reads. Been googling madly the last couple of years to get a handle on
the ins and outs of cams and come across them many times before

Not sure I can follow the 70cfm flow requirement thing, though
A standard untouched port will give you that, so why is improving a port even necessary?
I know the maths is correct, but is there a factor left out somewhere?

I have a set of 1.75 su’s to put on, but they’ll be one limiting factor if I want to see every bit
of the top end hp possible
I have noticed you are a massive fan of your 500 Holley, and also the size of your 900c roller cam
along with the rpm’s you plan to use
The 3” 500cfm number when put into 4 barrel ratings (apparently the conversion number is .7071)
becomes 353cfm, less than a 390.
Have you ever considered a vac sec 4 barrel?

This might interest you a little bit

 BD1C8F7C-17AE-47DD-AA06-17A87FD9E660.png   343.23K   11 downloads

[RallyRed]

I'm just trying to follow this thread, as it is interesting.....

 

Just askin' - where did the 120000 come from?  i.e. 120000 divided by 1728 cubic inch to a cubic foot = 69.4 C.F.M.

 

Apologies if it's an obvious answer.

[N/A-PWR]

As a guess, it is time Bruce,

 so your piston area will fill quicker, and you go faster.

Not sure I can follow the 70cfm flow requirement thing, though
A standard untouched port will give you that, so why is improving a port even necessary?
I know the maths is correct, but is there a factor left out somewhere?


This might interest you a little bit

BD1C8F7C-17AE-47DD-AA06-17A87FD9E660.png

Thanks for the chart too. 

 

I'm just trying to follow this thread, as it is interesting.....

 

Just askin' - where did the 120000 come from?  i.e. 120000 divided by 1728 cubic inch to a cubic foot = 69.4 C.F.M.

 

Apologies if it's an obvious answer.

Oop's your right Col,

it should of been 102,000 cubic inches = 59 C.F.M

59 x 6 = 354 C.F.M Carby is perfect.

  sorry for the confusion.

Edited by N/A-PWR, 01 March 2023 - 01:53 PM.

[RallyRed]

All good, ta mate

[N/A-PWR]

Must have a lot to do with efficencies,
So the carby produces the correct Fuel to Air ratio,
and your great head flow of yours will get 99% of that into the pot, for a big bang.

[Bruiser]

59cfm? Maybe we should be putting smaller valves in our heads instead of bigger😁
Something there doesn’t quite add up, but I can’t put my finger on it
Anyone here could tell us that Holden 6 heads are the major obstacle to making power



 0E0805D2-F0A1-4734-BA1F-C9974FE67B0D.jpeg   222.11K   7 downloads

Took my manifold down to him as well for a proper port matching job, and some nifty dowels
so I can’t bolt it on crooked. Just a lynx 202 one. The grey shit inside the port is jb weld,
I had started to fill up the exit area and a very ugly ski jump on the floor
to rectify what the last idiot had done to it. (15 year ago me).
The bugger ground most of it back out again anyway

After all that,
I Never would have guessed it cost around 14 cfm flow at high lifts though

[N/A-PWR]

59cfm? Maybe we should be putting smaller valves in our heads instead of bigger
 

Yep,

the standard 308 valves work well, in the 9 port head.

[I'm a Red Motor fiend]

Liking this Bruce. Time for those 2" SU's, the 1.75's will run out of puff!

Be real careful with your clearances mate. I have just pulled my build apart and found valves have been touching the bore and kissing the piston.

Same lift .600 and slugs are just under the deck.
How much has been taken off the head and what gasket will you use?

[Bruiser]

Yeah, I’ve read enough stories from guys on here about 2” su’s, so I’m not kidding myself about that one
Tony would have talked me into webers If I’d let him
I reckon I’ll be pretty happy with mine for a while, at least.
It’s good to know there is another upgrade to make for more if I want to go there anyway.

Hadn’t actually thought of valve piston clearance, but I told him about the zero deck height, and
I’m betting he considered it. I ‘ll definitely add it to my list of questions next time I see him, though.
The inlet valves are yella terras with the yt stamp on them, in the picture of the flow figures
the valve size is entered as 1.675”. I thought standard yt’s were 1.68? Maybe he shaved them down .005”
Will double check on that bore clearance, too.

Head was decked a bit years ago and had 52cc chambers when I took it in. He sunk the valve seats I think .020”
Another .080” off for 10.5 comp.
Not much left of the thumbprints now, but he reckons that leaves a fair bit of meat still.
Was just about to order a permaseal ag390r head gasket.
Unless there is a better option out there

Why did yours need to come apart? Not too big a problem, I hope

[klevliend]

I followed Tony's facebook post on this head quite closely, very interesting to hear the customers perspective!
Also couldn't believe how much flow the Lynx manifold robbed ... good to know as I've the same manifold 
Keep us updated on the build, I'm very curious about the rest of the engine and any figures with the 1 3/4" SU would be very valuable. I've read constantly how they are too small but never seen any dyno figures showing them holding back the engine. Not that I doubt that they would hold it back, just very curious to see the real world impact as I'm running 1 3/4" SU my self, and have a set of 2" HD8s sitting on the shelf ...

[I'm a Red Motor fiend]

Use a graphite gasket instead of stock composite or an MLS even better.

Oil pressure was always too low for my liking, dicked around for ages with pumps, oils, shimming the valve with no change. Decided it had to be a pinhole leak somewhere on the suction side.

So pulled the motor to reweld AN fitting to sump for external pickup and build a new pickup line to eliminate leaks.

Pulled a few bearing caps for peace of mind and glad I did as they were well starved and scuffed.

Whilst out I thought a may as well pull the head and have a look and low and behold witness marks on the pistons and bores.

Have already fitted new bearings and re assembled the short motor.

Am looking at having another 9 port done that has less taken off in order for the valves to clear. Yay.

[Bruiser]

Hi Klevliend, it’s not too much of a build, just started out as a simple cam swap in my motor I built years ago.
Head went from a slight improve to a much needed freshen up and then turned out to be a ripper.
That manifold effect floored me too, he said it’s to do with the taper and csa change over the shortish runner.
Thought I understood a few things about this, but it just looks like a straight pipe to me (?)
The only other thing I’ve come across like this is an armours manifold on a 198cfm head dropped it to 192
The only dyno’d 1 3/4 su report I have been told about achieved 200ish rwhp. Not too shabby, really
Which bookface page is the head story on? Wouldn’t mind having a nosey at that

The only update so far is that my cam is there waiting to be picked up, hopefully tomorrow

Thanks for the reality check Adam, if your valves made contact,
I guess it’s on me to give it the plasticine check to be sure.
Shame about your engine, you put a lot into that one. Good thing you found it before it went tits up though.
Do you reckon you got close to your 300hp target?

[I'm a Red Motor fiend]

This was checked with plasticine and looked ok, just, tight but ok.
At 7000rpm things stretch a lot I guess.

If a do have another 9 port done I will up compression and hopefully get a bit more flow and then yes I should say 300.

[warrenm]

With the cam you have, shouldn't have any troubles with valve to piston, but valve to cylinder wall can be an issue. Did he move the dowels on the head to move it across? My 9 port flows similar to yours, runs 2" HD8's on an Armours manifold, bit bigger cam with more exhaust lift, makes nearly 300 at the tyres. 2" SU's will liven yours up, but the manifold is too small at the carb end for 2" SU's.

[Bruiser]

Cheers Warren
You’ve had the bore contact issue, If I remembers right
Was that with 1.68 valves?
Head location not changed.

Interesting news about the 2” on the lynx manifold
As it is, they barely fit into the vk, number 3 is so close to the fuse box
in the back corner it’s a turd of a job getting the air cleaner on.
So do the 2” only fit onto the longer seton/armours manifolds?
Looks like some measuring might be needed to make that plan work.
300 at the wheels?? That might explain the wheelies and light steering

[warrenm]

Yes, that was with 1.68" valves.

Armours/Seton manifolds were made to suit 2" SU's, most others haven't got enough metal at the carb flange to open up for the larger throttle bore, I think the Seton can be opened up for a 2 1/8" SU

The Seton manifold might be the pick, as the rear part of the manifold kicks forward to clear the firewall of the early Holdens.