Topic: cylinder head airflow figures

[johno]

Ground the buggery out of both sides, didnt strike the oil gallery, the small oils holes are clear , should work.
Johno

[johno]

Bewdy, the lobes clear the cam bearing supports. BUT BUGGER bangs into the head on the bottom of the rotation.
Measured it and I need to mill 3.5 mm (.140 though)  to get lobe clearance for .490 lift lobe
Ciao Johno

[johno]

The red outline is the interference area, need a mill to do it, radius of the cam lobe is 26.5mm so will use a cutter about 50 mm or so should do the job.

Tomoz, now cuppa time , ciao boys. Johno

[johno]

For the lobe to miss the head we needed to remove about 3.5mm from the head, you can see at 3mm exactly it started to break through the head into fresh air, bummer !

[johno]

Here it shows the head set up to mill the cam clearance , lot of dicking around.

[johno]

Here you can see the quick easy way , hack a hole out, that will get some clearance.   I done this as at this point I would cust all 4 squares out and weld in some sections of thin walled pipe to seal the head, get required clearance, and a nice little oil resivoir.

[johno]

Well the big jigger is in so now time to check how the  rocker  pad gets used to the max, hopefully doesnt come of the edge of the pad.
How the valves slide across the valve stem through the lift range and what the overlap brings between the exh and the inlet, lets go.

[johno]

First issue the cam lobe just kisses the bottom of the rocker on both inlet and exhaust, it looks as if it will need a mm of a high ridge spot on the rockers.

[johno]

Here I have marked up where the rocker pad touchs the lobe, it goes from edge to edge, mid lift in middle of the pad, this is OK as it looks as if it might just be on the pad enough for the rocker pad to be built up slightly and reground a little longer just for security.

[johno]

 

 The valve overlap position
Well this is serious valve interference on a mega scale !   F#*K I need an Aspro

HHMMMMMMM something to think about.

[johno]

Try this pic , got the stutters from looking at the result and pressed the wrong button LOL

[johno]

Not very clear but the best I could do !
The position of the adjuster on in or exh ?

[johno]

    both valves,  the adjuster is in an acceptable position that can be changed by valve stem length or lash pad or both to a get a reasonable geometry. This is good !

[johno]

Hey, first time Ive seeen .500 lift on a SOHC Honda , mate this is what it looks like 

Pity the valves are beating each other up 

I wonder if I use a different profile on the exhaust to make some room for the inlet  ?

ciao boys .... Johno

[mick7504]

 The valve overlap position
Well this is serious valve interference on a mega scale !   F#*K I need an Aspro
HHMMMMMMM something to think about.

Hey johno
Terry's got some 160 proof Wild Turkey in his cupboard.
That'll blow the doors off an Aspro. 
Lookin' good mate.
The old sayin' - If was that easy, every bugga would be doin' it. 

[johno]

What a wonderfull suggestion, A full bottle will be needed tonight Mick just for medicinal purposes only of course, oh and to ease the pain. ciao Johno 

[Greg H]

Hi johno . I'm lovin  this, it's making for some very interesting ( and thought provoking) reading, so keep up the good work mate    Regards Greg "H".

[dragracer]

Did you previously mention the size motor this monster of a head wold be going on?

Very interesting work so far. Lots of determination going into this one.

Keep it coming- we're waiting to see this thing finished.

[Doctor_D]

Great stuff, Johno.  Keep it coming.

[johno]

 dragracer
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Re: cylinder head airflow figures
« Reply #117 on: October 27, 2012, 09:53:06 am »
Quote
Did you previously mention the size motor this monster of a head wold be going on?

Very interesting work so far. Lots of determination going into this one.

Keep it coming- we're waiting to see this thing finished.


Cheers , I'm impressed with your current project, I love to see people under pressure 
Regarding the ideal displacement for the big cam its kind of deceiving. At this point anyway I,m only chasing lift. Its part of having a look at the hi port advantages and potential.
On any of the ports I have flowed so far the horizontal ports all peak in flow around .400 lift and the 15 degree hi port kept flowing strongly past .500 lift

So the hi lift cam and head port diameter can be tuned to any displacement eg 750cc would require approx  (depending on valve size eg 33.5mm) 30.2mm average diameter and the cam duration / centreline adjusted to suit the RPM characteristics. where a 1,000cc engine would like approx 31.5 (assuming 35mm valve) If you stray too far from these examples it just lowers the torque curve if bigger and raises the torque curve if smaller,  Hard to be too generic as HP  tends to go bigger with bigger diam port but generally you have to chase the revs to 10,000 RPM and higher to make the advantage and its a small advantage eg 1 or 2 HP.   If you chase those extra couple of HP the engine is really really flat mid range and definately race only and still needs to be set up really well.

The higher lift would make the hi port come alive and could be tuned for any displacement by adjusting the valvetiming / port diam etc     EG if a good horizontal port is approx 70CFM @ .400, and the hiport is 85 to 90 CFM @.500 thats a whopping 25% increase in air flow. I have refrained from running it on the computer engine simulator for fear of seeing how good the HP numbers look.      ( flow @10 inchs)
Certainly enough to keep me persevering,  an old SOHC fan like me. 
ciao johno

[754]

 If you were using a custom frame, say an Amen, you could run the Webers with raised ports, should have a bit more room. Of course it would not be good for. A cafe. Style of riding, but good for drags or. Landspeed...