early heads cc

[Unorthodox-racing]

whats the average cc's in early cast closed chamber heads?

[vkberlina]

whats the average cc's in early cast closed chamber heads?

my old HQ heads measured 57 cc, if that helps.

[Unorthodox-racing]

my pistons are .030 flat tops .018 down the hole, thats would give me about 10.1 to 1, nice

[Unorthodox-racing]

why? .040 head gasket, thats plenty of quench, this engine is not my daily driver anymore & I dont mind buyin ultimate or 103 for it, but Im not a fan of avgas, I wont be using this engine on the street much ..... Iv got a 4.44 10 bolt with a mini spool so only to go to the bottlO & thats only seldom, mostly looking at driving it 1/4 mile at a time

[Unorthodox-racing]

Iv been using a sealed power 473" 497" 214@ 50 & 224 @ 50 on a 112 lobe sep, with no issues (except for the issues in my 308 affair thread) its a great cam, I like it
Im going up to a cch286 496" 230@50 110 lobe sep, installed strait up.
But the difference will be going from the open to closed chamber heads,

the split cam & open chambers actually went pretty good,

[vkberlina]

Darryl. i'm sorry mate , but im getting a bit lost here when you say your going from open to closed chamber heads. Were the original heads counter-bored, or the chambers edge layed over.?

[Unorthodox-racing]

I have never seen open chamber heads on a holden v8 untill this morning,
Iv got 4 sets of heads here & one set is definitly cast open chamber, (low compression) I have seen it plenty of times with iron BB chrysler heads to where the closed chamber is a minority, but never a holden, I cant wait to try these closed chamber heads, I would say at a guess the cc would have to be in the 70cc range, A bb chrysler open is usally around the 88cc range and closed iron heads in the mid low 70s,
but these holden heads a definitly open chamber yet non egr cross over but have the later bigger valves, the cast # is 2812174

[vkberlina]

I don't know the numbers.... can anyone here shed some light?

[Unorthodox-racing]

they got me stumped, I had to look twice with the "what the f#*k???" thing goin on, but I was also doin surgery on the 308 so didnt realy take a lot of notice untill beer Oclock when I took a second look

[PVE]

From research and feedback in this forum aim for 0.040”; optimum in quench type engines. Any closer than 0.040” there is a risk of collision between piston and cylinder head, any greater and the chance of inducing detonation at even low static comps is increased.

Also refer to link below:
http://racingarticles.com/article_racing-10.html

.......... If you are building an engine with steel rods, tight bearings, tight pistons, modest RPM and automatic transmission, a .035" quench is the minimum practical to run without engine damage. The closer the piston comes to the cylinder head at operating speed, the more turbulence is generated. Turbulence is the main means of reducing detonation. Unfortunately, the operating quench height varies in an engine as RPM and temperature change. If aluminium rods, loose pistons, (they rock and hit the head), and over 6000 RPM operation is anticipated, a static clearance of .055" could be required. A running quench height in excess of .060" will forfeit the benefits of the quench head design and can cause severe detonation....................

[Unorthodox-racing]

I don't know the numbers.... can anyone here shed some light?

you have mail

[Unorthodox-racing]

From research and feedback in this forum aim for 0.040”; optimum in quench type engines. Any closer than 0.040” there is a risk of collision between piston and cylinder head, any greater and the chance of inducing detonation at even low static comps is increased.

Also refer to link below:
http://racingarticles.com/article_racing-10.html

.......... If you are building an engine with steel rods, tight bearings, tight pistons, modest RPM and automatic transmission, a .035" quench is the minimum practical to run without engine damage. The closer the piston comes to the cylinder head at operating speed, the more turbulence is generated. Turbulence is the main means of reducing detonation. Unfortunately, the operating quench height varies in an engine as RPM and temperature change. If aluminium rods, loose pistons, (they rock and hit the head), and over 6000 RPM operation is anticipated, a static clearance of .055" could be required. A running quench height in excess of .060" will forfeit the benefits of the quench head design and can cause severe detonation....................

even a dished holden piston is not dished in the quench zone, Iv run BB chrysler with zero deck hieght & closed chamber iron heads before wih avgas and had good results, just that avgas burns way too slow

[vkberlina]

you have mail

Unbelievable, i have never seen open chamber 308 heads till now.
Like i said, i have seen counter-bored heads for Methanol, but this is different!

[Unorthodox-racing]

Your running quench at at least .060, obviously you dont want to deck the Block !
230 degrees on this particular 286 , well that gives a ABDC of 60 degrees, so your
Dynamic compression will be a whopping of
Wait for it
8.5 : 1 , now I see why , it will be fine on standard unleaded !!!!!
Just rev the crap out of it !!!!

& if I took say .010 off the deck??

[Unorthodox-racing]

Unbelievable, i have never seen open chamber 308 heads till now.
Like i said, i have seen counter-bored heads for Methanol, but this is different!

its got me fuked too m8, I will be useing the heads on the left of the photo, when I brought them Im sure the guy said they where 55cc but I cant remember, been a while