Speed-Talk is running on www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

Search found 1469 matches

by panic
Fri Jan 22, 2021 1:26 pm
Forum: Engine Tech
Topic: Piston to Valve Clearance
Replies: 6
Views: 290

Re: Piston to Valve Clearance

There's a range of radial ("ringing") clearance.
Heads with long, thin stems, short guides, and high lift need more, etc.
Heads with angled valve stems (almost everything Except Heron) also need clearance along the lift axis proportionate to the angle (15 degrees hardly moves, 45 degrees move more).
by panic
Mon Jan 18, 2021 11:26 pm
Forum: Engine Tech
Topic: Bottom of booster vs venturi with straight throat section
Replies: 8
Views: 404

Re: Bottom of booster vs venturi with straight throat section

The discharge end of the booster is frequently 1/32" below (downstream) the smallest diameter of the main venturi.
by panic
Fri Jan 15, 2021 10:44 am
Forum: Engine Tech
Topic: 350 sbc reduce compression ratio or retard cam?
Replies: 40
Views: 1139

Re: 350 sbc reduce compression ratio or retard cam?

Worried about knocking and not worried about quench are opposites.
by panic
Wed Jan 13, 2021 5:50 pm
Forum: Engine Tech
Topic: Flat Tappet vs Roller Specs
Replies: 36
Views: 1272

Re: Flat Tappet vs Roller Specs

To calculate maximum velocity (Vm) of a flat (actually, it may also be 50" radius convex shape) tappet per degree of camshaft rotation (.040” is a safety margin to prevent edge contact, use whatever number you feel comfortable with): Vm = (tappet diameter - .040”) ÷ 114.6 Maximum for some common tap...
by panic
Sat Jan 02, 2021 2:47 pm
Forum: Engine Tech
Topic: Piston to Head Clearance Minimum
Replies: 23
Views: 897

Re: Piston to Head Clearance Minimum

A remark I've heard:
"If the block is alloy it will expand faster and taller than the piston, so if it doesn't touch when cold it never will".
Unless you run the engine hard when it's still cold....
by panic
Thu Dec 31, 2020 10:17 am
Forum: Engine Tech
Topic: Ignition , combustion statement
Replies: 14
Views: 1019

Re: Ignition , combustion statement

From "Nashville" (Robert Altman film): "You asked a lawyer what time it is, and he told you how to make a watch".
by panic
Fri Dec 25, 2020 10:53 am
Forum: Engine Tech
Topic: LS intake on a SBC gen1
Replies: 16
Views: 934

Re: LS intake on a SBC gen1

a Splayed valve head looks KINDA like an LS

The LS has parallel valves, just like SBC...
... and 1949 Oldsmobile & Cadillac.
by panic
Wed Dec 23, 2020 3:29 pm
Forum: Engine Tech
Topic: Solid roller wheel size
Replies: 25
Views: 911

Re: Solid roller wheel size

My remarks on roller tappets on my site here: http://victorylibrary.com/mopar/roller-adapt.htm
by panic
Tue Dec 22, 2020 8:40 pm
Forum: Engine Tech
Topic: Solid roller wheel size
Replies: 25
Views: 911

Re: Solid roller wheel size

I wonder if Spintron will say the same thing...
by panic
Tue Dec 22, 2020 9:58 am
Forum: Engine Tech
Topic: E/I flow percentages...
Replies: 23
Views: 954

Re: E/I flow percentages...

Too big of an exhaust valve diameter will kill the blowdown
Less gas flows from a larger window?

Fixed numbers are meaningless, too many variables.
by panic
Tue Dec 22, 2020 9:55 am
Forum: Engine Tech
Topic: Solid roller wheel size
Replies: 25
Views: 911

Re: Solid roller wheel size

The plot of valve motion vs. cam lobe position is different between .750" and .815". The larger wheel accelerates faster as some points, but the change is not linear, the curve is distorted.
Ask the cam manufacturer.
by panic
Tue Dec 08, 2020 7:26 pm
Forum: Engine Tech
Topic: cam area vs power
Replies: 18
Views: 1248

Re: cam area vs power

The area is only one difference, there are more
by panic
Thu Dec 03, 2020 7:13 pm
Forum: Engine Tech
Topic: EA Modeling of a Chevy 292 Inline Six, Siamesed Ports
Replies: 40
Views: 1583

Re: EA Modeling of a Chevy 292 Inline Six, Siamesed Ports

But where's the fun in that!
by panic
Wed Dec 02, 2020 7:56 pm
Forum: Engine Tech
Topic: EA Modeling of a Chevy 292 Inline Six, Siamesed Ports
Replies: 40
Views: 1583

Re: EA Modeling of a Chevy 292 Inline Six, Siamesed Ports

The problem is not the CFM, it's the pressure and directional changes that occur during the intake stroke. Blair refers to the exchanged effects as "superposition" because flow is never continuous and uni-directional.
by panic
Mon Nov 30, 2020 10:14 am
Forum: Engine Tech
Topic: EA Modeling of a Chevy 292 Inline Six, Siamesed Ports
Replies: 40
Views: 1583

Re: EA Modeling of a Chevy 292 Inline Six, Siamesed Ports

W/r/t "each cam lobe was ground on a different centerline"
Vizard describes doing this to a BMC Mini L4 way back, not sure who was first.