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OriginalGriff7-Aug-15 0:34

7-Aug-15 0:34

Everything about the cam design can affect power, both in terms of absolute maxima, and the delivery of it in terms of sharpness. Even the slope of each side of the lobes. Too sharp a "descent" for example, can cause the valve to float, or even bounce - neither of which is good for combustion chamber sealing!

I remember (IIRC) one Honda motorcycle which produced better power with the inlet and exhaust cams swapped over! Laugh | :laugh:

[edit]What happened to the end of the first sentence? Confused | :confused:

[/edit]

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

Munchies_Matt7-Aug-15 3:56

Munchies_Matt

7-Aug-15 3:56

OriginalGriff wrote:
Too sharp a "descent" for example, can cause the valve to float, or even bounce

Float yes, bounce is from valve springs whose resonance frequency matches the rpm of the cam, hence double valve springs. Smile | :)

But the subtlety of widening and advancing/retarding the cams is very interesting. And my alfa is producing too much torque low down and not revving, so its a good bet the last cam belt change was done wrong. Time to take a look.....

OriginalGriff7-Aug-15 4:45

7-Aug-15 4:45

Float is when the valve doesn't follow the cam profile at the top of the lobe, but you can get bounce when the close profile is too steep and the valve bounces off the seat and re-opens against the spring. Changing the spring rates is the normal solution, but it can seriously mess up the gas flow enough to reduce the amount of charge you get in the cylinder for the next compression stroke.

That's one of the advantages of desmodromic valves - because they are positively opened and closed by cams they can't float or bounce without something breaking. Of course, they are a bugger to get set up right, and if you get them wrong...it gets expensive very quickly. Laugh | :laugh:

Engines are horribly complicated when they start running hard and fast!

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

Munchies_Matt7-Aug-15 4:57

Munchies_Matt

7-Aug-15 4:57

I know what float is, but bounce is a different matter and its to do with the resonance frequency of the spring:
Valve bounce is a related condition where the valve does not stay seated, due to the combined effects of the valve's inertia and resonance of metallic valve springs that reduce the closing force, and allow the valve to re-open partially[^] Smile | :)

Dual springs of course don't have a resonance frequency, and that's why decent engines have them.

GenJerDan10-Aug-15 4:55

GenJerDan

10-Aug-15 4:55

Pfah. The only reason to change your cam is to make your car sound like it has indigestion when idling, then let out a riiiiiiipping fart as you accelerate.

We won't sit down.
We won't shut up.
We won't go quietly away.

YouTube
and
My Mu[sic], Films and Windows Programs, etc.

Munchies_Matt10-Aug-15 9:36

Munchies_Matt

10-Aug-15 9:36

Or to undo the mess someone else made of changing the cam belt previously... Smile | :)

Google's psychiatric atrocities

GenJerDan10-Aug-15 9:38

GenJerDan

10-Aug-15 9:38

Ouch.

We won't sit down.
We won't shut up.
We won't go quietly away.

YouTube
and
My Mu[sic], Films and Windows Programs, etc.

BillWoodruff6-Aug-15 23:10

BillWoodruff

6-Aug-15 23:10

Dear Larry and Sergey,

Remember your own words: "Don't be Evil." And, ask yourselves: is your legacy going to be your being remembered as swash-buckling pioneer heroes of the Digital Era, or are people going to think of the word "Google" as synonymous with "Gulag" ?

Okay, I was trying to have no name in Chrome, and that failed ... that deprived me of the opportunity to express the wholly holy ineffable wooly zilch-nada out of which the fiction of a "self continuous in time" wrapping a void with an illusory personality via the virus of language ... appears to appear.

So, I made up a "nonsense" name ... ignoring the fact that all names are nonsense.

Now, I alt-button-click on that nonsense name, and Chrome drops down a little text-area that says "Person 1."

This flagrant violation of my innate, inherent, inalienable, rights to multiple personalities, whose numbers, flavours, and degrees of sanity, vary with tides, winds, whims, and chemistry ...

I have to tell you ... frankly ... that, in spite of everything you've done for me over the last few years, like reading my e-mail in order to keep me up to date on things I never need to buy ... I do have my limits, and they have been breached.

We (that is, the many in us) demand all our money back, and the payment of reparations to all your millions of victims !

p.s. Getting rid of "Google+" was a step in the right direction, thanks !

«I want to stay as close to the edge as I can without going over. Out on the edge you see all kinds of things you can't see from the center» Kurt Vonnegut.

Slacker0077-Aug-15 0:03

Slacker007

7-Aug-15 0:03

What are you carrying on about now? I didn't understand your post. I must be stupid or something. Smile | :)

Amarnath S7-Aug-15 0:07

Amarnath S

7-Aug-15 0:07

BillWoodruff wrote:
We (that is, the many in us) demand all our money back

How much per person? Any suggestions on how they should disburse?

modified 7-Aug-15 6:21am.

W∴ Balboos, GHB7-Aug-15 2:09

W∴ Balboos, GHB

7-Aug-15 2:09

Avijnata wrote:
Any suggestions on how they should disburse?

Free access to Chrome ?

"The difference between genius and stupidity is that genius has its limits." - Albert Einstein

"As far as we know, our computer has never had an undetected error." - Weisert

"If you are searching for perfection in others, then you seek disappointment. If you are seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010

WSO FSOW OTD 2015-08-07 (Hint 2 added)

Amarnath S7-Aug-15 2:40

Amarnath S

7-Aug-15 2:40

OriginalGriff6-Aug-15 22:07

6-Aug-15 22:07

[]|<=:|

Hint: It's probably in your phone right now

Hint2: You'll be malfunctioning within a day, you near-sighted scrap pile!

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

modified 7-Aug-15 5:23am.

Wastedtalent6-Aug-15 22:12

Wastedtalent

6-Aug-15 22:12

Gremlin

OriginalGriff6-Aug-15 22:16

6-Aug-15 22:16

Nope, sorry!

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

P0mpeyBoy6-Aug-15 22:15

P0mpeyBoy

6-Aug-15 22:15

What a chasim in the scorecard yesterday!

Edit : Sorry meant to reply to the cricket thread D'Oh! | :doh:

OriginalGriff6-Aug-15 22:16

6-Aug-15 22:16

And probably to not add an "I", as well... Blush | :O

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

P0mpeyBoy6-Aug-15 22:19

P0mpeyBoy

6-Aug-15 22:19

or remove "in the score"... Wink | ;)

Nagy Vilmos6-Aug-15 22:38

Nagy Vilmos

6-Aug-15 22:38

For the aid of a drunks and/or holidaymakers, what is an FSOW?

veni bibi saltavi

HobbyProggy6-Aug-15 22:39

HobbyProggy

6-Aug-15 22:39

Its a F... Obfuscated S... Word Smile | :)

Rules for the FOSW ![^]

if(this.signature != "")
{
    MessageBox.Show("This is my signature: " + Environment.NewLine + signature);
}
else
{
    MessageBox.Show("404-Signature not found");
}

OriginalGriff6-Aug-15 22:42

6-Aug-15 22:42

It's a new game, standing for "F... Obfuscated S... Word", started by HobbyProggy[^]
The rules are here: http://www.codeproject.com/Members/Th3F3aR?msg=5100314#xx5100314xx[^]

I'm amazed I got it yesterday...

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...