New SX Rules

bogdan912
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bogdan912
Edited Date/Time 1/23/2012 7:24pm
I just caught this rule

g. 4-stroke cylinder head valve angles must remain the same as the homologated
model.


Seems like an oddball rule to just throw in there. Why are they limiting what engine builders can do?
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strongsurvive405 10/31/2008 10:31am
10/31/2008 10:31am
where can you view all the new rules for this year?
SteveS
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SteveS 10/31/2008 10:41am
10/31/2008 10:41am
To change the valve angles you'd have to have a different head, or the ability to make a different head look like the same one.

That would defeat the purpose of a production-based class, and make it a prototype motor.
Tiki
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Tiki 10/31/2008 11:12am
10/31/2008 11:12am
SteveS wrote:
To change the valve angles you'd have to have a different head, or the ability to make a different head look like the same one. That...
To change the valve angles you'd have to have a different head, or the ability to make a different head look like the same one.

That would defeat the purpose of a production-based class, and make it a prototype motor.
I believe they are talking about valve seat angles? But like you said to change the angle of the stem you would have to do some serious modification and I wouldn't put it past anyone to try. A single degree could make a dramatic difference for specific tracks.
bogdan912
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bogdan912 10/31/2008 11:19am
10/31/2008 11:19am
I read it as seat angles too.. Doesn't MDK make heads, or do they buy stockers and mod them?

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Tiki
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Tiki 10/31/2008 11:23am
10/31/2008 11:23am
Williams just took his shirt off!
mxer146
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mxer146 10/31/2008 12:13pm
10/31/2008 12:13pm
bogdan912 wrote:
I read it as seat angles too.. Doesn't MDK make heads, or do they buy stockers and mod them?
MDK mods stock heads I believe.
CamP
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CamP 10/31/2008 12:37pm
10/31/2008 12:37pm
It would cost a lot of money to produce a head with non-stock valve angles. The factories could do it more easily than any private team because they have access to unmachined head castings.
casper
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casper 10/31/2008 3:17pm
10/31/2008 3:17pm
Couldn't you do it on the cheap if you just made the valve guides offset? Like -.5 a degree on one end and +.5 a degree on the other. Then all you would have to modifly is the valve seat and maybe the rocker arm.
500guy
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500guy 10/31/2008 5:05pm
10/31/2008 5:05pm
it's valve angle not seat angle,

I'll give you an example , some people made 4 Valve heads for Yamaha's when they were 5 Valves stock. because they could change the angle and get the heads to flow better with 4 valves. vs 5
Mod Killer
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Mod Killer 10/31/2008 5:30pm
10/31/2008 5:30pm
500guy wrote:
it's valve angle not seat angle, I'll give you an example , some people made 4 Valve heads for Yamaha's when they were 5 Valves stock...
it's valve angle not seat angle,

I'll give you an example , some people made 4 Valve heads for Yamaha's when they were 5 Valves stock. because they could change the angle and get the heads to flow better with 4 valves. vs 5
how did they do it?

i mean, with a oem head, how can you add or remove a valve?
500guy
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500guy 10/31/2008 5:43pm
10/31/2008 5:43pm
Honestly , I was told by someone they did this, I didn't see it done.
Mod Killer
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Mod Killer 10/31/2008 6:07pm
10/31/2008 6:07pm
i dont put it past the oem's to cast some worx heads, that look production from the outside. its more than do-able for them and has happened in the past.

but to take an actual production head and add/remove a valve seems unrealistic, but i could easily be corrected here, if someone knows more on how this could be done i'd love to read.
Sinbad
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Sinbad 10/31/2008 6:39pm
10/31/2008 6:39pm
They don't follow the OLD SX rules why are they making new ones?

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