[finbullet]

https://www.google.com/url?sa=t&source=web&rct=j&url=https://m.youtube.com/watch%3Fv%3DJ14YuRstuT4&ved=2ahUKEwjF0tG9wMrhAhVCz6YKHSvJBscQwqsBMAB6BAgCEAU&usg=AOvVaw1vzL9ZkyrArSwuoGzAPAt7

Here's an indian version of a ported high compression head

[ace.cafe]

Oh boy!
 

[cyrusb]

Aren't these guys something else?

[pushrod]

Man, that's something else. Takes backyard mechanic to a new level.

[Adrian II]

This looks like a MUCH cruder version of what Bullet Whisperer does on some of his ASBO cast iron Bullets.

In B.W.'s case the combustion chamber is fully machined after welding and a domed piston also machined to provide a 1mm squish band.

Note one of the youtube comments:

This is really good idea to improve that hemi chambers but they shrouded the valves way too much, sacrificing cylinder fill...

ASBO 14's head is shown in the attached picture.

A.

[ace.cafe]

From what I see, it is not likely that these cats know what valve shrouding is.

Also, using that crappy OEM piston with much higher compression ratio is very ill advised.

[Unlucky_soul]

Only in India man... only in India....

[blasphemous]

 

From what I see, it is not likely that these cats know what valve shrouding is.

Also, using that crappy OEM piston with much higher compression ratio is very ill advised.

They might not know what valve shrouding is, but you gotta love the fact that they are trying, albeit crudely, to improve upon something. And that's what matters. Also what is valve shrouding? I am curious, how does to impact performance?

[ace.cafe]

They might not know what valve shrouding is, but you gotta love the fact that they are trying, albeit crudely, to improve upon something. And that's what matters. Also what is valve shrouding? I am curious, how does to impact performance?

I understand the sentiment, but doing things like this "crudely" most often results in making things worse, not better. I am pretty sure that this engine is going to self destruct in a short time, due to this modification.

Valve shrouding is basically what it sounds like. Walls of the combustion chamber or cylinder are too close to the valves, thereby "shrouding" them and dramatically reducing flow around the valve by blockage.

In this case, probably the flow was reduced by half, compared to stock. Since flow is directly related to power production, it would not be a good result.

Additionally, the combustion chamber was dramatically reduced in volume, raising compression ratio equally dramatically. There is a strong chance that detonation will occur, causing piston failure and engine damage, unless fuel octane additives are used. Even then, that terrible stock piston is hardly up to the task of high compression or detonation.

It is okay to try things, but it is a good idea to know what you are doing, first.
 

[Arizoni]

I honestly don't think the guy who modified that cylinder head could have come up with a worse design if he tried.

Where the original engine head has a very small amount of valve shrouding close to the cylinder wall, this "new improvement" has placed the valves down into a trench that will totally restrict any gas flow around over 60 % of the valve head.  The only place where any sort of free flow now exists is towards the center of the combustion chamber.  The rest of the valves gas path is choked off. 

With this design I wouldn't worry about the effects of any increase in compression ratios.  The restricted gas flow thru the valves won't let in enough air/fuel mixture to begin to use that higher compression.

I can't believe that anyone would think this revision to the cylinder head was a good idea. 

[blasphemous]

Thanks for the explanation guys, makes sense.

[Unlucky_soul]

It is okay to try things, but it is a good idea to know what you are doing, first.
 

You said it brother....

[cyrusb]

If you must attempt this, remember to hold the head with your feet.   

[chuychacon]

start with a coarse 60mm grinding stone on a regular drill