Unsaid info about high compression heads

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I've not found a single case of a person saying his new squish band head didn't gve more power but I believe that is because it's near impossible to make one without drastically raising the cranking pressure. The increased pressure raised the power, not the squish band. The beauty of that research paper is that they kept the cranking pressure the same between all heads tested. Here is the horsepower graphs of the 4 heads. Do you see much difference? One of them has no squish band.
4headspower.png
 
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It is not impossible to change squish area while keeping CR the same.
Far from it. Just make the chamber deeper.
How many people do you know doing serious investigation into squish?
It's been one of my 2 stroke and 4 stroke power secrets since reading Jennings book in the 70s.

Comparisons. Change one thing while keeping others constant to see the effect.
This is how we learn. I'm no scientist, but I do get paid to do this sort of stuff in industry.
Results. Find what works and go with it. Chase the real results that you find and demonstrate.
Listen and read the other's work but question it. Test it. Peer review.

Note the 3 KTM heads below, all are the same cc displacement but slightly different chambers to test effect.
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These two heads are the same cc displacement, just looking at chamber shape:
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These below are both the same displacement (within 0.5cc), although smaller displacement than the ones above to investigate the effect of increased compression ratio.
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I did earlier experiments with squish area that push me to 50% area being an important dimension.
Compression the same, more squish has a huge effect on power, not always good, but a huge effect.
It also affects timing.

Hey Jaguar, conflicting ideas and theories are a very good thing. They push the envelope of learning.
Just don't shake a 44 year old graph at me and wish me to accept it as holy gospel. Test it yourself.
These engines are so easy to work on, they are the perfect experiment media for these ideas.
That is what I am doing here, and I enjoy reading your work, your sources and your ideas.
If I disagree, I'll tell you why, where it comes from.

And best of all, we can test these things on these engines quickly and cheaply.

Steve
 
your right about these engines providing a virtual 2 stroke classroom. Most of what I know about 2 strokes I learned while riding a motorized bicycle and experimenting with it.
It doesn't matter how old the research is. They used modern test methods and their test results were not in any gray area.
But of course you are free to believe what you want to. What you were inadvertently doing was changing the timing (because of squish velocity) and seeing the power difference.
I was one step ahead of you in that I was using the Jaguar CDI and adjusting its timing to match each head I tried. That way each head had its optimum timing.
 
So you guys are saying that a high comp head that I buy from a dealer will have to have some work done to it to achieve maximum output?
If so how about a video that SHOWS what you mean for us VISUAL LEARNERS
 
save your money and just modify the stock head.
buy a good iridium spark plug, tougher nuts/bolts/studs, a better carburetor, a better CDI.
 
I think the included pictures show my "experience" is very deep.
I read those research papers (from the 1970s) and considered them very carefully.
Understand there have been "unbiased" research papers on eggs, coffee, oatmeal and alcohol are both very good and very bad for you. Read carefully for understanding. My guru, Gordon Jennings, wrote a very well researched article that more oil makes more power. He recommended 16:1 ratios. Why don't we do that now? We might for the same circumstances.
I am biased! I want more power! I'll follow the results that get to it.
Read and think. Experiment to find truth.



I'd have hard time explaining it any better than alazylightning@mail.r earlier in this post.
sdc10504-jpg.72245


sdc10519-jpg.72251


I did the similar thing with my slant plug head:

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Stock head in the back, modified in the front, aftermarket to the left.
Open up the squish to the full diameter of the cylinder/piston bore.
Set the squish up to 0.010" to 0.030" with either the base gaskets or head gasket surface.
Expect noticeable improvement and no more detonation.

Steve

Hi Steve,

Wow! More oil, more power? Sounds quite interesting! I will have to go back to more oil rich mixes and give it a try. Have you gotten into trying racing coatings on the parts? There is a special dry lubricant that is baked onto all the moving surfaces and a ceramic thermal barrier that is baked onto the inside of the head chamber and on top of the piston crown. It completely turned my engine into another speciaes of animal. It's really worth trying. I ordered the stuff in the internet, and they have a line for amatuer enthusiasts in small bottles. First the surfaces have to be sandbalsted with aluminum oxide that has a certain grit size. I bought two peices of special stainless screen with specific hole sizs from a scientific supply to get the proper fraction from some typical aluminum oxide powder also available at a scientific supply store. After washing with acetone, the coatings are carefully applied with and aerographic paint pen so thin that it doesn't affect the size of the piston diameter of the upper or lower pins. When it is really good and dry, it is then baked at at least 150C for an hour and a half. Some green scotch bright is used on the dry lubricant surfaces to make sure they are even and a final powder lubricant is rubbed onto the dry lubricant surfaces for extra super slipperiness. It's a mega game changer. I highly recommend it.
In the photos, you can see how the thermal barrier was defective after baking it. I had to redo that piston. Maybe I didn't dry it good enough, or it absorbed moisture from wet humid weather. I will dry them in jars with calcium chloride next time just in case. The thermal barrier was a few years old when I finally got around to applying it to an engine. It may be just old. I just applied some more coatings to a new engine that I'm building and the dry lubricant still applys and bakes on perfectly. The thermal coating was still flaking off in places after baking, now four years after the purchase of the bottle of thermal barrier coating. As I see on their website, they have a new type of thermal barrier for amateurs and the previous one that I bought is discontinued. So perhaps it was a combination of circumstances and product development flaw. Still yet, well worth it. As you can see, I coated the gear teeth as well. Don't forget to do that. If the entire power train will have this coating on it, WOW!

Best Regards,
Paul
 

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For one, if your compression isn't rally high and you don't rev up to 9000 or more then you don't need squish.
Just use sandpaper on glass to grind down the mating surface of the head for more compression. Don't go over 135psi.
On the contrary when we talk about Harley's and other small motors it's said that you get a 10% boost with proper squish band.

If not correct would that make a slight retardation in timing? I'm here in regards to rse high compression heads.

Once 1500 miles pass I will commit to a new exhaust/head.

I want to be in the million mile club.
 
Research proved that squish does not directly boost power. But it lowers the piston temperature which helps prevent the normal power loss when the engine gets hot.
 
Research proved that squish does not directly boost power. But it lowers the piston temperature which helps prevent the normal power loss when the engine gets hot.
Who's research showed such b/s?.Why is it then that all the engines YOU list on your site as having ideal timming ALL have a squish band?Why is it then that ALL small displacement performance 2t's have a squish band, Are you saying all these manufacture's are wrong and that you know better than they do!You can say that I'm part of the wolf pack that pounces on you,But what do you expect when you constantly contridict yourself.
 
Jag and I have argued this one. He goes back to a 1970s SAE paper from a chain saw engineer comparing 4 heads with different squish. It goes in conflict with 40 years of research since and I'd suggest it might have even been put up to throw competitors off the scent trail. Blair, Jennings, Bell, David Vizard and others have covered this quite thoroughly. I don't want to diminish Jag's contribution in the slightest, and I think it all depends on how you look at it. A head does not significantly add to the intake charge, just changes how we burn it and alters the pressure/time rate. Jag has added a lot to these conversations and should be listened to. My interpretation could be wrong.
 
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