squish band questions

sporty982000

sporty982000

New Member
Jul 10, 2012
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Illinois
I have been following the video clips, pictures about the cylinder head. mods.

I understand it boosts compression, aka, power.


What I am curious about, it the long term use of one.

Is the heat increased ?

Is there more stress on the piston ?

Should the piston ring gap and cylinder wall clearance be adjusted or changed at all ?

Are stock bearings, going to be stressed more ? The same question for the crank, tranny and rod.

is there a greater increased risk for gasket failure ?

I know allot of questions, but They are the questions. I seem to find myself asking and wanting to know.

This is something I am interested in doing. But before I dive into something, that can effect so many areas of the motor.

I was really hoping to know allot more from someone running this for awhile and how they ride and what they have ran into.
what mods are needed along with this mod also.
 
SPORTY982000,
I've bee doing these heads a while now....long before getting on this forum.

I've just been getting into it more intensly lately,because I have the time to do so.

Is the heat increased ?

>>> Yes! But not by alot. I infrared (thermal gun) my tempuratures while riding all the time. I've noticed a marked increase of an average of 20 to 30 degrees more. I've been riding in 105 to 106 degree days too.


Is there more stress on the piston ?

Should the piston ring gap and cylinder wall clearance be adjusted or changed at all ?

Are stock bearings, going to be stressed more ? The same question for the crank, tranny and rod.

is there a greater increased risk for gasket failure ?

Yes! But... not anymore than you would get with any other modificationssuch as pipe,porting,air filter stroker crank,etc,etc,etc. Remember this...
ANYTHING that adds CYLINDER PRESSURE adds stress on parts.

You have nothing to worry about. Whats bad for your engine is improper jetting and poor maintenance!

It has become apparant that closing up the squish band CREATES MORE POWER even with lower compression.

I've had NO DETONATION TO SPEAK OF!

Remember ....its only 6 nuts and 6 washers to change it back.
 
ive been running my rechambered head for i think more then 10 months. First off i bought my blaster stock and fully built it up myself.

for the stock motor the head mod is perfect you dont need any other work on the motor. i bought my blaster almost 3 years ago with a new piston i drove it for over a year before rechambering the head drove it for a good 6 months then ported it months ago. i am still running the same piston and everything. When i take my bike out im not easy on it either high rpm, hill climbing, long distance wot. I recommend DOO ITT!! all blasters should have a rechambered head....its more efficient.
 
Joe,

thanks. I know it seems like allot of questions and I dont want it to appear as a negative aspect. I am just one, before I do mods to a engine. I prefer to know as much as I can.

I am in the process of building from ground up, out of parts , ect. another blaster. and this is something I am certainly looking at right now.

Will it be harder to kick over ? thats something I forgot to ask.

The one I will be building, will be for my other two sons to ride. and I know my step son, cant kick over the current blue blaster. hes tried. and thats stock. lol.

Sporty
 
Triplecrown421 said:
ive been running my rechambered head for i think more then 10 months. First off i bought my blaster stock and fully built it up myself.

for the stock motor the head mod is perfect you dont need any other work on the motor. i bought my blaster almost 3 years ago with a new piston i drove it for over a year before rechambering the head drove it for a good 6 months then ported it months ago. i am still running the same piston and everything. When i take my bike out im not easy on it either high rpm, hill climbing, long distance wot. I recommend DOO ITT!! all blasters should have a rechambered head....its more efficient.
Click to expand...

Thank you, this is good to know.

Thanks again,

Sporty
 
blasterBruce said:
Glad to see this Sporty , Glad you asked Questions and made a Thread !
Click to expand...


Yeps. Chat on here is a bit different, than what I am use to. its more chat, than Q/A.

But thats okay and since I couldnt find what i was looking for. said, start a Q/A.

This does sound like something I will do for the other blaster. My main concern was, I am not wanting to replace the crank, ect. So if those parts can handle this, then I am inclined to do it.

I will however, likely get a extra head to do this. my mini lathe is to small to do this, but I would have a friend do it 4 me for.

Sporty
 
SPORTY982000 ...

Your on the right track ...

ALWAYS ASK QUESTIONS!!!

This is how you learn things. This is also how you filter through alot of bullsh*t. I personally ask a crap ton of questions myself,because I know that somebody will eventually have the correct answer. After you get a bunch of answers,you can filter through it all,and get to the thickest part of the truth. I think you know what I mean.

What gets old is..."this pipe is better than that pipe"..."This builder is better than that builder",etc.etc

When you start doing your own work,none of that stuff matters any more.

One other thing...TEST,TEST,TEST!

Test things yourself! Why take someones word for it.There is alot of satisfaction when you can machine that head,bolt it on,and go for a ride,then come back with a huge smile on your face knowing that you just added enough power to now stretch your arms an extra two inches,....life is good! And ....you did it yourself.

Ask questions!
 
joeak47 said:
SPORTY982000 ...

Your on the right track ...

ALWAYS ASK QUESTIONS!!!

This is how you learn things. This is also how you filter through alot of bullsh*t. I personally ask a crap ton of questions myself,because I know that somebody will eventually have the correct answer. After you get a bunch of answers,you can filter through it all,and get to the thickest part of the truth. I think you know what I mean.

What gets old is..."this pipe is better than that pipe"..."This builder is better than that builder",etc.etc

When you start doing your own work,none of that stuff matters any more.

One other thing...TEST,TEST,TEST!

Test things yourself! Why take someones word for it.There is alot of satisfaction when you can machine that head,bolt it on,and go for a ride,then come back with a huge smile on your face knowing that you just added enough power to now stretch your arms an extra two inches,....life is good! And ....you did it yourself.

Ask questions!
Click to expand...

Awesome reply ! thanks.

Ya I have a mini lathe, not big enough to do this job.

I also totally, agree, im 40 years old and 4 kids and Me, I have tried to avoid, the whole, better builder stuff or this is better ect.

The best way is the way, that you find that works for you and makes you happy. Thats all that ever really matter.

Im a moderator at another forum, and there is always debates like that. this tool or this method better than the other.

I am one of the fastest pinewood derby guys around and I have always taught people, no matter what way you go or do or use. In the end, as long as you are happy with the results. thats all that matters.

Sporty
 
blasterBruce said:
Cool man Glad you have friends that have the tools , Me on the other hand I do have Friends but there All a Few States away at least , but I did my own Diy porting back in 2004 , I made a Thread for it , and a Slight Head mod from stock
- http://www.blasterforum.com/pics-vids-9/blasterbruce-diy-port-polish-pics-48955/
Click to expand...

i wont mention I have a small vinyl lettering machine then ! :o;)8-|:p

Ya my friend owns double star machine shop. they dont do engines, they do different kind of machine work. but I could go out there and use there lathe when I want and when they are not busy.

In a month or so, when I have a spare head or for that matter a job and im back to work, lost my job two weeks ago.

Sporty
 
I'll post this in my regular thread,but just a "heads up"....

I just step cut head #2 to decrease the squishdistance.

It is now set at .017 Thats close! REAL CLOSE!

I'm almost afraid to start it.

I'm now going to go and test ride it to see how it does and to see if there is any detonation.

We'll see.... Full report tonight...
 
joeak47 said:
I'll post this in my regular thread,but just a "heads up"....

I just step cut head #2 to decrease the squishdistance.

It is now set at .017 Thats close! REAL CLOSE!

I'm almost afraid to start it
Click to expand...

Holy moley dude If u dont have any detination your gonnaaa Fllyyyy!!!
I think im at around 0.055
 
Triplecrown421 said:
Holy moley dude If u dont have any detination your gonnaaa Fllyyyy!!!
I think im at around 0.055
Click to expand...

Results of .017 squish ,was that I was detecting DETONATION!

I did one quick hard pull and..... there wasn't any more power than my original head (head #1) that I cut to the DT200 specs that "BEST" posted in another thread.

My original head (head #1 DT200 specs) originally had .066 to .072 thousandths squish clearance. It worked AWESOME!
However,I was on the "outside" of being in the "optimum" range for squish clearance ,so thats when I "step cut" the sealing surface .031 thousandths,so I could bring the copper head gasket dead even with the outer edge of the squish band. This reduced the squish band clearance into
the .035/.041 thousandths range.

When I did this,the engine CAME ALIVE!!!

It went from working "AWSOME" to working

PHENOMINAL!

Thats why I've determined that when you get the squish in the .035 to .045 range (with the DT200 specs),you are pretty much where you want to be!!!

Anything past that,and you start hitting the "point of diminishing returns" and DETONATION

The reason I State that my squish distance is between .035 and .041 is because when I checked it with solder on both sides you get more of a difference with a cast piston,because of its cast top compared to a forged piston (not my favorite) that is machined on top.
If you want an average on my squish clearance it would be .038

.035 + .041 divided by 2 = .038 thousandths.

I LOVE my DT200 spec head!

Here is "Head #1" that is cut to DT200 specs. This is before I did the "step cut".
7319-before-after.jpg
 
GUARANTEED no contact. It was intermitent at very low rpms. I'm almost leaning toward the play in the spur gears between the crank and counter balancer,because of the higher compression.

I know that sounds goofy,but it seems the tighter that the squish gets the more noise I'm getting.

Perhaps its just nature of the beast,and being that everything is tighter in the combustion chamber,not to mention higher compression, and theres no cooling jacket to absorb sound,its just making me think I'm hearing things.

I know that I didn't notice any more power with it at .017

I think I'll put that head back on and re-evaluate.

I just cut my third head (head #3),bumped up a jet size,and noticed even more power than head #1,but I have to still try head #1 with the same jet.
 
If you're going to play like this, you need to install a knock sensor on the cylinder itself so you can determine when you are actually getting predetonation. Normal blaster engine sounds are hard to distinguish from knock when the predetonation is very light but even light predetonation is robbing the engine of life (and power) at an alarming rate. Lower rod bearings are already at a relatively high angle of loading when the power is applied as it is. Predetonation is REALLY bad for them.
 
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