Slant heads with squishband

moonerdizzle

moonerdizzle

New Member
I was looking over the slant head from a motor I got recently that grenaded. I was planning on smoothing out the combustion area and noticed that there isn't a squish band on this head like there was on my older slanthead. I'll take pics of my old head next time I have it off. But I'm interested in seeing how many peoples slant heads have a squishband and how many don't.


Untitled Album | Facebook


Sorry about the link to the photos, but my photobucket account is acting up.
 
All 6 engines that I've bought came with a slant head (the way I ordered them). All heads has a squish band. Is that not a squish band on that head you posted?
 
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Al.Fisherman said:
All 6 engines that I've bought came with a slant head (the way I ordered them). All heads has a squish band. Is that not a squish band on that head you posted?
Click to expand...

The head in the third picture appears to have a squish band...
All of my Grubee (2010) angle fire heads have had a squish band, fyi...
 
That is not a squish band, what appears to be a squish band is actually just a 1/16 of an inch or so lip in the material. My other head has a nice beveled squish band on it. I would take pics but I dont feel like taking it off and having to make another head gasket.
 
biknut said:
Here's the 2 types I've seen on motors I've bought from BGF and LEB

biknut-albums-biknut-repair-album-picture2841-t80-x80-squish-band.jpg
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The head on the right has the better combustion chamber, but I doubt they'll be much benefit from the squish band because there's too much clearance between the piston top and the head.

In order to have effective squish, you need a clearance of about 0.003". More than 0.004" and there's not much benefit. Much less than 0.003" and you run the risk of hitting the piston into the head.

Stock clearance is alot more than that. There are ways to make it less though. One way would be to mill the top of the cylinder down with sandpaper on glass.

The advantage of having proper squish, is anti piston ping, which allows for more compression, and thus more powwa. Throttle response becomes better too.
 
biknut said:
The head on the right has the better combustion chamber, but I doubt they'll be much benefit from the squish band because there's too much clearance between the piston top and the head.

In order to have effective squish, you need a clearance of about 0.003". More than 0.004" and there's not much benefit. Much less than 0.003" and you run the risk of hitting the piston into the head.

Stock clearance is alot more than that. There are ways to make it less though. One way would be to mill the top of the cylinder down with sandpaper on glass.

The advantage of having proper squish, is anti piston ping, which allows for more compression, and thus more powwa. Throttle response becomes better too.
Click to expand...

The head on the right is just like the head I got on my motor right now.
 
I have found the slant heads are really a poor design and do nothing to help performance. I have two bikes that run well with this head. Talk about a squishband...
 

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culvercityclassic said:
I have found the slant heads are really a poor design and do nothing to help performance. I have two bikes that run well with this head. Talk about a squishband...
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Without a lot of work I doubt you can get the squish band on that head close enough to the piston to help much.
 
I can see a problem with the shape of the piston crown, and the shape of the squish band. They have to be made to match each other. If the angles are different that's not going to work very well.
 
biknut said:
I can see a problem with the shape of the piston crown, and the shape of the squish band. They have to be made to match each other. If the angles are different that's not going to work very well.
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I'm not saying it won't work, it's just that the squish probably won't be able to be set tight enought to get much/or any squish effect.
 
In all honesty the puch head is a good cheap investment and works pretty good . The piston might nor fit the head perfectly but there is still a increase in performance over a stock head . Not only do you get a compression increase but also better cooling with the bigger fins . Also the stock heads are never flat I have mllled them flat to just have them start to blow head gaskets because now they are to thin . I am now squaring up the top of the cylinders because they are not flat at all as well .
If you want to invest some money into a cheap part that you will feel a difference with then the puch head is the way to go . I have three of them on three different motors and I have noticed a increase in performance on all three motors . These are not racing motors they are built loose and sloppy .So anything you can buy cheap and bolt right on and feel a difference is a win win .
 
biknut said:
I can see a problem with the shape of the piston crown, and the shape of the squish band. They have to be made to match each other. If the angles are different that's not going to work very well.
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I agree with that.
Aside from the MM head the only other head I have found that
does that is from www.ArrowMotorizedCycles.com which modifies the
standard head to include a squish band.

Head with squish band on the left.

472794_orig.jpg
 
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MotorBicycleRacing said:
I agree with that.
Aside from the MM head the only other head I have found that
does that is from ArrowMotorizedCycles.com which modifies the
standard head to include a squish band.

Head with squish band on the left.

472794_orig.jpg
Click to expand...

Nice site, and that head looks killer. Can't wait to start working again, damn cows need to hurry up! lol
 
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