Measuring squish when re-installing head.

[ChuenouXiao]

The video here he mentioned that using silver solder and rosin core with 30,000 or 50,000 width? Just don't know where to get and how to read the width.... when I'm actually buying the silver solder. What are your thoughts on measuring squish guys? Especially those who re-build engine a lot here....


squish measuring starts at 7:10


[ame]

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[Deluge]

It's .030" solder. You can get it at RadioShack. I don't like checking the squish on just one side of the piston, you don't get an accurate reading that way. What I do is tape a piece of solder to the top of the piston, making sure that the solder is parallel to the wrist pin and long enough to reach the edge of the piston on both sides. Then bolt the head back on with a gasket and cycle it 2 or 3 times. Then pull the head off, pull the solder off and measure both sides with a digital caliper, then average it. Anything between .019" and .031" is fine.

 

[alfred e numan]

solder- ect-ect

silver bearing solder - if it comes with a bottle of flux, used to flow brass tubing together- like and un like metals. not intended for electrical work. - yes, there are types of silver solder sold that are for electrical work- they have such a low percentile of silver-- not worth it- harder to flow a good joint- can i say that word here? Some engines - the squish clearance can be huge- and still have big compression- - If you are thinking about rasing the compression on your OBR mill- i really would advise you to talk to Your builder 1st. - changing the base gasket will also change the port timing on the cylinder---- just saying---

 

[krashkrieg]

silver bearing solder - if it comes with a bottle of flux, used to flow brass tubing together- like and un like metals. not intended for electrical work. - yes, there are types of silver solder sold that are for electrical work- they have such a low percentile of silver-- not worth it- harder to flow a good joint- can i say that word here? Some engines - the squish clearance can be huge- and still have big compression- - If you are thinking about rasing the compression on your OBR mill- i really would advise you to talk to Your builder 1st. - changing the base gasket will also change the port timing on the cylinder---- just saying---

All the dude was asking was how to measure squish...lol...

+1 what Deluge said, best way to measure and you should always check when rebuilding a head or any part of it.

 

[ChuenouXiao]

Just out of curiosity.... what if the squish is way off? Do you use thicker gasket or something?

 

[Guest]

Yes, you can use different gaskets to achieve different squish rates.

 

[the1320god]

But messing with the gasket thickness messes with the timing correct? What if I wanna set it up too run on 110 octane? Just less squish or what???

 

[ChuenouXiao]

Yes, you can use different gaskets to achieve different squish rates.

I wouldn't count on this but if i use the exact zenoah gasket... most likely I wouldn't need to measure the squish right? I know... stupid question....

 

[Guest]

You still should do it to make sure you are with in spec.

 

[Deluge]

But messing with the gasket thickness messes with the timing correct? What if I wanna set it up too run on 110 octane? Just less squish or what???

You don't set up to run 110. Higher octane doesn't mean more power. It just prevents pre-ignition in high compression engines. 110 is overkill, though.

 

[ChuenouXiao]

Guys... how come the Team Eddy guy recommended a different squish rating then my bud Deluge? Which one will be right for my OBR? I assume I will have to ask OBR.....?

 

[the1320god]

You don't set up to run 110. Higher octane doesn't mean more power. It just prevents pre-ignition in high compression engines. 110 is overkill, though.

I'm vary aware of this. But I wanna build a motor with high enough compression to NEED that fuel as i always have that fuel around for my drag car... why not NEED it for my RC car???

 

[Deluge]

Guys... how come the Team Eddy guy recommended a different squish rating then my bud Deluge? Which one will be right for my OBR? I assume I will have to ask OBR.....?

The measurements are the same. I just converted them to inches.

.5 mm = 0.019685" (You could round it up to .020")

.8 mm = 0.031496"

 

[Deluge]

I'm vary aware of this. But I wanna build a motor with high enough compression to NEED that fuel as i always have that fuel around for my drag car... why not NEED it for my RC car???

With these small engines, you'd never get the compression high enough to need 110.

 

[the1320god]

:-( that sux

 

[ChuenouXiao]

The measurements are the same. I just converted them to inches..5 mm = 0.019685" (You could round it up to .020")

.8 mm = 0.031496"

As always Deluge, you are my hero! My MAN!!! THANKS SO MUCH!

 

[Deluge]

No problem. Glad to help.

 

[ChuenouXiao]

Sean recommends

.018 - 0.025

I believe this format is in inches right? What is it in mm?

When buying a caliper, what should I look for? MM and Inches measurement feature?

 

[Guest]

Most of them will do both.

 

[Deluge]

Sean recommends.018 - 0.025

I believe this format is in inches right? What is it in mm?

When buying a caliper, what should I look for? MM and Inches measurement feature?

.018 " = 0.4572 mm

.025 " = 0.635 mm

This is the one I use...

OEM Dial Caliper