Measuring squish when re-installing head.

[rob64n]

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

don't underestimate anything. I've got one that will snap a stock pull rope

 

[alfred e numan]

don't underestimate anything. I've got one that will snap a stock pull rope

What sort of engine is this- just wondering-- On the engines i run- I want a solid baseline for fuel. - I mix 50% non ethanol 92. 50% vp 110c. More power? no. run cleaner? yes. The exception is the little cy 29. it produces quite a bit more power @ low-mid-rpms- no change on top end.

 

[Deluge]

don't underestimate anything. I've got one that will snap a stock pull rope

Does it need 110? I'm not saying you CAN'T run it, because you can. Many people do. I'm just saying with these engines, it's highly unlikely that you'll ever need it. I've talked to a few boat guys, and they run highly modified engines. The majority ran 87, while the others ran camp fuel.

 

[alfred e numan]

gas

I know on dirtbikes, too much octane -you lose top end power.- burns too slow. 2 or 4 stroke. Lots of riders also ran av gas- the old school stuff. gotta mix it with decent pump gas to speed up the burn. get this- i had a metal gas can. fillit with av gas- it leaked like a seive. fill it with automotive gas, never leaked a drop- its the solvents in the av gas. Bit o trivia- ever watch a SR 71 get filled on the tarmac? - jet fuel pours out of the seams. As this birds Ti comes up to temp- it seals its self off. And to think Kelly Johnson only had a slide rule back in the day- extreme I.Q. thats fer certan-- This bird was lit up with a modded g.m. 454 with a 671 blower- !!!

 

[ChuenouXiao]

Guys bought this... I believe this is the correct size for the job for measuring my head's squish? It says this one is 0.032" in diameter... which is what I need..... Please let me know....

http://www.radioshack.com/product/index.jsp?productId=2062711&prodFindSrc=cart#inTheBox

 

[Deluge]

That'll work.

 

[ChuenouXiao]

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.

If I remove my head now... the gasket will probably need to be replace its brand new.... maybe I should just use multiple solder and check all side from the spark plug hole? Just as long as I touch the side of the head where the edge of the piston is at?

 

[GTS 666]

The solder should face the same direction as the crank to get the most accurate reading. As the piston can rock in the bore and give you a different measure.

 

[Deluge]

You can re-use the head gasket since you haven't ran the engine, yet. As GTS said, you don't want to check it on the intake or the exhaust port side. The piston will rock and give you an inaccurate reading. Check it on the clutch side and the flywheel side. Use the method I posted, it's the most accurate.

 

[gofasterracing]

the only time you should run race fuel is when you have a high compression motor. Like someone said mix with a little 87 it will work a little better. Its the ethanol that kills these motors. I know a lot of people will not agree but I also change the piston ring about every 8 to 12 hours of run time. Its cheaper than a new top end.

 

[gofasterracing]

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

yes you can.

one of the RCMK I just built sheared the flywheel key right off. It was about 18 to 1.

 

[tsudo5th]

The motor gfr just built for me will be running 112 race fuel due to higher compression.

 

[Guest]

The motor gfr just built for me will be running 112 race fuel due to higher compression.

What kind of hp is expected from it? Is it more difficult to start?

I hope you can post some pics and vids when it's in.

 

[tsudo5th]

Will go over that with him. Get truck back today. And I will have videos and pics today.

 

[tsudo5th]

A buddy of mine owns a dyno shop, I want to see if I can put my truck on it to get a true wheel HP.

 

[Guest]

Will go over that with him. Get truck back today. And I will have videos and pics today.

Nice...

I'll be lookin forward it it.

 

[Guest]

A buddy of mine owns a dyno shop, I want to see if I can put my truck on it to get a true wheel HP.

That would be really cool!

 

[DreamState]

I have ran 110 race fuel a few times in my old baja with stock 26cc and a pipe, and I ran it in modded motors also. It makes the motor harder to tune and lost a little rpm. Smelled so much better though. 92-94 ethanol free race gas would be perfect. To bad no one sells that any where near here.

My main reason for running it was smell. My RC goes in the trunk when I take it places and with pump gas my car smells like a weed eater, even with castor 927 oil.

 

[Guest]

My main reason for running it was smell. My RC goes in the trunk when I take it places and with pump gas my car smells like a weed eater, even with castor 927 oil.Last edited by DreamState; Today at 10:37 AM.

I use this for that exact reason. http://www.davesmotors.com/s.nl/c.885035/n.1/it.A/id.4568/.f

 

[GTS 666]

yes you can. one of the RCMK I just built sheared the flywheel key right off. It was about 18 to 1.

How do you measure compression