dj apolaro

I know there are ways to check head clearance with the calipers or other methods. I am looking for a tool that screws into the turbo button and it can measure the exact head clearance. Any help would be appreciated.

DJ Apolaro

wingracer

iTrader: (24)

Well, even if you took a dial indicator and modified it to screw into the head it would only tell you the stroke, position of TDC and BDC etc. To get actual head clearance it would have to have some sort of arm to go up against the underside of the head to measure from and such an arm would not fit through the hole. Maybe there is some way to do it but I can't think of it. Seems to me the old solder trick is much easier and cheaper.

Roelof

No chance !

The plug does not directly come out on the squishband. The depth of the plug and the shape of the piston (flat, hollow etc) is makting to much differences.

Just a piece of solder works fine!

dj apolaro

thanks guys

lil-bump

iTrader: (89)

If there where a tool. It could be done. You would have to dis-assemble the cooling head. The tool could be attatched to the button head then you would have to zero the device by pushing the button head against something flat. This would give you a zero reference point. Now re-assemble the button head with the device still attatched. At this point you can bring the piston to TDC and the gauge should display a clearance difference between zero and TDC.

Pass you soon...

1fastdude

iTrader: (16)

There used to be a dial indicator tool that someone used to sell. The problem with it now is that the piston's are reversed domed or dimpled. I agree solder is the best method

fly_wheel

iTrader: (9)

exactly how to use the solder method??? n what n how is the WOT method for running in engine???

Roelof

Bend a piece of solder in a L shape. Put it through the plughole so the endtip is touching the wall of the cilinder. Move by hand the piston trhough the compression, the piece of solder will be squeezed to the size of the gap, that you can messure.

WOT stands for wide open throttle. It is just a very rich setting which makes the car move very slowly on full throttle. Start with a few tanks and then adjust it leaner in steps until you think you can go on sharp.

fly_wheel

iTrader: (9)

thanks for reply... but will different plugs cause different in the head clearance??? i simply add up a 0.20 shim to my JP 0.12 when i started using 25% nitro... what is the cause that we need to decrease or increase head clearance??? is it ok if i add too much shim??? maybe like 0.2 too much or so... thanks again...

Roelof

The headclearance is setting the compression. These Nitro engines are working on self combustion and as with any other engine the ignition timing is very important for maximum (and reliable) performance.

Ignition timing is set by:
- compression, a higher compression gives an earlier ignition
- plug, a hotter plug will give an earlier ignition
- nitro content, more nitro will give an earlier ignition
- outside temperature, hotter will give an earlier ignition.

Nitro content must be corrected with the headshims, the outside temperature must be corrected with the plug.

A standard .12 in Europe is set for the use of 16% nitro, running on 25% needs 0.1 or 0.2mm extra headshim. 10 degrees celcius higher temp outside needs 1 degree colder glowplug.

These are just standard indications to get the right ignition timings but you can always play with it, an early ignition will give more bottom power and and later ignition a tiny bit more rpm.

icm

dj i have one check your pm

Roelof

Interesting.... I would like to see how some device realy can messure the gap from the plughole. Give me some pics....

Jamie Corrado

iTrader: (17)

Empire Racing is the company that produces the tool that screws into the glow plug hole.

http://www.empirercracing.com/gauge.html

Roelof

And that can only be used if you know a calibration value but will never messure the real clearance. As stated before, there are different shapes in pistons and so also bombustion chambers even for 1 model engine, so you can never be sure.

wingracer

iTrader: (24)

Well, for flat top pistons just put the tool in the head with the head off and push it down on a flat surface. Then zero it and put it on the motor. Off course, by the time you did all that the solder trick would have given you the answer.