what size of head shim to use on a CMB.21RS Redhead??

[misshydro]

I'd poped a glow plug and was told to add a head slim on my motor. Come to find out it doesnt have one.. Do they come with head shims from factrory?? What size should I run/try out? I'm running 33% nitro.

 

[FloridaScaleBoater]

You would need to find out what your clearance is without a shim.

determine what you want for head clearance, and add shims as needed.

 

[John Knight]

Try a richer needle setting before adding any shim(s). Being too lean will pop a plug from here to Sunday and does not mean that the clearance is too short.

 

[Beef]

Try a richer needle setting before adding any shim(s). Being too lean will pop a plug from here to Sunday and does not mean that the clearance is too short.

My thoughts are the same. Richen the high end needle, 1/8 at a time.

Keith

 

[misshydro]

Try a richer needle setting before adding any shim(s). Being too lean will pop a plug from here to Sunday and does not mean that the clearance is too short.

My thoughts are the same. Richen the high end needle, 1/8 at a time.

Keith

the new glow plug coil is pushed in alittle.. was told thats a good sighn it needs to be shimed...

 

[steve wood]

run .007 head clearance. if it's more than that,you could be leaning the engine to compensate for the too much clearance. we normally only get 1 to 3 tanks per plug. if your doing better than this, you have nothing to worry about

 

[john v]

i got a set of head shim clearance guages from gary prusse where you remove the glow plug and insert the right angle guage and turn the motor over, they work great but they do not go below .010". got them a few years ago - maybe there is a improved set out there that go smaller?

 

[misshydro]

i got a set of head shim clearance guages from gary prusse where you remove the glow plug and insert the right angle guage and turn the motor over, they work great but they do not go below .010". got them a few years ago - maybe there is a improved set out there that go smaller?

how much does he sell them for?? Ok to let you guys know,I'm not running lean,, I have to pinch my fuel line in order to start it up.. cant let it idel or shell flood out on my,have to burp it a flew times before she hits the water. I got to be close on the mixture because It can hit the pipes and she'll speed up on me.. I can tell when she's lean,she'll hit the pipes and wont speed up anymore faster.its like hitting a dead spot on the carb.. Does these CMB's come with head shims form factory??or not??

 

[Sean Bowf]

How many tanks did you have on the plug??

It is not rare to burn a plug while running. Shoot...on a bad day I can go through half a dozen between the three or four boat we bring to the pond.

Sean

 

[John Knight]

i got a set of head shim clearance guages from gary prusse where you remove the glow plug and insert the right angle guage and turn the motor over, they work great but they do not go below .010". got them a few years ago - maybe there is a improved set out there that go smaller?

They are Keeley gauges and the last set went to .008. Gary Pruesse is the exclusive US dealer for them. Got my set about 2 years ago for about $10.

Shims can be obtained from the Woods or from Stu Barr, CMB distributor.

Still think you may have a high speed lean. If you have a low speed needle in the carb, lean it out and will idle better. Just bet the carb is not set right on either end.

 

[misshydro]

How many tanks did you have on the plug??
It is not rare to burn a plug while running. Shoot...on a bad day I can go through half a dozen between the three or four boat we bring to the pond.

Sean

the one plug that came with this CMB lasted 6 tanks.. To me that was great!! I got some MC Coy#9 on ordered.. I dont know what plus was in it..no makings on it....I got this to go by on tunning nitro motors..http://www.rc-truckncar-tuning.com/Glow-plug-reading.just chic to undefined and it will take you there. A friend sent that to me..undefined