Problems with the Glow plugs

[Gattorno]

Hi guys,

I have a problems with the glow #8 O.S. , this burns very quick, alone a tank and ready, glow plug new ???

I use fuel to the 30% nitro (WILCAT all oil syntetic), at the level of the sea, K&B head clearance. 0195, cooling by water, tunned pipe IRWIN,

crank shaft turbo, crank case it modified for greater air/fuel mixture flow, RPM conecting rod, carb 40b O.S., remote needle O.S., props (x440,x438,x437/3,Pra220,Pra215), fuel filter Dinamite, etc.

And my tunnel goes very quick with most maximum peaks of 51 mph, but as already I said them 1 ó 2 glow plugs by tank that if that is costly :-.

Which is the problem, because burn the glow plugs? ???

Gatt.

 

[mark james]

try a different plug

I would use a ROSSI R6 or try McCOY MC-9 plugs work well also!!

If that dont work,then try raising your head clearance a small bit. (.002-.003 ) and then try then again..

hope this helps!!

mark

 

[TomMoorehouse]

from your description.... i think your too lean. have you tried to richen the mixture? Or possibly you need to add a head shim?

 

[GTR]

Hola Gatt

Your head clearance looks like heaps (0.008 recommended) so I wouldn't be adding any shims. Good speed from the boat so you must have a nice balance of mods happening. To fry the plugs like this it must be lean. You could also try adding a little castor to your brew for added protection.

When you say the plugs are blowing are they loosing the element, failing to light up again? Try taking the needle back out 1/2 turn and check the plug colour and wire appearance. Wire can be pulled to one side or slightly out of the plug body but should remain shiny. If dull and really distorted your still too lean.

What is the bore on the OS carb and what type of remote needle? could be that the needle just can't flow enough fuel when the motor is on full song or maybe the tank is a bit low and causing it to lean out further. Does it blow the plugs at the start or end of the tank or doesn't it matter when?

GT

 

[nitrotoys]

Try the R5 OS plugs, and I would change out your fuel lines, and or make them larger. i was blowing on small lines, so next size up and problem went away.

Do you temper the plugs first? before running?

 

[james irwin]

SOUNDS LIE YOU HAVE A MAJOR OVER LEAN AT TOP END , THE ONE THING WE DO IS TO PRESSURE CHECK ALL THE FUEL SYSTEM , WE EVEN PRESSURE CHK ALL NEW FUEL LINE AS IT WILL HAVE VERY SMALL HOLES IN IT , AND WILL DRIVE YOU NUTS TRYING TO FIGURE IT OUT . J. IRWIN

 

[izitbrokeyet?]

hola Gatto,

are you "popping the plug" so that you can move the electrode element inside the isolator(plug will not hold compression) or are you burning the element in the plug?

 

[Gattorno]

GTR,

burn whether full tank middle or to a 1/4 in any moment, the diameter of the carb is of 0.2720in and needle is for .20 to .60 engines, the filament remains of white color and a little side is done and breaks to the half or in the fund that is to say himself does not break for strange material that strike the filament as is common parts of bushing, your you say that use 0.008 instead of .0195, Mark say (.002-.003), I am going to test these glow plug (A5, R5 and Mc-Coy #9) that already buy, to see that it happens this weekend.

Thanks by its comments, I took them into account in the tests of this weekend.

Gattorno.

 

[GTR]

Hola Gatt

If the filament is white rather than shiny silver you are too lean. I have heard the OS A5 plug works OK but I have never tried one. The needle if for a 20-60 size may well be too small - you would probably need a 60-90 size as a lot of fuel flow is required for that % of Nitro and the amount of revs required.

Have you tired lowering the head clearance? As strange as it may sound it often makes engines run better. Keeps the combustion in the bowl rather than across the squish area. There is some good discussion on this susbject on rcboats.com in the technical forum.

Keep trying you will find 'the' set-up.

GT 8)

 

[Gattorno]

Hi Guys,

Here is a good info for all, about best-kept secrets of glow plugs in tunning your engine.

http://www.ic-online.co.uk/glow1.htm

Gatt.

 

[duc]

great info on that website

 

[Ian Inverarity]

Gatt,

The OS 8 is a pretty fragile plug, try a McCoy 8 or 9. I tried an OS 8 in my K-90 once, it got on pipe for about 50 feet before the element went out the exhaust! Engine runs fine on Mc 8's...

Ian.

 

[izitbrokeyet?]

Hola Gatto,

Also, if you have a bad rear bearing it can cause plug elements to break from vibration. If your element is not burned up, this could be the reason the elements are "breaking". Often you won’t feel this type of bad bearing when you turn the motor over in your hands…..it’s not a “grind”, but more of “slop” in the bearing that can often be missed unless the motor is disassembled.

Hope this helps,

KB

 

[Gattorno]

Hi guys,

I put the head clearance at .0215in, glow plug #A5 or Mc-Coy 9 and I am finished the problem, and increment the velocity of acceleration.

Gatt.