stek79

Hi Bax,
I purchased this fantastic engine, I'll fly it next season, when my new pattern plane will be ready.

I see that most people suggest me to run with OS type F glow plug, with extra head shims....

The question is: why? The standard A5 plug will not be fine? The extra shims are actuallly needed?



Thanks for your precious words Bax!!!!!!!!!!!!!!
Bye bye

Bax

My Feedback: (11)

I depends upon prop, fuel, and tuned pipe setup. We'd suggest an O.S. #8 or #A3 plug. Type F would be for lower nitro and lower RPM.

stek79

Hello Bax, thanks for the reply!

I'm really interested in glow plug type, could you be more precise? How can I tell if I need a given glow plug or another? Why so many people use OS Type F? You instead suggest #8: why?

The setup that I have in mind is: APC 16x12, 15% nitro - 18% oil fuel, standard Hatori header & pipe.

THANKS!!!!!!

Bax

My Feedback: (11)

If your engine tends to detonate, you need to go to a colder plug. With low-nitro, you need a hotter plug. The O.S. #8 glow plug is probably the best general-purpose glow plug to use. The #A3 is a slightly-hotter plug, and the Type F a little hotter than that.

We always run a #8 if we don't know where to start.

stek79

Thank you Bax for the reply.

Very last question: could you shed some light on the "extra head shims" issue? Is it related with glow plug type?

If I put a little colder glow plug than the OS F, for example the #8 or A3 as you suggest, I will not need to put them?

Consider a fuel with 10-15% of nitro.

THANKKKKKKKKKKSSSSSSSSS!

Bax

My Feedback: (11)

If your engine is detonating, then either it's over-compressed for the nitro, or you have a too-hot plug. Finding what works is of the "try and see" kind of thing. Try a colder plug, try lowering compression by adding a shim, and so on. This, of course, assumes that the engine's mixture is properly set.