$\pi$ enlarged?

[Frans Goddijn]

Hello, one more from me. I've defined this font:

\font\fgtop=cmmi12 at 26pt

and when I do this I get the large version:

{\fgtop test}

but when I do this I get just a tiny pi:

{\fgtop $\pi$}

How can I get the \pi in the large font?

Thanks for your time,

Frans