1966 small block ignition shielding

[Michael M.]

I know the judging guide says that the left side horizontal shields are stainless steel which is not magnetic, but I have a left side set that came off a origional car and a magnet sticks to it. Can anyone help me with this matter. Thank you.

[M W.]

Re: 1966 small block ignition shielding

Michael I am trying to get the same answer. Let me know what you find out.

Thanks,
Craig

[Jeff S.]

Re: 1966 small block ignition shielding

Michael

The original LH horizontals are indeed stainless steel. They are a "ferritic" grade -- most likely type 409 -- which is strongly ferromagnetic. Type 409 is sometimes known as "muffler steel", since it is widely used in catalytic converters and other modern exhaust system parts.

If you have an original distributor cover, you will find that the top section is non-magnetic stainless -- likely type 304 -- while the lower wrapped section is a magnetic/ferritic grade.

There are many grades and entire families of stainless steel that are strongly magnetic.

[Wayne W.]

Re: 1966 small block ignition shielding

They were stainless, but, a magnet will stick to cheap stainless. It is not as strong of an attraction though.

[Wayne M.]

Re: 1966 small block ignition shielding

....If you have an original distributor cover, you will find that the top section is non-magnetic stainless -- likely type 304 -- while the lower wrapped section is a magnetic/ferritic grade. .

What a neat observation . Just checked it out on two smal block distr. top shields I have, and sure enough, the top has zero magnetic attraction, whereas the "skirt" does.

Also checked original '65 BB top and bottom distr. shield pieces, and they are highly attracted, as befits their chrome-plated steel description in the '65 TIM&JG.

There is a fair amount of shielding discussion, w/drawings, in Noland's Vol 2; mostly in the 1963 U69 section, that calls for (depending on part)... ie. 430 stainless (optional C.R. steel AISI C-1008 or 1010) [for LH vertical] .... stainless type 430; (no steel optionals) [for LH horizontals], ...etc.

[Brant H.]

Re: 1966 small block ignition shielding

Michael

There are many grades and entire families of stainless steel that are strongly magnetic.

Correct, but are most judges aware of this? It has been several years since I have shown my car; but at that time, no judge could be convinced that a magnet would stick to certain types of stainless steel.

[Jeff S.]

Re: 1966 small block ignition shielding

Correct, but are most judges aware of this? It has been several years since I have shown my car; but at that time, no judge could be convinced that a magnet would stick to certain types of stainless steel.

Brant,

I would hope so. But, being a metallurgist -- not a judge -- I can without qualification report that many folks harbor many myths about the physical, mechanical & chemical properties of stainless steels.

[William C.]

Re: 1966 small block ignition shielding

I believe that was addressed in the most recent edition of the JG, coming soon (someday)

[Dan H.]

Re: 1966 small block ignition shielding

Hi, you might add that the 'original' stainless tail pipe extensions were also a very low magnetic grade stainless, repros are not.
Dan

[William C.]

Re: 1966 small block ignition shielding

That is one of the other corrections. I believe the new edition should be out shortly.