Core Plugs

[Bondo]

Ayuh,.... We're droppin' in a brand new GM 5.0l motor into another Hi-liner over at the shop,....
The last few motors We've changed out with new, had brass core plugs, right from GM,....
This one had these core plugs, which to the eye, appeared to be steel,...
So,... I went to the local Napa, 'n bought a set of brass core plugs,....

Everything was goin' accordin' to plan, til changin' the core plugs in the front of the block, one was dropped inside the coolin' passage,....
No problem,.... grab a magnet on a stick, 'n try to pull it out,....
Of course the magnet would rather stick to the block, but it just wasn't workin' out, at All,...
Switched to a grippy fingered grabber, 'n finally got it out, 'n beat in the brass core plug,...

Later putzin' 'round with it, Bob, 'n I came to the conclusion, GM has gone to Stainless Steel core plugs,....
To heavy for aluminum, sparks on a grinder, so it ain't zinc,....
Lookin' closer at it, it does have the slightly bluish tint of ssteel, 'n a magnet won't attract it 1 bit,....

Excuse the blurriness,... used my old camera insteada my newer camera,....

 

[Scott Danforth]

Thanks for the update Bondo.

I had noted Stainless Core plugs available when buying parts for my BBC. Pioneer Auto makes them and ships to GM http://www.pioneerautoinc.com/catalogs/

if they are not magnetic, the material is most likely 316L

 

[alldodge]

Thanks, very good thing to know. Hope I remember this (CRS and all) so I'll check with a magnet if I see something like it

 

[Grub54891]

Interesting info. Not long ago we were servicing a mercruiser, the motor was replaced by the po. We saw the "steel" plugs, and told the owner that they should be changed, but he just said he would keep an eye on them for leaks. I guess they are stainless......HUMmmm

 

[HT32BSX115]

Back in the 80's, my mo'inlaw bought a new Chrysler K-car with a transverse mounted Chrysler 4-banger.

Drove it for several years until one of the front core-plugs came out and went into the timing belt(and "popped" it). The engine quit and spewed coolant. (aside from the fact that it was a REAL POS) It didn't really hurt anything but the core plugs rusted and became loose enough to pop out. (she never had the coolant replaced)

I would venture to guess, if the core plugs were SS, it wouldn't have happened. I like the idea of SS core plugs!

Merry Christmas Y'all!! (can we say that?)

Rick

 

[alldodge]

Merry Christmas Y'all!! (can we say that?)

Needs to be All Y'all to be plural otherwise we might feel slighted thinking your just talking to Bondo

 

[Scott06]

Scott I think you may have it reversed , 316 normally is slightly magnetic, 304 is not.

 

[HT32BSX115]

Needs to be All Y'all to be plural otherwise we might feel slighted thinking your just talking to Bondo

Merry Christmas ALL Y'ALL!!lane:

 

[Scott Danforth]

Scott I think you may have it reversed , 316 normally is slightly magnetic, 304 is not.

316 is slightly more magnetic than 304 and both are more magnetic than 316L the L is for Low Carbon which is also the most corrosion resistant out of the 3

magnets do not stick to 316L unless it is excessively work hardened and changes the grain structure

 

[Bondo]

magnets do not stick to

Ayuh,..... I just did a magnet test again here at my desk,....

Settin' the core plug on top of a 3" speaker type magnet, 'n turnnin' the magnet over,....
The core plugs quickly slides off the magnet onto the desk,....
Not magnetic, at All,...

With my readin' glasses on, 'n a magnifyin' glass,....
I can see that it was die-cut, 'n stamped into shape,....
No stress marks as some ssteels do,...
Looks smooth, typical mill finish, just the usual stamp, 'n dies marks,.... edge is stamp cut, not ground,...

Donno the alloy,... donno whether it's better or worse than brass,....

Great Idea by GM though,.....
I was Happy back when they switched to brass Oem,....
One less pain in the butt step in the long block swap gig,....

 

[JustJason]

There is stainless and then there is stainless. Hit them with some saltwater and see if they rust.

 

[Dave-R]

The last new GM 5.7 long block I bought probably had the same thing. I replaced all of them with the NAPA brass ones also. I never even thought of them being stainless.
They were a bugger to get out, and I got that Indian head gasket sealer all over me. Thanks Bondo for the heads up. Dave-R

 

[achris]

Back when I first started pulling engine apart (in the 70s) I would always replace old core plugs with stainless.... Been wondering why everybody here recommends brass and not stainless....

Chris.......

 

[alldodge]

From what I can find is brass is slightly less ionic then stainless. This is assuming this is 316 stainless and not a one with less nickel