View Full Version : Core plug woes

08-18-2008, 02:44 PM
Got a call from the machine shop where my 259 block is being prepared for it's fresh parts, saying one core plug hole has probably from corrosion over the years, lost most of the inside step for the disk to rest against and be seated. My machinist says it's not unusual for some of it to be gone, but he's not seen it this bad.
I suggested grinding off the remaining step and seating a cup plug there. He said a hand grinder couldn't make the cut to the perfection needed to seal the plug and welding the core plug in would be tough, due to the necessary heat required on the block.
Wouldn't you know, this block's been hot tanked, honed, had the small cracks repaired - now this.
Has anyone had to deal with anything similar? I'll forward any posts to Garry at Pacific Auto Machine who owns the joint and a GT Hawk,too.
Many thanks!

Western Washington, USA

Mike Van Veghten
08-18-2008, 03:30 PM
As with many of these things...very difficult to tell much without seeing it in person...or very detailed photos.

On the other hand...as you say...WITH very carefull grinding or better yet, hand filing...I'd be willing to bet a cup plug and some sealer of some kind would work.

Another way...would be to tap the hole with a 1-1/4" pipe tap and screw in a pipe plug! I'm doing that to my 299 Stude engine. A nice clean flat (interior square drive) plug, screwed right into the hole.
Though, the tap cost me $38 and the plugs as I recall were about $4 bucks each, I think it's still worth it, at least for my use.


Dwain G.
08-18-2008, 03:44 PM
What year engine is this Tom? Just last week there was a topic on this. Search "Installing Freeze Plugs" and read the responses, especially Gords and WCPs.

Dwain G.

08-18-2008, 03:47 PM
Without seeing it, I would just go with the expandable Neoprene (rubber) type of core plug after dressing the opening a little bit. I have had good results with these.

Gary L.
Wappinger, NY

SDC member since 1968
Studebaker enthusiast much longer

08-18-2008, 04:03 PM
yup, if you have the tools I like Mike's idea, but if you don't I would go with the epanding rubber plug.


55 Commander Starlight

08-18-2008, 04:51 PM
I've gone to using the expandable copper plugs in my engines.

Miscreant Studebaker nut in California's central valley.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President two door

08-18-2008, 06:33 PM
Bob, I've heard that recommendation from several people, but I've yet to find a FLAPS that sells 'em. Irrelevant to me at the moment because I don't need to do a "full flush" on anything, although this fall I should probably pull the starter and do the drain plug flush because the engine's been in over a year now.


55 Commander Starlight

08-18-2008, 06:44 PM
We all sell those as 801353 Nate, I think you need to join the Stude crowd, these are NOT VW's you know, and get an S.I. Catalog and quit wasting your time at the FLAPS i.e. AKA: (Honda,Toyota,Mazda parts store) !!! :D[}:)]

Studebakers Northwest
Ferndale, WA

08-18-2008, 10:58 PM
To even suggest welding in a core plug indicates he has no clue. Do like you said; with the cup plug. If it leaks, then go with the expandable rubber one.

08-19-2008, 09:32 AM
<<To even suggest welding in a core plug indicates he has no clue>>

I've never claimed to have a clue, just a curiosity and willingness to refresh a tired old engine. I ask questions because I want to learn. You don't need to tell me I'm stupid, pal.

Western Washington, USA

08-19-2008, 09:48 AM
I have good luck with NAPA EPC30B10 cups along with JB weld

55 SPEEDSTER (in work)
63 R2 LARK (in work)
85 AVANTI (9K miles)

08-19-2008, 10:20 AM
I read your post to mean a machinist suggested welding.

09-10-2008, 06:14 PM
Thanks Mike, and everyone for suggestions!


The pipe plug did it!

Western Washington, USA

Mike Van Veghten
09-10-2008, 07:02 PM
Cool...glad to hear it.
While it is more work...it is about as permanent a fix as there is....unless you want to weld them...!


09-10-2008, 07:46 PM
That's pretty dang slick!


Clark in San Diego
'63 F2/Lark Standard

09-11-2008, 03:43 AM
Any one using an expanding rubber plug should expect it to FAIL!!
within a year or two, or less. See instructions on most packages.
Not a good solution, especially when it falls out followed by all
your coolant.