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MG MGB GT V8 Factory Originals Technical - Core Plugs

Looks like the core plug nearest the block drain tap (the easiest to get to?) is weeping. I've changed one on the roadster before (again the easiest to get to), any thing special to watch out for on the V8 block?
Paul Hunt

Paul, hope you don't mind if I ask everyone an additional question...I have an SD1 engine about to get reconditioned, is it worth doing the core plugs at the same time?? They seem to look ok.

Stainzy
David Staines

David,
Cores are "cheap" and if you are competely tearing the motor down and having the mains align honed etc, they will probably remove them anyway. If you are tearing her down that far I would recommend pulling them, having the block cleaned and flushed and then installing new ones.
Larry Embrey

David, as Larry implies, *not* replacing them while the engine is out and stripped is one of those false economies. Now if only everyone with a wrinkle on replacing them posts it here before I change mine ...
Paul Hunt

Be sure to get the brass replacements. Although harder to find and a little more expensive they will never rust through. I like to use a little sealant on them for insurance. I smear it in the hole, on the plug, and over the joint after the plug is seated. Currently using "Right Stuff" for this sort of thing. I have usually driven them in with a close fitting socket, but I think a large pine dowell might be much better, or perhaps plastic.
Jim Blackwood

No answer, just another question. Since brass is higher on the galvanic scale than steel, should brass be used on an aluminum block? The plugs are in a electrolitic solution, so it may be of some concern.
George B.

David,

You really need to change all core plugs. I overhauled the SD1 engine in my B and the core plug looked oke from the outside but when i took them out i could see that rust wae eating its way from the in-side to the out-side. Since the core plugs are cheap and easy to replace when the engine is out, you should do it.
Good luck
Peter
Peter van de Velde

Thanks Peter, I think you're right..I'll do all of them while the engine is out.

George, I think you're also right...I checked with Triumph Rover Spares in Adelaide today and they said definitely no brass plugs...steel only.

Stainzy
David Staines

Good point George but here's my question too... since the Zinc in the brass alloy of the core plugs will presumably sacrifice first, isn't that better than the aluminum of the engine block sacrificing -in the long run?
Brass core plugs are specified for both fresh water and sea water cooled marine engines around here so they must have something going for them even though additional Zinc anodes are usually present in the cooling and wet exhaust manifolds of marine engines.
Anthony


Don't forget to use a good quality anti-freeze/additive even in the summer as it will stop anycorrosion of the aly block..Not sure about the brass core plugs though...

John

Anthony,
Except for outboards, marine engines tend to be of an iron alloy, not aluminum.
George B.

Be sure to check plug at rear of camshaft. This is usually aluminium and holds mostly by good luck. Good source of oil leak. Use a sound sealant technique such as wiping with isopropol alcohol before applying thin coat of sealant.

Ross
Ross Hannah

Steel core plugs are often cadmium plated which makes them look like brass.............

Fitting them is straightforward but put the new ones in with some anaerobic glue like Loctite - they are prone to leak otherwise.
Chris Betson

Removal of core plugs at rebuild time allows the block to be properly cleaned out, especially in a cleaning bath.

Rog
Roger Parker

This thread was discussed between 07/12/2001 and 24/12/2001

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