Core Plug

[Neil Clark]

Yesterday I noticed an oily seepage, no more than that, around the 2" round dished plug at the back of the engine.  It did its first drive two weeks ago (a few miles to the wheel aligners) and hasn't been used or started since.  Is this unusual?  I can't find any references in the forum search I've done.  Thanks

[johny]

Thats one of several core plugs your engine has and theyre associated with the water cooling system which if it freezes pushes out the plugs instead of cracking the engine. If they leak it should be water/coolant that comes out so in your case its more likely the oil is coming from the rear of the cylinder head gasket and running down. Its annoying but quite common and the options range from leaving it, retightening the head fixing bolts to removing the head to replace the gasket....

[ahebron]

Or in my case when you have reinstalled the head and all the bits and bobs that go with it, fill the engine with coolant and notice a running water sound from the rear of the engine. Engine reconditioner forgot to  replace the welsh plug and I never noticed till it leaked.
Lesson learnt check the parts on pickup.

[68vitesse]

I thought there is a core plug at the back of the camshaft this would leak oil not coolant.

Regards

Paul

[Colin Lindsay]

You can't see the camshaft core plug if the engine is reassembled and running, so I'd assume it's the one at the rear of the head.

First thing I'd check, if it's oily, is that it's not coming from the rear of the rocker cover and just running down.

[Neil Clark]

Thanks for the pointers.  Looking at it it's more watery with a bit of brown that might be oil or rust, than oily / greasy.  And the engine outside surface is a bit oily anyway so it will have mixed with that.  I'll keep a close eye on it.   I suppose in the extreme heat under its cover last week when we cooked in the sun here the water might have expanded just as it would with freezing.  Our drive is sandstone and very reflective of heat and our cars can get very hot indeed.

[DanMi]

yes the big 2 inch one is blocking the camshaft drilling so would leak oil. I can't recall that one being visible in situ though. If you have a mk2 spit engine with cam bearings it is actually 2 1/8 inch but none of the suppliers seemed aware of this I had to get it from a core plug supplier

[Ian Foster]

1 hour ago, Neil Clark said:

around the 2" round dished plug at the back of the engine

It could just be a weep from the rocker box. Dry it off and monitor.

Ian

[DanMi]

the other possible oil source in that area (if an 1147) is the pushrod tubes 

[Neil Clark]

Thanks again.  The engine number is the original from 1964 Dan.  Will monitor anyway.  I need to get the steering fixed and run it around a bit more in real world conditions.

[johny]

36 minutes ago, Neil Clark said:

Thanks for the pointers.  Looking at it it's more watery with a bit of brown that might be oil or rust, than oily / greasy.  And the engine outside surface is a bit oily anyway so it will have mixed with that.  I'll keep a close eye on it.   I suppose in the extreme heat under its cover last week when we cooked in the sun here the water might have expanded just as it would with freezing.  Our drive is sandstone and very reflective of heat and our cars can get very hot indeed.

Neil, you need to confirm if its water as that, in this case, is surprisingly more worrying than a bit of oil. The core plugs corrode and start to leak so you lose coolant and it could possibly get worse quite rapidly while driving. Unfortunately that plug isnt very accessible although its not the worst, to change it have a read of this thread:

 

[Neil Clark]

Could well be rust as it has sat since the smash in 2018 and it only had water in it when I got it and first drained it.  When I rebuilt the car and had the radiator restored I re-filled with water to test it for leaks in early 2020 then it got stuck in a body shop until a few weeks ago - I forgot to replace the water with proper coolant until a couple of months ago.

Is it a threaded plug or just a pressure fit?

[Stratton Jimmer]

1 minute ago, Neil Clark said:

Could well be rust as it has sat since the smash in 2018 and it only had water in it when I got it and first drained it.  When I rebuilt the car and had the radiator restored I re-filled with water to test it for leaks in early 2020 then it got stuck in a body shop until a few weeks ago - I forgot to replace the water with proper coolant until a couple of months ago.

Is it a threaded plug or just a pressure fit?

Core plugs in my experience have always been an interference fit, never threaded. The last one I had to change was on a Morris Marina 1.3L (a few years back) and I drifted it in using a spark plug socket wrapped round with some insulation tape to hold the core plug. Having lined it up I drifted it in by standard percussive methods.

[Neil Clark]

There are a few terms here that I need to work on Jimmer as a total novice to engine issues - "interference fit", "drifted", "standard percussive methods".  I've a lot to learn!  The only "drifting" I know of so far in the cars world is the sport and then only because my son competes!

[Josef]

I feel like ‘standard percussive methods’ means hitting it with an appropriately sized hammer Neil

[johny]

30 minutes ago, Josef said:

I feel like ‘standard percussive methods’ means hitting it with an appropriately sized hammer Neil

oh its far more technical than that🙃But yes Neil the core plugs are tapped into place but they do come in two types and a range of sizes....

[Aitch]

 

I was watching this on YouTube yesterday and might be of relevance. Stick with it as it's lengthy. Hope it helps,

Aitch

 

Triumph Spitfire | Amateur Restoration | Mystery Water Leak - YouTube

 

[Colin Lindsay]

If it is core plugs then depending on your cylinder head you'll need bucket or domed plugs.

  

If you've one, it's domed, if two, they're bucket. All you need is the relevant size of socket for the core plug; try various sockets in each core plug until you find one that will fit inside the edges for bucket or as close to the outer edge for domed as you can get, offer it up to the hole in the engine, and tap it in with a hammer using the socket as a drift (the percussive drifting!). This keeps the force out round the edges and avoids bending or distorting the centre, thereby pulling the edges in and maybe causing a leak. Make sure the edges of the hole where it will fit are dry and free from debris, especially dried crud that has built up over the years. You cannot push these too far in as there's a definite lip but I would coat the edges in sealer to prevent leaks.

However I'd still wipe the rear of the head clean then watch for tell-tales as to where it's escaping from. I'd doubt if it's from the push-rod tubes as this would run along the edge of the head where it joins the block, and off the rear lower down, but I'd first suspect the rocker cover.

[DanMi]

a 64 spit will be the domed ones.

When my pushrods tubes were leaking the oil moved slowly down the flat part of the head and then off the back pooling on the back of the block pretty much exactly where a leak from the rocker feed in the head gasket would be but then the part of the casting on mine looks flatter than those pics so they may have changed the casting slightly

 

[Stratton Jimmer]

17 hours ago, Colin Lindsay said:

and tap it in with a hammer using the socket as a drift (the percussive drifting!).

Spot on Colin. Sorry if I used terms unfamiliar to some. Having worked in RAF engineering, it was always assumed that everyone knew the concept of percussive maintenance - "Hit it with a hammer". Using the old spark plug socket bound around with some insulation tape ensured that the new core plug stayed attached to the socket which is the "drift". It was easier to keep the whole thing square to the plug hole that way. You must avoid a lopsided fit. A drift is a length of steel bar (other materials are available) which is used to transfer the impact of a hammer to an otherwise difficult target.

[Casper]

See https://en.wikipedia.org/wiki/Core_plug

I'm booking the car in today for all welch plugs to be done.  Some have been weeping for a while but the ?one behind the engine front plate has now gone big-time.  They are all the same age so the will all need doing.

Engine out, front plate off. Watch the walllt.

C.

[johny]

Ouch! Dont want to make things worse but is there anything else to be done at same time: oil seals, gaskets, paint, crankshaft bearing renew?

[Wagger]

Ahem! I always found it best to have a spare engine. Rebuild it as the one in use ages, then swap it before it dies. Learned this in my motorcycling days, but they were air cooled and would store in a nice dry wardrobe.

Anyone got an unwanted six pot? (Only joking)

[Pete Lewis]

Ive just looked in my wardrobe but i dont have one    Ha !

[Badwolf]

1 minute ago, Pete Lewis said:

Ive just looked in my wardrobe but i dont have one    Ha !

I had a look too, but ended up in this strange land with snow and some sort of lamp post.