Core plugs

[Hugo]

I bought a set of core plugs a while back. Now that I have my engine stripped down I thought I'd check that I had the correct ones. Unfortunately, or as it turns out, fortunately, I am one short. So I looked on good old eBay and found Core Plugs International. They supply core plugs in stainless and also in brass if you are so inclined. So I've ordered a new set in stainless from them, plus a tube of sealant.
Their instructions are to Google 'core plugs international' and they will be top of the page, although that is not the name that appears on Google for some reason. Then you can buy direct from them rather than through eBay.
I found them most helpful, and the whole package, including VAT & shipping, came to less than 34 quid.
Got my pistons & shells from Barratts today also, twenty four hours after placing the order.
Nice shiny Mahle pistons, with circumferential grooves all the way from top to bottom that you can feel with your finger-tip. I assume this is for oil retention rather than cheap machining! They have steel strips inside to re-inforce the gudgeon pin area, and one odd characteristic is that the gudgeon pin will slide out of the piston if inclined more than 45 degrees, although they are a perfectly snug fit with no play at all. It feels really odd. Maybe they've been coated with Teflon or something?

[Hugo]

I have just had a query from the suppliers of these core plugs. They are asking how many of each size these engines require. Here is my reply to him, which I hope will be self-evident;

### I’m fairly ignorant myself, as I’m new to these cars. But as far as I’m aware, there are at least two versions of the 4.2 engine. Mine is the later type, with very long head studs that go right down through the water jacket. This block has lots of core plugs (9 x 1.625”; 2 x 1.25” and 1 x 0.875”), as there is one where each stud screws in. There are actually ten studs (plus two shorter ones at each end), but one of the holes is occupied by a screw-in plug which is a take-off for a block heater, hence only nine core plugs.

I have just looked at SNG Barratt’s catalogue. This lists the following core plug requirements;
For the 3.8 engine – 7 x 44mm; 1 x 25mm.
For the 4.2 up to engine no 7R1914/7R35388 – 6 x 41mm; 1 x 23mm; 4 x 32mm.
For the 4.2 from engine no 7R1915/7R35389 – 9 x 41mm; 1 x 23mm; 4 x 32mm.

Somewhat irritatingly, they are all listed as metric, but I’m sure they are all Imperial; 23mm = 7/8”; 25mm = 1”; 32mm = 1.25”; 41mm = 1.625”.
To add to the confusion, mine is the later engine, but it only has two of the 1.25” plugs, not four as listed here (unless I’ve missed something!).
To try to get to the bottom of this, I will post your question on the Forum, where there are people more knowledgeable than I about the vagaries of this engine!

[christopher storey]

Hugo : interesting, isn't it? I have just looked at photos of my last long stud rebuild . On the inlet side of the block I see 4 large plugs ( + the infamous heater plug) 2 medium plugs and 1 small plug which is presumably the 23mm one . On the exhaust side there are 5 large plugs ( and is there 1 small one above the dipstick area or is that an artefact on my photo?). On any view I can only find 2 of the medium size on the block , but IIRC there are also 2 fairly similar plugs somewhere on the cylinder head or manifold