Drilling for core plug straps

Just idly musing.

When drilling the holes to be tapped for retaining core plug screws, do you drill through? Then blodge sealant on the screw?

Or shallower blind hole?

Hi Ben, if I were intending such a thing I expect I would drill a blind hole and use an intermediate tap followed by a plug tap - threading to depth. I have seen these in place but have never felt the need to fit. I have a 3.4, a 3.8 and a 4.2 long stud and have yet to have a welsh plug fail. Paul.


For a street car, it really is overkill: it’s used on race cars where the blocks are subject to extreme vibrations and torsional forces. I wouldn’t go to the trouble of it on a streeter.

I’ve no intention of doing it.

I happened to spot the kit in the Guy Broad catalogue and I was only looking at that cos Guy Broard is a chum of a chum of mine!

My 240 is midway to becoming a 4.2, but just a run of the mill road car.

I have had a core plug depart, going up hill to a tv photo shoot, they were using my old ‘S’
I noticed a LOT of ‘smoke’ as I went up a hill (immediately after hearing a ‘ting’) the ‘smoke quickly cleared and I reached the top of the hill with no further occurrence. As you do I scanned the guages and noticed the temp was on cold, on a XK engine, yeh right (Tuis Adv for some of us)
The rear core plug had shot out and dumped all the water out in about 2 seconds flat, hence the ’smoke’
Finished the journey on a flat bed, both to the photo shoot and then home.

Hi, I have used JB weld to hold in all my core plugs, never had problems with any of them.

I dont know how many I’ve fitted, but I’ve rebuilt a dozen or so old British engines, I had had 1 come out, heard the pop then saw the steam!

I’ve no need to fit them on my 240, was just wondering about the drilling!