welsh plugs leaking, advice needed....

[gordont]

The 2 welsh plugs in the head are leaking after a recent rebuild, I have no experience in how to fix these and would appreciate any suggestions.
Not a lot seems to be coming out but a noticible dribble down the motor, woudl rather fix before it turns into a flood or they pop out.

Thanks in advance for any advice

Gordon

[mikealdren]

They're always worth replacing while an engine's apart, plugs on the back of the block can need the engine out and it's better to do them than regret it later.

I drill out the plug centre, then lever out the old plug with a large screwdriver and carefully clean up the area where the plug fits. To fit a new plug you will need some Welch plug sealer, you want enough to make sure that there are no gaps and you can wipe excess off the outside. You don't want large quantities going into the waterways but it's unlikely that you have a problem.
The drift back a new plug. The plugs are convex and as you drive then in with a suitable piece of metal pushing on the centre, they expand and lock into place.

It's really very straightforward

Mike

[andyelan]

Hi Gordon

Sound advice from Mike about replacing plugs in the cylinder block, that's how I've done the job. I usually use an old socket for drifting the new plug in place.

I am a bit puzzled though. You say it's the plugs in the head which are leaking, which ones are they. I can't visualise where they are. There are 2 in the back, which I seem to remember are just socket head grub screws, and one in the under side which seals the oil chamber and is pressed into place

Andy

[512BB]

The 2 welsh plugs are located on the inlet side of the head, at the back, on the face that mates with the block. They are easily missed, and rarely changed during an overhaul, but should be. They measure approx 1" in dia. You should be able to see them from under the car.

Leslie

[rgh0]

There are 4 core plugs into the water jacket on the head and one into the oil disengaging chamber on the lower face of the head.


The 4 water jacket core plugs ( 2 exhaust side, 1 inlet side and 1 at the rear) are normally a screwed in square socket head plug. Though one of my early heads has welsh plugs instead of screw plugs but i dont know if these are original but they are installed in the reverse direction to normal like the oil disengaging plug described below so may be original.

The oil disengaging plug is always a welsh plug but installed with the flange facing inwards which is the reverse of how they are normally fitted. I dont know why Lotus did this. I have one head without this plug but this may be a later welded up mod but I cant see any sign of welding so maybe some heads did not have this plug.

If the screw in plugs are leaking (which is unusual) reinstall the existing or new plugs with a suitable loctite thread sealant.

If you have welsh plugs that are leaking knock them out by driving in one side and then then pulling them out. If you drill a hole in them to lever them out be careful the drill does not catch and go into the casting behind - I ruined a block doing this once . Install new plugs with a suitable loctite sealant ensuring the sealing surfaces are in good condition. If I was installing new welsh plugs I would install with the flanges facing out as the design of these plugs intends.

regards
Rohan

[gordont]

thanks for the feedback guys, it was the 2 small ones on the extractor side that were leaking. I have ordered 2 new ones and in the interim gave them a small tap with a socket on extension pole to knock them in a bit and see if that makes a difference.

seems I have a few water issues, other is water coming in in the rain (for those of you in the UK yes it does occasionally rain here) via top of windscreen where rod attaches, doors and down near pedals. Will sort out most in time and what the heck it won't rust so not a major drama

cheers

Gordon

[neilsjuke]

Check that the drain hole in the plenum chamber is unblocked look down the grill in take to heater.
I use a dent slide hammer after punching a hole with a centre punch to remove core plugs.

http://www.flickr.com/photos/16638375@N ... 202952079/
See link have a look at my heater motor it was still working

Neil