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MG Midget and Sprite Technical - Sills

Do Frogeye sills have drainage holes?

The later cars do have drainage holes, though they aren't immediately obvious. They are formed as small gaps between the flange seam inner and outer sill panels. They are difficult to spot unless you know to look for them.

I am just wondering whether to drill some drainage holes before it is painted, and what sort of size to make them. I don't want them to allow road dirt etc get into the sill!
GuyW

Guy,
I drilled about six or so 6mm holes in each sill a good number of years ago as I had water collecting at the end of one sill and they haven't rusted (I did once Waxoyl the sills) or dirt got in.

I made the holes 6mm so that I could use a reasonable sized cable-tie to keep them clear. My logic was that the pointed end of the cable-tie would push through any muck rather than push the muck in the hole and as the cable-ties are plastic and bendy they're easy to use and won't scratch the paint or inside.

I'm lost with your drain holes on the later cars, though they were on my wife's previous modern car (not looked at the present car). The good book details the drain holes and I thought I'd found them but perhaps I'm looking at the wrong holes. The diagram in the good book shows one just forward of the A-post and another just behind the seat. Mine is a Heritage shell so I don't know if that makes any odds.

If you could put up a photo of them I'd be most interested.


Nigel Atkins

Nigel, it was specifically Frogeye sills I was asking about as the aftermarket sill panels that came when I bought the car don't have any built in drainage.

On both my '78 and my '71 car the original outer sill had short depressed sections so that when spot welded to the inner sill it created drainage slots down through the seam. I have yet to see any replacement sill panels manufactured that way. On both of those cars I made drainage holes in the sill and in the door bottoms. But I think 6mms is probably too small to overcome surface tension unless you also make a slit and bend the leading edge of the hole down a bit.
GuyW

Hi Guy

Well mine does. I used NOS BMC cills when it was rebuilt in 2009. They are along the bottom edge where the outer cill meets the inner one. There are 3. The are 3/16"dia.
Bob Beaumont

Thanks Bob, quite a bit smaller than l would have expected.
As that flanged joint is turned downwards they would need to be close up against the inner sill edge in order to drain from the lowest point.
GuyW

Wherever you put them, you NEED them.
Mike Howlett

They are in fact roughly in the middle rather than against the joint. Not sure how much effect they have! useful however for injecting the nozzle of a rattle can wax treatment!

That of course is the factory approach nothing to stop you enlarging the diameter or making it h nearer the joint. I introduced additional drainage across the floor pan using the same design adopted for the drainage in the footwells, ie a hole with a cover plate open towards the rear. I installed them behind the rear bulk head and along the floor line under the top hat section. Also drilled drainage at the bottom of the bonnet below the sidelight.
Bob Beaumont

Mine don't. I used genuine British Leyland single-jacking-point inner and outer sills when I restored mine in about 1988.
Simon Wood

I acquired the sills back in 1977! so perhaps the later ones changed??
Bob Beaumont

I suppose if rain never gets into the sill you don't need drain holes. My MGF, which was one of the earliest cars sold, had the drains blocked by cr*p and as I drove along I could hear the water sloshing back and forth inside the sills. When I cleared the holes, pints of rusty water came out. Needless to say the sills developed corrosion holes in true British car fashion. Thankfully I don't own it any more. Shame because it was fun to drive.
Mike Howlett

Only just seen this, Guy. I will look tomorrow, at my one 1960 sill.
I know it has them, because I remember taping the one(s) I wasn't using to spray waxoyl through.
Nick and Cherry Scoop

My original 1963 sills have about 3 holes as Bob describes. I'll have a look and come back later with dimensions if I remember!
John Payne

TBH Guy I can't recall seeing water dripping of the holes I made but whether it was the number of holes or their proximity to each other or something else entirely it stopped the water build up in that area.
Nigel Atkins

Had I guessed, I would have said three holes, but this morning I can only find two. I poked all the way along, but couldn't find another (the sill underside is schutzed black, which matches the gunge I sprayed in, now blocking the holes).

The rear dimension is taken from the bottom edge point AT THE FACE. That part of my sill splays out quite a lot as the face turns inboard.

Sometime soon when I can jack her up, I will check again for a third hole, but it's awkward at the moment because Laura is still rollering white paint onto screens, and she's taking up a lot of room.

(Cherry is covered)


Nick and Cherry Scoop

My replacement shell sills doesn't have them but I'm not surprised. Another job!
Bill Bretherton

Thanks for all that help authorisation and sizes of drains. It was always my intention to drill sill and door drainage holes as I have done with my other cars. What I was wondering about is how drainage was achieved in factory frogeyes. Certainly on some of the later cars this was by narrow slots formed at the flange, between inner and outer sills. I don't think that was very effective, easily blocked and hard to replicate when sills are replaced.

The other drainage /ventilation hole that I add, though I know this wasn't original, is a 5/8" hole between the A post cavity and down into the top of the sill. This obviously can only be done during full repair of that area. Some may recall that Lawrence then decided to take this idea a stage further and inserted a drainage tube from the A post, right down through the sill to exit under the car.
GuyW

On the subject of sills, my outer sills will need replacing shortly and I was just wondering if they can be done with the front wings in situ or if they have to be removed.

Trev
T Mason

If you are replacing the full outer sill, then yes, the front wing needs to come off.

And anyway, with the wing off you may find the footwell side needs some repair also.
GuyW

Thanks Guy, thought that would be the case. Just means trailering it to the welders then.

Trev
T Mason

Trev,
one thing you could peraps do is to unbolt the front wing so that you know all the fixings will undo. Depending on the model I think there are around 10 bolts in all. Then rehang it with perhaps just a couple of bolts to secure it in place. There is also obviously the wiring for lights and the indicator to unplug. But it will then be easy to remove the wing after driving to your welder and you can quickly take it off to view and discuss the work to be done
GuyW

This thread was discussed between 08/11/2018 and 11/11/2018

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