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MG MG Y Type - YT coolant drain on the block

I need guidance here please. My YT is under restoration. Body off, engine still in chassis.
I have removed the welsh plugs on the cylinder water jacket (head is still in place.)
Using a pressure water cleaner in the plug holes, seems to have cleaned out the cylinder jacket. But the block drain is still , well, blocked.
When the cock was removed, it seemed to have a dry powdery "rust" in the bore, but that was easy to tap out. The inner face of the cock wasn't rust stained.
I don't seem to have any communication between the water jacket and the void behind the drain cock.
I have tried bent wire probes, but I don't have any idea just what orientation to use on the probe.
Is it possible the casting is a little odd and the drain never worked?
Additionally, there is a small hole at the back of the water pump chamber on the block. This would allow some flow into the cylinder water jacket for cylinder one just inside the front upper welsh plug. Does this require remediation? It is presently smallish, but I guess it may not stay that way.
regards all
Kevin Mills, Adelaide Aust.
K G Mills

On the IMGYTR site there was photo with core plugs removed and wire and drawing illustration of flow water jacket. I can't find it. Sure this article may helped you.
R E Knight

Thanks for that. Only too pleased to go probing around web sites. It is a reward in itself. A good diagram would certainly help.
But, and please don't snort, neither my browser nor I can find anything called the "IMGYTR site".

My understanding is this... The water flow is pumped along a side gallery and rises up to the head at the rear of the block. From there it flows forward through the head and back to the radiator. The water jacket around the cylinders is fed less directly via ducts down from the head. Circulation in the water jacket is caused by either the pressure drop through the head, or by thermo-siphon effects.
If that is correct, the question I have is just where does the block drain connect to the cylinder water jacket chambers. My "drain" doesn't seem to go anywhere at all, other than into a closed chamber.
Either that is the away it has been made, or the connection is occluded by 60 years of rust, Bar's leak and whatever. If it's the former, do I just leave it as was, or retap a port for the drain cock somewhere else. If the latter, is there some way of clearing the debris away and opening up the connecting passage.
K G Mills

The series of photos that clearly explain the water movement around the XPAG block and head is located on the News Page - and down the left sidebar - it was created by Gene Gillam and is just brilliant work.

Here is the link :-http://www.mg-cars.org.uk/imgytr/pdf/xpagcool.pdf

Maybe another link should go on the Technical Data page or Hints & Tips - I knew it was on the website but could not find it.

Then I used the search function - Bingo !.

Tony
IMGYTR
Down Under Rep
A L SLATTERY

Kevin,
You need to get in there with wire and scrape out the rust and debris and re-open the drain passage.

A good hit with high pressure water blaster from the top will loosen most of it - but when you think you have it all - keep trying as there will be more crud to move !.

Tony

PS - You need to search for the "International MG Y-Type Register". Free to use, free information to all Y-Type owners and enthusiasts !. All contributions welcome...
A L SLATTERY

Thanks to you both. One thing that was worry was the small passage from the pump chamber to the water jacket. Mine is just an irregular split, about 5 mm long and varying width ~ 2-3 mm. Seems it is meant to be there. That's one worry less.
Everything is beautifully explained and illustrated in the web article. I am very appreciative of the time people take to set up things on the web site.
But I still have the problem of a dry block drain. The web article is unfortunately silent on that point.

Clearly my drain tap has been dismantled at some point. (The nail used at the bottom of the tap's plug is not original I fear.) It was really only finger tight in the block as well. I did use a spanner on it, but even while engaging the jaws of the spanner on the tap, it was rotating anyway. Its brass thread is quite bright, as is the thread in the block. It doesn't seem to have ever been in contact with the sludge in the block. The picture shows it as it was when withdrawn. It hasn't been cleaned except to tap out a dry rusty powder in the bore and dust it off with a cloth.
I still have the question in my mind, was it ever connected to the water jacket?

K G Mills

Kevin, I have a couple of blocks in the shed with the drain taps out, so I will try & get an idea on the direction you need to probe to get rid of the scale/rust deposits and get back to you in a few days.

Tony
A L SLATTERY

Hi Tony,
that would be much appreciated.
In meantime, given warmish weather, I'll persevere with the flushing in the next few days. (Or I'll get a rain coat.)
There is a black mess directly between the front lower welch plug and the drain tap location. I couldn't see that outside in the sunlight, but it is easy to see with a torch at night. (Old eyes I fear.)
Very tough stuff but maybe it can be scrapped away with a strong wire. Maybe that's where I need to go.

(Are plugs welsh or welch?)

FYI I don't know the history of this car, except it was sold new here in Adelaide 1950. The motor has most probably been overhauled before. Chrome rocker cover, sump studs in wrong places. Last owner bought it in 79 and did very little mileage and repairs etc after that. Just belts and hoses and the like. It has been shedded since before 2000.

Question - It seems to have polished ports in the head and intake manifold. Was that as it would have come ex factory? Head seems to be original thickness as best I can measure it.
cheers KG
K G Mills

Kevin,

The drain cock will most certainly go to the water jacket, so work on the crud between the welch plug hole & the tap location.

If it's black, it could well be the original casting sand that was never removed at time of manufacture !.

Put a sample in a little bottle for posterity - period casting sand is hard to find these days.....

Cheers

Tony
A L SLATTERY

"Welch" plugs apparently named after the brothers Welch in the early 1900s; I always thought it was from the verb to welch, or withdraw from something previously set in place ... shows how wrong we can be!John.
J P Hall

Thanks John and Tony.

Didn't save the black stuff, sorry.
Wet or dry it was hard and tough. I "drilled" it with a piece of fencing wire in a low speed drill. Sufficient flex to get access. Then found it softened easily with WD40. All gone now hopefully. Water gushes through like the fountains of Rome, though I'll wait for warmer weather before I blast the water jacket out on my next YT.
regards KG
K G Mills

This thread was discussed between 20/09/2015 and 21/09/2015

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