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MG TD TF 1500 - Hot tanking your block tip and a question...

I brought my block home from the machinist yesterday to do a couple of small jobs (see "cooling system perplexities" thread on adding a small hole for cooling in one of the core plugs, and see "cooling system bottleneck" on enlarging the water entrance/exit points in the block for better cooling). I think they did a great job "magnafluxing" it, it looks like new on the outside and very clean on the inside.
That is, until for the heck of it, I started fishing in the water drain tap outlet hole. While as far as I could see all passages were squeaky clean (magnafluxing had even cleaned out the 3/16 hole in the rear core plug referred to in "cooling system perplexities", which is often completely hidden under scale and rust), in this one area it was filled with gunk! I took out about half a small baggie of dirt to show to my machinist!
So, I suggest when cleaning you pay particular attention to the drain hole, the passage there is virtually "blind" in that access is not easy and thus it may tend to fill up faster with accumulated crud than other areas.
However, the particular nature of this crud has me a little concerned... it was viscous and somewhat oily. While I was able to get a bit of dirt out of the long water passage between the core plugs, that dirt was dry and rusty; the dirt in the drain area was quite different and oily.
Should I be concerned about this? Firstly, we think we know the block is good and not cracked, by visual inspection. Secondly, we're rebuilding the head and replacing piston rings so any oil to water mixing that might have occurred in the past, through the head gasket over time, should be solved. (The head had the wrong gasket on it, by the way, the round hole gasket, not the banana gasket).

Anything else I should check to make sure oil and water aren't going to mix?

In the meantime, they will be magnafluxing the block again and paying particular attention to the water drain tap hole....
Geoffrey M Baker

Hi Geoffrey,

The magnafluxing process is used to check castings for cracks and so forth - this is distinct from the cleaning process. Just wanted to clarify that - based on your statements above, it seems you have those confused.

Sounds like you are doing a great job on preparing your engine - good luck with the rebuild.
DLD

Geoff,
Magnafluxing is not a cleaning, it is a method to show if there are any cracks in the head or in your case, the block,, If your engine guy has told you the it will clean it, I think you should find another engine guy.
MHO
Steve
Steve Wincze

Thanks, I just thought magnafluxing was a baking/cleaning process, thanks for clearing that up.
Steve, no that is my use of the word, he never used it. I've always just thought it was a term to describe the cleaning process, my error - not my machinist's!
So I learned something new this am!
Geoffrey M Baker

Thanks, I just thought magnafluxing was a baking/cleaning process, thanks for clearing that up.
Geoffrey M Baker

From Google:

"Magnafluxing is an advanced procedure that uses strong magnetic fields to test the structural integrity of metals, especially iron and iron-based alloys. The procedure can determine even microscopic flaws in the surface structure of metals, and so is used to check the quality of a variety of metal parts, pieces and tools."

Youtube also has videos of the process.

I cleaned my cooling system during resto with a cleaning product from Napa and a garden hose. All kinds of crap came out. Engine was out of the car at the time so was easy to do. Runs cool, no leaks.

Ed
efh Haskell

Please, before we spin endlessly off-topic discussing my misuse of the word "magnaflux" - for which I sincerely apologize - could we actually look at the question I am asking about the oily nature of the crud I found? :)
Geoffrey M Baker

I just realized how cranky I sounded just there ... need more coffee this a.m. Thanks Ed, Steve, DLD, for the explanations, which now make it clearer to me what the term actually means. Sorry, didn't mean to be rude. I still am worried about the oily crud in the drain passage, though.
Geoffrey M Baker

Geof,
The block I'm working on now was caked with gunk in the water passages. The machine shop cleaned & baked the block so well, the old Moss paint turned orange. The crap is so tenacious within all the nooks and crannies, there was probably 1% that didn't come out.

I've planned to pressure wash those passages to remove more before reassembly, especially since I've done some grinding on the block. That should get it down to 99.9% clean. I have a commercial steam cleaner that would get it down to 99.99% but it isn't worth the effort.

Before the rebuild, your engine ran merrily with all that crud with no serious consequences. Anything is an improvement. Any remnants of oil will, in time, float to the top of the radiator. If you're worried about it, occassionally overfill the radiator to float out residual oil.

I certified with the American Society for Nondestructive Testing Level III in magnetic particle testing and have to question why go to the trouble of magnetic particle testing in the first place, let alone the second place. Sounds like a bit of overkill.
JRN JIM

ArGGGGG! :) JRN, I have been mistakenly using the term "magnafluxing" just thinking it meant the normal cleaning and baking process machine shops use to clean the parts. So it has not so far as I know been magnafluxed once or twice, but never sorry, that's my error.
Geoffrey M Baker

I just spoke to my machinist and he confirms what you all knew but I didn't, the nature of "magnafluxing". Good news, he not only cleaned it but he did magnaflux it and found no cracks in the process.
He'll be cleaning it again today...
Live and learn!
Geoffrey M Baker

To return to my initial question; the fact that there was an oily gunk build up in the drain passage but it was drier in other passages... does this indicate anything, or just the fact that the stuff "pooled" in this area where the water probably never hardly moved (as I doubt that drain was ever open in 35+ years)...?
Geoffrey M Baker

Hi Geoffrey - back to your question about the drain passage, I would not worry about the type of build up in your drain passage - I would just clean it out as you intend. The build up can take various forms - it has been 60 plus years! Sounds as if you will have a nice clean block when you are done.
DLD

Thanks all... here's something to amuse you.
While thinking about my misuse of the word "magnaflux" it occurred to me that hey, that's not too bad, I'm sure there are other words that I use incorrectly, and that let me to think (here I am randomly wandering) what the size of my actual vocabulary is (I like to think, above average) and that let me to type into bing search "What is the average size of an American vocabulary?" and by the time I got to type the words "What is the average size" bing kindly filled in the rest with the question it obviously most frequently gets asked, which, of course were ... "What is the average size of the male .... (words left off here).
Made me laugh pretty hard, guys :)
Geoffrey M Baker

Geoffrey - "... by the time I got to type the words "What is the average size" bing kindly filled in the rest with the question it obviously most frequently gets asked, which, of course were ... "What is the average size of the male ....
Just goes to show that the ubiquitous computer is not as smart as it is cracked up to be :-))

As for the oily residue in the block drain area, it could be some antifreeze residue. Antifreeze has a viscous substance in it that always feels like some king of oil when it get on your hands.

By the way, did you ever determine what the average size of the male vocabulary is? Cheers - Dave
D W DuBois

After I stopped laughing I found it was 60,000 words.
Geoffrey M Baker

Kinda funny Geoff that the average male vocabulary is 60,000 words when I believe the average male appendage is 6 inches.
Lol I wonder if your vocabulary increases with size?
Rich (TD 3983) Taylor

60.000 words vocabulary for a male person??
I know people who probably have not SPOKEN that many words yet ;-)

Rgds Mike
Mike Fritsch

That's for the average American, not the average male, Mike. Which I guess means the average American woman has a vocabulary of 119,998, and the average American male has a vocabularly of "Yes, dear"... :)
Geoffrey M Baker

Considering there a half million words in the english dictionary, we're all categorically illiterate.
JRN JIM

Geoff, the gunk is normal. Nothing to worry about. Do a thorough high pressure flush and reverse flush before final filling, just to be sure anything that can clog the radiator is out. But no matter how well you clean it, there will still be some junk floating around the system. Just the nature of old cars.
Steve Simmons

If you have a tank large enough hot caustic soda will clean an engine block really well. It will strip all paint and oil slime and sludge with ease. It is vicious stuff though and gauntlets and a face shield are essential. Make certain there are no aluminium bits though, caustic eats it for breakfast.


Jan T
J Targosz

This thread was discussed between 17/04/2015 and 18/04/2015

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