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MG TD TF 1500 - Need some engine help?

Good morning all. I am helping a friend replace the core plugs in his 1952 TDC. Since the old core plugs are removed I showed him Horst Schach restoration manual and suggested he drill the hole in the front water passage as shown on page 94 and 95. Rather than wait for me and in his exuberance he drilled the upper front hole, which seems to be in the front cylinder liner/bore. The question is what’s the fix. I don’t think J-B weld to fill the hole is going to take care of the problem as; 1-it won’t seal the hole and will let water into the oil. 2- The cylinder will be rough and ragged and tear up the rings as they pass. I believe the engine needs to be pulled and sent to a shop that can re-line the front bore and the hole welded by someone capable of welding cast iron. Any ideas for the fix for a MG 1250 engine with a hole drilled through the #-1 cylinder bore? Suggestions/recommendations for the welding shop/ machine to do the work would be greatly appreciated. Thanks in advance, John H





John Hambleton

Hi John

I guess you can not do it without the help of a machine shop. The solution may be drilling and inserting a sleeve. Wait for the specialists.
Bela

Ouch, major mistake. Are you positive that is where it ended up?? I would think have to sleeve that cylinder. May as well do total rebuild at that point, etc. George
George Butz

Agreed, strip the engine and take it to a machinist who can install a sleeve. Then buy him one of those motivational posters about patience. ;)
Steve Simmons

John - That fall in the category of No good deed will go unpunished :( Cheers - Dave
DW DuBois

that really sucks, I was worried about doing the same thing and reread the threads multiple times before attempting it. I would think that the engine must be pulled and a new sleeve inserted, but you could probably just fill the block hole with JB weld..?
Geoffrey M Baker

John,
As George asked,,, Are you sure the hole is into the cylinder ????? Did you take the the head off??

Steve
Steve Wincze

A hole drilled in the upper front core opening is high up in the cylinder, where the rings would pass.

It would probably make it a while on JB weld. Now just imagine driving down the road, the epoxy plug disintegrates and water squirts into the cylinder on an intake stroke. Water doesn't compress and the engine would likely "hydraulic".... as the piston can't compress water, it immediately and instantaneouly stops, with dire consequences.

As a welding engineer that does a good deal of machining, my recommendation is forget the idea of welding. When the oldtimers weld repaired engine blocks, they soaked them in a furnace and repaired them red hot. I don't go that extreme. You can plug that hole with a weld, but trying to achieve a smooth bore would be a serious challenge, even with boring and honing. The cast iron cylinder and the weld metal would be dissimilar enough where they won't machine the same. The weld would likely need dressing down by hand very carefully- very slowly and very carefully.

If someone were VERY competent with an oxyacetylene torch, that hole could be brazed, from the backside of the cylinder in the water jacket and then brazed flush+ inside the bore. The brass could be smoothed down with a flapper wheel or abrasive polishing wheel, and then honed smooth.

The safest approach is sleeving.

By the way, I wouldn't bother with drilling that extra hole. Most figure it was put there for cooling, which isn't very logical. I believe it was there to drain the channel when the block gets drained, otherwise, it would freeze and break as the channel will not empty without a hole.
JRN JIM

Would it be practical to drill and thread tap the hole and inset a threaded plug, expansion and contraction of the block may make this nonviable.Dressing up the bore and a hone may then be possible. Someone will rule on this solution.
G Evans

A threaded plug doesn't give me a warm, fuzzy feeling. I'm not an expert in this area, but I feel that a sleeve is the only reliable and permanent fix.
Steve Simmons

This thread was discussed between 15/03/2016 and 17/03/2016

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