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MG TD TF 1500 - Funny core plugs

When I pulled the engine out yesterday I noticed a strange black mark on most of the core plugs. These are brass Core plugs that I had the machine shop install. My first thought was that they were leaking but I have well over 1000 miles on the car since the plugs were put in and it seems that a leak would be more profuse. Also, why are they black?
Any observations would be most welcome.
Mort

Mort 50 TD

Permatex aviation sealant? It is really gummy. Just a guess.
George Butz

Maybe it's a sealant that has started to seep. It looks like the block was painted after the plugs were installed.
Don TF 4887 "Figaro' TC 1736 "Sibelius'
Don Walker

Look like sealant to me.
Steve Simmons

Mort,
One of the"brass" plugs looks like it has rust on it ! I agree that the black is some sort of sealer. Don't know why they would use it.
What are you doing to the motor?
Are you two going to the GOF in Nova Scotia ?

Steve
Steve Wincze

Steve,
Last winter I had a machine shop do some work on the engine.
Overbored to 60+.
Billet crank.
Forged pistons.
Machined the rear scroll area to .001" clearance.
New valves, guides and rocker shaft.
It already has Len's roller lifters and cam.
Light weight flywheel.
Routed the breather pipe to the carburetor intake via a PCV valve.
Overall the car is running great. At 87 mph there was not a vibration or shake and it was cruising at about 4200 RPM. The car seemed capable of a lot more but my stomach wasn't.
However the front seal, the machine shop put it in was leaking, so I have pulled the engine and I will replace the seal. I did it five years ago and there was never a drop of oil from the seal.

Unfortunately Fredda and I will miss the GOF in Nova Scotia. We will also miss your show in June. We have a one month trip planned for Eastern Europe. We will be bicycling around the Budapest area for two weeks and then a two-week river cruise up the Danube.
Mort
Mort 50 TD

Interesting set-up but I am wondering if the PCV is doing anything connected to the carb intake. Normally, say on an MGB, it would go to the intake manifold or to the carbs inside the butterfly valve (more vacuum in either case). I only mention it because I am considering doing just that.
Dave H
Dave Hill

Dave,

Perhaps I was too brief in my description of the PCV valve. It is indeed after the butterfly. As you can see from the picture there is a port in the front plate of my supercharger where the carburetor bolts on.

My side cover is from a Wolseley. All of the dimensions are the same except, as you can see, the output is through a swivel cap that has a short piece of exit pipe. I just turned it in the direction I required.

The PCV valve is at the top of that first large rubber tubing and just before that little oil scrubber I made up. This scrubber seems to be either ineffective or unnecessary since I have accumulated just a few drops of oil in over 1000 miles. I am sure there is a quantity of oil that accumulates on the inside walls of the tubing and drips back down.

One thing is for sure I am not blowing hot oil splatter on the undercarriage of my TD.

Making is set outlook respectable is low on my priority list right now.

Hope this is helpful.

Mort

Mort 50 TD

Yes, its very helpful thanks. Its an advantage having only one carb to contend with. Some further questions if I may. I see its not an MGB type PCV valve, which would probably have been my first choice, but what is it from? Also, did you find a need to fit a restrictor in the pipe? Vented oil filler cap? As I have twin carbs I have been weighing up the pros and cons of either drilling a hole in the centre of the inlet manifold, tapping it at both ends and using a Y tube, or even drilling the insulating spacers behind the carbs and connecting to those with a Y tube. The last of these seems the closest to your set up and is more reversible.
Dave H
Dave Hill

Dave,
The machine shop put the PCV valve in so I have no information on its specifications.

No restrictor for my set up.

As you can see from the angle of this picture, there is no vent hole in my oil filler cap and the valve cover breather has been capped. I want to induce as much vacuum as I can, in the crankcase, to keep the pressure down and avoid oil leaks through gaskets and seals.

Mort

Mort 50 TD

Many thanks.
Dave H
Dave Hill

Did anyone note the special core plug that can be fitted with a spanner rather than a hammer in a recent Octagon Bulletin. If the rear core plug fails this would be much easier to fit than removing the engine.

Jan T
J Targosz

Jan. When I lost a core plug in my xpag I looked for a bolt in replacement, but had no luck whatsoever finding any in the UK. Those with a large squashy rubber seal seem, in any case, to be just a temporary fix. For the rear core plug, perhaps useful to have, but not for those under the exhaust manifold. The best solution seems to be to make a metal one - various designs around, some with an O ring seal and some without.
Dave H
Dave Hill

This thread was discussed between 11/12/2016 and 15/12/2016

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