Cylinder Head Nuts

[philthehill]

The crud on top of those pistons does need to be removed. Only remove what is within the dish.
Use a blunt scraper and plus a vacuum cleaner to catch and dispose of the displaced carbon.
That build up of carbon could cause pre-detonation when it gets hot.
Phil

[dalebrignall]

i would leave well alone , only going to risk putting dirt down the bores

[myoldjalopy]

Crikey! Makes you wonder how the old time mechanics ever did a decoke without knackering their customer's cars! And after all, if a tiny bit does go down, its only a bit of carbon, not like tipping iron filings down the bore And if all due precautions are taken, I can't see it going horribly wrong.........

[dalebrignall]

what i might suggest is you put some redex down the carb with the engine running that tends to burn the muck away

[bmcecosse]

Water dribbled in while the hot engine is running (fast idle) burns away any excessive carbon. I suspect the Redex trick was just an idea to sell more Redex. When young and foolish i did it a couple of times - makes a great smokescreen - best done well away from any habitation!

[les]

Anyone remember putting a spoonful of castrol R in their petrol tank?

[philthehill]

Les
I could only afford Tigers

My neighbour runs his K3 on Castrol R and a lovely smell it is too

Phil

[amgrave]

For us uninitiated what is Castrol R

[dalebrignall]

a lovley smelling old engine oil

[bmcecosse]

Castor oil - lovely smell - I had a couple of bottles of it (begged it off a Castrol {hence the origin of the Castrol Brand name} Salesman!) - and yes - I used at as 'upper cylinder lubricant' in my TR7.... Can be found on ebay - not inexpensive unfortunately.

[myoldjalopy]

OK, now while the head is being sorted, I have another problem. There was no drain tap on the engine block, merely a 'plug' of some sort that appears to have been made out of a stud and a nut welded together. It had obviously been put in with lashings of some sealant and, on removing it, I can see why. Its not a taper thread as I had been led to expect and you can push it in a way before it begins to bite. I then got a drain tap, but can't even get it to start to screw in .

If you look at the pic, you will see the threads don't even appear the same......

So not sure what to do about it......I'm not too fussed whether its a tap or a plug in there as long as it does the job properly. I note the recent topic on cylinder block drain tap thread size, but can anyone give me some further advice -where to get something that fits would be good, or can either the plug or the tap be 'made' to fit in some way.[frame][/frame]

Thanks,

Pete

[philthehill]

I suspect that what has been fitted has damaged the internal/female threads.
Whether you fit a blanking plug or tap you will need to get a 1/4" BSP parallel tap to clean up the threads and the drain tap (or blanking plug) will then fit.
http://www.tracytools.com/taps-and-dies ... 19-tpi-bsp

Very quick service from the above - next day if ordered before 15:00 hrs.
I would recommend that you get the intermediate (2nd cut) or plug (3rd tap).

The drain tap and blanking plug threads are parallel threads.

Phil

[myoldjalopy]

Thanks for that link, Phil. I think you are right - today the makeshift 'plug' wouldn't even screw in at all. And the tap thread just starts to bite and then gets stuck or just falls off. So neither will screw in right now! The threads of the 'plug' were pretty crudded up and the thread in the hole looks full of rusty dirt. So, yes, a good clean up I guess. But I don't understand what you mean by "recommend that you get the plug or 3rd tap." What's the third tap?
Cheers,
Pete

[philthehill]

Threading taps are graded by the angle of the taper at the start end.

First cut (No: 1) has a shallow taper along about 2/3rd of its length so as to get a start to cutting the thread.

Second Cut (No: 2) has a less shallow taper reaching about 1/3rd along its length and is used to open up the thread past start.

Third cut/Plug (No: 3) has little or no taper at its start end and is used to get a thread right to the bottom of a blind hole.

I have amended my post above to include a Second cut because if the thread is damaged the second cut will enter the damaged thread much easier.

Do not force the threading tap into the damaged thread feel it in by just useing gentle force forwards and backwards and all will be well.
Smear the threading tap with plenty of grease as the grease will pick up the crap as it is screwed in and when unscrewed the crap comes with it.
Phil

[myoldjalopy]

Ah yes, I understand. Thank you, that is very helpful advice. I can move forward again, although I doubt I can do much this week as there I have a lot of other stuff going on.............

[bmcecosse]

You may end up drilling it next size up - and putting a plug in.

[oliver90owner]

Head studs to manifold to block taps.... threads diverge...

Re taps on blocks - just not needed these days. Taps hark back to the days when cooling systems were drained regularly in the winter (and sometimes the constant refilling with hard water scaled up the system). One advantage was that of filling with hot water for a better start in the mornings, I think. Since antifreeze has become the universal(?) route and engines are not troubled with sludging in the cooling system, nearly all means of draining eventually became a tap on the bottom radiator tank and more recently nothing at all. IIRC, plugs were fitted to the blocks on 1100 cars from around '65. Only need a tap if wanting to retain originality, I would say. And very few were of the type pictured here, on later vehicles - most were of the 'butterfly' type, often used for draining carburettors on TVO burners.

RAB

[bmcecosse]

The opening was completely eliminated in later blocks.

[oliver90owner]

On the subject of Castrol R. Never mix vegetable and mineral oils - you may end up with a thick viscous gunge! Many poor unsuspecting motorcyclists have had seized engines from trying that trick.

RAB

[bmcecosse]

Indeed - it can only be used in a completely fresh/rebuilt engine. But a few teaspoons of UCL doesn't do any harm!