Head oil leak

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Dec 29, 2007
Fired the old girl up today.

Head oil leak

This is the main oil leak that has me worried. In the casting V where the verniers point is a fault in the casting and oil is running out.

Head oil leak

Meant to ask has anyone had this and how they repaired. I have some ideas but as has been pointed out before there is a wealth of knowleged on this site and I will wait before I attack it and do some damage that I will regret.

Head oil leak

The tacho was a bit slow getting of the mark but after a rev or two away she went. The bike runs without the battery connected one kick when warm and with my left foot as yesterday when I kicked and kicked with my right foot I pulled my calf muscle and spent the rest of the day limping around. Pulled the timing cover even though I knew I had it right and on reassembly I found the workshop manual reads yellow/black wire is left side coil and rear points set but on mine it is right side coil and rear points. The wiring harness only fits that way due to the lead lengths. Problem solved. I have only to fix the headlight high/low beam fit the chain guard and register with the RTA and Im on the road.

That oil leak is close to the valve guide so hopefully the damage was from a nick on the outside of the head. It looks that way in the photo but still you have to wonder why it leaks there. Hopefully someone didn't crack the head when fitting new or oversize valve guides.

A weld would always be the best repair but maybe someone has experience with a quality product (in a tube like a locktite liquid alloy) that can withstand the hot/cold expand/contract nature of the cylinder head and still cost less than welding :).

The bike looks great!
I've not repaired my Nortons there but I've had fins welded on one Norton head when I got a bit clumsy in a club race. If it was just a tiny area I'd be tempted to drill a very small hole there and thread it. If you could find a small alloy screw, or steel or brass would work too I suppose, you could inset it with high temp Loctite and trim it off.
With out the Loctite this type of repair was often used for on the job block repair, they would actually install sections where an engine had tossed a rod out. There were tapered screws made for the job and special taps.
Not that long ago I fixed a Mikuni slide guide by drilling it out and making a brass tab. This could be easier as long as you did not go very deep.
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I think you may be right as new valve guides were fitted when the head was serviced. Due to the heat at that location I not sure what would seal and stand up to the heat. Would have to pull the head and clean all the residual oil for what product might stand up to the heat.

Your idea of drilling and tapping a thread was my 1st thought. I will see what I can find to fill the drill and tapped hole. May fit a allen grub screw or some type of aluminium material with similar expansion rate. Will look at the area with a magnifying glass now it has cooled over night. I am sure it is a flaw in the casting but Rennniek has me a bit more worried with his valve guide point. I will sit back and think about the problem till the weekend. I do not realy want to pull the head but if its cracked I wont have much choice.
I'd also guess it came from fitting valve guides a bit tight. I'd try the screw as I don't think I know of any sealer that would last there. All you would need would be about four threads, more is better of course.
I've also seen cracked heads run fine and seal themselves over a period of time so I'd run it after the fix to see what happens.
I know some Triumphs used to crack and guys would run them until they sealed with carbon, not a racing fix, just street stuff.
if you do use a threaded repair,get an alloy crack repair plug from a cylinder head repairer,it's designed to actually seal on the threads.
devcon might work , just rough the surface up a bit to give it some key to stick to, they do diferent varieties for diferent metals
You never know until you try it I guess. I was thinking the heating and cooling might break it loose,
i used it on a dommie head some years ago with no problems , but it was around the inlet ports which is slightly cooler than where scruff would be using it ,could be worth a try,araldite is good also
Thanks for all the advice and links. I like the Lock n Stitch repair Cookie but i hope its not that bad. Smoke was coming out from the right hand muffler just before I turned the engine of. Will remove the right pipe this weekend and let you all know what I find. Hope its not a crack but I think you may be right with the valve guide as the cause of my problem.

if you really think your leaking at that spot, i would throw some baby powder on it just to confirm. read too many posts where the wind blew the oil around and pooled it somewhere away from the source.
Tip of the Iceberg?

First let me say that you have done an excellent job of bringing back this fine example of a Fastback, my favorite model!
If I have read correctly you have a visible, leaking, crack on the right side of your cylinder head. This crack is time coincident with the installation of new valve giudes and, according to your last entry, the right side cylinder is smoking.
Sounds like the crack may be considerably more substantial. If the service that installed your guides is worthy they should be replacing your cylinder head, if it is indeed cracked through.
Just before I sent my head out I spoke with the service and offered to punch out the guides, I have the Norton giude remover. The gent on the other end said, "absoultely NO" !!! He told me that they machine out the old guides, that the heads are vernable to cracking.
Heads don't just crack, they need to be coaxed into this behavior by something (someone) else. I could see a scenario where the guides were slightly oversized and when you went to torque the head the extra stress did in the head. All the indications I see point to the service. I hope this all works out for you.

metal fix?

Gday Scruff
Firstly congrats mate a on a sweet looking Norton, sorry to read about the devastating oil leak. I read in replies possible fixes using Devcon or a Loctite product, no mention of JBweld from the USA. Its an two tube epoxy product claiming to fix all metals ceramics plastics etc etc. What caught my attenttion was its claim to even fix valve seats and guides!!! among others like engine blocks tractor axles torn keyways copper pipes hot and cold,Sounds pretty goood as its other claim is to withstand temps of 600 deg F (315 deg C), twice the rating of other products mentioned. (Araldite is of no value as it looses its strength when warmed up.) Maybe this could be of some help,$15 Ozzie to buy, not too exspensive,pending on what color it dries out to, I guess you could touch it up with heat proof paint? Rgds Joe
Hi Foxy, Thanks for the info on the JBweld it sounds like what I would try before any of the other sugestions. I have used Devcon on a clutch cover years ago and it fell out as it did not expand at the same rate as the cover. I was going to drill where the oil appeared to be coming from, tap and plug as I did not want to remove the head being so close to being back on the road. I slept on it and woke up a few nights in a row thinking about it at about two am and decided to remove the head and do the job right. Could not see any cracks or reason for the leak even removed the valve and tipped petrol into the spring seat , no sign of any in the port from loose valve guide, tipped petrol onto the spot where the oil appeared to be coming from and could see no sign inside the head anywhere of a damp spot. The oil leak spot by rough measurement is a long way from any source, about 25 mm/1" from the pushrod tunnel and about the same from the valve guide. Will refit tomorrow and check again. I hope it was not the small leaks from the rocker shaft end plates that had run down and pooled at that spot, I was sure it was not but by the time the wife pointed to the oil dripping of the head it had been running for a while and was hot so it was hard even wipeing the oil away to clearly see as all the small leaks were runing every where. On the up side if thats all it was I will consider myself lucky and you can never have enough practice playing with the toys can you. Will report back after the head is back on tomorrow.
like i said, baby powder. puff it on there and as the oil runs, it will leave it's trail behind.
Good news, need new glasses. GavinJuice you have confirmed the old saying your never to old to learn. I had never tried baby powder before but I can see that it would help an old half blind person like myself. I did not try your advice as the bike at this stage is still inside the house and I moved it out the front last weekend to have a test run. I was looking and playing with things like the throttle, love that sound, and it was my wife who pointed out the puddle of oil forming on the gound after dripping from the front under side of the head. Used a silicon type gasket under the rocker shaft end covers with the normal gaskets. I normally use permatex aviation gasket sealant, and as I had decided after the advice from the helpfull members here that I would remove the head and check all the above sugestions. Any way the problem is I still have not mastered the multifocal glasses I wear and only after about 12 years, I started with a clean head and permtex on the end caps so there was not small leaks all over the head and only from the crack in the steel pipe into the banjo on the top RH feed to the rockers. I did see the leak there but thought it was the copper washers under the banjo bolt. Run for some time and that is the only leak now, will try and repair as I am trying to keep it as origonal as possible, if not sucessfull I will fit a later flexible pipe. Thanks to everyone who offered help and now back to the heavy clutch only had two goes at it so far.
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