Hitchcocks Forum

Hi. Just bought a 1966 RE Continental GT 250. Previously was a Triumph man, so I’m totally new to things RE.

It has a very bad oil leak around the pushrod tunnel joint with the cylinder head. The head gasket seems good as there is no problem with compression.

The head is the later type with the 2 allen screws adjacent to the tunnel, and a previous owner has followed what I believe to be the recommended practice of replacing the countersunk screws with cap heads. However the screw holes in the head have not been spot faced so the screw heads are fretting the head around the screw holes.

I have discovered that both screws could be unfastened quite easily. I could just try tightening the screws but I’m not sure that is the complete answer. Hence my (possibly novice) questions:

Firstly, I have a faint suspicion that the allen screws may be bottoming out the thread holes in the barrel. To fix that would it be acceptable to put some washers under the heads of the allen screws? I know this would not be ideal but it would also help stop the screws fretting the head.

Secondly, the pillar in the head where the screws go through does not seem to be very substantial to me. I’m concerned about fracturing the head at this point. I know that you cannot apply very much torque using a stock allen key as it springs, but a long reach allen socket could apply a lot more torque. But is that really advisable?

Thirdly, I don’t know if the head gasket is copper or composite. But if I have to replace the gasket is it better to use composite or copper? Also although I’m not a fan of using sealant on a cylinder head joint would something like Wellseal be advisable in this case bearing in mind the situation with the oil leak?

Sorry that my first post is so long!!

Promise I'm not laughing. I can't really offer any advice, being a bit of a 'newby' myself, but don't worry. I'm sure the resident experts will chime in with loads of help. They're a good bunch here. Welcome aboard and good luck with this...

Not enough Araldite/Silicone used on assembly?


(Bad taste jest) Ultimately you will have to strip and inspect, all else is speculative. Simply 'over tightening' nuts - screws may effect a cure? But is never the real answer.


Besides, it gives you a chance to check Guides, Valves, and Seats etc...

This cylinder head joint is notoriously difficult to seal but it can be done. Copper gasket is better than compo in my opinion. Anneal properly (of course,) then use silicone, not Welseal or Hylomar on either side.. Get holes spot faced or, better idea, make some countersunk washers for Allen screws. Tighten Allen screws first (use your judgement, no torque setting suggested,) on assembly then diagonal normal tighten pattern to 22-23 ft/lbs. There is a Yahoo News Group just for the 250 and 350 unit models at [email protected] so come and join in.

REgards, Mark

Way back when a Crusader Sports was my first bike I had this issue, the "cure" was Instant Gasket, the orange stuff. I'm sure there are better ways and kit today but as a 17 year old with limited gear and knowledge (anything changed?) I found this to work. I would caution against using too much - just enough to see it squidge out once assembled, since the lad I sold it to seized it and the bloke fixing it said he found "bit of the *^%$#$U*&* stuff" all around the motor where it shouldn't be.

I've had success with a composite gasket and a smear of Wellseal.
A top end overhaul is in order here and make sure you prepare the mating surfaces properly by lapping (wet and dry stuck to a sheet of MDF will do) You won't get a seal is there are scratches on the surfaces.