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Plus I'm always overly nervous about cooling systems having run ancient cars with one eye on the road, and one eye on the temp needle. For the ultimate paranoia run a 1975 Mini when you're 18 with little or no money. Haed gasket central....

and seeing JR's name and the word 'cunning' in the same sentence. ;}

yup I'd be keen on that big bore kit as well!!!

yes.....interested!

The bike equipped with that cylinder, head and carbs was Dyno'd at 55 BHP.

The head joint is a constant worry though. The big bore means the mating surface for the gasket is very narrow, particularly round the coolant passages at the front. Gary Rowe (who raced a big bore on the Isle of Man)talked of getting the head machined to take an O ring but I don't think he ever did. He did have his engine's head surface ground to eliminate any slight warping but still had problems.

The correct 'goo', correctly used, and careful torqueing and re-torqueing with known good studs helps. On the road, it may last for ever, but a few runs up the Ramsey 5000 hill climb made it fail. At least it usually doesn't blow as such but pressurises the cooling system under duress. The coolant then forced in to the expansion bottle is a good reason for having one When cold, you can persuade it back to the right place with a bicycle pump applied to the top of the expansion bottle.

overbomber wrote:

Plus I'm always overly nervous about cooling systems having run ancient cars with one eye on the road, and one eye on the temp needle. For the ultimate paranoia run a 1975 Mini when you're 18 with little or no money. Haed gasket central....

and seeing JR's name and the word 'cunning' in the same sentence. ;}

I used to run a 1426 "S" engine in a Cox GTM and always carried a spare head gasket and torque wrench, I know what you mean, as the proposed Nordie/GFR project fell through I doubt I would ever use the big bore kit, I also have an engine with the top end not assemble plus spar standard top end and TK carbs.
John

Are they in this country John or in the dark continent?