A7 WATERWORKS
A DA7C TECHNICAL FORUM REPORT
What goes in?
Most use tap water but better to use soft water such as rainwater.
Antifreeze—Use glycol ethylene (old fashioned Bluecol) not Halfords. Only use blue colour. See FBHVC advice in Newsletter or on their website (www.fbhvc.co.uk). Leave antifreeze in all year to avoid corrosion. Use 25% mixture of antifreeze. (2½ pints or 1.4 litres)
Special “run cool” coolant is available – but expensive.
What level?
Looking in tank, fill to ½ inch above top of core
An expansion tank can be useful for long journeys.
What to use for leaks?
Barrs Leaks, New Super Radweld, K-Seal is good – developed for K series engines
Watch mounting on Ruby – leave bottom nuts off
New cores can be narrow resulting in a gap at the front with rad shell.
No rad muffs in use – can use tin foil but might forget!
Oil leaks from head gasket can sludge up rad.
Often blocked because old.
Caustic soda can flush out – cheapest is patio cleaner—but take care!
Drain tap blockages - poke with wire.
Beware fretting between neck and rad shell top—protect with webbing ring.
Take care not to fill with cold water when engine is hot.
Pressure testing useful (max 15psi?)
Repairs and renewals
Ferns on Woolsbridge Estate at Three Cross offer options.
Bryan & Son of Tunbridge Wells advertise in A7CA mag.
Wessex Rads of Bursledon used by members
Vintage Rads will do any pattern at a price.
Fan Blade
Bobbie says “always carry a spare”!
Make sure you have the right one – mag engine is opposite pitch to coil – blows outwards in a coil engine – check with paper on rad.
Incorrect fitting can put blade off centre – ensure grease nipple on exhaust side of engine
Use 4 bladed fan for hot climate touring – it might fly!
Fan Belt
Bobbie says “ always carry a spare”!
Not too tight.
Hard green ones wear out pulleys.
Leather goes one way only.
Mounting & Pulleys
Beware over-tightening pulley nut - might split taper.
Taper wears.
If belt keeps riding off, may need a new bottom pulley.
Fan pulley removal – loosen nut & tap on side of hole. Use hot air gun?
Ensure all mounting bolts tight especially on mag mounting – need to ensure blade does not fly off into rad!
Use thread locker preparation
Chummy needs new dog and pulley – use ¼ inch roll pin to lock to dog.
Check top pulley bush for wear/noise.
Lubricate but not too much!
Beware stiff top hose can damage rad/top water inlet.
Bottom hose can kink under dynamo (can find bent hose to use at Autojumbles)
Silicon hoses are good but non original—Samco classic range in black from Merlin Motorsport.
Can use stainless steel internal spring to stop hose collapsing.
Ease hose on with washing up liquid.
Use wide clips to stop cutting in.
Inlets
Can corrode badly – electrolytic? – dissimilar metals create cell
Modern rubbery gaskets slip – old cork ones better –use silicone (Loctite 5910) and let go off before fitting
Use stainless studs with brass nuts
Willy McKenzie does stainless reclaim kit for when block webs are corroded away.
Dome nuts can stop water going up thread.
Always carry spares.
Use large flat punch just under plug diameter size.
Some bulkheads have bulkhead access hole for block plug - doubles as heater inlet!!
Use Loctite 5910 or Red Hermetite to bed into recess.
With many thanks for Phil conducting the lively debate and for writing up the results of our joint deliberations. These will appear on our club website.