What’re you talking about in the CDB world? We’ve a packed letters page this time.
I thoroughly enjoyed issue 48 and your piece on the 3TA engine/bike project. I’ve spent most of my working life in the auto and motorcycle business, so have amassed a reasonable amount of skills, tricks of the trade and spent time showing other apprentices how to do it.
Please don’t reuse those valve springs, they may look alright and clean up lovely with your cleaning techniques but they are old and most probably getting to the brittle stage; the cost of new items and the peace of mind that you won’t drop a valve on your first fistful of revs will far outweigh the uncertainty.
Your valve compressor: neat as it is, is a real tiddler compared to the chunky equipment used in the trade. Maybe a piece of steel bar welded or sif bronze welded to the outside long edge? This should prevent bending in future. When the spring compressor is in tension a sharp tap with a small ball peen hammer on the tool at the top of the frame should see the collet let go. Do you need a 3TA or any Triumph head for bits of fin? There might be suitable finning to be had from many a scrap cylinder head, most fins usually being very close in thickness. If it’s thicker then a dressing down with a suitable abrasive wheel is needed before your magician ally welder gets working.
You may have a spare Bultaco head that could be the donor. Otherwise a piece of aluminium plate from a metal suppliers could be the answer, compatibility with the alloy of the cylinder head and aluminium plate might be a sticking point but it’s worth a try. The metal supplier may be able to offer you advice on this.
There will be some that say your original valve springs will be perfectly alright, but as so much of your engine is unknown and the thought of a valve hitting piston and the potential destruction, I’d go with other collets due to the rust.
Tony, a thought occurs as I read through your letter, surely someone out there will know what spec aluminium Triumph used for casting cylinder heads? Oh, thanks for the tip on the valve springs, I’ve ordered new ones. Since the feature was written I remembered where I got the spring compressor, it came from Norton Commando spares specialist RGM when they were in Gateshead. Tim
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