14-03-2022, 09:32 AM
Is it possible that the ignition timing is retarded?
Jim
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What have you done today with your Austin Seven
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14-03-2022, 11:39 AM
(13-03-2022, 10:53 PM)David Stepney Wrote: Steve, Back in the eighties, when I ran my special, that had a Cambridge head, Jack French cam, 'A' series valves and twin SUs, all on a standard 2 bearing bottom end. It would do a genuine 70 mph and I never had a moments trouble from the crank or bearings. It is one of the cars that I regret selling. I have just had a 6 cylinder head stitched and ceramic sealed by Surelock in Oakham. I was recommended there by an acquaintance who has had several Wolseley Hornet 6 cylinder heads dealt with there over 20 years, with great success. The usual disclaimers, but I found Nick Hood to be a pleasure to deal with.
14-03-2022, 12:17 PM
Low compression heads are readily available for very little money. It would be cheaper to have another wedged head machined rather than have a duff one repaired.
14-03-2022, 07:25 PM
Hi All
What a lovely day for a trip out. Spring seems just round the corner. Took the B4358 between Newbridge and Beulah. It was once described to me as a road that is horizontally and vertically challenged. There are three “pitches” on the route two 10% and one 15%. Managed the two 10% ones in top but had to drop down to second for the “Rosser pitch” (as it is known locally) Here is a pic of the car outside Beulah Church, built by the Thomas family who were coal magnates in the late 1800s. Cheers Howard E7BDC4FB-D83F-4FFA-AABC-F5DE7EA0D31E.jpeg (Size: 183.46 KB / Downloads: 273)
14-03-2022, 08:29 PM
hi Howard, great photo, our Ruby is still in the garage, being attacked by my Mig Welder, but will escape soon. S&P
14-03-2022, 08:47 PM
Lovely shot, I had a similar couple of wonderful drives over the weekend but I’m now sorting out stuck valves!
14-03-2022, 10:01 PM
Scanning through the comment history, there is much about hc and lc heads, and a number of individual views. What I do not quite understand is where the wedged head comes into this. The David Dye and other specialist heads all benefit from highly engineered improved gas flow as well as increased compression, and the late Ruby head claims better gas flow. But the wedged head has original combustion chamber shape. David, if our railway station was still open I'd hand a spare wedged head over to the guard. After a long passage through the branch lines of wales it would reach you at Bala station in due course.
Today's technical question. When the horn button unscrews itself and falls off, how does one screw it back on? Are there special tools, or an arcane technique involving blu tac or knitting needles?
15-03-2022, 12:35 AM
The limitation of the early heads is the restricted aperture into the cylinder. From reported performance of stock RNs cf RPs I suspect the raised cr of the latter might actually reduce power at revs. Wedging raises the cr without greatly reducing the passageway.
Apart from being lower cr the early heads lack the violent squish which much hastens burning and hence engine roughness, esp evident with the 2 brg crank and later head. As for original crank life, fatigue is enormously influenced by peak pressure which is roughly prorportional to cr. Under constant test conditons fatigue shows considerable life scatter. With varied loading the randomness is vastly increased, so some cranks survive remarkably. The stack of cracked ones under my bench were destined not to. (Curiously early overload can greatly increase fatigue life. Might not apply to nitrided which have high fatigue resistance anyway)
15-03-2022, 01:17 AM
(14-03-2022, 10:01 PM)Steve kay Wrote: Scanning through the comment history, there is much about hc and lc heads, and a number of individual views. What I do not quite understand is where the wedged head comes into this. The David Dye and other specialist heads all benefit from highly engineered improved gas flow as well as increased compression, and the late Ruby head claims better gas flow. But the wedged head has original combustion chamber shape. David, if our railway station was still open I'd hand a spare wedged head over to the guard. After a long passage through the branch lines of wales it would reach you at Bala station in due course. Most likely it involves unscrewing the clamp at the other end of the steering column to allow the horn push and stator tube to be sufficiently withdrawn to get access to the back of the switch... I may be able to furnish a photo.
15-03-2022, 07:46 AM
Nick, I suspected that might be the answer. A photo would be helpful. Thanks.
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