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RP Speeds
#1
The oil pressure topic morphed into a discussion of top speeds. I have mentioned the following previously but readers go and come.  
My standard car managed a rousing 50 mph but this very rapidly fell away. Moving the advance over a large range made little difference except to the noise. A decoke and all was restored for another four thousand miles or so. The car used a lot of oil but was never hopelessly carbonised. Has anyone else noticed this effect? I did not notice it with 37 head or any other make of car. It is hard to figure a cause A complaint years ago was that other cars went worse after a decoke due the lowered cr.

The speedo read somewhat lower than all cars compared so was presumably reasonably accurate. Incidentally few roads are truly flat. I travelled 60 miles north of Wellington most weekends. Most would guess the route as perhaps 40 miles flat, but as sensed by the Seven  only 2 actually were.

Curiously, although hill climbing, acceleration  etc was much improved top sped with 37 head and SU seemed little altered, although with a tail wind it would mange 60 and I was pulled over for this. (I was too surprised to insist on a ticket!) No other car sampled, including employer’s,  ever required the skill or produced adrenalin like the Seven at speed, so I have never been lured by supposed high performance cars!

Many contemporary road tests struggled to much exceed 45 mph. However many would be running SAE50 in cold conditions, and were not bored oversize as most are now with associated cc and cr increase.
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#2
I know what you mean about hills Bob! A Seven has an uncanny knack of finding slopes no-one else notices.

I only once tried a low compression head on my Nippy, borrowed while I did something or other to my high compression Speedex head. It absolutely slaughtered performance and I was pleased to hand it back to the kind donor!

And yes, I've driven a few powerful cars over the years and mostly found them as boring as hell on public roads. Would much rather drive a Seven flat out at legal speeds!
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#3
To get an accurate MPH reading try using a "sat nav",I have found the speedo in my RP is about correct at 30mph.
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#4
I suspect that the speedo in my RP probably reads a bit high. It is afterall from a later car, but whatever. It's probably only doing about 48mph but nevertheless its a challenging speed. 40-45mph real is a good cruise.
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#5
The PA speedo on my 1929 saloon agrees with my TomTom Satnav within about 1mph until above 50mph where it's about 3mph fast.
I use the satnav most of the time as it's much more visible then the speedo.
Jim
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#6
I don’t think I have ever de-coked a head once rebuilt, is this something that others routinely do these days?
Whatever you do, don't take my word for it!

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#7
(11-07-2018, 11:37 AM)Ruairidh Dunford Wrote: I don’t think I have ever de-coked a head once rebuilt, is this something that others routinely do these days?

Not me. I'll clean a head up if I have to remove it for some reason but that's it. 

Steve
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#8
I think the fuels and oils available these days are an awful lot cleaner than in years past making de-coking a bit redundant.
Stephen
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#9
(11-07-2018, 11:37 AM)Ruairidh Dunford Wrote: I don’t think I have ever de-coked a head once rebuilt, is this something that others routinely do these days?

De what?
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#10
Back in the day I routinely scraped off a thick deposit from head and piston crowns, with an assortment of not-too-sharp knives, wire brushes and what-have-you. Couldn't tell you when I last did it though.

I also used to set my ignition timing by taking the car up the cliffside at Stoke Fleming and backing off bit by bit till she stopped pinking. Nowadays I have no idea when it is right!
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