exhaust port

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Rob Ripley
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exhaust port

Post by Rob Ripley »

Just curious, why are they so different ? Is there an advantage in one or the other ?
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Oyster 49
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Re: exhaust port

Post by Oyster 49 »

Different castings from different foundrys perhaps?
headdownarseup
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Re: exhaust port

Post by headdownarseup »

I wouldn't say they're different as such, possibly not quite as well finished as they could be and on first glance they might seem to be different. As Oyster has mentioned, possibly from different foundry's.

A lot of these 102 blocks look a bit "rougher" than your typical century block, and as far as i can measure the timing appears to be more or less in the same "ball park" apart from the casting flaws giving the illusion they seem slightly different somehow.Other members will have far more accurate ways of measuring timing, but my way is good enough for me to see whereabouts things are.

You're 2 pics are fairly typical of what i've found whilst messing around with 102's of all ages.
I still find it amazing that some of these seagulls manage to run at all what with all the variances in ports being slightly "off" somewhere along the line.
There can't be much wrong with the basic layout of the ports in these 102's or they wouldn't run very well in the first place. Not as sweet as some, but good enough to last for several decades without too much bother.


Jon
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NaughtyBits
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Re: exhaust port

Post by NaughtyBits »

There's quite a few different castings throughout the 102 range (40's, Centuries & Silver Centuries, too).

Quite a range in port timing, too, from cast to cast. You'll also find inconsistencies in machining that push all the timings earlier or later, cylinder to cylinder from the same cast.
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Oyster 49
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Re: exhaust port

Post by Oyster 49 »

So, I suspect you racing boys are always on the look out for a particular block casting then? 8)
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NaughtyBits
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Re: exhaust port

Post by NaughtyBits »

I, uhh... um... well...
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Oyster 49
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Re: exhaust port

Post by Oyster 49 »

:lol: :lol: 8)
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Nudge
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Re: exhaust port

Post by Nudge »

Not at all! :roll:
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