BRM V16

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
johnny comelately
johnny comelately
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Joined: Thu Apr 09, 2015 11:55 pm
Location: Australia

Re: BRM V16

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gruntguru wrote:
Sun Sep 11, 2022 10:05 pm
saviour stivala wrote:
Thu Sep 08, 2022 8:43 pm
Inlet valve 31.8mm. exhaust valve 37.8mm.
Pretty sure the inlet valve was larger than the exhaust - like most engines.
Just a typo, everything I type has them mandatorily :wink:

saviour stivala
saviour stivala
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Joined: Wed Apr 25, 2018 11:54 am

Re: BRM V16

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gruntguru wrote:
Sun Sep 11, 2022 10:05 pm
saviour stivala wrote:
Thu Sep 08, 2022 8:43 pm
Inlet valve 31.8mm. exhaust valve 37.8mm.
Pretty sure the inlet valve was larger than the exhaust - like most engines.
Yes. it was a typo between inletand exhaust sizes.

Billzilla
Billzilla
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Joined: Tue May 24, 2011 12:28 am

Re: BRM V16

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With those valve and bore diameters, the valve timing must have little-to-no overlap. Looking at the cross-section of the heads in that first video pretty much confirms that I think. Small amounts of lift with one valve seems to largely preclude the other from lifting as well.

johnny comelately
johnny comelately
75
Joined: Thu Apr 09, 2015 11:55 pm
Location: Australia

Re: BRM V16

Post

Billzilla wrote:
Mon Sep 12, 2022 10:13 pm
With those valve and bore diameters, the valve timing must have little-to-no overlap. Looking at the cross-section of the heads in that first video pretty much confirms that I think. Small amounts of lift with one valve seems to largely preclude the other from lifting as well.
Yes, we call that the clip, for obvious reasons

Tommy Cookers
Tommy Cookers
592
Joined: Fri Feb 17, 2012 3:55 pm

Re: BRM V16

Post

Billzilla wrote:
Mon Sep 12, 2022 10:13 pm
With those valve and bore diameters, the valve timing must have little-to-no overlap. Looking at the cross-section of the heads in that first video pretty much confirms that I think. Small amounts of lift with one valve seems to largely preclude the other from lifting as well.
yes ...
neither the exhaust valve period (that I quoted) nor the exhaust system design correspond to large overlap
ie they were normal for the supercharged era

the era started by Mercedes & Fiat c.100 years ago - (the 2 valve large VIA fashion came from NA Fiat design diaspora)
at first boost was at limited to high rpm only
https://motorsportmagazine.com/archive/ ... -1922-1925
(btw the very successful Sunbeam (NA 2 litre) GP car had a 3 speed gearbox (saving length/weight) ...
some earlier famous NA cars ie Peugeots had such large ports and valves they had 5 speed gearboxes)

(imo)
high mechanical supercharging wouldn't develop worthwhile 'tuned length' exhaust effects
then with NA F1 (emulating GP motorcycles) overlap became important and designers chose smaller VIAs