The Spares Company
Club Shop/Regalia
Parent Website
Contact Officials
Machine Registrar
Club Secretary
Membership Secretaries
MPH Editor and Forum Administrator.
Section Newsletters
Technical Databases
Photos
Home
What's new
Latest activity
Forums
New posts
What's new
New posts
Latest activity
Information
Bike Modifications
Machine Data Services
Manufacturers Manuals
Spare Parts Listings
Technical Diagrams
Whitakerpedia (Vincent Wiki)
The Club
MPH Material Archive
Flogger's Corner
Obituaries
VOC Sections
Local Sections
Local Section Newsletters
Miscellaneous
Club Assets
Club History
Club Rules
Machine Data Services
Meeting Documents
Miscellaneous
Essential Reading
Magazine/Newspaper Articles/Letters
Adverts and Sales Brochures
The Mighty Garage Videos
Bikes For Sale (Spares Company)
Log in
Register
What's new
New posts
Menu
Log in
Register
Install the app
Install
Home
Forums
Forums: Public Access
General Chat (Vincent Related)
I just found a photo...
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="Tom Gaynor" data-source="post: 8646" data-attributes="member: 4034"><p><strong>Four-valve Rudges</strong></p><p></p><p>Answering another query first, the combined petrol / oil tanks were on road bikes. I had one for a while, apparently dated 1932 or 33. Replicas had the oil-tank "wrapped round" the seat tube, similar to a Manx Norton tank. I actually have one of those. </p><p>I haven't time to dig something out now (off on vacation tomorrow), but it's easy to explain how it was done.</p><p>The four valves were placed radially, so that if one pushed rods into the guides, they'd all meet at the same place, near-as-dammit the centre of the hemisphere that was the combustion chamber. Two small valves give a better opening area and better combustion than one big, with less valve-gear inertia, so four valves. (The 500 Rudge I raced was safe to 8000 rpm) The radial disposition gave more space between the valve seats than parallel valves, reducing the risk of cracking between the seats (which is relatively common).</p><p>On each side, the rocker operated by the pushrod had its axis across the bike (so operated fore and aft). There were two other rockers with their axes parallel to the long axis, operating starboard to port, as it were, i.e. at 90 degrees to the first one. The near end of one cross rocker was in contact with one closed valve, the far end of the other with the other. When the pushrod rocker rose at the pushrod end, it pushed down on the next (cross) rocker which opened one valve with the end going down, while the other end rose (see-saw) and raised one end of the last rocker. At the far end of the last rocker was the other valve which was thus opened. It paid to make the remote valve "lead" the near valve by about 0.006" to take up any slack in the train so they opened simultaneously. Everything ran on needle rollers, which require very little lubrication. Assembly however was (was? It still is!) finicky.</p><p>Nothing new under the sun: Rudge made four valves work, but so did Ricardo among others before them. Ducati "are" desmo. But Mercedes Benz perfected it first, in their pre-war GP cars.</p></blockquote><p></p>
[QUOTE="Tom Gaynor, post: 8646, member: 4034"] [b]Four-valve Rudges[/b] Answering another query first, the combined petrol / oil tanks were on road bikes. I had one for a while, apparently dated 1932 or 33. Replicas had the oil-tank "wrapped round" the seat tube, similar to a Manx Norton tank. I actually have one of those. I haven't time to dig something out now (off on vacation tomorrow), but it's easy to explain how it was done. The four valves were placed radially, so that if one pushed rods into the guides, they'd all meet at the same place, near-as-dammit the centre of the hemisphere that was the combustion chamber. Two small valves give a better opening area and better combustion than one big, with less valve-gear inertia, so four valves. (The 500 Rudge I raced was safe to 8000 rpm) The radial disposition gave more space between the valve seats than parallel valves, reducing the risk of cracking between the seats (which is relatively common). On each side, the rocker operated by the pushrod had its axis across the bike (so operated fore and aft). There were two other rockers with their axes parallel to the long axis, operating starboard to port, as it were, i.e. at 90 degrees to the first one. The near end of one cross rocker was in contact with one closed valve, the far end of the other with the other. When the pushrod rocker rose at the pushrod end, it pushed down on the next (cross) rocker which opened one valve with the end going down, while the other end rose (see-saw) and raised one end of the last rocker. At the far end of the last rocker was the other valve which was thus opened. It paid to make the remote valve "lead" the near valve by about 0.006" to take up any slack in the train so they opened simultaneously. Everything ran on needle rollers, which require very little lubrication. Assembly however was (was? It still is!) finicky. Nothing new under the sun: Rudge made four valves work, but so did Ricardo among others before them. Ducati "are" desmo. But Mercedes Benz perfected it first, in their pre-war GP cars. [/QUOTE]
Insert quotes…
Verification
What was Mr Vincent's Christian Name?
Post reply
Home
Forums
Forums: Public Access
General Chat (Vincent Related)
I just found a photo...
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top