Raining for the last 4 days so I pick and choose, what to do next! I needed to place most of the crossflow engine parts on the engine to determine where the exhaust manifold will go after I found it not available from the usual vendors. With a starting point of 1-3/8” pipes in mind, local shops mentioned 1-1/2” was the smallest diameter pipe available. Starting with a base 1/4” steel plate I traced out the outline of the exhaust manifold. Finding the oval exhaust ports are approximately
4-1/2 “ diameter the 1-1/2” pipe fits on the Slightly larger side when Formed into a oval so off I went forming something.
So moving along I was reading a new members ,MRN I J , post , and wow what a coincidence , allmost the same design. Let you know after I make the rest of the cuts . A/C compressor should have plenty of room above exhaust.
Dakazman
this bunch of bananas is what replaced the log manifold a year after that picture, it hasn't been used for 25 years, I was fairly disapointed to find that the primary's aren't all the same length, however with reasonably current thinking that different lengths (about 4 ins IIRC) broaden the torque curve.
The flange was matched with the port, however from personal experience with 1950s Aston engines and consulation with our head guy at the time (ex Cosworth dfv), a mismatch is required with the flange being at least 3mm larger than the port but don't enlarge the port, on an Aston making the port the same size as the flange cost us 20 to 30 hp on a 2.922 ltr 1/2 race engine or 4/ 5 hp per pot.
I cut the flange off & fitted the manifold with a larger bore flange.
The manifold & box fitted under the luggage box, the only downside ? was that after switching off the engine the unburnt fuel used to explode 30 seconds to 2 minutes after depending on hard you had driven it.
It caused a few hard looks by the armed police at Birmingham airport, they reached for their machine guns after the bang
