Triumph crossflow

[johny]

Look at this lovely Gloria engine - even in 1938 Triumph were using a crossflow design and then later on for our models went back to the older technology, why!!!

[Pete Lewis]

meddlers and button counters had alot to do with the demise of great ideas from the past 

Pete

[Iain T]

I believe the first Bentleys had 4 valves per cylinder. Overhead cams all done in the same era by many including Wolseley. 

The 1930s Dolomite Roadster is a lovely looking car again with the crossflow engine? 

Iain 

[Pete Lewis]

Peugeot did a 16 valve 1.5ltr in the early 1920s   just   1.5ltr and  single cylinder 

from a distant talk on engines by Cosworth  was the optimum is 5 per cyl 3 inlet 2 exhaust   from memory 

there is a ratio of what diameter quantity  is a best fit in the head /bore 

pete

 

[johny]

Cant imagine theres a great difference in production cost cross flow versus non (unless the head casting is a lot more complicated?) but I suppose Triumph as usual used whatever design they already had rather than start anew....

[NonMember]

A cross-flow head will be more complicated to design, and probably to cast, especially for a push-rod engine. And if you really want the best advantage from it, you need the valves not to be in a single line - the TR7 engine has awkward exhaust porting because of the single cam. That makes a "proper" cross-flow, like the Sprint (or the Rover 2600 that was derived from it) quite a lot more expensive to produce. Post-war, when the Triumph SC engine was designed, it was worth it for Jaguar but not really for anyone else.

(I don't know about Bentley but Skoda built engines with four valves per cylinder way back in the 1920s)

[johny]

oh dear, sounds like Triumph went down market after the Gloria days😭

[Wagger]

Ricardo had much to do with the 4 valve head on the 1921 Triumph motorcycle. I forget when the cars and bikes separated into different companies.

[ahebron]

And when you lookup the Gloria Vitesse which like a good Vitesse has a 6 cylinder engine you will see it is a reverse flow engine (non crossflow)

https://en.wikipedia.org/wiki/Reverse-flow_cylinder_head.

I have been working on a DOHC twin carb 1100cc engine from the 1930s which puts out 50hp as standard. Not bad for those times.
It is a big lump of an engine it was designed to be aluminium but due to the accounts dept was cast iron.
Standard it came with a forward exiting head hugging hockey stick exhaust manifold similar to those fitted to the Stag.
There was no reason I can see for this as the engine bay has plenty of room.
It has been swapped out 4 into 1 headers.

[Pete Lewis]

it always amazes me that when it goes bang the gas as any idea where to go 

but it does 

Pete