Bristol 410 engine sump removal

[Thor]

Just to confirm, the 407s to 410s all had the early engine. When launched it was called the 'A' series engine, but when the later 318 was introduced that was also called 'A', so somewhat confusing. The general term for these engines is 'Polysphere' or even just 'Poly'. I think that the crankshafts are more or less identical to later 318s but all else is different. Camshafts are not interchangeable. The later engines are a bit lighter, but many people have a high regard for the early engine, it makes good power for its size and the period.

407s and 408s have an earlier iron-cased version of the Torque-flite transmission, where 409s and 410s have the aluminium case.

I'm not so sure about this next comment but I think some 407s and possibly 408s had 313 cu.in. engines, earlier types than the 318. They look the same but have slightly smaller bore (?).

[Kevin H]

Originally Posted by Thor

Just to confirm, the 407s to 410s all had the early engine. When launched it was called the 'A' series engine, but when the later 318 was introduced that was also called 'A', so somewhat confusing. The general term for these engines is 'Polysphere' or even just 'Poly'.

Just to clarify, the later 318 was officially called an 'LA' series engine, but for some strange reason no one ever mentions the 'L'. This 318 engine was first made in 1967. It was used by Bristol in the 603E. The 360 engine used in the 603S and later Bristol models was also an LA engine.

As stated by Thor, the earlier 'A' series engines were know as 'polysphere' engines, this was because they have polyspherical combustion chambers. If you use the term 313 or 318 'Poly' when talking about engines in the Bristol 407-410, everyone in the Mopar world will know what you are talking about. Unfortunately, any reference to the 'A' engine will be taken to mean the LA engine.

I'm not so sure about this next comment but I think some 407s and possibly 408s had 313 cu.in. engines, earlier types than the 318. They look the same but have slightly smaller bore (?).

Correct. The 313 poly was used in the 407 and 408 up to chassis 7200.
The lighter transmission and 318 (poly) engine were fitted to the 408 Mk2 from or after chassis 7200.

Hopefully I haven't just added to the confusion!