I just put ‘7/16 BSF bolts’ in Google, they are widely available online.

Tony

If it’s 7/16 BSF must be a P Series, and pretty old?

If they are Big End bolts, be careful, they need to be good quality; or else the engine could shed a rod, and be terminal!

Howard

On 16 June 2024 at 17:17 John Hinkley Said:

How do you get from a boat repair in Sardinia to the big-end bolts for a P-type MG?

John

 

I wouldn’t dare to speak for Howard … but I suspect he was thinking of the Perkins P

… as per Tony Martyr’s second post.

https://en.wikipedia.org/wiki/List_of_Perkins_engines

MichaelG.

BSF bolts/nuts are available from LAS Aerospace ltd if high tensile strength types are needed.

CS

The P6 used the less efficient “Aeroflow” combustion system. Which was effectively indirect injection, and having a larger surface to volume ratio made cold starting more difficult.

Having moved on from a 1930s combustion system, the 1960s 6.354 was a direct injection engine, which made it a better cold starter, and more fuel efficient.

Also, the P series were vacuum governed, so that on part throttoe, the compression ratio was effectively lower, making for a softer combustion note. The D I engines are almist always mechanically, or hydraulicall governed, so that the induction is not throttled to utilise as high a compression ratio as possible.

But DIs tend to have greater rates of cylinder pressure rise, which makes the “knock” (caused by combustion delay) more apparent.

Some IDIs having higher compression ratios (20+:1), to improve cold starting and fuel efficiency, tend to be even noisier!

Modern low emission engines, tend to have later injection timing which reduces the rate of pressure rise, aided by the need for lower compression ratios to limit cylinder pressures when turbocharged. Sometimes the turbocharger is there to provide a “blow down” during valve overlap, if only to dilute the exhaust gases, so showing lower gaseous emissions.

Howard