A- / A+ Engine Terminology Question

[NardisCNC]

Hello, I'm a newbie with many questions. In the meantime I've been reading Daniel Stapleton's book "The MG Midget A-H Sprite High-Performance Manual".

My question is this: He keeps referring to either A- or A+ engines. What is the difference?? Did I overlook something. I could not seem to find it in the book. Besides this and other forums are there any other recommended books to read on the subject of Midgets?

 

[JPSmit]

welcome! not sure what you want to read.

if you want to know about originality etc Horler is the standard

https://tinyurl.com/cbrtfh

If you are restoring, you need Haynes

https://tinyurl.com/dlt952

and Bentley (yes, you really want both)

https://tinyurl.com/csd9tk

If you are tuning Vizard is the guru

https://tinyurl.com/c2nlg5

not sure A+ A- but I suspect they are specific runs of the A-series engine

 

[Trevor Jessie]

A+ was a later version of A series. Used in transverse orientation only I believe. I'm guessing it was only in the Metro's and late minis(not imported to the US).

I think Hap rebuilt an A+ engine last fall.

 

[lbc_newbie]

Are they inter-changeable?

 

[Hap Waldrop]

The A+ block is primarly used in FWD tranverse application, and was the latest evolution of the A-series block, is has a more renforced block, and the crank had larger rod journals . You can convert a A+ block for inline use, but it a ton of work, the front and back of the block need a few drilling and tapping for the inline engine plates, then you need the the main caps for a inline 1275, a inline 1275 crnakshaft, a set of A series connecting rods, and of course you have to line bore the block for the new main caps. IMHO it's not worth it, if SCCA racers can explode the normal A series block at 15.0 to 1 at 9000 rpms, thats a pretty good example of how good they are to begin with, and worthy of the wildest street performance builds.

 

[Hap Waldrop]

Besides this and other forums are there any other recommended books to read on the subject of Midgets?

David Vizard's "Tuning The A Series Engine" by far the most in depth book ever wrote on the subject of A series engine, I don't subcribe to everything wrote in the book, but it is best one ever written on the subject.