[Mgs] Fw: MGB Question

David Councill dcouncill at karamursel.org
Wed Jan 11 09:32:38 MST 2017

To add to these replies, which I agree with, it does depend on how you want to use the car. I faced a similar scenario with my 72B’s rebuild about ten years ago. Although it is an 18V engine block, I went with HC +0.060 pistons that I acquired from the UK (ebay dealer mechspec who also has an Internet site). This put the compression ratio around 9:1. I also used a 270 cam. I did not modify the head except to have hardened seats installed. I was looking for increased performance while maintaining the car as a driver. I was hesitant to increase the compression ratio too much as that would make it harder to find fuel for it, particularly in rural areas. This was based on previous experience – with my first MGB, a 1965 B, I installed an engine with a 10:1 compression (as I recall but it could have been higher, this was several decades ago). It was a fast car but back then, when leaded fuel was still available, I sometimes had problems finding a high enough octane fuel and in those cases, the car would keep running after I turned the ignition off. I don’t recall the octane back then but where I live now, the highest octane rating I can find locally (within a 30 mile or so radius) is 93 at two stations, 91-92 is typical for the rest.


David Councill

67 BGT

64 B

72 B


From: Mgs [mailto:mgs-bounces at autox.team.net] On Behalf Of Richard Lindsay via Mgs
Sent: Wednesday, January 11, 2017 8:03 AM
To: Jack Wheeler
Cc: mgs at autox.team.net List
Subject: Re: [Mgs] Fw: MGB Question


Hi Jack, et al.,


Thought I would chime in, philosophically. 


Just please remember that any engine design is a tradeoff between power, reliability, and cleanliness. Add to that known adage, 'drivability'. Old engines have fixed cam timing. That means the valve timing is set to the give optimum drivability - so maximum top end performance is not achieved. But if you tune for 5000rpm, the car is beast to drive at lower speeds.


Okay, I've said what everyone else has said, perhaps except for this: What is YOUR goal? Decide upon that then build accordingly, and accept the limitations associated with that solution.



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