MGB Register Forum

Someone asked me the other day what the compression is like on my B engine. Whilst believing it should be good as it has only done a few hundred miles since a full and thorough rebuild it would be good to actually check. Basic compression testers arent expensive so it would probably make sense to buy one rather than borrow. Would anything that includes a 14mm adapter do the job or does the B engine require a special spark plug thread type that today's units might not cater for ??

Chris,. I have an ancient one which simply has a hard rubber cone to push into the spark plug hole. This has always worked very well for me, needs 2 people of course, but is universal.

Ian F

The Gunson version fits and can be used without an assistant, as it screws into the plug hole.

https://www.ebay.co.uk/itm/362876807629 ... MQQAvD_BwE

John Twist says that if the difference between cylinders is within 10%, all is well.

The B-series engine uses standard 14mm plugs, so any compression tester should be fine. I have the Gunsons one that Tom mentioned.

Thanks for the replies.I'l order one.

Compression testers scare me… I may not want to know what the results tell me!

I have the 14mm colourtune and that fits perfectly.