Engine knocking

[Pvoyles]

My 27 Ajax is knocking ,should I rebuild or replace if someone has on avaliable 

[JFranklin]

A knock can be have many causes and doesn't always mean a rebuild is necessary. Locate the problem first and come back for informed advice. I once had a pronounced knock that turned out to be a faulty fan belt!  

[Pvoyles]

thanks,  I am still looking but it seems to be coming from the no. 1 cylinder. It appears someone has rebuilt the head ,it does have a new carb and the gaskets all look newly replaced [ intake,exaust,head].The bottom half is not clean and doesn't appear to have been worked on. I'll continue checking to find it before I decide the best route to take. I thought maybe i can remove the plug and turn the engine by hand and see if there is play in the piston. Will that work? 

[Pvoyles]

I pulled the plugs and found them covered with carbon except no. 5,it was wet with oil. I know a plug can tell you a lot about how the engine runs. I have worked on my own cars since I was a teenager but only once with a flathead, and it was a 46 ford with v8. I do want to keep it original if it is possible.