I just checked the price of compression testers over here in the UK. Cheapest was about £14 up to £30 ish. Google compression testers and you will probably find a local supplier, otherwise I expect you could get one sent from the UK. Have you checked that with the plugs out the engine is easy to turn over? Just wondering if a valve is hitting a piston or something is hitting inside either the tappet inspection caps or the valve spring caps.