Source and Size of ERG Block Plug

by Chuck Hobbs

My ERG valve was very rusty, I did not think it worked. It had already been disconnected from the intake manifold (which was plugged). The ERG valves are no longer supplied by TRF, so I decided to remove mine from the engine block and plug the hole in the upper block. It took me a little while to find an appropriate plug. The engine block hole size is 3/4" diameter and it looks like a pipe thread will work, but that is not correct (pitch is 16 for pipe thread) as the thread is actually a 14. I went to Home Depot and found that for plumbing pipe they use a finer thread (pitch is 14) for pipe compression fittings. So the correct plug to buy is a nice brass Watts A-259 (39-P) Flare Plug (PN:48643074590) at a cost of less than $3.00. As I did not have to find a plug for my intake manifold, I do not know what plug to buy, but it appears to be a 1/2" size rather than the 3/4" of the ERG valve and is also probably a compression fitting (size 4) rather than the standard pipe (size 16).