Diverter Cap Openings

[Unregistered]

Hi, I just purchased a diverter cap from you and noticed it has no holes. I assume I'm supposed to drill the holes myself. How many holes and what location should they be?

[Don Moyer]

Here is a technical note that we prepared some time ago which should answer your questions regarding the installation of a diverter cap:

“The diverter cap is a standard brass 3/8" hex-headed pipe cap located on the inside of the water jacket side plate, and is installed on the stem of the "T" fitting in the center of the side plate.

The cap is modified after installation by drilling a 3/8" hole on the side, to divert water aft and down approximately 45 degrees, and a second 1/4" hole in the original top of the cap to divert some incoming water directly across to the manifold side of the engine.

INSTALLING A DIVERTER CAP:

1) If the "T" fitting does not extend in past the back of the side plate by at least three threads, the hole will have to be opened up a bit, using a 3/8" tapered pipe tap. Don't overdo the enlarging process in the beginning, and try the "T" fitting frequently to determine the fit of the "T" fitting.

2) After getting three threads (or so) of the "T" fitting through the side plate, dry fit the diverter cap on the end of the "T" fitting, tightening the cap until one of the hex sides faces aft, and down about 45 degrees. Remove the cap and drill a 3/8" hole in that hex side, and a second 1/4" hole in the front of the cap. The 1/4" hole should face in the direction of the manifold side of the engine.

NOTE: Because the stem of the 3/8" "T" is a tapered pipe thread, it is not possible to know on which side of the hex the 3/8" hole will need to be drilled until the cap has been actually "dry fitted" to the "T".

3) Reinstall the cap on the end of the "T" fitting, using a good sealer. Permatex cold-weld works well on the stem of the "T" fitting and on the inside threads of the cap itself. You can then remove the cap and drill a 3/8" hole in that hex side, and a second 1/4" hole in the front of the cap. The 1/4" hole should face in the direction of the manifold side of the engine.”

Regards,

Don Moyer