Packard Forum Index » Project Blogs

The tappets should all be ground slightly convex and any good automotive machine shop should be able to rework them for you.

Quote:

Don, thanks! I assume you're talking the top of the tappet adjusting screws? So they aren't case hardened? I now have a method to get them sorted, but always interested in learning more.

Bump - anyone know anything about the different styles?

They are indeed hardened or case hardened so need to be reground but if worn too much to be below the hardening, replacement is necessary. I'm not sure if the hardening is through or case-only.

This is what allows the tappets to rotate properly when the engine is running to evenly distribute oil around them but they eventually flatten or even become concave with a lot of use and are often ignored during a rebuild rather than getting the reconditioning that they need to work properly.

Well, a lot done, but few pictures.

Installed new exhaust valves (original Packard parts, fit MUCH nicer in the guides), lapped the valves, had help getting the cylinders honed, and re-faced the tappets. Many, many thanks to my friend for the mentorship, advice, and direct assistance!

Also got a ride in a genuine Packard hot rod, and saw some old friends! A good weekend.

Attach file:

---

  (301.81 KB)


  (169.31 KB)


  (219.16 KB)


  (212.59 KB)

Grinding the tappets in the lathe with a whizzwheel. Some of them were quite lumpy from previous rework.

Attach file:

---

  (362.40 KB)


  (241.19 KB)

Ken - progress is great! And how cool to be able to do that with your daughter. And Ross's rod looks sweet. On that note, I'm jealous you are able to have Ross work on your car. What a great way to learn!

-Kevin

Kevin - thanks! Ross is a great teacher, and very patient!

Haven't done too much - got the Packard back in the garage, then went camping. I have gotten all the carbon cleaned off, and everything except the cylinder bores and the valve guides cleaned out. Once I clean out the cylinders, I'll decide on knurling the pistons.

Did measure some valves. The NOS Packard exhaust valves were noticeably tighter in the guides. Now I'm wondering if the valves are almost right, but not quite.

The stock exhaust valve measures 0.3390". Two of the pulled valves from the engine measured 0.3370". One is marked DVMC on the head. The other has no markings on the head, but is marked Thompson S990 MADE IN THE USA on the stem. Anyone have a cross reference book?

The DMVC intake valve stems measure 0.3408". Wonder if the Packard intake valves are similarly slightly larger.

Attach file:

---

  (173.79 KB)

S990 is Pontiac...or is it 992...one or the other

Check the specs, I believe valve stem diameters are given.

Flackmaster- thanks!

Dave, I had looked in the service manual and the parts manual with no joy. Is there somewhere else to look?