1922 Oldsmobile Model 47 Engine Rebuild

[rustyjazz1938]

@Laughing Coyote

 

The tappet is a two piece affair that has an outer shell which which is a light press fit into the crankcase and has an anti-rotation for the roller. The inner piece has a wheel on one end and the adjustment screw and nut on the other end for valve lash. The valve is really like any other flathead engine valve. It's neat to note that the valves are on a slant from being parallel to the cylinders (I believe 7 degrees) which is a trick to help with airflow. Olds was advancing engine design even then!

 

I spoke with Tim via telephone and we determined his engine was missing the inner pieces of the tappets (he bought a project, a very brave soul!), and I was able to help somewhat in getting an incomplete set in the mail to him. He's confident he can machine up the missing parts.

 

Thanks for reading,

 

Rusty Berg

[rustyjazz1938]

Hello all,

 

My apologies in not writing an update sooner. Life, work, and other things, including the Olds itself have crept in and kept me busy and I neglected moving the story along. 

 

In looking at the pistons, I had a complete set of original bore sized, cast iron pistons from the engine I got in New Jersey. They had their original engine serial number, and bore location stamped in the tops. The engine that was in the car had a mismash of pistons some oversized, some not, some with 3 rings (2 compression, 1 oil control) some with 4 ( 2 compression, 2 oil control). I figured (whilst keeping an eye on cost) that I might be able to reuse the OE nominal size set I had. The bores needed cleanup to .020 oversize, but I found a local company that could diamond coat that thickness onto my pistons.

 

NOT MY BEST IDEA.

 

I was trying to avoid making new pistons. It's an odd bore size (2.875") so nothing is readily available. The grooves were worn for the rings though, so I reached out to the Otto Gas Engine Works to see about ring spacers. I have a close friend of mine (he's on the forum, and his car runs great!) who recommended Dave Reed and his NOS source of parts for what I was looking to do. I've got a lathe and enough skills to be dangerous enough to assume I could do the machining job at hand.

 

Here's what had to happen:

 

Pistons needed to be coated 0.010" per side to make up the bore difference. Any machining work had to happen before hand.

 

Ring grooves were worn as normal. Needed to be turned square to allow for ring spacer to take up ring height differences (make compression seal).

 

With grooves being turned square again, NOS rings oversized 0.020 from Otto Gas Engine Works could be used with the spacers provided to compensate for the piston diamond growth and increased bore diameter.

 

I spoke with Dave Reed at length about my plan. I had plenty of High Speed Steel (HSS) that I could grind to be a good cutter, and it was winter so I could spend some time in the shop with a fun machining project. 😁

 

It went south at the blink of an eye. Not for the reasons one would think...

[aron_budapest]

These spacer rings are new for me. Here the ring manufacturer can made any kind of cast iron ring produce. Nice work anyway, I wait for the updates!